Table of Content

20 July 2000, Volume 36 Issue 4

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Two Membrane Levels of Early Afterdepolarization in Sheep Purkinje Fibers and Their Possible Ionic Mechanisms

XU Jian,WANG Zhiqing,WANG Zhongmin,LIU Taifeng

2000, 36(4):  517-524. 

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Sheep Purkinje fibers were used to investigate early afterdepolarization (EAD) generation and its possible ionic mechanisms with bielectrode voltage clamp technique. Under low K⁺ (2.5mmol/LK⁺) superfusion, two levels (-25 and -55mV) of EAD could be induced on the background of automaticity. The bursts in low membrane level EAD were abolished by nifedipine (2.0μmol/L) whereas those in high membrane level were abolished by lidocaine (10μmol/L) and low temperature (30℃). The quasi-steady-state Ｉ-Ｖ relationship of the background currents obtained with step and ramp voltage clamp showed a negative phase in outward part of the rectification under 5.0mmol/LK⁺ superfusion, while an inward current phase appeared between -55 and -25mV level in the curve under 2.5 K⁺ treatment. Under the condition of EAD generation, the low and high membrane level (-25 and -55mV) of voltage were clamped during the repolarization phase of action potential. On low membrane level of -25mV, a slow inward current similar to Ｉ_Si occurred followed by a slight outward current like I_k, whereas on high level of -55mV, a continued inward current looked like I_f occurred. It was suggested that the two levels of plateau were based on the two zero current point in Ｉ-Ｖ curve under 2.5mmol/LK⁺ superfusion, whereas bursts were based on the Ｉ_Si, mainly I_Ca, for the low membrane level and I_f (and slow inactivated I_Na) for the high one.

The Application of the Index of Geoaccumulation to Evaluate Heavy Metal Pollution in Sediments in the Benxi Section of the Taizi River

JIA Zhenbang,ZHOU Hua,ZHAO Zhijie,TAO Shu,ZHANG Baoquan,ZHAO Lihua

2000, 36(4):  525-530. 

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Based on the principle of sedimentology and the environmental behavior characteristics of heavy metals, The Index of Geoaccumulation (Igeo) is used to evaluate heavy metal pollution in sediments in the Benxi section of the Taizi River. The results show that heavy metal pollution in the sediments are serious. The main heavy metal pollutions are copper, lead, zinc, cadmium and mercury.

Geostatistical Study of Au-comprehensive Chemical Exploratory Anomaly at Guilaizhuang Au-deposit

XIAO Bin,ZHAO Pengda,HOU Jingru

2000, 36(4):  531-538. 

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Synthesizing multivariate information, Au-comprehensive chemical exploratory anomaly was discussed with geostatistical methods at Guilaizhuang Au-deposit. Main work included: using cokriging, influence of regional chemical elements (W, As, Sb) to Au-anomaly and Au-mineralization has been studied. Contribution of g(Au/Ag) to Au-anomaly has been probed into making use of indicator kriging and some suggestions for the future work have been given.

Synthesis, Structure and Magnetic Property Study on the Mixed Valence Dodenuclear Manganese Clusters

AN Jin,CHEN Zhida,BIAN Jiang,GAO Song,WANG Shixi,XU Guangxian,CHEN Jiutong

2000, 36(4):  439-447. 

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In order to explore the influence of the ligands and solvents on the magnetic properties of Mn12 complexes, the syntheses and magnetochemical properties of [Mn₁₂O₁₂(3-Cl-C₆H₄CO₂)₁₆(H₂O)₃(3-Cl-C₆H₄CO₂H)]·3-Cl-C₆H₄CO₂H 1, [Mn₁₂O₁₂(CH₃CO₂)₄(3-Br-C₆H₄CO₂)₁₂(H₂O)₄] 2 have been studied. The crystal structure of the complex 1 has been characterized by X-ray diffraction method. The complex 1 crystallizes in the triclinic, space group of P1 with a=17.5779(3)A°，b=18.2712(3)A°，c=34.3616(5)A°，α=103.515(1)°，β=91.784(1)°，γ=116.25°，V=9508.5(3)A°³，Z=2，D_c=1.294mg·m^-3，μ=1.085mm^-１，F(000)=3696, and S=1.096. It is found that the complex 1 consists of a central cubane-like [Mn₄⁺⁴O₄]⁺⁸ held within a nonplanar ring of eight Mn⁺³ ions and eight μ₃-O^2- ions. For both complexes 1 and 2 the χ″_m signals are observed in the region 2～10K, measured at three different frequencies, and exhibit two-frequency dependent of χ″_m AC peaks with a predominant peak in the 4～10K region. The magnetization hyteresis loops for the complexes 1 and 2 show the step-like character. These steps are attributable to the resonant magnetization tunneling. The affect of ligands and solvent on the magnetic properties of the title complexes are briefly discussed.

Luminescence Studies on Eu-Sr-phthalate System

YANG Limin,ZHAO Ying,YANG Zhanlan,WENG Shifu,WU Jinguang

2000, 36(4):  448-452. 

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Using doped method in inorganic luminescence materials, lanthanide chelates have been put into complex matrix. Rare earth ion concentration is lowered and new kind of rare earth compounds are gotten. FT-IR, Luminescence and ESR spectra of the samples have been measured. The possible mechanism is discussed.

Kinetics of the Catalytic Reduction of SO₂ with H₂ on NiSO₄/γ-Al₂O₃

WANG Shizhong,YU Qiquan

2000, 36(4):  453-460. 

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The catalytic reduction of SO₂ by H₂ on NiSO₄/γ-Al₂O₃ has been investigated in detail in our Lab. In this paper we focused on the kinetics of this reaction. The experiments were carried out a packed flow glass in tegral reactor. The catalyst of 20～40 mesh NiSO₄/γ-Al₂O₃ was prepared by the method of impregnation, which was then calcined in air at 500℃ for 4 hours. NiSO₄/γ-Al₂O₃=3/10 (g/g). Isothermal experiments were carried out at t=370～430℃，the ratio of SO₂ to H₂ was 0.5～2.0，the inlet flow rate was 8000mL/h. With the method of orthogonal design and numerical integration, we got the reasonable mechanism kinetic equation as follows, r_SO2= Kp_H2b_SO2p_SO2/[ 1+b_SO2p_SO2+b_H2Op_H2O+(b_S2p_S2)^1/2]. This equation take a good agreement with the experiments. The adsorption and desorption experiments demonstrated that all reactants and products adsorbed on the surface of the catalyst except H₂. This result together with the kinetic equation make it clear that the mechanism of this reaction is R-E.

Expression of Engineering Bacterium and Function of Recombinant Human Interleukin-6(IL-6)

DONG Yuqing,LI Ronggui,DONG Chunxia,ZHAO Jindong,WU Guangyao

2000, 36(4):  468-471. 

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Interleukin-6(IL-6) cDNA was obtained from the mRNA of human peripheral blood. Gene was cloned and expressed in E.coli. Sixty grams wet pellet was obtained from per liter fermentation liquid in 20L fermentation equipment. There were more than 30% IL-6 protein in the whole protein of the bacterium and 60% IL-6 protein in the inclusion body. Upon the basis of normal of long toxicity and short toxicity, the experiment on rhesus monkey shows that IL-6 can increase the quantity of platelet and leukocyte obviously without the model of decreasing hemogram.

Establishment of a C57BL/6J ES Cell Line by Conditioned Media of Rat Myocardial Cells

TONG Ying,ZOU Jizhong,SHANG Kegang

2000, 36(4):  472-476. 

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A new method of deriving ES cell lines from C57BL/6J mice was described. One C57BL／6J ES cell line (MESPU 41) was established in medium conditioned by rat myocardial cells, without the use of feeder cells and Leukemia Inhibitory Factor(LIF). The frequency of establishment was 1.0%. MESPU 41 cells was XX type. 89% of them showed karyotypically normal and stable which were rare in XX type ES cells. They can differentiate into wide types of cells and form teritocarcinoma in vivo. Chimeras were made by injecting the ES cells into blastocysts, indicating that they had the potency to participate into the development of embryos. Using RT-PCR method, we found that rat myocardial cells expressed LIF mRNA, which might suppress ES cells differentiation and stabilize X chromosome. In order to simplify the process of preparing conditioned medium, we also immortalized rat myocardial cells. These methods broadened the conditions for the establishment of ES cell lines and open up a new point to study the stability of cultured ES cells.

Mechanism of Gold Solvent Extraction from Alkaline Cyanide Solution by Surfactant CTMAB
the Generation of the Third Phase

YAN Wenfei,MA Gang,WENG Shifu,YAN Chunhua,ZHOU Weijin,GAO Hongcheng,LI Wenhong,WU Jinguang,XU Guangxian,CHEN Jing,HUANG Kun,YU Jianmin,CUI Ning

2000, 36(4):  461-467. 

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The solvent extraction of gold and the structure of the organic phase were studied by FTIR, ³¹P-NMR and the dynamic light scattering (DLS) spectroscopy. The results show that the water content and the size of the reversed micelles increased with the increase of gold content in the organic phase. The P═O stretching decreases, while the ³P signal shifts to upfield. The increase of the surfactant cation cause the generation of the third phase.

Bacillus thuringiensis Insecticidal Protein Levels in Different Tissue and Growing Period of Transgenic Cotton Determination Using ELISA

ZHANG Xiaosi,LI Songgang,XU Chongren,ZHAO Jianzhou,ZHAO Kuijun

2000, 36(4):  477-484. 

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The insect-resistant activity of Bt cotton has significant variation in different tissue and growing period. Bioassay, the method used to determine the insect-resistant activity of Bt cotton to bollworm inside the country, can not determine the expression levels of Bt protein. The ELISA method established by us resolves this problem. Compared with bioassay, ELISA has the merits of spending shorter time, quantifying Bt toxin protein and easy operation. We find that Bt cotton has different Bt toxin protein content in different tissue and growing period using ELISA method. Leaves and flower petals contain more Bt toxin protein than boll and bracteal leaves. In the late growing period, Bt toxin protein content of every tissue decreases significantly.

Growth Inhibition of Cyanobacteria
by Decomposed Rice Straw

WAN Hong,ZHANG Yun

2000, 36(4):  485-488. 

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The present experimental study has proved that the rice straw, decomposed in aerated water for more than one month, efficiently inhibit the growth of Microcystis aeruginosa and other three cyanobacterial species in laboratory condition. However, the sterilized decomposed rice straw(treated with a sterilizer at temperature 121℃ for 15min) has no such inhibition effect. This indicates that the microbes associated with the decomposing rice straw possibly play an important role in producing and releasing the algal inhibitors from the straw. Fresh rice straw, without decomposing treatment, exhibited no efficiency of algal inhibition. The present study has proved that the rice straw may have great potential of application to the algal blooming control.

Change in the Concentration and Tissue-localization of Endogenous IAA during the Regeneration after Girdling
in Broussonetia papyrifera (L.) Vent.

CUI Keming,WANG Xiangbin,DUAN Junhua

2000, 36(4):  495-502. 

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Change in the concentration of endogenous IAA was monitored with enzyme-linked immunosorbent assays (ELISA), and IAA localization in the tissues was demonstrated by means of immunogold-silver microscopy, with authors modification, during the regeneration after girdling in Broussonetia papyrifera (L.) Vent.. The stimulation of girdling induced a rapid increase of about 100% of the endogenous IAA concentration. However, the concentration decreased during differentiation of the vascular tissues. Although removal of the tree crown and wrapping up in a black plastic sheet inhibited the regeneration of vascular tissues, but the change tendency in the concentration of endogenous IAA during the regeneration remained the same as if the tree crown was intact and the girdled trunk was wrapped up in a transparent plastic sheet. This suggested that rapid increase of endogenous IAA induced by wounding could result from a release of the combined form into free IAA. The tissue-localization showed that there were more silver-grains labelled in the ray, callus and regenerated differentiating vascular tissue cells than that in other tissues. It further suggested that the high concentration of endogenous IAA triggered the dedifferentiation of the immature vascular tissues after girdling, and the lower concentrated IAA flow could promote the initiation and activity of the regenerated cambium.

Construction of Murine Phage Antibody Library and Selection of N-peptide-binding Single-chain Antibodies

GAO Xinsheng,HUANG Yixiu,ZHU Shenggeng,GUO Zhenquan,CHEN Yuzhen

2000, 36(4):  489-494. 

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A murine phage antibody library containing 1.7×10⁸ independent clones was constructed and affinity panning of anti-N-peptide antibody fragments was carried out. First, mRNA was purified from the total RNA extracted from fresh spleens of nonimmunized mice of Kunming, then the cDNA library was achieved via reverse transcription PCR. Gene fragments encoding V_H and V_L were amplified and assembled into a single gene using a DNA linker encoding a polypeptide of 15 amino acid residues (Gly₄Ser)₃ through primary PCR. And finally the recombinant DNA fragments were cloned into the phagemid pCANTAB 5E vector and introduced into E.coli TG1 by means of electroporation. The phagemid particles displaying functional ScFvs were rescued by reinfection of helper phage M13KO7, thus a murine antibody library was obtained. One N-peptide-binding ScFv clone was selected from the phage antibody library using affinity panning. The target antigen, N-peptide was biotinylated using photobiotin first. Then the biotin-labelled N-peptide interacted with the phage antibody library. The streptavidin paramagnetic beads were added subsequently to bind the biotinylated N-peptide-specific phage particle complex. Washing, elution and reinfection were ensued sequentially. After 4 rounds panning, one clone was verified to show higher affinity to N-peptide by dot blot.

Study on Competition Reaction and Replacement Reaction of Metallothioneins with Lead Ion

JI Qingzhou,WANG Libo,ZHOU Yuan,RU Binggen

2000, 36(4):  503-508. 

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Two isoforms metallothioneins: Zn₇MT-Ⅰ and Zn₇MT-Ⅱ were prepared from the rabbit liver induced by zinc after isolation and purification. They were demetalled in acidic condition, then applied Sephadex G-25 to gain apoMTs free of metals. In a similar way, Zn₂Cd₅MT-Ⅰ and Zn₂Cd₅MT-Ⅱ were prepared from the rabbit liver induced by cadmium. By using Circular Dichroism (CD) spectroscopy method and Ultraviolet (UV) absorption spectrophotometry, competition reaction and replacement reaction of metallothioneins with lead ion were investigated. Competition reaction shows that ZnPbMT-Ⅰ is formed while lead ion and zinc ion bind competitively to apoMT-Ⅰ；however, apoMT-Ⅱ's metal binding sites are all took up by lead ion, which means apoMT-Ⅱ is more sensitive to lead ion than apoMT-Ⅰ. Replacement reaction shows that lead ion can't replace zinc ion either in Zn₇MT-Ⅰ or in Zn₇MT-Ⅱ; on the contrary, lead ion can replace zinc ion both in Zn₂Cd₅MT-Ⅰ and in Zn₂Cd₅MT-Ⅱ；moreover, these two isoforms Zn₂Cd₅MTs display differences in replacement reaction. It suggests Zn₂Cd₅MT-Ⅱ may detoxify lead effectively.

Anatomical Characteristics of Beech (Fagus L.) Species
in Zhejiang and Their Taxonomic Significance

FANG Jingyun,FEI Songlin,ZHAO Kun,FAN Yongjun,ZHUANG Donghong,WU Mingxiang

2000, 36(4):  509-516. 

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According to different authors, there are 4～6 beech (Fagus L.) species (including one variety) in Zhejiang Province, some of which are still unclear in their systematical taxonomy. In order to provide anatomical data for their taxonomy, an anatomical study on foliar and wood was conducted for 5 taxa, F.longipetiolata Seem., F.lucida Rehd. et Wils., F.bashanica Yang, F.tientaiensis Liou, and F.hayatae var. zhejiangensis Liu et Wu. As a result, anatomical characteristics of foliar and wood showed a remarkable inter-and intra-specific variation, but the interspecific changes in leaf surface and leaf anatomical features indicated a clustery trend. A cluster analysis by using the anatomical data showed that F.tientaiensis belonged to F.longipetiolata, and F.hayatae var. zhejiangensis to F.bashanica. Based on the present study and a literature review, it was concluded that 4 beech species, F.longipetiolata, F.lucida, F.bashanensis and F.engleriana, were distributed in Zhejiang Province. However, systematical relationship between F.bashanica and F.hayatae remained unclear and more studies should be needed.

The Meso-Cenozoic Evolution of Bachu Fault-Uplift in Tarim Basin

HE Wenyuan,LI Jianghai,QIAN Xianglin,ZHANG Chen

2000, 36(4):  539-546. 

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The Meso-Cenozoic evolution of Bachu Fault-Uplift is closely related to its south and north subsiding foredeep. Under the background of Indian Plate subducting under Asia-Europe Plate, Bachu forebulge was greatly affected by the development of Southwest Depression and Awati depression. Almost all of its structure reversed, and as a result of it, both of its south and north boundary migrated. According to its evolution history and its feature, the authors tentatively use both-side migration model to interpret the evolution of compound forebulge. Since Triassic, almost all the spheres above lithosphere synchronously became flexure. Because transpressional stress field became increasingly strong, Bachu forebulge continued uplifting and big faults formed. Then, Bachu uplift, as a whole, slipped upward along those big faults and showed migrating toward thrust zone in plane. In tectonic tranquility, the lithosphere bounded back and in consequence of it, Bachu uplift slipped down and showed migration toward craton, at that moment negative inversion structures developed. While the forebulge migrated toward its south and north foredeep, it was very possible that locally extensional stress appeared in the forebulge.

The Records of δ¹⁸O and δ¹³C for Climate Changes in Weiminghu Lake, Peking University since 1747a A.D.

XIA Zhengkai,CHEN Fuyou,ZHENG Gongwang,MA Jun,JIN Deqiu,ZHOU Xihuang

2000, 36(4):  547-554. 

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According to the variation of stable isotopic composition of carbonate in lacustrine deposite in Weiminghu Lake, Peking University, the section can be subdivided into four oxygen-carbon-isotope stages. They are as follows: a) 50～26cm (1747-1866a A.D.), which gave higher value of oxygen and lower value of carbon isotope. The δ¹⁸O value of samples ranges from -4.70‰ to -6.03‰, the δ¹³C value ranges from -3.63‰ to -6.03‰. b) 26～22cm (1867-1886a A.D.), which is characterized by a rapid change of value of oxygen and of carbon isotope. The δ¹⁸O value have a rapid downfall from -5.23‰ to -7.58‰, and the δ¹³C value have a rapid uplift from -5.70‰ to -2.18‰. c) 20～0cm (1886-1997a A.D.), which gave lower value of oxygen and higher value of carbon isotope. The δ¹⁸O value of samples ranges from -7.02‰ to -8.08‰, the δ¹³C value ranges from -2.03‰ to -2.63‰. Generally, the values of δ¹⁸O in lacustrine sediment has a positive correlation with that of the δ¹⁸O values of rainwater in the Asian monsoon region, and the latter are controlled by monsoon climate. The summer monsoon have a lower value of oxygen isotope, and the winder monsoon have a higher value of oxygen isotope. The values of δ¹³C of carbonate in lacustrine sediment are controlled by that of the algae activity in the lake water and the latter has a positive correlation with temperature and humidity. So the high value of oxygen and lower carbon isotope (δ¹⁸O and δ¹³C) in lacustrine sediment in Weiminghu lake represents a relatively cool and dry weather while the low value of oxygen and higher carbon isotope represents a rather hot and wet weather. The variation of oxygen and carbon isotopic value among the section indicates a cool-dry climate during 1747—1866a A.D., a hot-wet climate during 1886—1997a A.D., and a rapid change of climate from 1866 to 1886a A.D..

The Multi-angle Thermal Infrared Remote Sensing and Retrieval of Component Temperatures of Mixed Pixel

XU Xiru,ZHUANG Jiali,CHEN Liangfu

2000, 36(4):  555-560. 

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A new method was offered to retrieve component temperature of mixed pixel with multi-angle thermal infrared data based on the law of directionality of thermal radiance of mixed pixel. To take continuous vegetation canopy as an example, the correlation coefficients among multi-angle thermal infrared data are less than their counterpart of multi-channel which mainly depend on the distribution function of leaf angle(LAD), therefore, it is easier to keep accuracy of retrieved component temperature within 1K than its counterpart.

BF₃ Etherate Catalyzed Lactonization Reaction: Synthesis of 4-Aryl-2-pheny1-4, 6-dihydrofuro［3, 4-c］furan-6-ones

NIE Xiaoping,YE Xiulin

2000, 36(4):  561-565. 

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Under the catalysis of boron trifluoride etherate, the hydroxy acids(5-Phenylfuran-4-arylcarbinol-3-carboxylic Acids)were converted to lactones(4-Aryl-2-phenyl-4, 6-dihydrofuro［3, 4-c］furan-6-ones)smoothly.

The Role of Chalcone Synthase Gene in the Defense Response of Higher Plants against Pathogens

LIAO Jingjun,AN Chengcai,WU Si,CHEN Zhangliang

2000, 36(4):  566-575. 

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This article presents the relationship between the Chalcone Synthase(CHS) gene and pathogens in the defense response of higher plants. According to recent results, we discussed the interaction between cis-acting elements and trans-acting factors related to inducible expression, demonstrated the important role played by CHS gene in the defense response of higher plants against pathogens.

The Role of Chalcone Synthase Gene in the Defense Response of Higher Plants against Pathogens

LIAO Jingjun,AN Chengcai,WU Si,CHEN Zhangliang

2000, 36(4):  566-575. 

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This article presents the relationship between the Chalcone Synthase(CHS) gene and pathogens in the defense response of higher plants. According to recent results, we discussed the interaction between cis-acting elements and trans-acting factors related to inducible expression, demonstrated the important role played by CHS gene in the defense response of higher plants against pathogens.

Perspectives on Innovation in Physical Geography

CAI Yunlong

2000, 36(4):  576-582. 

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The study on synthesis,region-locality and human-natural dimensions are not only a deep scientific tradition of physical geography, but also a new insight in the research on global environmental change. There are broad development prospects and innovation opportunities for physical geography in the domain of basic applied research. Physical geography has distinctively contributed much to national development and construction. Based on the traditional themes and academic foundation and oriented to the social demands, physical geography will make innovative fruits for man-nature relation optimization, territorial management and resource conservation. The extreme complexity of the study object requires methodological innovation of physical geography. In new insights and approaches,appropriate `physical'models should be established and the mechanism study should be emphasized. Physical geography research projects should clearly identify detail scientific questions, setting clear priorities of what should be studied at the regional and local scales and how,and making the relationship of various issues at various spatial and temporal scales clear in particular. These may be the innovation points and the unique contribution that physical geographers can do for global environmntal change study. Integrated researches on unique physical geographical regions and unique problems usually result in innovative achievements. Physical geography should pay more attention to Chinese characteristics and address Chinese situation. This is not only the practical requirement of the nation but also beneficial for strengthening the place of Chinese geography in the international academic community.