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Preparation of Dendrimers from Macromolecular Cores and Papain Immobilization

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Chinese Chemical Letters 1998年第3期9卷 263-264页

作者： liu, LJ sh., sh.Zhuo, RX Lu, ZR Wuhan Univ Dept Chem State Educ Commiss China Lab Biomed Polymer Mat Wuhan 430072 Peoples R China

Using amino-poly(ethylene glycol) and amino-propyl silica gel as initiator cores, two dendrimers were prepared by a two-step procedure. The progress of dendrimers during each step was monitored by infrared spectroscopy and elemental analysis. Papain was crosslinked to the solid dendrimer with silica gel core by glutaraldehyde, and the enzymatic activity of the immobilized papain kept almost unchanged after repeated usage for fifteen times.

关键词： amino-poly(ethylene glycol) amino-propyl silica gel dendrimer immobilized papain

Methylene green-mediated sensor highly sensitive to hydrogen peroxide based on entrapment of horseradish.peroxidase in composite membrane of regenerated silk fibroin and poly(vinyl alcohol)

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Chinese Journal of Chemistry 1996年第4期14卷 359-366页

作者： Wu, YX liu, HY Qi, DY liu, YC Qian, JH liu, sh.Yu, TY Deng, JQ sh.NGHAI UNIV DEPT CHEM & CHEM ENGNSHANGHAI 200072PEOPLES R CHINA FUDAN UNIV DEPT MACROMOL SCI & CHEMSHANGHAI 200433PEOPLES R CHINA

A novel composite membrane of poly(vinyl alcohol) and regenerated silk fibroin was employed to immobilize horseradish.peroxidase (HRP) and IR was used to give a useful insight into the structure of the composite membrane before and after ethanol treatment. A methylene green-mediated sensor sensitive to hydrogen peroxide was fabricated, based on the composite membrane as immobilization matrix for HRP. Cyclic voltammetry and amperometric measurement were for the first time utilized to demonstrate the suitability of methylene green as an electron transfer mediator between immobilized HRP and a glassy carbon electrode in bioelectrocatalytic reduction of hydrogen peroxide. Performance and characteristics of the sensor were evaluated in respect to response time, detection limit, applied potential and concentration of the mediator. The sensor possesses a variety of characteristics including good sensitivity, rapid response time and low detection of limit of 0.1 mu mol/L.

关键词： sensor poly(vinyl alcohol) regenerated silk fibroin methylene green horseradish.peroxidase hydrogen peroxide

Stark characteristics of cesium atom studied in a thermionic bulb

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Chinese Science Bulletin 1997年第22期42卷 1877-1880页

作者： Gu, sh.liu, BM Wang, JM Dai, ZY Gong, SS Chinese Acad Sci Wuhan Inst Phys & Math Lab Magnet Resonance & Atom & Mol Phys Wuhan 430071 Peoples R China

MOST of the spectral studies of atomic strong electric effect are carried out by means of atomicbeam and pulse laser. The spectral linewidth is ranged from the order of one to ten GHz. Inrecent years, with the applica... 详细信息

关键词： cesium atom electric fleld Rydberg state spectrum.

Selective Dealumination of ZSM-5 by Hydrothermal Treatment

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Chinese Chemical Letters 1998年第4期9卷 397-400页

作者： Zhang, K Zhang, HB Xiang, sh.liu, SY Li, HX He, F Nankai Univ Dept Chem Catalysis Lab Tianjin 300071 Peoples R China Tianjin Univ State Key Lab C Chem Tianjin 300072 Peoples R China

We studied the factors affecting the framework aluminium distribution in the ZSM-5 structure by hydrothermal treatment under different conditions. (27)AlMASNMR, XPS and chemical analysis revealed that with steaming at lower water vapor pressure, the framework aluminium located at the external surface is less stable. Steaming at higher water vapor pressure is beneficial in removing the framework Al in HZSM-5, and especially helpful in removing that located at the internal surface of HZSM-5. By changing steaming conditions, one may control the framework aluminium distribution in the HZSM-5 structure.

关键词： selective dealumination water vapor pressure steaming HZSM-5

‘C-type’ closed state and gating mechanisms of K2P channels revealed by conformational changes of the TREK-1 channel

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Journal of Molecular Cell Biology 2022年第1期14卷 47-55页

作者： Qiansen Zhang Jie Fu sh.oying Zhang Peipei Guo sh.ie liu Juwen sh.n Jiangtao Guo Huaiyu Yang sh.nghai Key Laboratory of Regulatory Biology Institute of Biomedical SciencesSchool of Life SciencesEast China Normal UniversityShanghai 200241China Department of Biophysics and Department of Pathology of Sir Run Run sh.w Hospital Zhejiang University School of MedicineHangzhou 310058China

Two-pore domain potassium (K2P) channels gate primarily within the selectivity filter, termed ‘C-type’ gating. Due to the lack of structural insights into the nonconductive (closed) state, ‘C-type’ gating mechanisms remain elusive. Here, molecular dynamics (MD) simulations on TREK-1, a K2P channel, revealed that M4 helix movements induce filter closing in a novel ‘deeper-down’ structure that represents a ‘C-type’ closed state. The ‘down’ structure does not represent the closed state as previously proposed and instead acts as an intermediate state in gating. The study identified the allosteric ‘seesaw’ mechanism of M4 helix movements in modulating filter closing. Finally, guided by this recognition of K2P gating mechanisms, MD simulations revealed that gain-of-function mutations and small-molecule activators activate TREK-1 by perturbing state transitions from open to closed states. Together, we reveal a ‘C-type’ closed state and provide mechanical insights into gating procedures and allosteric regulations for K2P channels.

关键词： K2P state selectivity filter C-type gating

A NEW. NEO-CLERODANE DITERPENE FROM AJUGA NIPPONENSIS

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Chinese Chemical Letters 1995年第7期6卷 581-582页

作者： liu, Z Li, ZQ Zhang, CX Chen, RY Zhang, YG Qiu, YT Zhao, sh Nankai Univ Inst Elementoorgan Chem Tianjin 300071 Peoples R China S China Agr Univ Dept Plant Protect Lab Insect Toxicol Guangzhou 510642 Peoples R China

This paper describes the structural elucidation of a new insecticiaal neoclerodane diterpene Ajagamarin L-2 from Ajuga nipponensis,based on spectral data and X-ray diffraction analysis as 4,18-epoxy-6 alpha -hydroxy-1... 详细信息

关键词： NEO-CLERODANE DITERPENE FROM AJUGA NIPPONENSIS A NEW

Twelve-frame camera for soft X-ray

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Chinese Science Bulletin 1997年第14期42卷 1215-1217页

作者： Cheng, JX Yang, CB Wen, TS Wen, sh.Tang, DY Zheng, ZJ sh.n, B liu, JY Chang, ZH liu, XQ Gao, SC Institute of Nuclear Physics and Chemistry Chinese Academy of Engineering Physics Chengdu China Xi’an Institute of Optics and Precision Mechanics Chinese Academy of Sciences Xi’an China

THE procedure of inertial confinement fusion (ICF) takes place in sub-nanosecond period. Inorder to investigate the hydrodynamic instability and asymmetry during the implosion, weneed to measure the two-dimensional distribution of plasmas temperature and density as well asits relationsh.p with time. For this purpose, an X-ray picosecond multiframe technique hasbeen developed.

关键词： gated microchannel-plate picosecond frame microstrip line.

Influence of Fe on electronic density of defects in NiAl alloys

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Chinese Science Bulletin 1997年第21期42卷 1783-1787页

作者： Deng, W Xiong, LY Wang, sh.Guo, JT Long, QW Guangxi Univ Dept Phys Nanning 530004 Peoples R China

NiAl alloy is considered to be a good candidate material for high performance, high-tempera-ture structural applications since this material offers a wide range of attractive mechanical andphysical properties, such as low density (5. 86 g/cm^3), high melting point (1 640℃), goodthermal conductivity (4--8 times compared with Ni-based superalloys) and oxidation resis-tance. However, the use of NiAl is limited by its room-temperature brittleness. Georgeand liu have investigated the effects of microalloying elements B, C and Be on the fractureproperties and grain boundaries of NiAl alloy. Their results sh.wed that the improvement

关键词： NiAl alloy positron lifetime microdefects electronic density.

Orbitronics for energy-efficient magnetization switching

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Science China(Information Sciences) 2025年第1期 398-399页

作者： Yuxuan YAO Daoqian ZHU Qingtao XIA Jianing LIANG Yuhao JIANG Zhiyang PENG Jiaxu LI Chen XIAO Renyou XU Wenwen WANG Xiantao sh.NG sh.yang LU Dapeng ZHU Hong-Xi liu Kaihua CAO Weish.ng ZHAO Fert Beijing Institute School of Integrated Circuit Science and Engineering Beihang University National Key Lab of Spintronics Institute of International Innovation Beihang University Qingdao Research Institute Beihang University Truth Memory Corporation

Spin-orbit torque （SOT）,as a promising writing method for magnetic random-access memory （MRAM）,has garnered widespread interest for over a decade [1].Heavy metals,such as β-W,have been broadly adopted as spin current sources,but suffer from phase change at a limited thickness,resulting in a dramatic reduction of the charge-tospin conversion efficiency θsh.2].The thickness limitation leads to stringent etching conditions and large distribution among devices,posing challenges for simultaneously satisfying SOT efficiency,etching-stop margins,and back-end-ofline （BEOL） compatibility.

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