国外科技基础设施科技政策特点和制定流程分析

为探索如何最大限度地发挥战略规划的效用,通过分析国外科技基础设施战略规划在编制目的、范围和过程方面所表现出的特点与不足之处,对我国重大科技基础设施战略规划的制定提出思考和建议。</p

不同经济发展水平区域物流与经济增长的协整关系研究

根据协整检验和因果关系检验等计量方法,利用中国各省1991～2007年物流发展水平和国内生产总值的年度数据,将31个省(市、自治区)按经济密集度不同分成三大类地区,并对其物流和经济增长的关系分析进行了实证分析。实证结果表明:三个区域的物流与经济增长均存在协整关系,发达的一类地区两个变量存在双向Granger因果关系,而后两类地区两个变量仅存在单向的Granger原因。国家自然科学重点资助项目“中国城市化进程的资源环境基础研究”(40535026

生物信息学在药物不良反应研究中的应用

目的介绍生物信息学在药物不良反应(ADRs)机制研究中的应用。方法通过对国内外相关文献的分析,并结合实际研究经验,对生物信息数据库及软件在ADR s事件监测,ADRs机制研究及新药的不良反应预测等方面的应用进行简明而系统论述。同时,对目前Internet上公众可获取的ADR s相关的生物信息学资源进行一定的汇总和归类。结果事实表明,将生物信息学应用于ADR s机制研究和预测,是一种可行、前瞻和先进的尝试。结论生物信息学在ADR s研究中的应用可以促进药物毒理学的发展,成为理性新药开发的重要组成,并标志着ADR s的研究进入了后基因组时代。国家自然科学基金资助项目(30400573

天然橡胶的老化机理

采用人工紫外光老化和自然老化2种方法对天然橡胶(NR)进行老化研究,利用傅里叶变换红外光谱、核磁共振波谱及紫外-可见光吸收光谱测试法对老化产物进行表征,探究了NR的老化机理。结果表明,天然橡胶抗紫外光老化能力较差,在紫外光下照射3 h,其分子结构即发生明显改变,而在自然老化的条件下,天然橡胶经过30 d结构才发生变化。天然橡胶的老化机理:双键α-H最先被活化,随后发生氧化生成醛酮等氧化产物,同时双键被加成,烯氢含量减少;老化过程中,氧化降解与交联反应同时存在,老化前期以降解为主,后期产生交联。以核磁谱图为依据对烯氢的氧化百分比进行定量分析,建立了本实验条件下2种老化方程,并得出了自然老化时间与人工紫外光老化时间的关系,天然橡胶经紫外光老化7 d约相当于自然老化下3个月的老化效果

The Seismic Detecting Technique on Gas Hydrates Based on Wave Impedance Inversion

天然气水合物作为特殊的地质体,可以有效地粘结碎屑颗粒,降低沉积物孔隙度,它的存在改变了地层沉积物的物理性质,造成天然气水合物与围岩速度反差较大,从而与围岩之间存在明显的波阻抗差。为了对地层中是否有天然气水合物赋存进行地震检测,对南海北部神狐海域的天然气水合物赋存区域的地震资料进行波阻抗反演分析,结果显示波阻抗反演方法能够作为探测天然气水合物的一种技术手段,研究区天然气水合物矿体的波阻抗呈高值分布特征,波阻抗值约为3 850--3 960 g/CM3.M/S。综合分析认为,波阻抗反演方法能够用于天然气水合物的地震探测、储层分析和综合研究工作中,反演结果可以为天然气水合物储量计算提供比较准确的矿体面积和厚度参数。As specific geologic body,gas hydrate can cement effectively clastic particles and reduce porosity of deposition,so its presence changes physical property of the sedimentary strata and results in the difference of seismic-wave velocity between gas hydrate and the surrounding rock,and there exists obviously wave impedance difference.In order to detect the presence of sediments with gas hydrate,seismic data of gas hydrate zone in the Shenhu area of the northern South China Sea were used in the wave impedance inversion through practice,testing and summary.Wave impedance inversion method is considered as a kind of good seismic detection technique for identification of gas hydrates,meanwhile,the wave impedance of gas hydrate zone shows high value in the study area,and the wave impedance value is about 3,850-3,960 g/cm3·m/s.All the results suggested that wave impedance inversion can be used for detection,reservoir analysis and comprehensive research of gas hydrates.The wave impedance inversion results can provide comparatively accurate area and thickness parameters of gas hydrate zone for reserves calculation.国家高技术研究发展计划项目(2006AA09A202);国土资源部公益性行业科研专项项目(200811014);国土资源部海洋油气资源与环境地质重点实验室资助项目(MRE200911);国家重点基础研究发展计划项目(2009CB219502

三元乙丙橡胶的紫外光老化机理

利用紫外老化箱对三元乙丙橡胶（EPDM）进行紫外光老化试验,采用核磁共振氢谱（1H-NMR）与傅里叶红外光谱（FT-IR）两种表征方法,追踪EPDM紫外光老化过程的化学结构变化,探讨了EPDM的老化机理。结果表明:EPDM的紫外光老化始于第3单体中活泼氢的断裂,氧化生成含氧产物,进而影响整个分子链。EPDM的抗紫外光老化性能较差,随着老化时间的延长,第3单体中的活泼氢的含量迅速减小,羰基含量呈现非线性增加。EPDM在紫外光老化过程中发生Norrish Ⅱ型光化学反应,生成了端烯烃结构。老化过程中生成了醇、酮、酯和烯烃等多种产物。以羰基相对亚甲基的吸光度A1715/A1464来表征老化程度,建立了本实验条件下的老化方程

吉西他滨联合化疗一线治疗晚期胰腺癌生存结果的亚组meta分析

【目的】Meta分析提示吉西他滨（GEM）联合化疗一线治疗晚期胰腺癌优于标准的GEM单药化疗,在此基础上进行亚组生存结果的meta分析及资料更新,旨在寻找确切有效的化疗方案。【方法】通过MEDLINE、EMBASE、ASCO、ECCO等数据库及论文集检索相关文献。按纳入标准筛选新增文献并进行资料更新。主要对各亚组进行半年生存率、其次是1年生存率的meta分析。【结果】17个随机对照临床试验（RCT）共3 821例患者纳入分析,按化疗方案分为GEM联合顺铂（GEMDDP）、GEM固定剂量率输注联合奥沙利铂（GEMOX）、联合5FU（GEMFU）、联合卡培他滨（GEMCAP）以及联合伊立替康（GEMIRI）等5个亚组,各亚组半年生存率的治疗优势（RD）分别为5%（P=0.24）、9%（P=0.005）、2%（P=0.46）、7%（P=0.03）和-1%（P=0.88）;1年生存率RD为6%（P=0.11）、5%（P=0.07）、4%（P=0.19）、5%（P=0.08）和0（P=0.97）。【结论】现有的证据提示GEMOX、GEMCAP联合化疗方案一线治疗晚期胰腺癌,有较好的应用前景,值得进一步的临床试验

Lithium Storage Performance of Hard Carbons Anode Materials Prepared by Different Precursors

以聚丙烯腈、石油沥青和花生壳为前驱体,在1200℃下碳化制备三种不同的硬碳材料。通过扫描电子显微、X射线衍射、氮气吸附/脱附测试和拉曼光谱等方法探究不同前驱体所制备的硬碳材料的表面形貌和物相结构。通过恒流充放电测试考察了这三种硬碳负极材料的电化学性能。结果表明,花生壳基硬碳的初始放电比容量最高,但首圈库仑效率最低,石油沥青基硬碳的首圈库仑效率最高但是比容量最低,聚丙烯腈基硬碳具有较高的循环比容量和稳定性。Hard carbon is one of the most promising anode material for lithium ion batteries (LIBs) owing to its high stability, widespread availability, low-cost, and excellent performance. The electrochemical properties of hard carbon materials depend strongly on the type of precursors. It is, therefore, very important to choose an excellent hard carbon precursor. Polyacrylonitrile, petroleum pitch and peanut shells were used as raw materials to prepare different hard carbon anode materials for LIBs. These hard carbon anode materials were successfully synthesized in two steps. The selected precursor was firstly carbonized at 600℃ for 1 h in argon atmosphere using heating rate of 1℃·min-1, and then was further carbonized at 1200℃ for 1h in argon atmosphere using heating rate of 5℃·min-1. Under such a low heating rate, a relatively small specific surface area could be obtained as much as possible for the hard carbon anode material. The surface morphology and phase structure of as synthesized hard carbon materials were analyzed by scanning electron microscopy, X-ray diffractometer, nitrogen adsorption analyzer and Raman spectrometer. The ion carrier storage mechanism was further investigated using cyclic voltammetry by examining whether the ion insertion/extraction mechanism is surface-controlled pseudocapacitance or diffusion-limited intercalation. It was further verified that the lithium storage mechanism of hard carbon anode materials is in line with the “adsorption-intercalation” mechanism. The results indicated that polyacrylonitrile-derived hard carbon anode material had low impedance by EIS test. This may be the reason why the low voltage platform of polyacrylonitrile-derived hard carbon materials had a higher specific capacity. The electrochemical performance of different hard carbon materials were investigated through galvanostatic charge and discharge tests. The peanut shell-derived hard carbon material showed the highest initial specific capacity (579.1 mAh·g-1), but the lowest initial coulombic efficiency (49.35%). The petroleum pitch-derived one delivered the highest initial coulombic efficiency (85.97%), but the lowest initial specific capacity (301.7 mAh·g-1). Comparing the cycle performance of these three hard carbon materials, polyacrylonitrile-derived hard carbon materials exhibited the excellent cycling performance (87.17% of capacity over 500 cycles). This study would provide useful assistance to understand the precursor-derived electrochemical properties of hard carbon anode material in practical applications.国家自然科学基金面上项目(21673051);广东省科技厅国际合作项目资助(2019A050510043);广东省科技厅产学研重大专项(2017B010119003)通讯作者:施志聪E-mail:[email protected]:Zhi-CongShiE-mail:[email protected]广东工业大学材料与能源学院,新能源材料与器件系,广东 广州 510000Department of New Energy Materials and Devices, School of Materials and Energy, Guangdong University of Technology, Guangzhou 510000, Guangdong, Chin