Table of Content

20 March 1998, Volume 34 Issue 2

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Stratigraphy and Paleo-Geomorphology of the Dongfang Square Paleolithic Site, Wangfujing, Beijing

XIA Zhengkai,ZHENG Gongwang,YUE Shengyang,YU Jincheng

1998, 34(2):  387-391. 

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The Paleolithic site found in Dongfang Square Wangfujing in Beijing is a late Paleolithic cultural site. It consists of two cultural layers. The TL age of the sample from the upper layer we obtained is (1.5- 1.9)×10⁴a B.P. and the age of the lower layer is (2.2- 2.6)×10⁴a B.P.. This site is located on a plaeo-levee of a river and is a place of ancient human activity during a short period. This discovery has a important significance for studying the relationship between human active history and paleoenvironment evolution on Beijing Plain.

In Vitro Induction of Apoptosis in Purified Nuclei and A 27 kD Nuclease Activated in Xenopus Egg Extracts

JIANG Zhengfan,ZHU Shan,ZHAI Zhonghe

1998, 34(2):  324-331. 

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A cell-free system has been developed based on Xenopus egg extracts that induced the morphological transformations characteristic of apoptosis in isolated nuclei. Purified nuclei from mouse liverceels are induced into apoptosis in this apoptotic cell-free system. Two best characterized hallmarks of apoptosis:formation of apoptotic bodies and DNA fragmentation into nucleosomal fragments were observed. In attempts to characterize and identify the nuclease associated with apoptosis, that a Mg²⁺-dependent, Ca²⁺-independent, Zn²⁺-inhibitable nuclease was examined in induced apoptotic extract and a 27 kD protein was found to be a possible candidate by SDS-PAGE-DNA assay.

Research on Protein Engineering

TANG Jianguo,RU Binggen,XU Changfa,HU Meihao,ZHU Shenggeng

1998, 34(2):  342-349. 

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Recent developments on protein engineering of some related proteins in our research are introduced. Specificity change, antiautolysis and role of less conserved disulfide bonds of trypsin are demonstrated. Function of single domain and multi-copied domains of metallothionein is explained. Studies on intra-A chain disulfide bond and C-peptide of insulin, chimera of prourokinase and tissue-type plasminogen activator, mutation of plasminogen activator inhibitor-1, and RGD-containing proteins are also described.

Functional Genomic Analysis of Rice Dwarf Virus

LI Yi,XU Hong,CHENG Mingfi,ZHENG Honghong,MAO Zhijun,XIAO Jin,ZHANG Fujian,MING Xiaotian,QU Lin,LIU Yifei,LI Wei,ZHAO Xiaolan,PAN Naisui,CHEN Zhangliang

1998, 34(2):  332-341. 

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Rice dwarf virus full genome 12 gene segments were cloned and 25000 nucleotides were sequenced. The gene functions of each segment were analyzed according to amino acid sequences and experimental data. The coding regions of segments S6, S9, S10 and S11 encoding nonstractural proteins were cloned into expression vector pTricHisA, pBV221, pTric HisB, pBV221, respectively. The expressed products were analyzed by SDS-PAGE and further confirmed by Western-blotting. Using the E.coli expression products, the function of Pns11 was studied. The results showed that Pns11 is a ds-/ss-RNA and DNA binding protein and it may play very important roles in virus genome assortment or packaging. Gene segments S2, S7, S8 and S9 which encode virus most outer coat protein, minor core protein, outer coat protein and nonstructural protein were transferred into rice via biolistic bombardment and regenerated rice plants were obtained. The resistance to RDV infection of these transgenic rice plants are in testing.

Research on Protein Engineering

TANG Jianguo,RU Binggen,XU Changfa,HU Meihao,ZHU Shenggeng

1998, 34(2):  342-349. 

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Recent developments on protein engineering of some related proteins in our research are introduced. Specificity change, antiautolysis and role of less conserved disulfide bonds of trypsin are demonstrated. Function of single domain and multi-copied domains of metallothionein is explained. Studies on intra-A chain disulfide bond and C-peptide of insulin, chimera of prourokinase and tissue-type plasminogen activator, mutation of plasminogen activator inhibitor-1, and RGD-containing proteins are also described.

A-Type Granites with the Character of Enrichment and Loss with Particular Reference to Both Suites of the Yanshan, North China and Wulunguhe, Northwest China

XU Baoliang,WANG Shiguang,HAN Baofu,YAN Guohan,HE Zhongfu

1998, 34(2):  352-362. 

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Two suites of A-type granites with the character of alkaline-oversaturation are discovered in both of the Yanshan region, East China and the Wulunguhe region, the Xinjiang Uygur autonomous region. The Yanshan's A-type suite occurs in sitting of within-plate in tectonic, with character of Poor Nb, low εNd(T) and high εSr(T), the Wulunguhe's one are distributed over a late-organic sitting, being poor Nb, high εNd(T) and low εSr(T). Geology, petrology and data of major-trace-elements for the granites are summed, analysis results of Sm-Nd and Rb-Sr isotope are reported, derived-materials and subdivision for them are discussed in the paper. Two kinds of sources of derived-material, that one is enriched but another is lost, are implicated by these data for the A-type granites of both regions of the Yanshan and the Wulunguhe.

Chemo-biostratigraphic Study on the Devonian Frasnian-Famennian Event

BAI Shunliang

1998, 34(2):  363-369. 

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Study on the Nandong Section of South China reveals that the Devonian Frasnian-Famennian (F-F) bio-event was a stepwise mass-extinction. The devastating diversity loss occurred in the latest linguiformis Zone, which was 0.1 Ma in duration. Across the F-F boundary there are three nickel-iridium moderate anomaly beds, which are also enriched in chalcophile elements, and also accompanied with the carbon isotope negative anomalies and microtektites. The last Ni-Ir anomaly was followed immediately by tsunamis. In fact, the F-F event is an integrative event-biotic, geochemical, sedimentologic. Such integrative events occurred five times in the Middle and Upper Devonian with a frequency of 4.6×10^-6a^-1. This frequency approximates to the frequency of the impact of 1 km sized asteroids on Earth, estimated by Shoemaker(1990). The possible cause of the F-F mass-extinction is herein discussed. Asteroids(probably 1 km sized) struck the Earth with a frequency of 4.6×10^-6a^-1. These impacts intensified the global(or vast regional) hydrothermal activities on fracture zones, with anomalous Ni-Ir and chalcophile deposits ensuing. The main Ni-Ir excess might have a hydrothermal origin. Hydrothermal metal toxicity might be one of the kill mechanisms in mass-extinction. Sea level change and regressive anoxia excursion were ongoing phenomena which might create appropriate stagnant condition for the preservation of element excess, but might not be the main causative factor of mass-extinction.

Milk Composition and Nursing in a Giant Panda(Ailuropoda melanoleuca)

PAN Wenshi,Olav T.Oftedal,ZHU Xiaojian,Sara Childs,WANG Dajun,Devra G.Kleiman

1998, 34(2):  350-351. 

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Milk samples of a wild female giant panda were collected from all the 4 nipples at 77 days postpartum in the Qinling Mountain area. At this lactation stage the giant panda milk averaged(32.0±2.1)% dry matter, (18.4±2.1)% fat, (8.34±0.16)% crude protein, (2.7±0.12)% sugar, and in two samples (7.6±0.6) kJ/g gross energy. The fat concentrations were very variable, with particularly high fat(25.9%) in milk from the nipple just suckled; the remaining nipples yielded milk containing 14.5%-19.3% fat. Protein accounts for about 22% of the energy in giant panda milk, which is higher than that of the American Black Bear(Ursus americanus)milk at the same lactation stage. This difference may due to the different selective pressure these two species faced during evolution.

A Discussion on the Earth System

HE Guoqi,LI Maosong

1998, 34(2):  370-378. 

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The paper reviews the history of the earth science, that is, it began from understanding a certain area and a geological process, through a long accumulation of knowledge, than developed a huge system of knowledge. In particular, the paper also discusses three leaps of knowledge on the earth science during the 20th century. From two sides, development of geology and new challenge, the paper discusses inevitability of emergence, present situation and future development of a new and high level comprehensive discipline dealing with material system of the earth. In order to suit development of discipline and new mission, the authors from geological point of view suggest some adjustment measure, such as, enhancing research work to the modern and present geological process, enhancing cross and osmosis with close discipline, reforming teaching methods and adjusting higher geological education and so on.

A Discussion on the Earth System

HE Guoqi,LI Maosong

1998, 34(2):  370-378. 

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The paper reviews the history of the earth science, that is, it began from understanding a certain area and a geological process, through a long accumulation of knowledge, than developed a huge system of knowledge. In particular, the paper also discusses three leaps of knowledge on the earth science during the 20th century. From two sides, development of geology and new challenge, the paper discusses inevitability of emergence, present situation and future development of a new and high level comprehensive discipline dealing with material system of the earth. In order to suit development of discipline and new mission, the authors from geological point of view suggest some adjustment measure, such as, enhancing research work to the modern and present geological process, enhancing cross and osmosis with close discipline, reforming teaching methods and adjusting higher geological education and so on.

The Role of Acid-Volatile Sulfide for Toxicity of Heavy Metals in Sediment of Rivers in Hong Kong

JIA Zhenbang,LIANG Tao,LAM Kinche,LIU Fengwei

1998, 34(2):  379-386. 

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The contents of heavy metals in sediment are decided by lots of factors such as pH, Eh, TOC, Fe-Mn oxide etc. And their toxicity are up to their forms, bioavailability and environmental features. It is well know that heavy metals can form sulfides that are not soluble in water, but we are not quite clear with acid-volatile sulfide (AVS) can also form sulfides with the heavy metals. AVS plays an important role on mediating the toxicity of the heavy metals in sediment. We assessed the pollution of heavy metals in the main rivers of Hong Kong based on the molar ratio of Simultaneous Extract Metals (SEM) and AVS. This method is helpful on predicting the toxicity of heavy metals.

The Study of Urban Photochemical Smog Pollution in China

ZHANG Yuanhang,SHAO Kesheng,TANG Xiaoyan,LI Jinlong

1998, 34(2):  392-400. 

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Based on the studies on photochemical smog in Xigu and Yanshan petroleum industrial areas, Beijing city and Guangzhou City, the current pollution level of photochemical smog and its characteristics in China are discussed, its formation mechanism is explored, and its changing tendency in near future is predicted. The results show that photochemical smog pollution is serious in above areas and the effective way to control the photochemical smog in China is to decrease NO_x emission. The ozone peak appears not only earlier, but also is higher year by year at Zhongguancun, Beijing, which phenomenon indicates that the atmospheric photochemical activity is enhanced. As the fast increasing of the vehicle population, the air pollution in some big cities is in a transition from coal burning caused problem to automobile exhaust related pollution or the pollution combined them.

Theoretical Frame of Brain Cognitive Function and its Methodological Foundation

SHEN Zheng

1998, 34(2):  401-408. 

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The paper reviews the important theories on brain cognitive function and abstracts five basic points of view on brain function and four theories in cognitive science:symbolism, subsymbolism, modulism, and ecological realism. At present, there has been a historical milestone of the research field, because a new theory, techniques and facts appeared in the past few years will changed the theoretical system on brain research. The new trends and the critical dilemma in different levels of the research field are commented, including molecular neurobiology, molecular biology of cell, neurophysiology, neural networks and systems, brain functional imaging, psychology, cognitive theory and neurocomputational theories. Author suggested a new concept on efficiency of brain energy metabolism as a universal quantitative schema in order to communicating among the researchers in different field. The theoretical and methodological bases of the conception are interpreted in detail. The interdisciplinary research will help to establish a new theory in future.

Theoretical Frame of Brain Cognitive Function and its Methodological Foundation

SHEN Zheng

1998, 34(2):  401-408. 

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The paper reviews the important theories on brain cognitive function and abstracts five basic points of view on brain function and four theories in cognitive science:symbolism, subsymbolism, modulism, and ecological realism. At present, there has been a historical milestone of the research field, because a new theory, techniques and facts appeared in the past few years will changed the theoretical system on brain research. The new trends and the critical dilemma in different levels of the research field are commented, including molecular neurobiology, molecular biology of cell, neurophysiology, neural networks and systems, brain functional imaging, psychology, cognitive theory and neurocomputational theories. Author suggested a new concept on efficiency of brain energy metabolism as a universal quantitative schema in order to communicating among the researchers in different field. The theoretical and methodological bases of the conception are interpreted in detail. The interdisciplinary research will help to establish a new theory in future.

An Inverse Compton Scattering Model for Radio Pulsars

QIAO Guojun,ZHANG Bing,XU Renxin,LIN Weipeng

1998, 34(2):  181-192. 

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The inverse Compton scattering (ICS) model of the pulsars are reviewed, including the inner gap structure involving the ICS process in the polar cap region, the basic idea of the ICS model for pulsar radio emission, an interpretation of the various observational data in terms of the ICS model, such as the radio emission beams (especially the core and the two conal components), the polarization position angle jumps, and the sense-reversing of the circular polarizations. It is shown that the ICS model is a successful model in understanding the magnetospheric structures and the radiation mechanisms of pulsars.

An Inverse Compton Scattering Model for Radio Pulsars

QIAO Guojun,ZHANG Bing,XU Renxin,LIN Weipeng

1998, 34(2):  181-192. 

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The inverse Compton scattering (ICS) model of the pulsars are reviewed, including the inner gap structure involving the ICS process in the polar cap region, the basic idea of the ICS model for pulsar radio emission, an interpretation of the various observational data in terms of the ICS model, such as the radio emission beams (especially the core and the two conal components), the polarization position angle jumps, and the sense-reversing of the circular polarizations. It is shown that the ICS model is a successful model in understanding the magnetospheric structures and the radiation mechanisms of pulsars.

A Study of Interstitial Atom Effects in the R(Fe, M)₁₂ Compounds

YANG Jinbo,YANG Yingchang

1998, 34(2):  167-175. 

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The studies of interstitial atom effects on the crystallographic and magnetic properties of R(Fe, M)₁₂ compounds have been carried out by using neutron diffraction, magnetic measurements and band structure calculations. The original of interstitial atom effects has been investigated by systematic analyzing the calculated electronic structure and its relationship to the magnetic moments, hyperfine parameters and curie temperature.

QCD Axial Anomaly and (η)'-(η)_c Mixing

ZHAO Guangda,CHAO Kuang-ta

1998, 34(2):  176-180. 

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A new approach for the (η)' (and (η))-(η)_cmixing is discussed on the basis of the axial anomaly in QCD. Through (η)'((η))-(η)_c mixing the calculated J/(ψ)->(γ)(η)' and J/(ψ)->(γ)(η) decay widths agree with experimental data. By the mixing of (η)'((η)) with excited state (η)'_c, branching ratios BR((ψ)'->(γ)(η)') = (1.8±0.9)×10^-4 and BR((ψ)'->(γ)(η)) = (3.4±1.5)×10^-5 are predicted. In particular, by the mixing between (η)' and color-octet(cc)₈ pair and b->(cc)₈s decay, the large branching ratio for B->(η)'Xdecay observed by CLEO recently may be explained.

A New Approach to Error Estimates for Conservation Laws

TENG Zhenhuan

1998, 34(2):  137-142. 

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A new approach is introduced to prove optimal L¹-error estimates for various approximate methods, such as viscosity methods, monotone difference schemes and stiff relaxation approximations, to conservation laws. The new approach is a matching method, which is quite different from the well-known Kuznetsov's approach, an error analysis method for conservation laws. So far the best available L¹-convergent rate, by using Kuznetsov approach, for these popular approximate methods is only half-order, even though these methods are of first-order accuracy to conservation laws. But by using the new approach a first-order rate of L¹-convergence for these methods can be approved, which is an improvement over the half-order rates of L¹-convergence.

On a Problem by Huppert

ZHANG Jiping

1998, 34(2):  143-150. 

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It is proved that there exists no finite solvable group G with the following as its character degree graph: .____.____.____. . The result solves an important open problem by Huppert and provides more evidence supporting the well-known conjecture which claims that the diameter of the degree graph of any finite solvable group is at most 2.

New Development of Prof. Zhou's Statistical Theory of Turbulence

HUANG Yongnian

1998, 34(2):  151-158. 

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About forty years ago Prof. Zhou and Tsai had suggested a statistical theory of the axisymmetric vortices structure of homogenous isotropic turbulence. Now it was generalized to nonaxisymmetric vortices case. A Zhou-Saffman average method is used to study the statistical average rules. An exact general calculating formula of the orientation average is given. It can decrease the calculating time of the high order correlation functions and moments greatly.

Surfaces and Interfaces of Group-IV Semiconductors

GAI Zheng,ZHAO Ruguang,JI Hang,YANG Weisheng

1998, 34(2):  159-166. 

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Apparently, silicon-a group-IV semiconductor is the basis of the multi-billion dollar industry of microelectronics. On the other hand, our knowledge on almost every aspect of group-IV semiconductor surfaces and interfaces is quite incomplete. Thereby, by means of scanning tunneling microscopy, low-energy electron diffraction, and Auger electron spectroscopy, a systematic investigation on the surfaces and interfaces has been carrying out in a bid to gain a more comprehensive understanding of them. In the investigation more effort has been put on germanium surfaces because they have been, from the basic scientific point of view, unfairly neglected. As a result, the atomic structure of the most stable high-index surface Ge(113) and several others, such as Ge(103), (216), and (105), has been determined. It has been found that not only the adatoms on Ge(111) but also, surprisingly, the subsurface interstitial atoms of Ge(113) are able to migrate at room temperature, and the activation energy of the migrations has also been determined with a high precision. In the interface aspect, the three common characteristics of the III/IV interfaces, the prototype of group-IV interfaces, have been disclosed for the first time.

Surfaces and Interfaces of Group-IV Semiconductors

GAI Zheng,ZHAO Ruguang,JI Hang,YANG Weisheng

1998, 34(2):  159-166. 

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Apparently, silicon-a group-IV semiconductor is the basis of the multi-billion dollar industry of microelectronics. On the other hand, our knowledge on almost every aspect of group-IV semiconductor surfaces and interfaces is quite incomplete. Thereby, by means of scanning tunneling microscopy, low-energy electron diffraction, and Auger electron spectroscopy, a systematic investigation on the surfaces and interfaces has been carrying out in a bid to gain a more comprehensive understanding of them. In the investigation more effort has been put on germanium surfaces because they have been, from the basic scientific point of view, unfairly neglected. As a result, the atomic structure of the most stable high- index surface Ge(113) and several others, such as Ge(103), (216), and (105), has been determined. It has been found that not only the adatoms on Ge(111) but also, surprisingly, the subsurface interstitial atoms of Ge(113) are able to migrate at room temperature, and the activation energy of the migrations has also been determined with a high precision. In the interface aspect, the three common characteristics of the III/IV interfaces, the prototype of group-IV interfaces, have been disclosed for the first time.

A Synthetic Substorm Expansion Model

PU Zuyin,KANG Kongbin,FU Suiyan,CHEN Zuxing,HONG Minghua

1998, 34(2):  193-200. 

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Magnetic field configuration instability in regions near the inner edge of the near-Earth current sheet is further studied with the generalized progressing wave expansion method in the one-fluid MHD approximation. Previous work on drift ballooning instability in the equatorial region has been extended to include a decelerated non-stationary flow and to consider the off equator regions. It is found that the presence of a decelerated earthward flow causes the magnetic field configuration on a large portion of the field lines to be absolutely unstable and substantially reinforces the instability. A high level synthesis thus exists in global substorm initiation processes. An integral NENL-NECD model of substorm expansion onset is proposed which seems to be in agreement with a variety of satellite and ground-based observations at substorms. Different substorms may be initiated by different triggering processes.

Radiocarbon Dating by Accelerator Mass Spectrometry with High Precision and Accuracy

GUO Zhiyu

1998, 34(2):  201-206. 

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The precision and accuracy of AMS ¹⁴C dating have been studied. The main source of error comes from the statistical error of ¹⁴C counting and the instability of beam transmission efficiency. For high precision measurement the non-linearity error of current-frequency- conversion in beam current integrator and the time-dependent fractionation introduced by crater effect in ion source should also be considered. To meet the requirement of Xia-Shang-Zhou Chronology Project, PKUAMS upgrade was carried out. The stability of power supplies and the system vacuum were improved. The ion source has been replaced by a new one with better performance and reliability. With new data acquisition system the precision of lived time readout could reach 0.005%-0.01%. In order to obtain high precision age data, it is necessary not only to improve the precision of ¹⁴C measurements, but also to use the series samples in dendrological calibration by wiggle-matching method based on the Bayesian approach. The reliability of sample age depends on suitable sample selection and preparation, as well as the elimination of systematic error in measurement.

Canonical Theory of Chromatic Aberration in Glaser's Bell-shaped Magnetic Lens

XIMEN Jiye,LIU Zhixiong

1998, 34(2):  207-213. 

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A powerful technique of integration transformation on eikonals has been applied to Glaser's bell-shaped magnetic lens. Consequently, first-and third-order chromatic aberrations have been analytically derived and numerically calculated. This theoretical research may be helpful for estimating first-and third-order chromatic aberrations in rotationally symmetric magnetic lenses.

Study on WDM and FDM Optical Fiber Communications

WU Deming,XU Anshi,ZHU Lixin,WANG Ziyu,ZHANG Zhaoyi,XIE Linzhen

1998, 34(2):  214-220. 

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Wavelength division multiplexing (WDM) and frequency division multiplexing(FDM) can be used to exploit the huge bandwidth of the optical fiber to transmit large capacity of information. A 4×2.488Gbit/s two-direction 154km nonrepeatered WDM optical fiber communication system was built in our lab and was demonstrated with Guangzhou to Shengzhen telecommunication transmission. The system has been operating for more than 5 months stably and reliably. No error bits were detected during that period. In the meantime, a 4×155Mbit/s FDM optical fiber communication system was also built. In the system, the channel spacing was 0.1nm, transmission distance was 18km. The system has been built in module structure, so that it was of good stability. No error bit was detected within 24 hours. The system can be used as a basis of application in optical fiber access networks.

The Acquisition and Application of the Knowledge for Recognizing the Predicate Head of a Chinese Simple Sentence

SUI Zhifang,YU Shiwen

1998, 34(2):  221-230. 

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It is necessary to grasp the main structure of the sentence through its predicate head for the sentence similarity calculation in EBMT. Taking 3000 tagged Chinese simple sentences as training set and the syntactic attributes and the contextual information as the classification features, this research acquires the knowledge of recognizing the predicate head through constructing a statistical decision tree model. The problem of applying the statistical decision tree to recognize the predicate head is also discussed.

The Model, Method and Instances of Multimodal User Interface

DONG Shihai,CHEN Min,LUO Jun,LIN Yingming,JIANG Yuqian

1998, 34(2):  231-239. 

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Multimodal Interfaces employ many kinds of interactive devices, such as speech input/output, pointing, gazetracking, and tactile and force feedback devices, make them cooperate with each other and take the advantage of their complementarily so as to facilitate the communication between user and computer, increase the efficiency of interaction, enhance its naturalness and ultimately make it possible for computer-naive people to interact with computers using their everyday skills. This paper summarizes part of the work completed in the key project Multimodal User Interface Research supported by National Natural Science Foundations of China. First, we described its concepts, advantages and some terminologies, then proposed an Architecture and integration for Task Oriented Multimodality (ATOM) model, a Hierarchical Multimodal Interface Specification (HMIS) method, and a new interface paradigm (VIR-Virtual Information Room). Finally, two case studies developed under way and conclusion are given.

The Model, Method and Instances of Multimodal User Interface

DONG Shihai,CHEN Min,LUO Jun,LIN Yingming,JIANG Yuqian

1998, 34(2):  231-239. 

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Multimodal Interfaces employ many kinds of interactive devices, such as speech input/output, pointing, gazetracking, and tactile and force feedback devices, make them cooperate with each other and take the advantage of their complementarily so as to facilitate the communication between user and computer, increase the efficiency of interaction, enhance its naturalness and ultimately make it possible for computer-naive people to interact with computers using their everyday skills. This paper summarizes part of the work completed in the key project Multimodal User Interface Research supported by National Natural Science Foundations of China. First, we described its concepts, advantages and some terminologies, then proposed an Architecture and integration for Task Oriented Multimodality (ATOM) model, a Hierarchical Multimodal Interface Specification (HMIS) method, and a new interface paradigm (VIR-Virtual Information Room). Finally, two case studies developed under way and conclusion are given.

Physical Model of Floating Body Effects and Its Suppression Study in Fully Depleted SOI MOSFETs

WANG Yangyuan,XI Xuemei,ZHANG Xing

1998, 34(2):  240-247. 

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A new analytical model for SOI MOSFET with floating-body-effect(FBE) is developed to described the SOI MOSFET's strong inversion current characteristics. Considering all current components, the model can explain the physical mechanism of the current kink and breakdown phenomena as well as the dependence of I-V characteristics on various bias and channel length successfully. Based on this model, the dependence of FBE on several device parameters is studied. The results show that lowing source/drain doping, decreasing minority-carrier life time, optimizing the silicon film thickness and reducing channel doping will effectively suppress the FBE with much improved breakdown voltage characteristics. The experiments corresponding to the suppression of FBE with LDD&LDS structure and channel defect engineering, etc., demonstrate the calculated analysis, thereby enabling the theoretical result's realization in CMOS/SOI technology.

The Remote Sensing of Land Surface Temperature

XU Xiru,LIU Qinhuo,CHEN Jiayi

1998, 34(2):  248-253. 

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The land surface temperature (LST) plays an important role in the course of interaction between land and atmosphere. The distribution of land surface temperature with two dimensions can only be offered by remote sensing. The retrieval of sea surface temperature (SST) has been in operational use for a long time with split windows method. Is it possible to solve LST problem by split-windows data? People argue on it. Many people hope to solve missing equations by adding middle infrared information, but new problems will be brought in. For example, how to eliminate the effect of sun direct radiation and how to solve scattering problem by atmospheric aerosol. This paper proves the feasibility of retrieval of LST with accuracy less than 1 ^oC by digital simulation approach only using split windows data. Results had been tested by real time NOAA-AVHRR data.

A Knowledge-based Research for Road Extraction from Digital Satellite Images

CAO Wufeng,QIN Qiming

1998, 34(2):  254-263. 

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As a kind of base geographical information, road extraction from satellite images is important in the practice and theory of automatic satellite images recognition, and its results can be used for the data updating of geographical data base. Using existing approaches to automatic road extraction from satellite images for reference and according to the road properties in China, this paper presents a new road extraction method that combines image processing techniques with artificial intelligence methodology. In this approach, an operator is applied to an image to enhance the road information first, then road detection based on the shape index and other priori knowledge is performed to find possible road points. After using more contextual information or global constraints to extend the road seeds to form a road segment, the existence of a road is inferred and the gap between the road segments is connected by employing knowledge-based rules. Finally, experimental results on SPOT data are elaborated.

Automatic Painting of Animation Serial Pictures with Theory of Image Segmentation and Matching

GUO Zongming

1998, 34(2):  264-267. 

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This paper introduces and analyses the application of fundamental principles of image segmentation and matching to automatic painting of animation serial pictures, lists out an algorithm of segmentation and matching, submits a new idea about distribution function on basis of the Freeman chain code. We have successfully realized the automatic painting in traditional cartoon animation with this new idea.

A Unified Method for Conics Based Stereo Vision

FENG Jufu,SHI Qingyun,CHENG Minde

1998, 34(2):  268-274. 

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In this paper a new method for conics based stereo vision was proposed. By using the new method for the detection of general quadric curves proposed by the authors, we investigated the global solutions of planar quadric curves and quadratic surfaces in the space and proposed a unified representation and solving algorithm. The main results about the multi-solutions are as follows: (1) if there exists solution of planar quadric curves then there exists solution of quadratic surfaces; (2) if and only if there are three views then there exists only one solution.

Text-independent Speaker Identification in Combining Multiple Classifiers with Different Features

WANG Lan,CHEN Ke,CHI Huisheng

1998, 34(2):  275-282. 

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Combining Multiple Classifiers can be viewed as a novel hybrid system to achieve high recognition accuracy for Text-Independent Speaker Identification. This article has summarized current methods of combining multiple classifiers, and investigated on embodying different features as input vectors. The experimental results have shown that Combining Multiple Classifiers with different features can result in satisfactory and significant improvement in recognition performance.

Density Functional Theory on Electronegative and Hardness in Molecular Fragment Chemistry and Its Applications

CHEN Zhida,DENG Yuqing,XU Guangxian

1998, 34(2):  283-295. 

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On the basis of the density functional theory of grand canonical ensembles, the definition on electronegative and hardness of atoms and molecules proposed by Parr are extended to molecular fragment chemistry. Energy E(N) versus △N curves for certain transition metal carbonylmetallates are calculated by using density functional theory at the local density approximation(LDA) level and at the LDA/NL level with further non-local corrections for exchange and correlation included self-consistently. It is shown that the energy curve of the molecular fragments is convex. In general, derivative discontinuities of the energy at integral electron number N are found. Therefore the finite-difference method is used in calculation on the electronegative and hardness of the molecular fragments. It is revealed from the calculated results for certain typical compounds that the calculated electronegative and hardness are reasonably in agreement with Pearson's values. On the basis of the calculated electronegative and hardness, relative acidities for HMn(CO)₅, [HFe(CO)₅]⁺, H₂Fe(CO) and HCo(CO)₄ are explained reasonably, and mechanisms of substitution reactions between [Mn(CO)₅] and Cr(CO)₅, as well as between Co(CO)₄^- and Fe(CO)₅ are in detail discussed. It is shown from our calculations that chemical properties of the molecular fragments may be characterized by the electronegative and hardness of density functional theory.

Photochemical Synthesis of Fulleromulticarboxylates and Their Langmuir-Blodgett Film Formation

GAN Liangbing,HUANG Chunhui

1998, 34(2):  296-301. 

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Photolysis of aminopolycarboxylates with C₆₀ has been shown to be an effective method for the preparation of isomerically pure fullerene derivatives. A series of fullerroaminopolycar-boxylate derivatives have been prepared by this method. For example, glycine esters react with C₆₀ to give C₆₀(ROOCCHNHCHCOOR), the mechanism of which is proposed to involve complicated bond breaking and formation processes. Aminoacid esters with secondary and tertiary amino groups can add to C₆₀ by simply losing two H atoms. Irradiation of tetramethyl ethylenediaminetetraacetate(EDTA) with C₆₀ yields the EDTA containing fullerene monoadduct C₆₀(MeOOCCH)₂NCH₂CH₂N(CH₂COOMe)₂. Compared to well-known 1, 3-dipole addition method of fulleropyrrolidine preparation, the photoreaction reported here avoids the use of aldehydes or ketones and is specially suited for the preparation of the fullerene containing complexones such as the EDTA C₆₀ derivative. Langmuir-Blodgett film formation and the photoelectric properties of these fulleropyrrolidine compounds are investigated. Due to the presence of hydrophilic groups the derivatives form stable and transferable monolayer. By using metal ion sonlution as the subphase, metal complexes of the fullerocarboxylic derivatives are prepared at the air/water interface. Photoelctrical behavior of the LB film fabricated on ITO are studied under various conditions. For most of the compounds electrons flow from the electrolyte through the LB film to the ITO. The quantum yield of the fullerene derivatives can reach 8%.

Spontaneous Dispersion of Oxides and Salts to Zeolites and Its Applications

XIE Youchang,TANG Youqi

1998, 34(2):  302-308. 

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It has been shown that metal oxides and salts can disperse spontaneously to the surface and pores of zeolites as atomically dispersion. The reason for the spontaneous dispersion is the decrease of free enthalpy of the whole systems, owing to that the dispersion results in significant increase in entropy and formation of surface bonds comparable to the original bonds of the compounds. For a compound with not too high melting point, its dispersion to a zeolite can be done by heating it with the zeolite at a suitable temperature well below its melting point. For a compound with high melting point, its dispersion to a zeolite can be done by using its solution or its precursor solution to impregnate zeolites then drying or thermolysis. The dispersion has been verified by XRD, XPS, EXAFS etc. Dispersion capacities of compounds on zeolites measured by XRD and XPS are listed(table 2). The dispersion of a salt or an oxide to a zeolite includes that both cations and anions disperse on the external surface and , on the internal surface (wall of larger cages and channels) of the zeolite, inclusion in small cages of the zeolite, in addition, solid ion exchange might occur at the same time. Spontaneous dispersion of oxides and salts to zeolites as a principle and method for modification of zeolites might have extensive applications. For example, highly efficient adsorbents for CO and ethylene adsorption has been made by dispersing CuCl to zeolites. Highly selective catalyst for making para-xylene can be obtained by dispersing oxides such as MgO, Sb₂O₃, B₂O₃ and P₂O₅ etc. to HZSM-5 zeolite. Solid electrolytes with high conductivity can be made by dispersing salts such as NaCL, LiCL to zeolites.

Spontaneous Dispersion of Oxides and Salts to Zeolites and Its Applications

XIE Youchang,TANG Youqi

1998, 34(2):  302-308. 

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It has been shown that metal oxides and salts can disperse spontaneously to the surface and pores of zeolites as atomically dispersion. The reason for the spontaneous dispersion is the decrease of free enthalpy of the whole systems, owing to that the dispersion results in significant increase in entropy and formation of surface bonds comparable to the original bonds of the compounds. For a compound with not too high melting point, its dispersion to a zeolite can be done by heating it with the zeolite at a suitable temperature well below its melting point. For a compound with high melting point, its dispersion to a zeolite can be done by using its solution or its precursor solution to impregnate zeolites then drying or thermolysis. The dispersion has been verified by XRD, XPS, EXAFS etc. Dispersion capacities of compounds on zeolites measured by XRD and XPS are listed(table 2). The dispersion of a salt or an oxide to a zeolite includes that both cations and anions disperse on the external surface and , on the internal surface (wall of larger cages and channels) of the zeolite, inclusion in small cages of the zeolite, in addition, solid ion exchange might occur at the same time. Spontaneous dispersion of oxides and salts to zeolites as a principle and method for modification of zeolites might have extensive applications. For example, highly efficient adsorbents for CO and ethylene adsorption has been made by dispersing CuCl to zeolites. Highly selective catalyst for making para-xylene can be obtained by dispersing oxides such as MgO, Sb₂O₃, B₂O₃ and P₂O₅ etc. to HZSM-5 zeolite. Solid electrolytes with high conductivity can be made by dispersing salts such as NaCL, LiCL to zeolites.

Tip Chemistry--A New Challenge of Chemists

LIU Zhongfan

1998, 34(2):  309-316. 

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A new concept Tip Chemistry is proposed, and several representative studies we conducted along with tip chemistry are presented, including using a chemically functionalized scanning probe microscopy(SPM) tip to monitor the local dissociation of surface acid-base groups, directly estimating chemical bonding strength by adhesion force measurements, and fabricating nanostructures by localizing chemical reactions with SPM tips. In these studies, a chemically-designed SPM tip plays a key role, which serves as the probe, the site, and the lens of chemical reactions, respectively.

Tip Chemistry--A New Challenge of Chemists

LIU Zhongfan

1998, 34(2):  309-316. 

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A new concept Tip Chemistry is proposed, and several representative studies we conducted along with tip chemistry are presented, including using a chemically functionalized scanning probe microscopy(SPM) tip to monitor the local dissociation of surface acid-base groups, directly estimating chemical bonding strength by adhesion force measurements, and fabricating nanostructures by localizing chemical reactions with SPM tips. In these studies, a chemically-designed SPM tip plays a key role, which serves as the probe, the site, and the lens of chemical reactions, respectively.

Bio-Accelerator Mass Spectrometry Study on Bio-Macromolecules Adduction with Nicotine

WANG Haifang,WU Xiaohong,LIU Yuanfang

1998, 34(2):  317-323. 

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Since 1992 we have carried out the accelerator mass spectrometry(AMS) study of the bio-macromolecule adduction in vivo with the tobacco specific ¹⁴C labeled nicotine and its nitrosamine derivative NNK. We quantified the DNA adducts as well as the histones (H1 and H3) adducts in mouse liver by means of the AMS system on the 2×6 MV EN Tandem of the Institute of Heavy Ion Physics, Peking University. In most cases, the dose range administered was from 0.1 to 400 microgram/kg b.w., the lower levels of which were equivalent to the human exposure to the environmental cigarette smoke. In all the adduction systems studied the definite biomacromolecule adduction with nicotine or NNK was observed. The number of adducts increased with increasing dose in different graphic fashions, exponential, linear or non-linear. The DNA adduction is well recognized as an effective biomarker or molecular dosimeter, indicating the early detectable and critical step of chemical mutagenesis and carcinogenesis. Our findings have revealed the fact that nicotine per se is a potential carcinogen other than the well-known addiction fact. Besides, we first observed the histones adduction with nicotine that did harm to the gene-regulatory function of the DNA binding protein histones. The detection limit of adducts was 1 adduct per 10¹⁰ nucleotides for DNA and 4.6×10^-17mol/mg H1 protein for histone. The latter is the highest sensitivity to date in biomarker measurements compared to the data previously reported.