中国国际收支双顺差形成的微观机理探究——基于全球价值链视角的实证分析

我国双顺差形成及外汇储备持续扩大的原因与中国在全球价值链中的定位有密切的关系。中国在加入GVC时,由于处在"世界工厂"的低端位置,形成了以外资代工为主的生产贸易模式。中国国际收支双顺差现象只是中国经济嵌入GVC模式的货币镜像。从微观视角探究到的双顺差的国际分工基础,对中国汇率政策的制定具有重要的参考价值

Design and measurements of the high gradient accelerating structures

The purpose of this thesis was to study on design and measurements of the high gradient accelerating structures. After introducing the main parameters to characterize Linacs we explained the application of the periodic accelerating structure. Then we studied TW accelerating structure operating at K-band frequency in order to linearize longitudinal space phase to increase beam brightness in the framework of the Compact Light XLS project in order to produce hard x-ray. We estimated group velocity as a function of frequency both analytically and numerically. Analytical results have a good agreement with the numerical results. The main parameters such as shunt impedance, quality factor (Geometric factor) and R/Q independently from the operating frequency for the TM010, TM110 and TM011 for a single cylindrical “pill-box” have been determined analytically as they provide accurate model for the accelerating structures. In order to characterize a normal conducting high accelerating structure with maximum gradients operating at X-band with extremely low probability of RF breakdown, an electroformed SW structures has been fabricated and characterized by SLAC and INFN with collaboration of other institute around the world at 11.424 GHz, coated with Au-Ni. We designed a gold plate RF high gradient structure operating at the X- band coated with Au-Ni. Bench measurements have been performed in the Department of SBAI of the University of Rome “La Sapienza”. The Slater method for the SW cavity has been employed in order to quantify the electric field inside the structure. Comparing the results with the results exposed from HFSS we report the features that have been quantified, showing good agreement. We continued working on the perturbation effect due to the aperture coupled between a waveguide and a cavity but for our application in SW multi-cell high gradient accelerating structure we studied on theoretical approach for reflection coefficient calculation in a SW cavity coupled to a waveguide. One method was based on circuit theory in which we found the overall Q of a resonant circuit for a cavity coupled to an external waveguide containing the RF generator. Q calculation led to the determining of the shunt impedance and consequently the reflection coefficient calculation. Comparison of the results shows a good agreement with the numerical results carried out by using the numerical code, HFSS. Another method of reflection coefficient calculation has been accomplished. We applied the modified Bethe’s theory presented by Collin and developed by De santis, Mostacci and L.Palumbo for TM01 mode cavities coupled by a small hole with a thickness size comparable to the wavelength. The amplitudes of forward and backward waves due to polarizabilites have been determined and we found equations for reflection and transmission coefficients. We demonstrated that our equation for reflection coefficient calculation is an analogous of the reflection coefficient obtained by Collin for TE10 using the circuit theory

Simultaneous Determination of Ultra-trace Level of As,Sb,Bi,Ge,Sn and Hg in Coastal and Estuarine Seawater by Chemical Vapor Generation and Inductively Coupled Plasma Mass Spectrometry

建立了化学蒸汽发生(CVg)电感耦合等离子体质谱(ICP MS)同时测定近岸及河口海水中超痕量AS、Sb、bI、gE、Sn和Hg元素的方法。研究了CVg过程中kbH4、盐酸和硫脲的浓度以及样品流速、载气流速、海水样品盐度等对方法分析性能的影响。结果表明,在0.70%盐酸、0.10 g/l硫脲、11.0 g/l硼氢化钾、载气0.40 l/MIn条件下,6种待测元素的信噪比最高。优化实验条件下,AS、Sb、bI、gE、Sn和Hg的质量浓度在0.1~5.0μg/l内呈良好线性,相关系数不低于0.996 6;方法对0.1μg/l加标样品的相对标准偏差(rSd,n=5)为3.9%~8.9%,实际海水样品的加标回收率为89%~112%;方法的流程空白为0.012~0.036μg/l,定量下限(lOQS,10σ)在0.006 7~0.026μg/l之间,可满足近岸及河口海水样品中超痕量元素测定的需要。A chemical vapor generation(CVG) and inductively coupled plasma mass spectrometric(ICP MS) method was proposed for the simultaneous determination of ultra-trace level of As,Sb,Bi,Ge,Sn,and Hg in coastal and estuarine seawater.Effects of operating parameters,including concentrations of KBH4,HCl and thiourea,pump flow rate and carrier gas flow rate on analytical performance were studied.The results showed that good signal to noise(S/N) ratios for all the analysed elements were obtained when 0.70% HCl,0.10 g/L thiourea,11.0 g/L KBH4,and 0.40 L/min carrier gas were used in the CVG procedure.The relative standard deviations(RSDs,n=5) for 0.10 μg/L spiked sample were in the range of 3.9%-8.9%.The spiked recoveries for the seawater samples were between 89% and 112%.The method blanks were in the range of 0.012-0.036 μg/L.The limits of quantitation(LOQs,10σ) for the developed method were obtained between 0.006 7 μg/L and 0.026 μg/L.The method could be applied in the simultaneous determination of As,Sb,Bi,Ge,Sn and Hg in coastal and estuarine seawater.近海海洋环境科学国家重点实验室自主创新项目(MELRI0703

早期糖尿病视网膜病变中eEF2K活性变化的实验观察

目的观察早期糖尿病大鼠视网膜中真核生物延伸因子2激酶(e EF2K)的变化,探讨e EF2K活性变化在早期糖尿病视网膜病变(DR)中的意义。方法建立SD大鼠链脲佐菌素(STZ)糖尿病高血糖模型,造模成功后,设立糖尿病大鼠(DM)组和正常对照(NC)组。qRT-PCR检测DM组和NC组4周和8周时大鼠神经视网膜中e EF2K的表达情况。免疫荧光法观察定位神经视网膜中e EF2K激活标志物-磷酸化真核生物延伸因子2(p-eEF2)和Müller细胞活化标志物胶质纤维酸性蛋白(GFAP)表达情况。结果 4周和8周时DM组大鼠神经视网膜中e EF2K的表达水平与NC组相比无明显变化。8周时DM组大鼠神经视网膜各层均出现e EF2K激活表现,即p-eEF2表达增强。神经节细胞层出现细胞凋亡样改变,凋亡样神经节细胞中e EF2的磷酸化水平增强最为明显。神经视网膜中Müller细胞活化,GFAP蛋白表达增强。结论 STZ诱导糖尿病大鼠早期视网膜病变中神经视网膜内e EF2K激活,在凋亡样神经节细胞中e EF2K活性上升最为显著。福建省自然科学基金项目(2016J 01412);;国家自然科学基金青年项目(81700864

Material and Energy Conversion of Integrated 100,t/a-Scale Bio-Jet Fuel-Range Hydrocarbon Production System via Aqueous Conversion of Biomass

以农业废弃物生物质为原料，利用水相转化技术，进行了百吨/年规模生物航油类烃(C8~C15)合成试运行.过程中采用两步酸解法分别将玉米秸秆中半纤维素和纤维素转化为糠醛和乙酰丙酸，作为生物质基平台化合物.在碱性条件下糠醛与乙酰丙酸经Aldol缩合反应实现碳链增长，生成的长链含氧中间体经过低温预加氢、高温加氢脱氧及精制，生成C8~C15范围内液态烃，可作为生物航油组分.以试运行实验结果为基础，进行了过程的物质与能量转化分析.结果表明，该路线获得液态烃类的基本性质满足合成航油ASTM-7566标准要求，并充分利用了原料中纤维素和半纤维素组分，是一条基于生物质的长链液态烃合成路线，1t航油约需10~12t干基玉米秸秆

304不锈钢表面十七氟癸基三甲氧基硅烷的缓蚀性能研究

采用电化学方法对十七氟癸基三甲氧基硅烷在304不锈钢表面的缓蚀性能进行了研究,结果发现,十七氟癸基三甲氧基硅烷对304SS有明显的缓蚀作用,增大了304不锈钢表面的电荷转移电阻,降低了自腐蚀电流密度并且提高了点蚀电位,缓蚀效率高达96%。国家科技支撑计划(2014BAE12B01

Reviews on Preparation and Determination of a-glucosidase Inhibitor

文中综述了国内外用天然植物和微生物制备具有降血糖作用的α-葡萄糖苷酶抑制剂的工艺过程,并对α-葡萄糖苷酶抑制剂的检测方法进行了总结。The preparation process of α- glucosidase inhibitor from natural plant and microorganism with hypoglycemic activity was detailedly discussed in this paper. And the main determination methods of this inhibitor were detailedly summarized.江西省教育厅科技项目(赣教技字[2007]285号);; 江西科技师范学院人才创新基金项

靶向HIV-1pol的高效人工miRNA的构建与体外抗病毒能力评价

RNAi技术在抗HIV-1治疗研究中已显示出巨大潜力,获得可高效特异抑制HIV-1的RNAi元件是进行相关研究的重要基础。miRNA在抑制和表达方式上相比siRNA具有更多的优势。本研究即探讨构建可高效特异靶向HIV-1的人工miRNA元件。选择以保守性较好的HIV-1pol基因为靶区筛选高效保守的RNAi序列,设计了16个可靶向pol区高保守区段的RNAi靶点,构建表达载体与HIV-1感染性克隆进行共转染抑制实验,筛选显示pol1026序列兼具高保守性及高抑制效率特点。以天然miR-30a为基础骨架构建了靶向pol1026靶点的人工miRNA元件,通过与HIV-1感染性克隆质粒的共转染抑制实验验证获得了可有效抑制HIV-1表达的人工miRNA元件(miR-1026E)。通过与携带靶序列的报告质粒的共转染实验证明miR-1026E具有良好的靶点特异性。本研究进一步构建了携带miR-1026E表达元件的重组慢病毒,转导MT-4细胞并对转导后细胞进行克隆化筛选,获得稳定整合miR-1026E表达元件的MT-4-miR1026E细胞克隆,该细胞在体外攻毒实验中可高效抑制HIV-1的复制,具有显著的抑制HIV-1的能力。同时应用实时RT-PCR方法检测显示,miR-1026E在细胞中不会影响内源性代表miRNA(miR-181与miR-16)的表达水平和干扰素效应相关基因stat1的表达水平,具有良好的特异性。所获得的可特异高效抑制HIV-1复制的人工miRNA元件可为抗HIV-1研究提供重要参考

环氧泽泻烯对2型糖尿病小鼠的降糖作用

目的探索环氧泽泻烯的降血糖活性。方法采用链脲佐菌素与烟酰胺建立2型糖尿病小鼠模型。腹腔注射链脲佐菌素与烟酰胺后的d 21测定血糖,d 22进行口服葡萄糖耐量试验。选择罗格列酮作为阳性对照药,每天按小鼠体重以10 mg·kg-1剂量灌胃给药,连续3周;环氧泽泻烯不同剂量组每天分别按小鼠体重以5、10、20 mg·kg-1剂量灌胃给药,连续3周。此外,采用油红O染色法探索了0.5、1μmol·L-1环氧泽泻烯对3T3-L1前脂肪细胞分化的影响。结果环氧泽泻烯不仅使2型糖尿病小鼠空腹血糖下降,而且在口服葡萄糖耐量试验期间也表现出降低血糖的趋势。在0.5、1μmol·L-1浓度下,环氧泽泻烯促进了3T3-L1前脂肪细胞分化过程。结论环氧泽泻烯可能具有降血糖活性,加速前脂肪细胞分化过程,其机制有待进一步研究。国家自然科学基金面上项目(No 81773601)福建省教育厅中青年教师教育科研项目(No JT180664)福建省卫生系统项目(No 2015-ZQN-JC-45)福建省中医药重点研究室项目(No ZD201405

江苏省部分地区散发戊型肝炎流行病学及病毒基因型

目的了解江苏省部分地区散发戊型肝炎病例的流行特征及病毒基因型。方法在江苏省部分地区开展为期一年戊型肝炎病例监测,用酶联免疫吸附试验(enzyme-linked immunosor-dent assay,ELISA)对各医疗单位报告的急性肝炎病例进行血清学分型,对其中确诊为急性戊型肝炎病例进行流行病学分析以及戊型肝炎病毒(hepatits E virus,HEV)RNA检测和序列分析。结果男女戊型肝炎病例比例为4.4∶1,84.0%的病例集中在40岁及以上的年龄组,全年均有戊型肝炎病例发生,70.5%的病例集中在上年12月份至次年的4月份间;HEV基因分型检测结果为HEV-1型与HEV-4型,所占比例分别为5.1%、94.9%。结论江苏省戊型肝炎发病比例男性高于女性,多见于40岁以上人群,冬春季节发病较高,戊型肝炎病毒株以HEV-4型为主