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Chinese Geographical Science 2015年第4期25卷 486-497页

作者： LI linshan ma Yanji Northeast Institute of Geography and Agroecology Chinese Academy of Sciences University of Chinese Academy of Sciences

The primary object of this paper is to examine the spatial-temporal pattern evolution of manufacturing geographical agglomeration of the old industrial *** spatial agglomeration index and concentration ratio are used in this *** linear regression models are also applied to try to explore the internal driving mechanisms on manufacturing geographical *** results show that:1) the manufacturing agglomeration degree of Jilin Province is increasing *** spatial polarization structure is visible;and the central region is the agglomeration area,in addition,the manufacturing industries of Changchun Proper present a trend of dispersion;2) the structure of manufacturing industries has changed,and the concentration ratio of labor-intensive manufacturing industry is declining,while the proportions of technology-intensive and capital-intensive manufacturing industry are relatively rising;3) marketing level,location accessibility,labor resources,capital,science and technology innovation capability,scale economy and the level of globalization affect manufacturing agglomeration with different *** are significant differences of the effects about employment,technology,the quality of residents and the export-oriented market on the industrial concentration ratio;4) in the future,the impact of policy and institution,export-oriented market and quality of resident on manufacturing geographical agglomeration pattern will be more profound.

关键词： old industrial base manufacturing geographical agglomeration industrial spatial agglomeration index concentration ratio Jilin Province China

Closed Strong Spacelike Curves, Fenchel Theorem and Plateau Problem in the 3-Dimensional Minkowski Space

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Chinese Annals of mathematics,Series B 2019年第2期40卷 217-226页

作者： Nan YE Xiang ma College of mathematics and Econometrics Hunan University LmaM School of Mathematical Sciences Peking University

The authors generalize the Fenchel theorem for strong spacelike closed curves of index 1 in the 3-dimensional Minkowski space, showing that the total curvature must be less than or equal to 2π. Here the strong spacelike condition means that the tangent vector and the curvature vector span a spacelike 2-plane at each point of the curve γ under consideration. The assumption of index 1 is equivalent to saying that γ winds around some timelike axis with winding number 1. This reversed Fenchel-type inequality is proved by constructing a ruled spacelike surface with the given curve as boundary and applying the Gauss-Bonnet formula. As a by-product, this shows the existence of a maximal surface with γ as the boundary.

关键词： Fenchel theorem Spacelike curves Total curvature maximal surface

On arithmetic properties of Cantor sets

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Science China mathematics 2022年第10期65卷 2035-2060页

作者： Lu Cui Minghui ma Academy of mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China School of mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

In this paper,we study three types of Cantor *** any integer m≥4,we show that every real number in[0,k]is the sum of at most k m-th powers of elements in the Cantor ternary set C for some positive integer k,and the smallest such k is 2~***,we generalize this result to the middle-1/αCantor set for1mage W of the Cantor dust C×C into the complex plane C,we prove that for any integer m≥3,every element in the closed unit disk in C can be written as the sum of at most 2^(m+8)m-th powers of elements in *** last,some similar results on p-adic Cantor sets are also obtained.

关键词： Cantor ternary set Cantor dust p-adic Cantor set Waring's problem

Remote sensing data classification using tolerant rough set and neural networks

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Science China Earth Sciences 2005年第12期48卷 2251-2259页

作者： ma Jianwen HASI Bagan State Key Laboratory of Remote Sensing Science Institute of Remote Sensing Applications Chinese Academy of Sciences Beijing 100101 China State Key Laboratory of Remote Sensing Science Institute of Remote Sensing Applications Chinese Academy of Sciences Beijing 100101 China

BP algorithm of neural net is used more in remote sensing data classification. One of drawbacks of BP algorithm is the overall low function when the net is training. To avoid this kind of problem, the paper introduces the tolerant rough set for classification-preprocessing the training data to reduce the influence elements of the training convergence in order to improve the net training successful rate. ETM+ data of Beijing in may 2003 is selected in the study. ETM+ data before and after classification preprocessing, respectively, are used for BP (Back propaga-tion) training. The result shows that such a preprocessing not only compensates the drawback of BP algorithm when processing ETM+ data but also improves classification accuracy.

关键词： tolerant rough set, neural network, BP algorithm, classification.

Torsions of 3-Dimensional Small Covers

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Chinese Annals of mathematics,Series B 2017年第6期38卷 1311-1320页

作者： Jiming ma Fangting ZHENG School of mathematical Sciences Fudan UniversityShanghai 200433China

In this paper, it is shown that for a 3-dimensional small cover M over a polytope P, there are only 2-torsions in H_1(M; Z). Moreover, the mod 2 Betti number growth of finite covers of M is studied.

关键词： Mod 2 Betti number growth Small cover Hyperbolic manifolds

Three-dimensional graphene networks: synthesis,properties and applications

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National Science Review 2015年第1期2卷 40-53页

作者： Yanfeng ma Yongsheng Chen Key Laboratory of Functional Polymer materials and the Centre of Nanoscale Science and TechnologyInstitute of Polymer ChemistryCollege of ChemistryNankai University

Recently, three-dimensional graphene/graphene oxide(GO) networks(3DGNs) in the form of foams,sponges and aerogels have atracted much atention. 3D structures provide graphene materials with high speciic surface areas, large pore volumes, strong mechanical strengths and fast mass and electron transport,owing to the combination of the 3D porous structures and the excellent intrinsic properties of *** review focuses on the latest advances in the preparation, properties and potential applications of 3D micro-/nano-architectures made of graphene/GO-based networks, with emphasis on graphene foams and sponges.

关键词： graphene graphene oxide three-dimensional network graphene foam graphene sponge graphene aerogel

Generalized binary discernibility matrix for attribute reduction in incomplete information systems

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The Journal of China Universities of Posts and Telecommunications 2017年第4期24卷 57-68,75页

作者： ma Fumin Zhang Tengfei College of Information Engineering Nanjing University of Finance and Economics College of Automation Nanjing University of Posts and Telecommunications

To extract and express the knowledge hidden in information systems, discernibility matrix and its extensions were introduced and applied successfully in many real life applications. Binary discernibility matrix, as a representative approach, has many interesting superior properties and has been rapidly developed to find intuitive and easy to understand knowledge. However, at present, the binary discernibility matrix is mainly adopted in the complete information system. It is a challenging topic how to achieve the attribute reduction by using binary discernibility matrix in incomplete information system. A form of generalized binary discernibility matrix is further developed for a number of representative extended rough set models that deal with incomplete information systems. Some useful properties and criteria are introduced for judging the attribute core and attribute relative reduction. Thereafter, a new algorithm is formulated which supports attribute core and attribute relative reduction based on the generalized binary discernibility matrix. This algorithm is not only suitable for consistent information systems but also inconsistent information systems. The feasibility of the proposed methods was demonstrated by worked examples and experimental analysis.

关键词： rough set generalized binary discernibility matrix attribute relative reduction incomplete information system

Seasonal Dynamics of Nitrogen and Phosphorus in Water and Sediment of A Multi-level Ditch System in Sanjiang Plain,Northeast China

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Chinese Geographical Science 2011年第4期21卷 437-445页

作者： GUO Le ma Keming State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China

The multi-level ditch system developed in the Sanjiang Plain,Northeast China has sped up water drainage process hence transferred more pollutants from farmlands into the rivers of this *** the seasonal dynamics of nitrogen (N) and phosphorus (P) transportation in the ditch system and the role of different ditch size is thus crucial for water pollution control of the rivers in the Sanjiang *** this study,an investigation was conducted in the Nongjiang watershed of the Sanjiang Plain to study the nutrient variation and the correlation between water and sediments in the ditch system in terms of ditch *** and sediments samples were collected in each ditch level in growing season at regular intervals (once per month),and TN,NO 3--N,NH 4+-N,TP,and PO 4 3--P were *** results show that nutrient contents in water were higher in June and July,especially in July,the contents of TN and TP were 3.21mg/L and 0.84mg/L in field ditch,4.04mg/L and 1.06mg/L in lateral ditch,2.46mg/L and 0.70mg/L in branch ditch,1.92mg/L and 0.63mg/L in main ditch,*** August and September,the nutrient contents in the water were relatively *** peak value of nutrient in ditch water had been moving from the field ditch to the main ditch over time,showing a remarkable impact of ditch system on river water *** nutrient transfer in ditch sediments could only be found in rainfall *** contents in ditch sediment had effect on that in ditch water,but nutrients in ditch water and sediments had different *** management in terms of the key fac-tors is hence very important for protecting river water environment.

关键词： multi-level ditch system nitrogen phosphorus spatio-temporal variation drainage water sediment

Clinical evaluation of sintilimab in conjunction with bevacizumab for advanced colorectal cancer with microsatellite stable-type after failure of first-line therapy

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World Journal of Gastrointestinal Surgery 2024年第10期16卷 3277-3287页

作者： Liang Wang Yong-Zhi Diao Xin-Fu ma yu-Shuang Luo Qi-Jing Guo Xiao-Qian Chen Department of Gastrointestinal Oncology Surgery Affiliated Hospital of Qinghai UniversityXining 810000Qinghai ProvinceChina Department of Gastroenterology The First People’s Hospital of XiningXining 810000Qinghai ProvinceChina Department of Medical Oncology Affiliated Hospital of Qinghai UniversityXining 810000Qinghai ProvinceChina

BACKGROUND At present,immune checkpoint inhibitors(ICIs)remain the 1st-line therapy me-thod for patients suffering from high microsatellite instability/deficient misma-tch repair metastatic colorectal cancer(mCRC).However,ICI treatments demon-strate minimal therapeutic efficacy against microsatellite stable(MSS)/proficient mismatch repair(pMMR)*** is mainly because this type of tumor is a“cold tumor”with almost no lymphocyte ***-angiogenic drugs have been found to improve the immune microenvironment by promoting many immune cells to enter the immune microenvironment,thereby exerting anti-tumor *** To investigate the effects of ICIs combined with bevacizumab monoclonal anti-body on tumor immune cells in MSS/pMMR advanced CRC patients with first-line treatment *** A total of 110 MSS/pMMR patients with advanced CRC after first-line treatment failure in the Affiliated Hospital of Qinghai University were enrolled for a ran-domized controlled *** short,patients in the experimental group(n=60)were given sintilimab plus bevacizumab for 4 cycles,and those in the control group(n=50)patients were treated with FOLFIRI combined with bevacizumab for 4 *** expression levels of cluster of differentiation(CD)8(+)T cells,tumor-associated macrophages(TAMs),and cancer-associated fibroblasts(CAFs)were comprehensively evaluated to assess the effects of sintilimab combined with bevacizumab on MSS/pMMR advanced CRC sufferers following failure of 1st-line *** The positive expression rates of CD8(+)T lymphocytes(30%vs 50%),TAMs(23.30%vs 60%),and CAFs(23.30%vs 50%)before and after treatment in both groups exhibited statistical significance(P<0.05).Additionally,the therapeutic effects of both groups(partial remission:26.67%vs 10%;objective response rate:26.70%vs 10%)were significantly different(P<0.05).Although the experimental group showed a higher progression-free survival,median progression-free survival,and disease control rate

关键词： Immune checkpoint inhibitors Bevacizumab Colorectal cancer Cytotoxic T lymphocytes Tumor-associated macrophages Cancer-associated fibroblasts

Detection of human leukocyte antigen compatibility and antibodies in liver transplantation in China

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Hepatobiliary & Pancreatic Diseases International 2009年第2期8卷 141-145页

作者： Meng, Xue-Qin Zhang, Xuan Fan, Jun Zhou, lin Hao, Bing Chen, Xiao-Ming ma, Wei-Hang Zheng, Shu-Sen Zhejiang Univ Sch Med Affiliated Hosp 1 Key Lab Combined Multiorgan TransplantatMinist P Hangzhou 310003 Zhejiang Peoples R China Zhejiang Univ Sch Med Affiliated Hosp 1 State Key Lab Diag & Treatment Infect Dis Hangzhou 310003 Zhejiang Peoples R China

BACKGROUND: The exact roles of human leukocyte antigen (HLA) compatibility, HLA antibodies and underlying diseases in acute rejection of liver transplants are not clear. Moreover, cytomegalovirus (CMV) infection, one of the most common infections after transplantation, is related to HLA genotype and the incidence of acute rejection. METHODS: Since there are controversial reports, we analyzed the impact of HLA matching, HLA antibodies and underlying diseases in 38 liver transplant recipients in China, and assessed the association of CMV infection and HLA compatibility. RESULTS: The frequency of no HLA compatibility was high in patients without antigenemia (P=0.019). All 17 patients with HLA-A matching developed antigenemia (Pmatches were not found in patients with acute rejection (P0.05). In patients with acute rejection, no differences were found in the incidence of acute rejection in transplants for hepatitis 13, tumors, or combined hepatitis B and tumors (P>0.05). CONCLUSIONS: There are fewer acute rejections in transplants with more HLA compatibilities. Specific investigations of underlying diseases and HLA typing may be necessary in liver transplantation. The mechanisms of CMV infection and HLA matching should be further studied. HLA before transplantation should be examined for the prevention of acute rejection and CMV infection.

关键词： HLA matching HLA antibodies cytomegalovirus liver transplantation