检索结果-南通市图书馆

Comprehensive understanding of glioblastoma molecular phenotypes:classification,characteristics,and transition

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Cancer Biology & Medicine 2024年第5期21卷 363-381页

作者： Can Xu Pengyu Hou Xiang li Menglin Xiao Ziqi Zhang Ziru li Jianglong Xu Guoming liu yanli Tan Chuan fang School of Clinical Medicine Hebei UniversityDepartment of NeurosurgeryAffiliated Hospital of Hebei UniversityBaoding 07100China Hebei Key Laboratory of Precise Diagnosis and Treatment of Glioma Baoding 071000China School of Basic Medical sciences Hebei UniversityBaoding 07100China Department of Pathology Affiliated Hospital of Hebei UniversityBaoding 07100China

Among central nervous system-associated malignancies,glioblastoma(GBM)is the most common and has the highest mortality *** high heterogeneity of GBM cell types and the complex tumor microenvironment frequently lead to tumor recurrence and sudden relapse in patients treated with *** precision medicine,research on GBM treatment is increasingly focusing on molecular subtyping to precisely characterize the cellular and molecular heterogeneity,as well as the refractory nature of GBM toward *** understanding of the different molecular expression patterns of GBM subtypes is *** have recently proposed tetra fractional or tripartite methods for detecting GBM molecular *** various molecular subtypes of GBM show significant differences in gene expression patterns and biological *** subtypes also exhibit high plasticity in their regulatory pathways,oncogene expression,tumor microenvironment alterations,and differential responses to standard ***,we summarize the current molecular typing scheme of GBM and the major molecular/genetic characteristics of each ***,we review the mesenchymal transition mechanisms of GBM under various regulators.

关键词： Glioblastoma molecular phenotype classification characteristic mesenchymal transition

Universal synthesis of metallophthalocyanine covalent organic frameworks as ultra-sensitive multifaceted electrochemical sensor

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2024年第6期67卷 2092-2101页

作者： Qi liu Qiqi Sun Yuming Zhang Hao li Wenmiao Chen Yuexing Zhang Sirong Yu yanli Chen Jianzhuang Jiang School of Materials Science and Engineering China University of Petroleum(East China)Qingdao266580China beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials School of Chemistry and Biological EngineeringUniversity of Science and Technology BeijingBeijing100083China College of Chemistry and Chemical Engineering Dezhou UniversityDezhou253023China

The universal synthesis of highly stable covalent organic frameworks(COFs)for ultra-sensitive and multi-component electrochemical detection in different scenarios remains a great ***,a series of metallophthalocyanine-based twodimensional(2D)dioxin(DXI)-linked metalophthalocyanine(MPc)-n DXI-COFs(M=Ni,Zn;n=1,2)are afforded in high yield(80%-96%)by a facile trace-quinoline assisted one-pot condensation of tetracarbonitrile *** X-ray diffraction and electron microscopy investigations disclose their lamellar texture 2D network with AA stacking *** and calculation results elucidate that the 2DXI-linked MPc-2DXI-COFs provide the stronger built-in electronic field and more electrostatic/hydrogen bonding adsorption sites than DXI-linked MPc-DXI-COFs,and the lower electrode reaction Gibbs free energy and stronger adsorption of analytes at Ni Pc than Zn Pc unit,which grants Ni Pc-2DXI-COF excellent sensing properties for various analytes including neurotransmitters,organic pollutants,and heavy metal ions,with high sensitivity and low detection limit of 0.53 to 25.66 *** in binary and ternary systems and even in real-world conditions,simultaneous multi-component detection could be achieved.

关键词： covalent organic framework metallophthalocyanine 2D materials electrochemical sensors multi-component detection

Application of three-dimensional discrete element face-to-face contact model with fissure water pressure to stability analysis of landslide in Panluo iron mine

在线全文

学校读者我要写书评

暂无评论

Science china(Technological sciences) 2005年第z1期48卷 146-156页

作者： ZHANG Lei1,2, WEI Zuoan1, liu Xiaoyu1 & li Shihai1 1.institute of Mechanics, chinese academy of sciences, beijing 100080, china 2.Graduate School, chinese academy of sciences, beijing 100060, china chinese Acad Sci Inst Mech Beijing 100080 Peoples R China chinese Acad Sci Grad Sch Beijing 100060 Peoples R China

Three-dimensional discrete element face-to-face contact model with fissure water pressure is established in this paper and the model is used to simulate three-stage process of landslide under fissure water pressure in the opencast mine, according to the actual state of landslide in Panluo iron mine where landslide happened in 1990 and was fathered in 1999. The calculation results show that fissure water pressure on the sliding surface is the main reason causing landslide and the local soft interlayer weakens the stability of slope. If the discrete element method adopts the same assumption as the limit equilibrium method, the results of two methods are in good agreement; while if the assumption is not adopted in the discrete element method, the critical φ numerically calculated is less than the one calculated by use of the limit equilibrium method for the sameC. Thus, from an engineering point of view, the result from the discrete element model simulation is safer and has more widely application since the discrete element model takes into account the effect of rock mass structures.

关键词： face-to-facecontactmodel, fissure water pressure, three-dimensional discrete element method,landslide.

An unprecedented synthesis of axially chiral biaryls by rearrangement and aromatization of carbocations with central-to-axial conversion of chirality

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2024年第9期67卷 2998-3003页

作者： Qi liu Xue-Dong li liang Cheng li liu beijing National Laboratory for Molecular sciences(BNLMS) CAS Key Laboratory of Molecular Recognition and FunctionCAS Research/Education Center for Excellence in Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of chinese academy of sciences Beijing 100049China

The central-to-axial chirality conversion represents a fascinating class of chemical processes consisting of the destruction of stereogenic centers and the simultaneous installation of axial chiral elements,which provides efficient methods for the preparation of axially chiral ***,developing catalytic asymmetric approaches for constructing these central chirality precursors and the efficient central-to-axial chirality conversion remains a challenge due to the requirement of aromatization or elimination *** this work,we have developed an unprecedented enantioselective intramolecular FriedelCrafts alkylation with unactivated-ketone carbonyls from which a chiral tertiary alcohol was generated with high efficiency and excellent *** addition,the central-to-axial chirality conversion strategy has been successfully applied to the synthesis of enantioenriched biaryls via a less-explored carbocation-initiated rearrangement and aromatization under the promotion of Lewis *** methodology provided a straightforward and sustainable access to a broad range of biaryl-2-carboxylic acid and in excellent yields(up to 92%)and excellent central-to-axial chirality conversion(up to 99%conversion percentage).This work could be a great model for developing new methods for synthesizing axially chiral biaryls and a general protocol for the rearrangement and aromatization of carbocations for further functionalization.

关键词： br?nsted acid catalysis desymmetrization phosphoric acid axially chiral biaryls central-to-axial conversion

Monaural voiced speech segregation based on elaborate harmonic grouping strategies

在线全文

学校读者我要写书评

暂无评论

Science china(Information sciences) 2011年第12期54卷 2491-2500页

作者： liu WenJu 1 , ZHANG Xueliang 1 , JIANG Wei 1 , li Peng 2 & XU Bo 2 1 National Laboratory of Pattern Recognition, institute of Automation, chinese academy of sciences, beijing 100190, china 2 Digital Media Content Technology Research Center, institute of Automation, chinese academy of sciences, beijing 100190, china 1. National Laboratory of Pattern Recognition Institute of Automation Chinese Academy of Sciences Beijing 100190 China2. Digital Media Content Technology Research Center Institute of Automation Chinese Academy of Sciences Beijing 100190 China

In this paper, an enhanced algorithm based on several elaborate harmonic grouping strategies for monaural voiced speech segregation is proposed. Main achievements of the proposed algorithm lie in three aspects. Firstly, the algorithm classifies the time-frequency (T-F) units into resolved and unresolved ones by carrier-to-envelope energy ratio, which leads to more accurate classification results than by cross-channel correlation. Secondly, resolved T-F units are grouped together according to minimum amplitude principle, which has been verified to exist in human perception, as well as the harmonic principle. Finally, "enhanced" envelope autocorrelation function is employed to detect amplitude modulation rates, which helps a lot in reducing half-frequency error in grouping of unresolved units. Systematic evaluation and comparison show that performance of separation is greatly improved by the proposed algorithm. Specifically, signal-to-noise ratio (SNR) is improved by 0.96 dB compared with that of previous method. Besides, our algorithm is also effective in improving the PESQ score and subjective perception score.

关键词： computational auditory scene analysis voiced speech separation harmonistic principle minimum amplitude principle elaborate harmonic grouping strategies

Experimental study of composite medium with simultaneously negative permeability and permittivity

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2004年第1期47卷 64-78页

作者： SUI Qiang1, 2 & li fang1 1. institute of electronics, chinese academy of sciences, beijing 100080, china 2. School of Information, beijing Broadcasting institute, beijing 100024, china Correspondence should be addressed to Sui Qiang (email: suiqiang@***) Received July 28, 2003 1. institute of electronics Chinese Academy of Sciences 100080 Beijing China 2. School of Information Beijing Broadcasting Institute 100024 Beijing China

This paper focuses on a composite medium structure that exhibits simultan- eously negative values of effective permeability and permittivity, and our experimental study in an anechoic chamber. The experiment results show that the artificial medium, based on a periodic array of interspaced conducting nonmagnetic split ring resonators and continuous metallic wires, can have a simultaneously negative effective permeability and permittivity within a frequency region in the microwave regime under certain linearly polarized waves.

关键词： permittivity, permeability, negative index of refraction, split ring resonator, LHM, RHM.

Design and performance investigation of modified dual reflector parabolic trough collector with double planar mirrors

在线全文

学校读者我要写书评

暂无评论

Science china(Technological sciences) 2024年第3期67卷 902-918页

作者： li Peijing liu TaiXiu QIN YuanLong li JiChao liu QiBin School of Energy Powerand Mechanical EngineeringNorth China Electric Power University Beijing 226China institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China University of chinese academy of sciences Beijing 100049China Department of Thermal Science and Energy Engineering University of Science and Technology of ChinaHefei 230027China

In a typical parabolic trough collector(PTC), sunlight is concentrated at the bottom of the absorber tube. This concentrated solar flux leads to uneven heat distribution, resulting in high local temperatures and significant thermal stress on the absorber *** limitations have restricted the application of PTCs in solar thermochemistry and other fields and have impacted their safe operation. In this study, a new PTC with dual planar mirrors(DPMS) is proposed to homogenize the circumferential solar flux distribution of the absorber tube. A design method and single-objective optimization of the new PTC with a DPMS are proposed,and an uncertainty analysis of the operational and structural parameters is performed. A coupled light-heat-structure numerical model was developed to study the heat transfer performance and structural mechanical properties. The thermodynamic properties of the PTC with DPMS under different boundary conditions were analyzed. The results show that the circumferential temperature difference of the new PTC is within 2.6 K, and the circumferential thermal deformation is within 0.9 mm under typical working conditions(the inlet velocity of the heat transfer fluid is 3 m/s, inlet temperature is 573.15 K, and the direct normal irradiance is 1000 W/m^(2)). Compared with conventional PTCs, the circumferential temperature difference is reduced by 74%–90%, and the maximum thermal deformation along the y-axis is reduced by more than 95% under all working conditions(1–5 m/s, 373.5–675.15 K, 200–1000 W/m^(2)). The new PTC maintains the uniformity of the circumferential solar flux distribution for different operating parameters(sun incident angle of 0°–3°) and installation errors(±3 mm), is suitable for solar energy applications in various fields, and has the potential for large-scale applications.

关键词： solar thermal energy parabolic trough collector secondary reflector solar flux distribution optical optimization

Experimental investigation on a parabolic trough solar collector for thermal power generation

在线全文

学校读者我要写书评

暂无评论

Science china(Technological sciences) 2010年第1期53卷 52-56页

作者： liu QiBin1,WANG YaLong1,2,GAO ZhiChao1,2,SUI Jun1,JIN HongGuang1 & li HePing3 1 institute of Engineering Thermophysics,chinese academy of sciences,beijing 100190,china 2 Graduate University of chinese academy of sciences,beijing 100049,china 3 china Huadian Engineering Co.,Ltd,beijing 100044,china 1. institute of Engineering Thermophysics Chinese Academy of Sciences Beijing 100190 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China3. China Huadian Engineering Co. Ltd Beijing 100044 China

Developing solar thermal power technology in an effective manner is a great challenge in *** this paper an experiment platform of a parabolic trough solar collector system(PTCS) was developed for thermal power generation,and the performance of the PTCS was experimentally investigated with synthetic oil as the circulate heat transfer fluid(HTF).The solar collector's efficiency with the variation of the solar flux and the flow rate of the HTF was *** collector efficiency of the PTCS can be in the range of 40%-60%.It was also found that there existed a specified delay for the temperature of the HTF to response to the solar flux,which played a significant role in designing the *** heat loss effect on collector efficiency was also studied,which was about 220 W/m for the receiver with a 180°C temperature difference between the collector temperature and the ambient temperature,amounting to about 10% of the total solar energy incident on the *** encouraging results can provide fundamental data for developing the parabolic trough solar thermal power plant in china.

关键词： solar energy parabolic trough solar collector collector efficiency lag behind heat loss

Optimal Design of the Modular Joint Drive Train for Enhancing Cobot Load Capacity and Dynamic Performance

在线全文

学校读者我要写书评

暂无评论

chinese Journal of Mechanical Engineering 2024年第3期37卷 26-40页

作者： Peng li Zhenguo Nie Zihao li Xinjun liu Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China beijing Key Lab of Precision/Ultra-precision Manufacturing Equipments and Control Tsinghua UniversityBeijing 100084China

Automation advancements prompts the extensive integration of collaborative robot(cobot)across a range of *** to the commonly used design approach of increasing the payload-to-weight ratio of cobot to enhance load capacity,equal attention should be paid to the dynamic response characteristics of cobot during the design process to make the cobot more *** this paper,a new method for designing the drive train parameters of cobot is ***,based on the analysis of factors influencing the load capacity and dynamic response characteristics,design criteria for both aspects are established for cobot with all optimization design criteria normalized within the design ***,with the cobot in the horizontal pose,the motor design scheme is discretized and it takes the joint motor diameter and gearbox speed ratio as optimization design ***,all the discrete values of the optimization objectives are obtained through the enumeration method and the Pareto front is used to select the optimal solution through multi-objective *** on the cobot design method proposed in this paper,a six-axis cobot is designed and compared with the commercial *** result shows that the load capacity of the designed cobot in this paper reaches 8.4 kg,surpassing the 5 kg load capacity commercial cobot which is used as a *** minimum resonance frequency of the joints is 42.70 Hz.

关键词： Multi-objective optimization Modular joint drive train design Load capacity Dynamic response performance