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SYNTHESIS AND CHARACTERIZATION OF NOVEL REACTIVE POLYORGANOSILOXANE CONTAINING NITRO GROUPS

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Chinese Journal of Polymer Science 2001年第1期19卷 1-6页

作者： chun-qing liu Yang liu Ping Xie Rong-ben Zhang Chao-bin He Neal Tai-shung chung PCLCC Center for Molecular Science Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China PCLCCCenter for Molecular Science Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China PCLCCCenter for Molecular Science Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China PCLCCCenter for Molecular Science Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China Institute of Materials Research and Engineering National University of Singapore Singapore 119260 Institute of Materials Research and Engineering National University of Singapore Singapore 119260

A novel reactive polyorganosiloxane containing nitro groups was first prepared by acid-catalyzed equilibration polymerization. The monomer, 3-(4-nitrophenoxy)propylmethyldichlorosilane (NPPMS), was synthesized by hydrosilylation reaction with dicyciopentadienylplatinum(II) chloride (Cp2PtCl2) catalyst in high yield. The synthesized polynitroorganosiloxane, which has potential application as a precursor for synthesizing advanced functional polymers, was characterized by FTIR, H-1-NMR, C-13-NMR, Si-29-NMR, vapor pressure osmometry (VPO) and gel permeation chromatography(GPC).

关键词： polyorganosiloxane equilibration polymerization hydrosilylation characterization

Cathepsin B protease is required for metamorphism in silkworm, Bombyx moil

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Insect Science 2008年第3期15卷 201-208页

作者： Gen-Hong Wang chun liu qing-You Xia Xing-Fu Zha Jie Chen Liang Jiang Key Sericultural Laboratory of the Agricultural Ministry College of Biotechnology Southwest University Chongqing China

Cathepsin B belongs to lysosomal cysteine protease of the papain family. Temporal and spatial expression analysis of cathepsin B of Bombyx mori （BmCtB） was carried out based on Expression Sequence Tags （ESTs） data, oligonucleotide microarray, reverse transcription polymerase chain reaction （RT-PCR） and quantitative real-time PCR. Expression of BmCtB was observed in all of the tissues and stages. Among the 10 tested tissues, the fat body and posterior silk gland are the two most enriched tissues with BmCtB. During Bombyx development, there was an expression fastigium of BmCtB during metamorphosis. RNA interference was used to suppress the expression of cathepsin B during metamorphosis. Significant developmental defective phenotypes were obtained in the RNAi treated group. The dramatically reduced expression of BmCtB was con^rmed by Northern blot and quantitative real-time PCR. These evidences strongly suggest cathepsin B proteinase was predominantly involved in the metabolism process of fat body and the posterior silk gland and was critical for metamorphism and development of silkworm, Bombyx mori.

关键词： cathepsin B RNA interference quantitative real-time PCR Bombyx mori

SYNTHESIS AND CHARACTERIZATION OF A NOVEL ALCOHOL-SOLUBLE POLYORGANOSILOXANE CONTAINING AMINO SIDE GROUPS

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Chinese Journal of Polymer Science 2001年第1期19卷 97-102页

作者： chun-qing liu Yang liu Zhong-rong Shen Ping Xie Rong-ben Zhang Chao-bin He Tai-shung chung PCLCC Center for Molecular Science Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China PCLCCCenter for Molecular Science Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China PCLCCCenter for Molecular Science Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China PCLCCCenter for Molecular Science Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China PCLCCCenter for Molecular Science Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China Institute of Materials Research and Engineering National University of Singapore Singapore 119260 Institute of Materials Research and Engineering National University of Singapore Singapore 119260

A novel alcohol-soluble polyorganosiroxane containing amino side groups, poly[3-(4-aminophenoxy)-aminophenoxy) propylmethylsiloxane] (2), was first prepared by the reduction of nitro groups on 4-nitrophenoxypropyl side chains of poly[3-(4-nitrophenoxy)propylmethylsiloxane] (1). The reaction proceeded easily with nearly 100% conversion. The synthesized alcohol-soluble polymer 2, which has potential application as a precursor for preparing advanced functional polymers, was characterized by FTIR, H-1-NMR, C-13-NMR, Si-29-NMR, VPO and GPC, respectively.

关键词： alcohol-soluble polyorganosiloxane reduction characterization

ARCHITECTURE OF LADDER,TUBULAR AND SIEVE-PLATE POLYMERS PREPARED BY STEPWISE COUPLING POLYMERIZATION

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Chinese Journal of Polymer Science 2000年第3期18卷 195-206页

作者： Rong-ben Zhang Ping Xie Dao-rong Dai chun-qing liu Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China 中科院化学所北京

'Stepwise-coupling polymerization' (SCP) is a very useful approach for preparing microstructure-controllable ordered network polymers, including soluble one-dimensional ladderlike polymers (LP) and tubular polymers (TP), and two-dimensional sieve-plate polymers. The novel reactive LPs are important precursors of micro-structure controllable polymers such as 'fishbone-' or 'rowboat-' like mesomorphic polymers and their metal complexes as well as tubular polymers (TPs). They are full of great potential for use as advanced materials.

关键词： stepwise coupling polymerization ladder polysiloxane tubular polymers

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The effects of various factors on spontaneous imbibition in tight oil reservoirs

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Petroleum Science 2024年第1期21卷 315-326页

作者： Cheng liu Tian-Ru Wang qing You Yue-chun Du Guang Zhao Cai-Li Dai School of Energy Resources China University of GeosciencesBeijing100083PR China School of Petroleum Engineering China University of PetroleumQingdao266580ShandongPR China

Slickwater fracturing fluids have gained widespread application in the development of tight oil reservoirs. After the fracturing process, the active components present in slickwater can directly induce spontaneous imbibition within the reservoir. Several variables influence the eventual recovery rate within this procedure, including slickwater composition, formation temperature, degree of reservoir fracture development, and the reservoir characteristics. Nonetheless, the underlying mechanisms governing these influences remain relatively understudied. In this investigation, using the Chang-7 block of the Changqing Oilfield as the study site, we employ EM-30 slickwater fracturing fluid to explore the effects of the drag-reducing agent concentration, imbibition temperature, core permeability, and core fracture development on spontaneous imbibition. An elevated drag-reducing agent concentration is observed to diminish the degree of medium and small pore utilization. Furthermore, higher temperatures and an augmented permeability enhance the fluid flow properties, thereby contributing to an increased utilization rate across all pore sizes. Reduced fracture development results in a lower fluid utilization across diverse pore types. This study deepens our understanding of the pivotal factors affecting spontaneous imbibition in tight reservoirs following fracturing. The findings act as theoretical, technical, and scientific foundations for optimizing fracturing strategies in tight oil reservoir transformations.

关键词： Tight oil reservoir Spontaneous imbibition Nuclear magnetic resonance Slickwater fracturing fluid Fluid utilization degree

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Modeling of LF refining process:a review

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Journal of Iron and Steel Research International 2024年第2期31卷 289-317页

作者： Zi-cheng Xin Jiang-shan Zhang Kai-xiang Peng Jun-guo Zhang chun-hui Zhang qing liu State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing100083China School of Automation and Electrical Engineering University of Science and Technology BeijingBeijing100083China Tangshan Branch Hebei Iron and Steel Co.Ltd.Tangshan063000HebeiChina Xinjiang Bayi Iron and Steel Co. Ltd.Baosteel GroupWulumuqi830022XinjiangChina

With the increasing demand for energy conservation and emission reduction,more attentions have been paid to the intelligentization,greenization and low carbonization during the transformation and upgrading of steelmaking *** furnace(LF)refining is one of the key procedures in steelmaking process and has been widely used in steelmaking plants for its high equipment matching degree,low equipment investment and outstanding refining *** to the main tasks of LF refining process,the modeling methods of temperature prediction model,slag-making model,alloying model,argon blowing model and model of inclusions behavior were systematically reviewed,and the advantages and disadvantages of each modeling method were *** addition,the technical framework for the future has also been proposed based on existing works,including classification of raw materials,graphic representation of knowledge,introduction,upgradation and management of device/equipment,customization of steelmaking,modeling of refining process,synergy of models,intelligentization of decision-making,automation of control,and digitization of processes and operations,aiming to provide a reference for the modeling and intelligent development of LF refining process.

关键词： LF refining Temperature prediction Slag-making Alloying Argon blowing Inclusion behavior Modeling method

Design parameter optimization method for a prestressed steel structure driven by multi-factor coupling

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Frontiers of Structural and Civil Engineering 2024年第7期18卷 1066-1083页

作者： Guo-Liang SHI Zhan-Sheng liu De-chun LU qing-Wen ZHANG Majid DEZHKAM Ze-Qiang WANG Faculty of Architecture Civil and Transportation EngineeringBeijing University of TechnologyBeijing 100124China The Key Laboratory of Urban Security and Disaster Engineering of the Ministry of Education Beijing University of TechnologyBeijing 100124China Beijing Building Construction Research Institute Co. Ltd.Beijing 100039China

To achieve efficient structural design,it is crucial to reduce the cost of materials while ensuring structural *** study proposes an optimization method for design parameters(DPs)in a prestressed steel structure driven by multi-factor *** accomplish this,a numerical proxy model of prestressed steel structures is established with integration of DPs and mechanical parameters(MPs).A data association-parameter analysis-optimization selection system is established.A correlation between DPs and MPs is established using a back propagation(BP)neural *** correlation provides samples for parameter analysis and optimization *** are used to characterize the safety of the *** on the safety grade analysis,the key DPs that affect the mechanical properties of the structure are obtained.A mapping function is created to match the MPs and the key *** optimal structural DPs are obtained by setting structural materials as the optimization objective and safety energy as the constraint *** theoretical model is applied to an 80-m-span gymnasium and verified with a scale test physical *** MPs obtained using the proposed method are in good agreement with the experimental *** with the traditional design method,the design cycle can be shortened by more than 90%.Driven by the optimal selection method,a saving of more than 20% can be achieved through reduction of structural material ***,the cross-sectional dimensions of radial cables have a substantial influence on vertical *** initial tension and cross-sectional size of the upper radial cable exhibit the most pronounced impact on the stress distribution in that *** initial tension and cross-sectional size of the lower radial cable hold the greatest sway over the stress distribution in that cable.

关键词： structure design association relationship performance analysis optimum selection experimental verification

Pb induced dislocation defects of PtCo systems: Strain-triggered oxygen reduction reaction for PEMFC

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Nano Research 2024年第4期17卷 2462-2472页

作者： chun Jin Qiheng Wang Jingjun liu Beijing Key Laboratory of Electrochemical Process and Technology for Materials Beijing 100029China Beijing University of Chemical Technology Beijing 100029China

Design and development of advanced electrocatalysts with high performance and low Pt consumption are crucial for reducing the kinetic energy barrier of the cathode oxygen reduction reaction(ORR)and improving the efficiency of proton exchange membrane fuel cells(PEMFC).In this study,we demonstrate a Pb-modulated PtCo system for efficient ORR,in which the inclusion of Pb in ternary alloys induces dislocation defects due to the significant difference in atomic ***-PtCoPb was confirmed to exhibit significantly higher ORR activity and stability in acidic *** practical PEMFC applications,it outperforms the corresponding commercial Pt/C with a mass activity of 0.58 A·mgPt^(-1),making it a promising alternative to state-of-the-art Pt-based *** combination of experimental results and density functional theory(DFT)calculations offers valuable atomic-level insights into the dislocation *** with a larger atomic radius is located in the lattice stretching region below the dislocation slip plane,forming a structure similar to a Cottrell atmosphere,which reduces the dislocation energy and puts the system in a lower energy *** Cottrell atmosphere pins the dislocation structure and stabilizes the ternary *** adjusting the amount of added Pb,a moderate level of dislocation density induces a tuned strain effect,thereby enhancing the electrocatalytic mechanism by optimizing the electronic structure of the alloy surface and the adsorption and desorption of oxygen *** work provides valuable insights into the design and development of lattice dislocation defect structures to trigger strain effects for improving ORR performance.

关键词： dislocation defect strain effect Pb-modulated oxygen reduction reaction

Contact engineering for temperature stability improvement of Bi-contacted MoS2 field effect transistors

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Science China(Information Sciences) 2024年第06期67卷 172-179页

作者： Zizheng liu qing ZHANG Xiaohe HUANG chunsen liu Peng ZHOU State Key Laboratory of Integrated Chip and Systems School of MicroelectronicsZhangjiang Fudan International Innovation CenterFudan University Frontier Institute of Chip and System Shanghai Key Lab for Future Computing Hardware and SystemFudan University Shaoxin Laboratory

Semimetallic bismuth（Bi） is one of the most effective strategies for reducing the contact resistance of two-dimensional transition metal dichalcogenide field effect transistors（FETs）. However, the low melting point of Bi contact（271.5℃） limits its reliable applications. In this study, we demonstrated that the temperature stability of Bi-contacted electrodes could be improved by inserting a high-melting point semimetallic antimony（Sb） between the Bi contacting layer and the gold（Au） capping layer. The proposed Bi/Sb/Au contact electrodes tended to form a metal mixture with a continuous surface during the heating process（Voids appeared on the surface of the Bi/Au contact electrodes after heating at 120℃）. Because of the improved contacting layer formed by the semimetal Bi/Sb alloy, the fabricated Bi/Sb/Au-contacted molybdenum sulfide（MoS2） FETs with different gate lengths demonstrated higher on-state current stability after heating treatment than the Bi/Au contact. Because of the Bi/Sb/Au contact and poly（methyl methacrylate） package, the MoS2FETs demonstrated time stability of at least two months from the almost unchanged transfer characteristics. The electrical stability indicates that the insertion of semimetallic Sb is a promising technology for reliable Bi-based contact.

关键词： temperature stability semimetallic bismuth contact semimetallic antimony contact MoS$_{2}$ FETs time stability