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Study on Influencing Factors of Hydrothermal Carbonization of Sewage Sludge
WANG Hang, LIU Yangsheng, WANG Dianchang, CHEN Xiang, LIU Feng, QIAO Xueyuan, LI Kun, WANG Xiankai
Acta Scientiarum Naturalium Universitatis Pekinensis    2024, 60 (4): 745-757.   DOI: 10.13209/j.0479-8023.2024.043
Abstract78)   HTML    PDF(pc) (1681KB)(20)       Save
The effects of reaction temperature, time, and medium on the properties of sludge hydrochar were experimentally studied. The results demonstrated that hydrothermal carbonization (HTC) treatment enhanced sludge dewatering and volume reduction, with a higher water removal rate (42.8%–53.3%) observed under acidic conditions compared to neutral conditions (28.9%–45.2%). Notably, the highest dehydration rate was achieved after HTC at 240°C for 1 hour. Increased reaction temperatures and longer reaction times led to reduced hydrochar yield due to enhanced dehydration and decarboxylation reactions. The H/C and O/C atomic ratios gradually decreased as a result. Furthermore, the regular and compact structure of sludge was disrupted to varying degrees following HTC treatment, resulting in the formation of holes and grooves that increased the specific surface area, pore volume, and pore size of the hydrochar produced. Specifically, hydrochar obtained from HTC at 220°C for 1 hour exhibited the highest specific surface area (129.98 m2/g) and pore volume (0.66 cm3/g). The composition and crystalline structure of hydrochar were primarily influenced by factors such as reaction medium > reaction temperature > reaction time. With the increase of HTC reaction temperature and residence time, the volatile content of hydrochar decreased while the fixed carbon and ash content increased. The main exothermic range during combustion of hydrochar occured between 250–550°C.
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Efficient Combined Simulation Research of Finite Element Analysis for Bolt Assembly Process
LI Xiang, SHEN Chao, LIU Zhao, LIU Caishan, LIU Yan, LIU Chao
Acta Scientiarum Naturalium Universitatis Pekinensis    2023, 59 (6): 923-933.   DOI: 10.13209/j.0479-8023.2023.087
Abstract238)   HTML    PDF(pc) (16629KB)(91)       Save
Current finite element (FE) simulating methods for pre-tightening process of thread fasteners have some shortcomings. In order to ensure the accuracy and efficiency simultaneously, the interference fit method and the direct torsion method are combined via ANSYS APDL to form a new pre-tightening means. Firstly, FE models of the thread pair structure before and after simulating the necking plastic forming process are obtained. Further assembly process simulation of the necking anti-loosening nuts is realized. Via different pre-tightening methods for simulating the assembly process, the thread pair load distribution, the contact stress state and the torsion-tension relationship can be obtained. Via comparing the numerical results of the zero closure amount nuts with some theoretical solutions, the reliabilities of the FE models and the simulation process are verified. Furthermore, the calculation time and numerical results of different pre-tightening methods are compared to prove the combined pre-tightening method is reliable and effective. 
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Characteristics of the Northward Propagation of Summer Intraseasonal Oscillation over the Tropical Indian Ocean
LIU Ya, YANG Haijun
Acta Scientiarum Naturalium Universitatis Pekinensis    2023, 59 (4): 569-580.   DOI: 10.13209/j.0479-8023.2023.044
Abstract245)   HTML    PDF(pc) (3095KB)(224)       Save
The propagation process and characteristics of tropical intraseasonal oscillation (TISO) in Indian Ocean from 1985 to 2017 (from May to October) are investigated using high-resolution satellite data and reanalysis data. There are three types of northward propagation of the TISO in Indian Ocean. The stable type: the convective signal is originated from the south of the equator, in the Western Indian Ocean, then steadily propagates northward to the Indian Peninsula. The attenuated type: it is similar to the stable type in the early stage, but attenuates rapidly after it propagating northward to the Bay of Bengal. The enhanced type: there is no strong convective signal in the early stage, about ten days later, the signal changes from the southern of the Indian Peninsula begin to intensify and developed the Himalayas. During the northward propagation of TISO, convective anomalies are accompanied by easterly shear anomalies, sea surface temperature (SST) anomalies and water vapor disturbances in the boundary layer, which have different effects on the three types of propagation. The positive sea surface temperature anomalies on the north side of convective events will promote the northward propagation of convection, playing a significant role in both stable and attenuated equatorial propagation processes, but the positive SST anomalies is more significant on the south side of the convective event in the enhanced type and inhibits the northward propagation of the convective event. The easterly vertical shear mechanism provides a continuous impetus for the stable propagation of the stable and enhanced types of events, with more significant effects later in the events. The disturbed water vapor in the boundary layer aggravates the instability of the atmosphere and induces the convection system to move northward before and after the stable events, the early attenuation events and the occurrence of the enhanced events. The research results can help improving the accuracy of predicting summer intraseasonal precipitation in Southeast Asia. 
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Investigation on Urban Heat Island Intensity Model of the Residential District in Mid & High-Density Cities
LIU Yan, LI Qi, YANG Liu, ZHANG Tengyue, LIU Jiaping
Acta Scientiarum Naturalium Universitatis Pekinensis    2022, 58 (6): 1077-1090.   DOI: 10.13209/j.0479-8023.2022.092
Abstract575)   HTML    PDF(pc) (3970KB)(245)       Save
Based on the physical process of the urban heat island (UHI) effect, the Urban Heat Island Intensity Model is established by solving the energy balance equation with the analytic method, which provides a basic model for further research on the correction of outdoor calculating parameters considering the impact of UHI. This model includes two parts: the urban surface energy balance calculation module and the urban canopy energy balance calculation module. At the same time, the Global (UHI) Data Set and the observation data in Xi’an, Birmingham, Madison, and Basel are used to verify the model. The validation results show that the urban under-lying surface energy balance calculation module has high calculation accuracy in both rural and urban areas (rural: RMSE<1℃; urban: RMSE<3.2℃); the calculation accuracy of the urban canopy energy balance calculation module is high (RMSE<1.5℃), which is similar to that of the same type of models, and the modelled data has a high consistency with the observation data. The observation data is used to verify the rationality of retaining only the first-order term in the construction of the urban heat island intensity model (RMSE<0.7℃). The sensitivity analysis results show that the sensitivity of urban underlying surface parameters are affected by climatic conditions; the wind speed is the most sensitive parameter in meteorological data. 
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Study on Coupling Simulation Method of Environmental-Economic System at Lake Watershed
ZHANG Baichuan, ZHANG Yang, LI Zheng, LIU Yanxiao, GUO Huaicheng
Acta Scientiarum Naturalium Universitatis Pekinensis    2022, 58 (5): 937-948.   DOI: 10.13209/j.0479-8023.2022.076
Abstract438)   HTML    PDF(pc) (1200KB)(245)       Save
In order to explore the internal conflict and synergy among water pollution control, water conservation and socio-economic development, a system of coupling simulation for the aquatic environmental-economic system of lake watershed was constructed and applied at Yilong Lake Watershed. Based on the scenario analysis, the following conclusions are drawn. 1) Under the condition of economic and social affordability, the nutrient load of Yilong Lake can be reduced to the level of aquatic environmental capacity corresponding to Grade IV water quality through the measures of controlling the pollution. 2) The implementation of industrial relocation or very strict scale restriction is extremely unfavorable for gross domestic product (GDP) growth and urbanization of the watershed, but does not play a significant role in protecting the aquatic environment of Yilong Lake. 3) The critical measures in the planning period are to change the planting practices of high water-consuming and heavy fertilizer-using, treat rural domestic sewage more effectively, promote sewage reuse, and reduce the transfer of sewage. 4) According to the simulation results, the optional scheme selected by the approach proposed here would reduce the water diversion demand by 45%, and cut down the total nitrogen (TN) and total phosphorus (TP) discharged into the lake from the land surface by 26.6% and 18.5% respectively, and eliminate the TN and TP load of the lake by 20.7% and 17.5% respectively, but only at a cost of 7% of GDP at the end of the planning period.
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Physiological and Biochemical Responses of Corbicula fluminea under the Stress of Graphene Oxide Combined with Perfluorooctane Sulfonate (PFOS) 
BI Chunqing, LIU Yan, GUO Wenjing, JIANG Xilin, LI Zhengguoshen, XU Nan
Acta Scientiarum Naturalium Universitatis Pekinensis    2022, 58 (4): 721-729.   DOI: 10.13209/j.0479-8023.2022.028
Abstract512)   HTML    PDF(pc) (4252KB)(198)       Save
In order to explore the combined toxicity of carbon nanomaterial graphene oxide (GO) and perfluorooctane sulfonate (PFOS) in freshwater benthic shellfish, Corbicula fluminea was used as the target organism to study the effects of single and co-exposures of 1 mg/L GO or/and 500 ng/L PFOS for 28 days on body length, body weight, filtration rate, level of reactive oxygen species (ROS), antioxidant enzyme system and malondialdehyde (MDA) content. The toxicity was evaluated by enhanced integrated biomarker response (EIBR). The results showed that the body length and body weight of C. fluminea did not change significantly after exposure. Compared with the blank control and solvent control groups, the filtration rates in the single and co-exposure groups significantly decreased. Both GO and PFOS stresses significantly changed the enzyme responses in gills and visceral masses of C. fluminea with consistent variation trends in both organs. The EIBR results showed that the toxicity in gills and visceral masses of the co-exposure group was stronger than that of the PFOS or GO single exposure groups. 
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Effects of Microplastics and PFOS Co-exposure on the Filtration Rate and Antioxidant System of Perna viridis
XU Peng, Muhammad Junaid, LIU Yan, CHEN Yupeng, BI Chunqing, XU Nan
Acta Scientiarum Naturalium Universitatis Pekinensis    2021, 57 (5): 894-902.   DOI: 10.13209/j.0479-8023.2021.066
Abstract811)   HTML    PDF(pc) (895KB)(261)       Save
In order to explore the composite pollution toxicity mechanism of microplastics and perfluorooctane sulfonate (PFOS) in Perna viridis, the effects of PFOS (10, 100, 1000 μg/L) and microplastics (0.2 μm, 4.55×108 numbers/L) were studied under single- or co-exposure on the filtration rate, reactive oxygen level (ROS), malondialdehyde (MDA) content, superoxide dismutase (SOD) activity, catalase (CAT) activity, glutathione S-transferase (GST) activity and gluathione reductase (GR) activity. The results showed that the filtration rate of mussels after exposure to microplastics and PFOS did not change significantly compared to the solvent control. In gills, visceral mass and gonads of mussels, the stress of microplastics and PFOS could cause significant changes in enzyme response. After co-exposure of microplastics and 1000 μg/L PFOS, compared with single-PFOS exposure groups, ROS level significantly increased in gills and gonads, whereas decreased in visceral mass; MDA content increased in gills and visceral mass, whereas decreased in gonads; GST and GR activity was significantly reduced in gills, whereas increased in gonads. The results indicated that microplastics could change the oxidative stress response of mussels to PFOS.
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Study on Deoiling Effect and Kinetics of Ozone Catalyzed Oxidation of Oil-bearing Clay
CHEN Hongshuo, LIU Yangsheng
Acta Scientiarum Naturalium Universitatis Pekinensis    2019, 55 (6): 1152-1160.   DOI: 10.13209/j.0479-8023.2019.089
Abstract929)   HTML    PDF(pc) (23915KB)(170)       Save
An ozone catalytic oxidation treatment technology with natural aluminum ore as a catalyst was developed to treat the byproduct of oil-bearing clay with oil content of 6.5% produced during the thermochemical treatment of petroleum sludge at tank bottom. Under the optimized treatment conditions, the oil content of oilbearing clay could be reduced to 1.2%, meeting the treatment requirements specified in the “SY/T7301-2016”. For further research on the contribution of the catalyst to the ozone catalytic oxidation system, the reaction activation energy and reaction rates of ozone oxidation and ozone catalytic oxidation were compared from the perspective of kinetics. The results showed that, with the catalyst sludge adding, the oil removal rate increased 2–3 times and the reaction activation energy reduced 84.2%, which showed the effectiveness of the catalyst on the kinetics of quantitatively. As a kind of deep treatment method of the oily clay, this technology further complements and improves the recycling and harmless treatment system of petroleum sludge at tank bottom.
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Synthesis and Photocatalytic Property of TiO2 Photocatalysts Using Hydrochars as Template
WANG Xiaojing, ZHANG Qiming, LIU Yangsheng
Acta Scientiarum Naturalium Universitatis Pekinensis    2018, 54 (6): 1332-1338.   DOI: 10.13209/j.0479-8023.2018.088
Abstract766)   HTML    PDF(pc) (6667KB)(317)       Save

Using hydrochars as template, TiO2 photocatalysts were prepared by the sol-gel method. The samples were characterized with X-ray diffraction (XRD), Fourier infrared spectrum (FT-IR), scanning electron microscope (SEM) and BET specific surface area measurement. The photocatalytic activity was investigated by degradation of methyl orange (MO) as target pollutant in the solution. The results showed that HTC-TiO2 remained anatase type at high calcination temperature due to the higher thermal stability than TiO2. The TiO2 particles were almost uniformly dispersed on the surface of HTC. HTC-TiO2 had smaller crystal sizes, bigger specific surface area and the flake structure, which had the same structure character as the hydrochars micro-structure and was beneficial to improve the photocatalytic activity. The degradation rate of MO under 550 W iodine-tungsten lamp illumination for 2 hours was 40.6% in presence of HTC-TiO2 calcined at 450ºC, which increased by 1.5 times more than those in presence of TiO2 (16.2%).

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Research on Analysis of Arrhythmia Based on pRRx Serials Derived from ECG Signals
LI Ran, WANG Xin’an, ZHAO Tianxia, LIU Yanling, LI Qiuping
Acta Scientiarum Naturalium Universitatis Pekinensis    2018, 54 (6): 1166-1172.   DOI: 10.13209/j.0479-8023.2018.081
Abstract1101)   HTML    PDF(pc) (1533KB)(320)       Save

In order to analyze arrhythmia, a noval practical method was proposed. Here the pRRx serials (x ranged from 1 to 100 ms) extracted from ECG data were taken as fundamental signals. There were obvious differences in distribution of the pRRx serials between 20 people with normal arrhythmia (group I) and 20 patients with arrhythmia (group II). By analyzing the linear indexes and nonlinear indexes of pRRx serials, the computed results show that there are significant statistical differences between the two groups. The linear indexes (AVRR, rMSSD, SDSD) are very different (P<0.001). The nonlinear indexes, from the entropy measures (Sdh, Sph, Spf) and the fractal dimension measures (Dsf, Dcf, Dvm, Drms), also maintain apparent differences (P<0.001). Therefore, the proposed pRRx-serial analysis can characterize the linearity and nonlinearity of the cardiac system to some extent, and can be effective in recognizing the arrhythmia and even heart-related diseases.

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Research on Land Use Functions Classification and Evaluation System Based on System Theory
LIU Chao, XU Yueqing, LIU Yanxu, SUN Piling, HUANG An, ZHOU Jian
Acta Scientiarum Naturalium Universitatis Pekinensis    2018, 54 (1): 181-188.   DOI: 10.13209/j.0479-8023.2017.132
Abstract1181)   HTML19)    PDF(pc) (642KB)(521)       Save

The authors systematically identify and classify land use functions based on the system theory, and then construct the multi-scale and multi-level evaluation index system of land use functions from three aspects of economy, society and ecology from the perspective of patch scale. A preliminary attempt is made to obtain and spatialize index data. The results show that land use functions has multiple levels and regional characteristics, corresponding classification and evaluation index system should be established according to different regional background and research scale. Land use functions are related to land use structures, and its evaluation scale is extended to the micro-scale, which is helpful to expand the scope and enrich content of the study of land use functions.

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Ecosystem Service Valuation and Value Transfer of Land Use Types: A Comprehensive Meta-analysis of the Literature
ZHANG Yaxin, LIU Ya, ZHU Wenbo, LI Shuangcheng
Acta Scientiarum Naturalium Universitatis Pekinensis    2016, 52 (3): 493-504.   DOI: 10.13209/j.0479-8023.2016.026
Abstract1364)   HTML    PDF(pc) (1009KB)(1049)       Save

Based on Meta-analysis, the ecosystem service value regression models for cultivated land, forest land, pasture, garden land, waters and unused land were established respectively. In addition to time and value method, the geographical division and socio-economic factors (including population density and GDP per capita) were also incorporated into the models. The performance of model indicates that these factors play a significant role in explaining ecosystem service value change. Using value transfer approach, the authors valued ecosystem service of land use types in Beijing, Tianjin, and 11 cities in Hebei Province. The results show that land use types ranked by ecosystem service value are waters, forest land, pasture, garden land, cultivated land and unused land. The ecosystem service values per unit area of cultivated land, forest land, pasture, garden land and water area in Beijing and Tianjin are more than other areas. The research results on the one hand can enrich the methodology and technology of ecosystem service valuation, on the other hand provide scientific support for land use sustainable management in study area.

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Hybrid CNT Film-Graphene Photodetectors with Low Noise and Broadband
LI Zishen, LIU Yang, XU Haitao, WEI Nan, YU Dangmin, WANG Sheng
Acta Scientiarum Naturalium Universitatis Pekinensis    2016, 52 (3): 383-388.   DOI: 10.13209/j.0479-8023.2015.127
Abstract1271)   HTML    PDF(pc) (976KB)(1558)       Save

Highly purified semiconducting carbon nanotube (CNT) thin films and graphene are used to fabricate hybrid photodetector. The results indicate that the hot carriers generated in graphene can tunnel into bottom CNT film through nanometer thick silicon film when illuminated. As a result, electrons and holes are accumulated at separated side of the silicon layer, resulting in a modulation of the current in the CNT film transistor due to the photogating effect. The photodetector shows a responsivity of 83 mA/W for visible light (633 nm) and a good response within the near-infrared range. Such CNT film-graphene photodetector, taking advantages of both broadband absorption of graphene and small dark current of semiconducting CNTs, paves the way to future high performance infrared photodetectors.

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Development and Trend Analysis of Wastewater Resource Recovery Research Based on Bibliometrics Methods and Data during the Period 1995–2014
ZHANG Li, LIU Yangsheng
Acta Scientiarum Naturalium Universitatis Pekinensis    2016, 52 (2): 374-382.   DOI: 10.13209/j.0479-8023.2015.152
Abstract1080)   HTML    PDF(pc) (808KB)(919)       Save

 For better understanding the global trend in wastewater resource recovery and reflecting major nation’s scientific capability and influences on the world’s science community in the field, a bibliometric analysis was conducted using the literatures in the Science Citation Index (SCI) database during the period 1995–2014. Results indicate that: 1) among all articles included by the SCI, water recovery from wastewaters account for the largest percentage with 72.0% of all related research fields. 2) The mainly involved subject areas are Environmental Sciences, Engineering Environmental, Water Resources, Engineering Chemical, Biotechnology Applied Microbiology, and so on. The number of the Environmental Sciences articles has the largest annual growth. 3) The topranked countries of both the total number of articles and the average impact factor are USA, Spain, and India. However, China has the fastest growth rate of publishing articles only. 4) Three research institute including University of California System, India Institute of Technology, and Consejo Superior De Investigaciones Cientificas are the most abundant research institutes in this field. The Chinese Academy of Sciences and Tsinghua University were the two toppest institutions in China that have advance its international influence in recent years.

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Research on the Construction of Bilingual Movie Knowledge Graph
WANG Weiwei, WANG Zhigang, PAN Liangming, LIU Yang, ZHANG Jiangtao
Acta Scientiarum Naturalium Universitatis Pekinensis    2016, 52 (1): 25-34.   DOI: 10.13209/j.0479-8023.2016.022
Abstract1328)   HTML    PDF(pc) (658KB)(1010)       Save

This paper proposes a method to construct Bilingual Movie Knowledge Graph (BMKG). The authors first builds Bilingual Movie Ontology (BMO) through a semi-automatic way, and aligns each data source with it in order to ensure semantic consistency of heterogeneous data sources. For entity linking, the proposed method makes best use of the field characteristics and calculate entity similarity based on both Word2Vec and TFIDF models, which greatly improve entity linking. For entity matching, a similarity flooding based algorithm is proposed, which utilizes the intrinsic links between the movie data sources, addressing the problem of similarity computation between cross-lingual entities. The experiment results show that the entity matching precision is over 90% when the threshold is above 0.75. In addition, a movie knowledge graph sharing platform is also built to provide open data access and query interface.

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Assessment of Heavy Metal Contaminated Soils from the Lead-Zinc Mine by Toxicity Characteristic Leaching Procedure
YUE Cong,WANG Qunhui,YUAN Li,LIU Yangsheng
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract953)      PDF(pc) (637KB)(735)       Save
The contents of heavy metals (Zn, Pb, Mn, Ni, Cr and Cd) in soils samples taken from the Laiyuan lead-zinc mine in Hebei Province were analyzed. The toxicity characteristic leaching procedure (TCLP) developed by US EPA was employed to evaluate the pollution status and assess the environmental risk. Extraction reagents used in the TCLP experiments were investigated, and the relationship was examined between the concentrations of heavy metals by TCLP extraction and those of their chemical different speciation. The experimental results indicate that TCLP agent B (17.25 mL of glacial acetic acid is diluted to 1 L with distilled water, and the solution pH was 2.64 ± 0.05) is more effective than method TCLP agent A (5.7 mL of glacial acetic acid and 64.3 mL sodium hydroxide were diluted to 1 L with distilled water, and the solution pH was 4.93±0.05) in extracting heavy metals from the polluted soils. A positive correlation has been found between the concentrations of heavy metals extracted by TCLP agent A and those by TCLP agent B. The contents of available heavy metals by agent B are correlated with the total contents of enchangeable and carbonate-bound species.
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Adsorption of Pb2+ and Cd2+ onto Biochars Derived from Pyrolysis of Four Kinds of Biomasses
DAI Jing,LIU Yangsheng
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract685)      PDF(pc) (4071KB)(666)       Save
Four kinds of raw materials including sawdust, rice bran, rice straw and corn stalk were used to produce the biochars by pyrolysing at temperatures of 300, 400, 500, 600 and 700℃ under the protection of the nitrogen atmosphere and the adsorption characteristics of these biochars for Pb2+ and Cd2+ were investigated in detail. Experimental results show that the biochars produced at 700℃ are more effective than those produced at the other temperatures for all these raw materials to remove Pb2+ and Cd2+ from aqueous solutions, and the rice straw biochar (C700, i.e. the rice straw biochar obtained at 700℃) has the highest adsorption capacity among these biochars. The adsorption capacities of C700 for Pb2+ and Cd2+ are 126.58 and 60.61 mg/g, respectively. The composition of mineral phase, the surface morphology and the BET surface area of the biochars are analyzed by XRF, SEM and BET surface area analyzer. The XRD patterns of biochars after adsorption of heavy metal are analyzed, which illustrates that the Langmuir isotherm model fits the experimental data of Pb2+ and Cd2+ adsorption by these four kinds of biochars, and the XRD patterns suggest that carbonate, phosphate, silicate and/or sulfite containing Pb2+ or Cd2+ are present in these biochars after adsorption.
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Analysis on the Knowledge Structure and Evolution Path of Core Authors in Domestic Cloud Computing Research Areas
WANG Jiandong,LIU Yang,WANG Jimin
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract599)      PDF(pc) (626KB)(411)       Save
Based on visual analysis method, the authors analyzed the emergence background and history of cloud computing research. Firstly, the core authors group of cloud computing research area was determined, and a co-word network was constructed using published literature bibliographic data of these authors in the last ten years. Then the community structure sampling algorithm and G-N clustering algorithm were introduced to analyze the overall distribution of the research field. Through counting the membership degree of a keyword to specific research groups, the authors made a comparative analysis on core groups’ research features. Finally, the migration path of core group’s research interest after and before entering this field was analyzed, and the domestic development of cloud computing was divided into several basic stages.
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Almost Simple DD-groups
LIU Yanjun,SONG Xueling,XIONG Huan
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract755)      PDF(pc) (421KB)(436)       Save
The main purpose is to investigate almost simple DD-groups. It proves that the almost simple group G is not a DD-group unless G is one of the following groups: 1) M22, J2, Co1, Fi'24, McL, Th, B, and the automorphism group of M12 or J2; 2) A5, A6, A7, A9, A10, A16, S5, Aut(A6), S8, S10, or An(62≤n≤205); 3) L3(2), Aut(L3(3)), or L2(q) for q=4, 5, 7, 9, 11.
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A Bibliometric Analysis of Incinerator Research during the Period 1991?2010
YUAN Li,LIU Yangsheng
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract540)      PDF(pc) (481KB)(277)       Save
A bibliometric analysis of incinerator research was conducted to evaluate the current trends, using the literatures in the Science Citation Index (SCI) database for the period 1991-2010. Articles were concentrated on the analysis by the document type, language, publication output, distribution of journals, the publication activity of countries and institutes, as well as keywords. The trend of publication outputs during 1991-2010 coincides with a exponential function model. English-language articles take the majority of all the publications. Incinerator research is primarily published in subject category of Environmental sciences, and Chemosphere is the most productive jour- nal with a number of publications of 344. The USA is the largest contributor of the total publications. While, China enjoys the highest growth rate in terms of publication over time. Finally, author keywords were analyzed to provide research emphasis. The results show that heavy metals, fly ash and dioxins were considered recent research hotspots. The generation of secondary pollutants can be effectively controlled by improved incinerator. Large-scale incineration equipment, such as grate incinerators and fluidized bed incinerators, will play a very important role in Chinese waste treatment in the future.
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Study on Relationship between Livelihood Capital and Livelihood Strategy of Farming and Grazing Households: A Case of Uxin Banner in Ordos
MENG Jijun,Amrulla,LIU Yang,XIANG Yunyun
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract936)      PDF(pc) (1273KB)(757)       Save
Based on the questionnaire survey and mathematical statistics, quantitative evaluation of the livelihood assets in Uxin Banner was made, revealing the relationship between livelihood assets and livelihood strategies and analyzing the influences of de-farming and anti-grazing policy on the local livelihood. The main research results are as follows. Firstly, pasture area, credit conditions, family income and livestock quantity are important livelihood assets for the local households, while the stocks of social assets and human assets are relatively lower, indicating rich natural resources, adequate financial inventory assets but less ability and quality of people, so that the configuration of livelihood assets couldn’t be optimized properly. Secondly, households possessing rich human, financial and social assets tend to non-agricultural activities, while those with abundant material and natural assets are more willing to agricultural activities. Thirdly, the implementation of de-farming policy leads to the changes in cultivated land amount and planting structure, mainly presenting the phenomenon of “farming for support” and the transfer of agricultural labor forces to non-agricultural activities. And the implementation of anti-gazing policy results in the changes of husbandry management into agricultural management modes, that is a tendency to yard feeding sheep and pigs and developing large-scale and specialty farming, leading to the issue of role-change and needs of vocational training. Fourthly, the implementation of these policies still has several problems, especially in the livelihoods guidance on immigration, protection on basic life, a reasonable determination of subsidies amount and guarantees of follow-up ones, transfer and absorption of surplus labors. Given the above aspects, suggestions on how to improve the local livelihoods strategies while promote the de-farming and anti-grazing policies at the same time have been put forward from the perspective of sustainable livelihood.
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Spatio-temporal Differentiation of County Multi-functions along the Bohai Rim in China
LIU Yu,LIU Yansui,GUO Liying
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract789)      PDF(pc) (4672KB)(451)       Save
Based on the definition of dominant functions as well as the building of multifunctionality evaluation index system and analysis models, the authors evaluated the functions of economic development, grain production, social security and eco-conservation. Major findings are summarized as follows. 1) In 2008, economic-oriented functional areas were mainly distributed in Beijing-Tianjin-Tangshan region, Shenyang Metropolitan area, Jiaodong Peninsula and other municipal districts; grain-oriented functional areas were mainly distributed in central plain of Liaoning, western plain of Shandong, piedmont plain of Taihang Mountain and alluvial plain of Haihe River; the spatial pattern of social security function was closely related to that of economic development; eco-conservation functional areas were concentrated in eastern mountain areas and northwest hill areas of Liaoning, and northeast mountainous-hilly areas in Hebei. 2) Compared with 1990, the indices of multi-functions demonstrated an upward trend, and functions of economic development and social security have been improved significantly. The increasing degree of grain production function was smaller with the gravity center of grain production gradually concentrated on the plain agricultural areas, while the distribution of eco-conservation function hadn’t change considerably.
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Removal of Lead from the Simulated MSW Incineration Flue Gas by Sulfur-Impregnated Activated Carbon Fiber (ACF/S)
MIN Yutao,YUAN Li,LIU Yangsheng
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract811)      PDF(pc) (6122KB)(919)       Save
The removal efficiency of Pb by activated carbon filters (ACF) modified by sulfur (ACF/S) was investigated. Two parameters (mass fractions of sulfur and atmosphere of simulated flue gas) were examined for their effects on the removal efficiencies. SEM (scanning electron microscopy) and FTIR (Fourier transform infrared spectroscopy) were used to investigate the mechanism of Pb captured by ACF/S. SEM images indicate that a large quantity of the sulfur is distributed onto the surface of ACF, and aggregation is present. Experimental results show that, the sulfur significantly enhance the ACF performance for Pb removal in different atmosphere of the simulated MSW flue gas (HCl, SO2, HCl+SO2) with efficiencies higher than 65% for particulate lead and 80% for volatile lead. In conclusion, ACF/S is a promising material for Pb removal from flue gas.
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Comparative Study on the Performance of Cordierite-Mullite and Industrial Paraffin Wax in Low-Temperature Energy Recovery
REN Chunrui,LIU Yangsheng,ZENG Hui
Acta Scientiarum Naturalium Universitatis Pekinensis   
Calibrating Group Attachment Scale: An Application of Item Factor Analysis
LI Tonggui,LIU Yang
Acta Scientiarum Naturalium Universitatis Pekinensis   
Effect of Chlorine-Containing Compounds on Evaporation of Heavy Metals in Secondary Gasification of Fly Ash from Municipal Solid Waste Incinerator
Lü Xiaolei,WEI Lin,LIU Yangsheng,ZENG Hui
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract778)      PDF(pc) (3529KB)(604)       Save
The experiment aims to investigate the influence of chlorination agents (NaCl, CaCl2, and FeCl3) on volatilization of heavy metals in fly ash from a Shenzhen municipal solid waste incinerator (MSWI) during thermal treatment by using a tube furnace. The results indicate that these three chlorination agents could promote the evaporation of heavy metal in fly ash with different performance. However, these chlorination agents had different effects on the volatilization of heavy metals. All of Pb and Cr could be almost volatilized without addition of chlorination agents, while chlorination agents addition produced significant effect on the volatilization of Zn and Cu: FeCl3≈ CaCl2> NaCl. The optimal parameters for vaporization were obtained as follows: fly ash with addition of 15% CaCl2 was treated at 1000℃ for 2 hours under the condition of N2 as carrier gas (0.6 L/min).
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Research on Regional Ecological Risk Assessment: A Case Study of Ordos in Inner Mongolia
MENG Jijun,ZHOU Ting,LIU Yang
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract716)      PDF(pc) (4266KB)(601)       Save
A conceptual model of ecological risk assessment is built, which includes the following procedures: to determine the objectives of risk management, to analyze risk probability, to choose appropriate assessment methods, to characterize assessment results, and to make risk management. Ordos, the study area, is located in the farming-grazing transitional zone of northern China. On the basis of Landsat TM images, historical records, survey data and socio-economic statistical data, the authors make the regional ecological risk assessment of Ordos in 2000 and 2008 using the RS, GIS and SPSS. The stressors such as drought, flooding, pollution, strong wind, sandstorm, desertification and soil erosion, are selected as the risk sources. Also, the index system of regional ecological risk assessment is set up. The results are presented as follows. The spatial differentiation of ecological risk level is evident in Ordos. The regions with high risk distribute in the Kubuqi Desert, Waowusu Desert, and Zhungeer and so on, which is directly related to their adverse environmental background and economic activities like large-scale mining. In 2000, the regions with moderate or high risk level mainly lie in the Zhungeer, Dalate, the Kubuqi Desert in Hangjin, and the middle, north, and southwest of Wushen. In 2008, the risk of most areas is lower. However, there are some exceptions, for example, the areas such as the middle and southwest of Dalate Banner, the northwest of Dalate Banner which lies in the Kubuqi Desert and along Yellow River, take higher risk. Dynamically, the risk degree presents a downward trend from 2000 to 2008, which is due to the implementation of various measures concerning eco-environmental construction and restoration. To be specific, the risk of grass and desert ecosystems decreases significantly, so does the farmland and forest. However, the risk of water and urban and rural ecosystems increases.
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Livelihoods of Farming and Grazing Households and Land Use in Farming-Pastoral Transitional Zone: A Case Study of Uxin Banner in Ordos, Inner-Mongolia
ZHU Likai,MENG Jijun,LIU Yang,ZHOU Ping
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract702)            Save
Based on the methods of questionnaire survey, semi-structured interview and mathematical statistics, 153 farming and grazing households in Uxin Banner, situated in Ordos city, Inner-Mongolia, were inquired systematically, and then livelihood strategies, land use pattern of these households were explored. The results are presented as follows. 1)Differences in livelihood strategies exist among distinctive types of households, and therefore income, the degree of living satisfaction, living pressures confronted and improving approaches vary accordingly. The households, engaging in just farming, encounter higher vulnerability and risk due to relatively simple livelihood strategies. Introduction and expansion of non-agricultural activities, and promoting livelihood diversity is a significant approach to reduce livelihood risk for these households. In contrast, households, living on both farming and grazing, confront lower risk as a result of higher and stable income. However, eco-environment is more vulnerable to their production activities. Therefore, developing economic-efficiently and environmental-friendly agro-pastoral industry is the key to address livelihood issues of these households and to protect eco-environment. Furthermore, transferring rural people in grazing regions scientifically, reasonably and effectively is indispensible to mitigate pressure on pasture and to develop modern agro-pastoral industry. 2) Fastening links exist between livelihood and land use types and intensity. Due to the inclination of labor force allocation to non-agricultural industries and the decrease in economic productivity of cropland, the households, engaging in just farming, invest less labors and capital, and so the land-use intensity become lower. In the pastoral area, the cultivated land derives from the reclamation of marginal land, and land users often adjust their investments according to the variations of net profits. When cropland falls into marginalization, grazing households will cease to cultivate. In addition, unreasonable grazing activities give rise to land degradation.
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Spatial Distribution and Mass Inventory of Polybrominated Diphenyl Ethers (PBDEs) in Surface Soil of Shenzhen, China
QIN Peiheng,NI Honggang,LIU Yangsheng,ZENG Hui
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract745)            Save
In order to investigate the polybrominated diphenyl ethers (PBDEs) contamination in typical urban area, a total of 110 surface soil samples were collected and analyzed in the laboratory to explore the spatial distribution and mass inventory in surface soil of Shenzhen, China. The results show that, the concentrations of 6 12 PBDEs and BDE209 in soils ranged from 1. 1 to 85. 8 ng/ g ( dw) and from 1.2 to 1931 ng/g (dw), respectively. The mean concentrations of 6 13 PBDEs in soils of different land-use types decreased in the following sequence: industrial area > residential area > commercial area > urban park > country park, and the wide spread usage of deca-BDE in Shenzhen manufacturing industry resulted in the high soil contamination in industrial area. Soil PBDEs contaminations in Nanshan District and Baoan District (in the west of Shenzhen) , were more serious than that in Longgang District and Yantian District ( in the southeast of Shenzhen). Additionally, the 6 13 PBDEs levels in soils had a significant exponent relationship with the build-up area percentage in different districts (r = 0. 98, p < 0. 01) , suggesting that the urbanization level was the key factor influencing the soil contamination. The mass inventories of 6 12 PBDEs and BDE209 in soils of Shenzhen were estimated at 1. 51 tons and 15. 9 tons, respectively, based on the variety of PBDEs concentration levels in different land use areas.
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Investigation of Heavy Metals Pollution in Predominant Plants around a Municipal Solid Waste Incineration Plant: A Case Study in Shenzhen Qingshuihe MSWI Plant
ZHONG Xiuping,WANG Junjian,ZHAO Hongwei,LIU Yangsheng,ZENG Hui
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract933)            Save
To investigate heavy metals (HMs) pollution in the different kinds of plants including trees, shrubs and herbs resulting from municipal solid waste incineration (MSWI), leaf samples in 34 species of 22 families around the Shenzhen Qingshuihe MSWI plant were collected. The levels and bioaccumulation factors of mercury (Hg), chromium (Cr), cadmium (Cd) and lead (Pb) in the leaves were determined. Results show that, these plants were polluted by HMs and the characteristics of pollution were different among trees, shrubs and herbs. Trees were mainly polluted by Cr, while shrubs and herbs by Hg. Significant differences ( Pt ≤ 0. 028) were observed in concentrations and bioaccumulation factors between trees and shrubs, and also between trees and herbs. The potential species for different HM pollution remediation are recommended as follows: 1) for Hg, the tree plants of Acacia auriculif ormis and Eucalyptus citriodora; 2) for Cr, the herb of Miscanthus floridulus and the shrub of Bougainvillea spectabilis; 3) for Cd, the shrub of Ilex asprella and tree of Acronychiapedunculata; and 4) for Pb, the herbs of Oxalis corniculata and Dicranopteris dichotoma. Consequently, building a multi-level botanical structure consisting of trees, shrubs and herbs is helpful to phytoremediate the pollution of heavy metals.
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