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Which Neighborhoods Have Easier Access to Online Home Delivery Services?A Spatiotemporal Accessibility Analysis in Nanjing,China

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Chinese Geographical Science 2024年第4期34卷 722-738页

作者： kong yu ZHEN Feng ZHANG Shanqi SHEN Lizhen School of Architecture and Urban Planning Nanjing UniversityNanjing 210093China Provincial Engineering Research Center of Smart City Planning and Digital Governance Nanjing 210093China

The rise in online home delivery services(OHDS)has had a significant impact on how urban services are supplied and used in recent *** on the spatial accessibility of OHDS are emerging,but few is known about the temporal dimension of OHDS accessibility as well as the geographic and socioeconomic differences in the spatiotemporal accessibility of *** study measures the spatiotemporal accessibility of four types of OHDS,namely leisure,fresh and convenient,medical,and catering *** geographic and socioeconomic disparities in the spatiotemporal accessibility of these four types of OHDS are then identified using spatial statistical methods and the Kruskal-Wallis test(K-W test).The case study in Nanjing,China,suggests that:1)spatiotemporal accessibility better reflects the temporal variation of OHDS accessibility and avoids overestimation of OHDS accessibility when only considering its spatial dimension.2)The spatiotemporal accessibility of OHDS varies geographically and *** located in the main city or neighborhoods with higher housing prices,higher population density,and higher point of interest(POI)mix have better OHDS spatiotemporal *** study contributes to the understanding of OHDS accessibility from a spatiotemporal perspective,and the empirical insights can assist policymakers in creating intervention plans that take into account variations in OHDS spatiotemporal accessibility.

关键词： online home delivery services(OHDS) spatiotemporal accessibility neighborhoods accessibility differences Nanjing City China

Fluorescence study on the interactions of PAMAM dendrimers and their derivatives with bovine serum albumin

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Chinese Science Bulletin 2005年第21期50卷 2436-2441页

作者： WANG Yanming SONG yu kong Deling yu Yaoting Bioactive Material Research Laboratory Nankai University Tianjin 300071 China

The interactions of amino-terminated, and ethylenediamine core poly(amidoamine) (PAMAM) den-drimers and their derivatives with bovine serum albumin (BSA) were investigated by fluorescence spectroscopy. Ex-perimental results showed that the fluorescence intensity of BSA decreased after the addition of different modified den-drimers, and the extent of the fluorescence quenching caused by various modified dendrimers strongly depends upon the different functional groups on their surfaces. We also inves-tigated the influence of pH and ionic strength on the interac-tion between various modified dendrimers and BSA. Circu-lar dichroism (CD) spectroscopic measurements showed that the content of α-helix structure of BSA decreased after the addition of different modified dendrimers, which indicated that dendrimers induced changes in the secondary structure of BSA.

关键词： PAMAM 高分子化合物化学结构荧光性分色性

Studies on the Renaturation with Simultaneous Purification of Recombinant Human Proinsulin with Unit of Simultaneous Renaturation and Purification of Protein in Semi-preparative Scale

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Chinese Chemical Letters 2003年第8期14卷 824-827页

作者： Quan BAI yu kong Xin Du GENG Institute of Modern Separation Science Kay Lab of Modern Separation Science in Shaanxi ProvinceNorthwest UniversityXi抋n 710069

The renaturation and purification of recombinant human proinsulin (rh-proinsulin) expressed in E. coli with the unit of simultaneous renaturation and purification of protein (USRPP) in semi-preparative scale was studied. The result shows that rh-proinsulin extracted with 8.0 mol/L urea can be renatured and purified simultaneously in 45 minutes with the USRPP (1050 mm ID). The purity of rh-proinsulin was found to be more than 90% and the mass recovery to be more than 80%. The renaturation effect of rh-proinsulin with the USRPP was tested by enzyme cleavage for obtaining insulin. In addition, the result was further confirmed with RPLC, SDS-PAGE electrophoresis, and MALDI-TOF, respectively.

关键词： Liquid chromatography hydrophobic interaction chromatography renaturation preparation recombinant human rh-proinsulin biotechnology.

The Wavelength Shifting and Temperature Athermalization of Fiber Bragg Grating

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光学学报 2003年第S1期23卷 283-284页

作者： yu'e kong Xi'an Institute of Optics and Precision Mechanics of CAS P. R. China 710068

The wavelength shifting properties and the temperature athermalization technology of fiber Bragg grating (FBG) were studied in this paper, and then two different athermalization methods were introduced. The research shows that FBG with athermalization by applying the substrate with negative coefficient of thermal expansion is effective and can be used in many fields.

关键词： Fiber Bragg grating negative coefficient of thermal expansion temperature athermalization

Performance Analyses of Planar Schottky Barrier MOSFETs with Dual Silicide Layers at Source/Drain on Bulk Substrates and Material Studies of ErSi_x/CoSi_2/Si Stack Interface

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Chinese Physics Letters 2020年第3期37卷 73-77页

作者： Bin Wang Hao-yu kong Lei Sun Institute of Microelectronics Peking UniversityBeijing 100871

A dual silicide layer structure is proposed for Schottky barrier metal-oxide-semiconductor held effect transistors(MOSFETs)on bulk *** source/drain regions are designed to be composed with dual stacked silicide layers,forming different barrier heights to silicon *** comparisons between the dual barrier structure and the single barrier structure are carried out with numerical *** is found that the dual barrier structure has significant advantages over the single barrier structure because the drive current and leakage current of the dual barrier structure can be ***,the dual barrier structure's performance is nearly insensitive to the total silicide thickness,which can relax the fabrication requirements and even make an SOI substrate unnecessary for planar device *** formation of ErSix/CoSi2 stacked multilayers has been proved by experiments.

关键词： Schottky MOSFETs drain

Poly(ethylene terephthalate)/Carbon Black Composite Fibers Prepared by Electrospinning

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Chinese Journal of Polymer Science 2015年第9期33卷 1234-1244页

作者： Zhuo-yue Xiong Xiao-yu kong 郭朝霞于建 Key Laboratory of Advanced Materials (MOE) Department of Chemical Engineering Tsinghua University

Poly（ethylene terephthalate）（PET）/carbon black （CB） composite fibers with improved mechanical properties in tensile modulus and tensile strength are prepared by eletrospinning. Stable dispersions suitable for electrospinning are obtained by dispersing melt pre-compounded PET/CB composites in hexafluoroisopropanol. The fiber morphology and CB dispersion are investigated by FESEM and TEM. The addition of CB has no obvious effect on fiber diameter, and the average fiber diameters for all the samples are around 2-3 ~tm. CB in the fibers is in the form of submicron-sized clusters. The thermal properties of the PET/CB composite fibers are evaluated by DSC, showing almost unchanged melting temperature and crystallinity. Uniaxial tensile tests are used to measure the mechanical properties of the PET/CB composite fiber mats. The fiber mats containing 1 wt%-8.5 wt% CB have significantly improved tensile modulus compared to neat PET fiber mat, showing reinforcing effect of CB. The electrical conductivity of the fiber mats has also been tested.

关键词： Eletrospinning Carbon black Mechanical properties Morphology Dispersions.

Characteristics of long period microtremor and validation of microtremor array measurements in inland areas of China

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Journal of Mountain Science 2016年第11期13卷 1910-1922页

作者： CHE Ai-lan ZHANG Teng-yu FENG Shao-kong School of Naval Architecture Ocean and Civil Engineering Shanghai Jiaotong University 800 Dongchuan-Road Shanghai 200240 China

To study the characteristics of long period microtremor and applicability of microtremor survey,we have made microtremor observations using long period seismometers of the China's mainland from coastal cities like Shanghai and Tianjin through Beijing,Xi'an,to the far inland cities of Lanzhou and *** observation shows that the level of power spectrum of long period microtremors reduced rapidly from the coast to the inland ***,the energy of long period microtremors in Beijing,Xi'an,Lanzhou and Tianshui area are only approximately ten-thousandth to thousandth of that in *** at the complexity of the underground structure in the far inland,a series of underground structure models with different distributions were assessed using three-dimensional,dynamic finite element method(FEM) *** results were used to evaluate microtremor survey methods and their limitations with regard to aggregate variability and thickness ***-wave reflections between layers with the change of underground structure distribution occurred,which have significant effect on the performance of the different field *** over a broad spectrum from which velocity-depth profiles were produced via inversion *** the thickness nor the shear waveVelocity V of the subsurface layer inversion results appeared over a large evaluation with increasing slope *** particular,when the angle of the model reached 45°,it could not be accurately evaluated using one-dimensional inversion ***,the array microtremor survey(AMS) was carried out in Shanghai City,*** AMS techniques do not have the layer sensitivity or accuracy(velocity and layer thickness) of borehole techniques,the obtained shear wave velocity structure is especially useful for earthquake disaster prevention and seismic analysis.

关键词： Long period microtremor Array Microtremor survey Power spectrum Inversion S-wave velocity structure

Interaction between poly(amidoamine) dendrimers and DNA studied by spectroscopic methods

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Chinese Science Bulletin 2005年第19期50卷 2161-2165页

作者： WANG Yanming SONG yu kong Deling yu Yaoting Bioactive Material Research Laboratory Nankai University Tianjin300071 China

The interaction between amino-terminated, and ethylenediamine core poly(amidoamine) (PAMAM) den-drimers and herring sperm DNA was investigated by various spectroscopic methods including UV spectroscopy, fluores-cence spectroscopy, microscopic FTIR- and circular dichro-ism (CD-) spectroscopy. Ethidium bromide (EB) is used as a nucleic acid probe for this study. Experimental results show that PAMAM dendrimers can form stable complexes with DNA and the dendrimers bind to DNA sufficiently strong which cannot be displaced by EB, and we also found that the formation of the complexes can cause the conformation change of the DNA secondary structure. According to the Scatchard analysis, the association constant of PAMAM to DNA is calculated to be 2.53 × 104 mol/L?1.

关键词：聚乙烯分光镜分子结构 DNA 荧光性

Studies on the refolding of the reduced-denatured insulin with size exclusion chromatography

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Science China Chemistry 2005年第Z1期48卷 55-59页

作者： BAI Quan kong yu DONG Cuihua GENG Xindu Institute of Modern Separation Science Shaanxi Key Laboratory of Modern Separation ScienceNorthwest UniversityXi'an 710069China

The refolding of the reduced-denatured insulin from bovine pancreas was investigated with the size exclusion chromatography(SEC).It was shown that the reduced-denatured insulin originally denatured with 7.0 mol·L-1 guanidine hydrochloride(GuHCl)or 8.0 mol·L-1 urea could not be refolded with a non-oxidized mobile *** the oxidized and reduced glutathione(GSSG and GSH)were employed in the oxidized mobile phase,the reduced-denatured insulin still could not be ***,in the presence of 2.0 mol·L-1 urea in the oxidized mobile phase employed,the reduced-denatured insulin can be refolded with SEC,and the aggregation of denatured insulin can be diminished by *** addition,the disulfide exchange of reduced-denatured insulin also can be accelerated with GSSG/GSH in the oxidized mobile *** three disulfide bridges of insulin were formed correctly and the reduced-unfolded insulin can be renatured *** results were further tested with reversed-phase liquid chromatography(RPLC)and hydrophobic interaction chromatography(HIC).

关键词： protein folding size exclusion chromatography reduced-denaturation disulfide bonding insulin