237 research outputs found
太子参环肽类化合物Pseudostellarin E对3T3-L1前脂肪细胞分化和葡萄糖吸收的作用
目的探讨太子参环肽类化合物Pseudostellarin E是否具有治疗2型糖尿病的潜力。方法在3T3-L1前脂肪细胞中应用了葡萄糖吸收试验和分化模型。结果 Pseudostellarin E不仅加速3T3-L1前脂肪细胞分化进程,而且在高浓度(30m M)葡萄糖条件下增加了分化的脂肪细胞对胰岛素刺激的葡萄糖的吸收。结论上述结果表明,Pseudostellarin E可能具有治疗糖尿病的潜能。国家自然科学基金面上项目(81773601);;福建省教育厅2015年第二批高等学校优秀学科(专业)带头人赴海外访学研修资助项目(闽教人[2015]103号);;福建省自然科学基金计划资助项目(2015J01065);;福建省卫生系统中青年骨干人才培养项目2015年资助计划基础项目(2015-ZQN-JC-45);;福建省厦门市科技局科技计划高校创新项目(3502Z20143026);;厦门医学院科研项目(Z2013-12,Z2013-25
模板法制备玻璃表面超亲水SiO2纳米柱阵列
以酸性SiO2溶胶作为涂层,通过阳极氧化铝模板压印法,在玻璃表面成功制备了规则排列的超亲水SiO2纳米柱阵列,考察了模板孔深和孔径对SiO2纳米柱阵列结构和性能的影响。结果表明,随着模板孔深的增加,长径比>10的纳米柱倾向于倒塌聚集,导致可见光透射比大幅下降;控制纳米柱长径比<10时,制备的直立纳米柱结构具有良好的透光性能,且随着模板孔径的减小,纳米柱直径减小,表面粗糙度增大,固体表面占比减小,亲水性逐渐增强。该方法可通过模板孔径调控SiO2纳米柱阵列的表面粗糙度和固体表面占比,使之呈现超亲水性和高透光性,为超亲水材料的制备提供了新的技术路线。福建省科技重大专项(2014HZ0005
Formation and solving for the micro-waves of fly-cut surface introduced by spindle error
为分析超精密飞切机床加工表面微波纹的形成机理,研究了主轴回转误差信息提取与表面形貌仿真技术,获取微波纹误差来源并研究解决方案。首先,在超精密飞切机床主轴上搭载五通道在线电容位移检测系统,并对采集到的信号进行误差分析提取。然后,建立飞切加工表面微观形貌三维仿真模型,仿真分析主轴误差引入的加工表面微波纹,并与表面检测结果比对确定误差来源。最后,通过调整主轴电机控制系统抑制该误差。三维仿真和实测结果相吻合,证实超精密飞切机床主轴转速波动导致的回转误差造成了工件表面1 Hz左右的规律性条纹,对主轴转速控制系统进行数字化改造后,基本消除了该因素导致的表面微波纹,表面粗糙度从5 nm以上抑制到2 nm左右,PV值优于10 nm。超精密飞切机床主轴转速波动会对飞切加工表面微观形貌以及表面粗糙度产生显著影响,需至少控制在0.5 r/min以内。In order to find out the formation mechanism of micro-waves on the fly-cut surface,the spindle motion error was sampled and a 3D topography simulation model was compiled. Firstly,a nano-class testing and evaluation system was established on the fly cutting machine,the displacement data was sampled and the spindle motion error was analyzed.Then a 3D surface profile topography simulation model was established to analyze the micro-waves caused by the spindle motion error. The simulated surface was compared with the measured surface to find out the error sources. Finally,the characteristics of spindle were improved by adjusting the control system of the spindle motor. The simulated 3D surface profile topography was similar to that of the measured profile,which verified that the macro-waves was caused by the undulate of the spindle speed. When the spindle characteristics was improved,the macro-waves caused by the spindle motion error almost disappeared,and the surface roughness reduced from more than 5 nm to 2 nm. It is thus concluded that the undulate of ultra-precision fly cutting machine spindle speed causes macro-waves on the work-piece surface,and the undulate spindle speed must less than 0. 5 r / min.基金项目:高档数控机床与基础制造装备《强激光光学元件超精密制造关键装备研制》(2013ZX04006011-102-001
贸易、FDI和企业的组织形式
国际贸易和外国直接投资(FDI)一直以来都身居全球增长最快的经济活动之列。2003年,全球货物出口额直逼73,000亿美元,全球商业服务出口额将近18,000亿美元;同时,全球FDI流入额也接近5,600亿美元[ FDI流量在2000年达到顶峰,为1,4000亿美元,但从2000年到2003年有所下降;参见UNCTAD(2004)。根据UNCTAD(2002),2001年跨国公司国外分支机构占世界GDP的11%,世界贸易的35%。上个世纪90年代,商品出口折算成实际价格水平后,以每年6.4%的速度增长;而商品生产则仅以每年2.5%的速度增长。]。然而,在1990年到2001年跨国公司海外分支机构营业收入的扩张速度甚至要比全球货物出口和非要素服务出口的迅猛增长快得多[ 根据UNCTAD(2002),大约为每年7%。]。服务业FDI前所未有的扩张是该增长的一个显著特点:1990年,服务业FDI流入累积额为9,500亿美元,而到了2002年,该数值已增加到40,000亿美元[ 参见UNCTAD(2004)。]。2001-2002年,投资到服务业的FDI占总FDI流入额的2/3。译者单位:厦门大学经济学院国际经济与贸易系(361005
The overview of rapid prototyping technique
【中文文摘】在研究快速原型技术发展历史和现状的基础上,介绍了快速原型制造的基本原理,重点介绍几种发展较成熟的RP技术的基本原理,分析RP技术的特点,并探讨其应用价值和发展前景,提出了目前发展快速成型的基本观点和未来发展趋势。
【英文文摘】Based on the history and development of rapid prototyping technique,the principles of Rapid Protyping(RP),especially several developed techniques,are introduced.The characteristics of RP techniques are analyzed and the opinions about future development tendency and prospect are put forward.福建省自然基金项目(k32014);; 国家留学回国人员基金资助项目(k3003
Development and Application of Micro-Electro-Mechanical System
【中文文摘】微机电系统是在微电子技术基础上产生和发展起来的多学科交叉的前沿科学研究领域 ,是面向 2 1世纪的高新科技 .介绍了微机电系统产生的背景影响、组成特征和基础研究内容 ,综述了微机电系统技术基础所涉及的材料、微机械设计和模、微细加工技术以及微封装与测试等领域 ,并对微机电系统的应用、典型的微器件、国内外的发展现状及前景进行全面分析 .在此基础上 ,论述了MEMS技术目前存在的问题和未来发展的趋势
【英文文摘】Micro-Electro-Mechanical System(MEMS) developes on the basis of microelectronics.It is a scientific researches frontier of multi-disciplines and a high technology in the 21st century.This paper presents the background,characteristics and basic research.The principal techniques of MEMS such as material,design and simulation,micromachining,packaging and testing are reviewed,Typic microapparatus,application prospect and the state-of-art of MEMS are also discussed in this paper.Furthermore,some points of view of developing on MEMS in the future are put forward
The Application of PLC in Pneumatic Control Electrode Board Cutting Machine
【中文文摘】本文详细阐述了气动控制系统、光电检测、可编程控制器在气动电极板剪切机中的应用。
【英文文摘】The pneumatic control system,optoelectronic detection system,the application of PLC in pneumatic control electrode board cutting machine was introduced in detail
闽南肝癌高发区肝细胞癌与HBV复制的相关性分析
目的分析闽南肝癌高发区乙型肝炎病毒 (HBV)复制与原发性肝细胞癌 (PHCC)的关系。方法用实时荧光定量聚合酶链反应 (PQ- PCR)技术测定 6 1例 PHCC患者、40 7例不同病程的 HBV感染者及 17例健康人血清中 HBV DNA的含量 ,对照分析 HBV标志物 (HBVM) ,同时检测 PHCC患者抗 - HCV- Ig G和 HCV RNA。结果PHCC组 HBV DNA阳性率高达 80 .3% (49/ 6 1) ,高于其他肝病组 ,差异具显著性 (P<0 .0 2 ) ,HBV DNA含量各组间差异无显著性。PHCC组抗 - HCV- Ig G和 HVC RNA阳性率为 0。结论闽南肝癌高发区 PHCC患者 HBV DNA阳性率较高 ,HBV感染并持续复制 ,可能是该地区 PHCC的主要致病因
The primary investigation of the value of whole body diffusion weighted imaging in diagnosis of metastatic tumor
背景与目的:随着临床上晚期肿瘤病例的增多,为了解治疗前、后全身转移瘤的大小及数量变化的实际情况,以往多采用分部位进行CT和(或)Mr扫描,少部分有条件的患者采用PET检查,但这些方法可能存在过多地暴露于射线、检查时间过长及经济负担过重等问题。因此,我们探讨磁共振的全身弥散加权成像(WHOlE bOdy dIffuSIOn WEIgHTEd IMAgIng,WbdWI)方法对肿瘤及转移灶的检出准确性及其临床应用的可行性。方法:对68例临床已发现原发肿瘤及多个转移灶或发现多个肿瘤病灶,但原发灶不明确的患者进行WbdWI检查,其中男性49例;女性19例。平均年龄61岁。68例均与CT和(或)MrI的检查结果进行比较,其中17例与PET的检查结果相比较。对病灶的检出率,以病灶长径大小分为:<1CM,≥1~<2CM,≥2~<3CM及≥3CM以上4组进行计数分析,同时,对不同部位间的病灶检出情况进行分析。结果:WbdWI对4组病灶的检出率分别为30%、78%、96%及100%。在各个部位的敏感性和准确性中以骨骼最高。对位于肺部小于1CM的病灶和位于颈部、盆腔小于2CM的淋巴结的诊断存在一定困难。结论:WbdWI对大范围的肿瘤病灶筛查是安全、简便、有效和经济的检查新方法。随着技术参数的进一步完善,WbdWI在发现和诊断全身多发肿瘤方面,具有良好的发展潜力。因此,本技术有望作为一种新的、效果好于PET的全身检查技术。Background and purpose:With the increased number of advanced tumors,it is important to evaluate the actual pre-and post-treatment changes in metastatic diseases,such as tumor size and tumor quantity.Previously,CT and/or MRI scan were usually applied,only a few patients could pay for PET(positron emition tomography).But there were several problems we should face,including redundantly exposure to radiation,too long verification time and heavy financial burden.Therefore we evaluated the application of whole body diffusion weighted imaging in diagnosing of tumor and metastatic tumor.Methods:sixty-eight patients(49 male,19 female,age from 29 to 84 years with mean age of 61 years) with a variety of tumors were investigated by combined CT and/or MRI scan,seventeen patients were compared with positron emition tomograph(PET).All tumors were classified into four groups,according to longest diameter of <1 cm,≥1-<2 cm,≥2-<3 cm and ≥3 cm.At the same time,the positive detection rates between different parts of the lesions were analyzed.Results:The detection rate of the four groups were 30%,78%,96% and 100%,respectively.The skeletal system had the highest sensitivity and accuracy in every part of body.There was difficulty in diagnosing lung cancer with longest diameter less than 1 cm as well as tumors located in neck and pelvic with longest diameter less than 2 cm.Conclusion:Whole body diffusion weighted imaging is secure,convenient,effective and economic for screening wide-ranging tumor focus.After improvement of parameters,WBDWI could be as a new effective whole body examination technique.厦门市科技计划项目(No:3502Z20074017
Structural Stabilities of Ordered Arrays of Nb-4 Clusters on NaCl(100) Surface
National Natural Science Foundation of China [10774124]Adsorption of ordered (2 x 2) arrays of Nb-4 clusters on the insulating surface of NaCl(100) is studied by the first-principles calculations within the density functional theory. The calculations on the relaxed geometries and cohesive energies show that both the tetrahedron and quadrangle-Nb-4 can be stably adsorbed on this substrate, which may have important applications. The adsorption of quadrangle-Nb-4 on the NaCl(100) surface is more stable than that of tetrahedron-Nb-4. Both the Nb-4 clusters studied and a single Nb atom prefer the top site of the Cl atom in the NaCl(100) surface. Electronic structure analysis suggests that the interactions between the Nb-4 clusters and the substrate are weak
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