检索结果-南通市图书馆

Chinese Science Bulletin 2014年第8期59卷 734-739页

作者： Song Gao Fei Wang dongqi he Shouyu Zhang Shanglian Bao Department of Physics Health Science Center Peking University Department of Biophysics School of Basic Medical SciencePeking University Medical Physics and Engineer Laboratory School of PhysicsPeking University

Many studies have shown that the magnetic resonance signal decay with an extend range of diffusion weighting(b-factor)is a bi-exponential attenuation in the diffusion-weighted magnetic resonance imaging experiments in *** on this feature and the two-compartmental model,we propose a twice-linear-fitting(TLF)algorithm to estimate the apparent diffusion coefficient(ADC)of the water molecules instead of the commonly used iterative Levenberg–Marquardt(LM)*** TLF algorithm consists of two liner fitting steps to estimate the fast and the slow apparent diffusion coefficients and their sizes,*** is unnecessary to guess the initial values in the whole fitting *** time consumption of the TLF algorithm is much less than that of the iterative LM ***,the TLF algorithm may avoid the extraneous solutions,which often deteriorates the results of the LM *** with the iterative fitting method,the TLF algorithm is a reliable and timeefficient approach to estimate the ADC of water molecules in vivo in magnetic resonance diffusion-weighted imaging experiments.

关键词：表观扩散系数非迭代算法磁共振信号成像实验水分子估计指数衰减装配过程

Effects of TFAR19 gene on the in vivo biorheological properties and pathogenicity of mouse erythroleukemia cell line MEL

在线全文

学校读者我要写书评

暂无评论

Science China(Life Sciences) 2007年第1期50卷 111-119页

作者： GU Li TANG ZhiYu he dongqi KA WeiBo SUN DaGong WEN ZongYao State Key Laboratory of Microbial Technology Life School of Shandong UniversityJinan 250100China hemorheology Center Department of Medical PhysicsSchool of Basic Medical SciencesHealth Science Center of Peking Uni-versityBeijing 100083China Department of Applied Science Health Science Center of Peking UniversityBeijing 100083China

After injecting VP16, MEL cells and MEL-TF19 cells into the body of mice, with those injected with the same dose of saline as the control group, we observed the mice for their blood pictures, histological changes of the liver and spleen, and the hemorhelogical indexes within 4 weeks. The results indicated that after injecting MEL cells, the mice entered into a pathological status similar to erythroleukemia, which had the following exhibitions: the tissue structures of the liver and spleen were damaged, a mass of proerythroblasts, basophil erythroblasts and polychromatophilic erythroblasts could be observed on the smears of the bone marrow and spleen, and the deformability and orientation ability of erythrocytes were both depressed. The pathogenicity of MEL-TF19 cells carrying TFAR19 gene was obviously lower than that of MEL cells, and the MEL-TF19 cells even lost their faintish pathogenicity under the apop-tosis-inducing effect of the chemotherapeutic reagent. The outcome from the animal experiments suggests that the TFAR19 gene suppresses the pathogenicity of MEL cells to the mice, and the effect may be better exerted with the synergy of the chemotherapeutic reagent.

关键词： TFAR19 gene erythroleukemia cell line MEL biorheological property

Metal-film-assisted ultra-clean transfer of single-walled carbon nanotubes

在线全文

学校读者我要写书评

暂无评论

Nano Research 2014年第7期7卷 981-989页

作者： Yujun he dongqi Li Tianyi Li Xiaoyang Lin Jin Zhang Yang Wei Peng Liu Lina Zhang Jiaping Wang Qunqing Li Shoushan Fan Kaili Jiang State Key Laboratory of Low-Dimensional Quantum Physics Department of Physics & Tsinghua-Foxconn Nanotechnology ResearchCenter Tsinghua University Beijing 100084 China

Transfer printing of nanomaterials onto target substrates has been widely used in the fabrication of nanodevices, but it remains a challenge to fully avoid contamination introduced in the transfer process. here we report a metal-film- assisted method to realize an ultra-clean transfer of single-walled carbon nanotubes （SWCNTs） mediated by poly（methyl methacrylate）（PMMA）. The amount of PMMA residue can be greatly reduced due to its strong physical adhesion to the metal film, leading to ultra-clean surfaces of both the SWCNTs and the substrates. This metal-film-assisted transfer method is efficient, nondestructive, and scalable. It is also suitable for the transfer of graphene and other nanostructures. Furthermore, the relatively low temperature employed allows this technique to be compatible with nanomaterial-based flexible electronics.

关键词： metal-film-assisted single-walled carbonnanotube transfer flexible substrate Schottky barrier

基于拟分布函数的中药色谱指纹图谱的相似性分析

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

北京大学学报（自然科学版） 2008年第5期44卷 695-699页

作者：安金兵许玉琼贺东奇蔡少青北京大学医学部公共教学部北京100083 北京大学药学院天然药物学系北京100083

针对中药色谱指纹图谱中色谱峰面积值存在较大变异性的问题,从拟分布函数的角度介绍了一种新的分析方法。采用秩变换将色谱峰面积值转化为相对秩次,然后通过一系列变换将原数据转换成拟分布函数的形式,再利用柯尔莫哥洛夫检验实现不同... 详细信息

针对中药色谱指纹图谱中色谱峰面积值存在较大变异性的问题,从拟分布函数的角度介绍了一种新的分析方法。采用秩变换将色谱峰面积值转化为相对秩次,然后通过一系列变换将原数据转换成拟分布函数的形式,再利用柯尔莫哥洛夫检验实现不同类别样品的色谱指纹图谱之间的相似性分析。通过对北马兜铃和南马兜铃样品的比较,说明了该方法有较好的灵敏度和稳健性,因而是比较合理的。

关键词：色谱指纹图谱秩拟分布函数柯尔莫哥洛夫检验

在线全文

学校读者我要写书评

暂无评论

Hamilton图的一个新的充分条件

系统科学与数学 2000年第1期20卷 11-13页

作者：贺东奇北京医科大学生物数学系北京100083

设Ｇ是一个ｎ阶３－连通１－坚韧图，以（Ｇ）表示Ｇ的四元独立点集的次和的最小值，（Ｇ）为Ｇ的连通度，证明若（Ｇ）（Ｇ），则Ｇ是Ｈａｍｉｌｔｏｎ图．

关键词：坚韧图连通度哈密顿图充分条件哈密顿圈

在线全文

学校读者我要写书评

暂无评论

Bondy定理的改进(英文)

数学进展 2001年第1期30卷 37-46页

作者：贺东奇刘振宏田丰北京大学医学部生物数学与生物统计系中国科学院系统科学研究所

设Ｇ是一个ｎ阶ｋ连通图（ｋ≥２）．于１９８０年Ｊ．Ａ．Ｂｏｎｄｙ证明：若ｋ＋１＞（ｋ＋１）（ｎ—１）／２，则Ｇ是Ｈａｍｉｌｔｏｎ图．本文证明对于坚韧图Ｇ，若ｋ＋１≥（ｋ＋１）（ｎ－３）／２，则Ｇ是Ｈａｍｉｌｔｏｎ图．

关键词：周长连通度坚韧图 HAMILTON图 BONDY定理连通

在线全文

学校读者我要写书评

暂无评论

3-连通、高次和坚韧图周长的估计(Ⅰ)

数学的实践与认识 1999年第4期29卷 85-92页

作者：贺东奇北京医科大学生物数学与生物统计教研室北京100083

设G是一个n阶3-连通图,周长为C(G),独立数为,若G是1-坚韧的,且,则G的每一个最长圈是控制圈且;又若G是5/3-坚韧的或,则G是Hamilton图。

关键词：坚韧图点独立数周长 3-连通图估计哈密顿圈

在线全文

学校读者我要写书评

暂无评论

硫氧还蛋白还原酶结构分形研究

北京大学学报（自然科学版） 2008年第2期44卷 165-170页

作者：韦珩贺东奇曾慧慧北京大学药学院化学生物系北京100083 北京大学医学部应用理学系北京100083

提出并应用改进的分形方法对硫氧还蛋白还原酶(TrxR)结构进行研究。建立了适用于TrxR的分形及数据处理方法。发现正常的TrxR的结构分维值约为1.33,氧化后结构分维值增大。提出了蛋白质结构分维值是表征蛋白质分子状态的重要特征之一的观... 详细信息

提出并应用改进的分形方法对硫氧还蛋白还原酶(TrxR)结构进行研究。建立了适用于TrxR的分形及数据处理方法。发现正常的TrxR的结构分维值约为1.33,氧化后结构分维值增大。提出了蛋白质结构分维值是表征蛋白质分子状态的重要特征之一的观点,并结合TrxR验证了该观点。提出了药物分子分维值应与靶酶的结构分维值相契合的观点,并结合以TrxR为靶点的药物研发实验验证了该观点。

关键词：分形分维值硫氧还蛋白还原酶药物分子设计

Recent progress in constructing fluorinated solid-electrolyte interphases for stable lithium metal anodes

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 270-291页

作者： Di Zhang Pengfei Lv Wei Qin Xin he Yuanhua he Civil Aircraft Fire Science and Safety Engineering Key Laboratory of Sichuan Province College of Civil Aviation Safety EngineeringCivil Aviation Flight University of ChinaGuanghan 618307China School of Chemical Engineering Sichuan UniversityChengdu 610065China

Lithium metal batteries(LMBs)are emerging as a promising energy storage solution owing to their high energy density and specific ***,the non-uniform plating of lithium and the potential rupture of the solid-electrolyte interphase(SEI)during extended cycling use may result in dendrite growth,which can penetrate the separator and pose significant short-circuit *** a stable SEI is essential for the long-term operation of the ***-rich SEI has garnered significant attention for its ability to effectively passivate electrodes,regulate lithium deposition,and inhibit electrolyte *** the structural components and preparation methods of existing fluorinated SEI is crucial for optimizing lithium metal anode *** paper reviews the research on optimizing LiF passivation interfaces to protect lithium metal *** focuses on four types of compositions in fluorinated SEI that work synergistically to enhance SEI *** instance,combining compounds with LiF can further enhance the mechanical strength and ionic conductivity of the *** metals with LiF significantly improves electrochemical performance at the SEI/anode interface,with a necessary focus on reducing electron tunneling ***,incorporating polymers with LiF offers balanced improvements in interfacial toughness and ionic conductivity,though maintaining structural stability over long cycles remains a critical area for future *** alloys combined with LiF increase surface energy and lithium affinity,challenges such as dendrite growth and volume expansion *** summary,this paper emphasizes the crucial role of interfacial structures in LMBs and offers comprehensive guidance for future design and development efforts in battery technology.

关键词： LiF lithium metal anodes solid-electrolyte interphase interface cycling stability

在线全文

学校读者我要写书评

暂无评论

溶解氧测定仪示值误差的不确定度评定

化学分析计量 2005年第4期14卷 11-12页

作者：蔡大川罗军何冬琦广东省测试分析研究所广州510070 广东省计量科学研究院广州510405

对溶解氧测定仪示值误差的不确定度进行了评定。分析了各个不确定度分量,溶解氧测定仪示值误差的扩展不确定度为0.05mg/L。

关键词：溶解氧测定仪示值误差测量不确定度评定水分析