期刊文献+
共找到6篇文章
< 1 >
每页显示 20 50 100
共协理论框架下信息通信技术对经济结构转变的作用:以美国1947-2016年数据为基础 被引量:2
1
作者 姜照华 马娇 《产经评论》 CSSCI 北大核心 2018年第5期18-29,共12页
经济数字化为当今世界经济结构变革的重要主题,信息通信技术(ICT)的应用极大地降低了通信成本和市场交易成本,降低企业运营和管理成本。以1970年为转折点,IT定价促进了美国经济运行机制的创新,对资源配置效率提高起关键性作用。ICT对经... 经济数字化为当今世界经济结构变革的重要主题,信息通信技术(ICT)的应用极大地降低了通信成本和市场交易成本,降低企业运营和管理成本。以1970年为转折点,IT定价促进了美国经济运行机制的创新,对资源配置效率提高起关键性作用。ICT对经济增长的贡献会随着经济增长和经济结构的转变产生一系列新的变化。根据共协理论,运用利益分解法,建立基于劳动者报酬、资本收益和共协利益关系的新的经济增长模型,并通过分析ICT对固定资产投资、科技进步等主要因素的拉动作用,进而测算出ICT对经济增长的作用。结果显示,1947-2016年间,ICT对美国经济增长的贡献变化趋势呈"S"型,且一直为正。把ICT "生产率悖论"放到共协理论框架下,测算服务业对经济增长和生产率提高的贡献率,分析表明服务业与工业的结构失衡抑制了ICT对经济增长的促进作用,导致了ICT的"生产率悖论"。 展开更多
关键词 信息通信技术 共协理论 生产率悖论 产业协调发展 经济增长
下载PDF
茶叶及大米中有机氯农药残留量前处理方法的研究 被引量:7
2
作者 江朝华 陈旭明 《包装与食品机械》 CAS 北大核心 2018年第3期59-61,68,共4页
采用气相色谱法对茶叶和大米中的六六六、滴滴涕8种有机氯农药残留量进行测定,分析超声波提取法、机械振荡提取法和索氏提取法等三种前处理方法对测定结果的影响。结果表明:三种前处理方法中索氏提取法耗费的溶剂最多,时间最长,但提取... 采用气相色谱法对茶叶和大米中的六六六、滴滴涕8种有机氯农药残留量进行测定,分析超声波提取法、机械振荡提取法和索氏提取法等三种前处理方法对测定结果的影响。结果表明:三种前处理方法中索氏提取法耗费的溶剂最多,时间最长,但提取率最高,是测定茶叶中有机氯农药残留量的一种可靠方法,特别适合于能力验证。 展开更多
关键词 有机氯农药残留量 前处理 茶叶
下载PDF
Determination of hydroxyl radicals in TiO2/Ti photoelectrocatalytic oxidation system using Fe(phen)3^2+ spectrophotometry 被引量:1
3
作者 jiang Yan-li LIU Hui-ling +1 位作者 WANG Qun-hui jiang zhao-hua 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2006年第1期158-161,共4页
A new method of determining the cumulate concentration of hydroxyl radicals in the TiO2/Ti photoelectrocatalytic(PEC) oxidation system was established by o-phenanthroline-Fe(Ⅱ)(Fe(phen)3^2+) spectrophotometr... A new method of determining the cumulate concentration of hydroxyl radicals in the TiO2/Ti photoelectrocatalytic(PEC) oxidation system was established by o-phenanthroline-Fe(Ⅱ)(Fe(phen)3^2+) spectrophotometry and using anion exchange membrane. Fe (phen)3^2+ can be oxidized to o-phenanthroline-Fe(Ⅲ)(Fe(phen)3^3+) by strong oxidization of hydroxyl radicals(·OH). Then the cumulate concentration of hydroxyl radicals can be calculated through determining the change of the Fe(phen)3^3+ absorbency at 509 nm. In addition, the research results showed the production rate of hydroxyl radicals was affected obviously by pH of solution, the cumulate concentration of hydroxyl radicals was the largest at nearby the initial pH 6.3 (isoelectric point), and the change direction of pH after illumination tended to nearby isoelectric point. 展开更多
关键词 TiO2 / Ti catalyst PHOTOELECTROCATALYSIS o-phenanthroline-Fe hydroxyl radical anion exchange membrane
下载PDF
Synthesis, Structure, and Photoluminescence Property of a Novel One-dimensional Inorganic-organic Hybrid Gallophosphate JGP-2
4
作者 YANG Yu-lin FAN Rui-qing +3 位作者 jiang zhao-hua WANG Fu-ping LIU Yun-ling PANG Wen-qin 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2009年第2期127-131,共5页
A novel one-dimensional inorganic-organic hybrid gallophosphate compound, Ga(2,2'-bipy)(HPO4). (H2PO4)(denoted JGP-2) was synthesized hydrothermally with 2,2'-bipyridine as a ligand and characterized by X-ra... A novel one-dimensional inorganic-organic hybrid gallophosphate compound, Ga(2,2'-bipy)(HPO4). (H2PO4)(denoted JGP-2) was synthesized hydrothermally with 2,2'-bipyridine as a ligand and characterized by X-ray powder diffraction (XRD), elemental analysis, inductively coupled plasma(ICP), TGA analysis, solid-state ^31p NMR, and luminescence spectra and structurally determined by single-crystal X-ray diffraction analysis. JGP-2 crystallized in the triclinic system, space group P^-1(No.2), with a=0.7818(1) nm, b=0.8611 (2) nm, c=1.0908(2) nm, V=0.6727(2) nm^3 and Z=2 with R1=0.0223. The structure of JGP-2 was built up by alternate arrangement of GaO4N2 octahedra, and HPO4(or H2PO4) tetrahedra to form an infinite one-dimensional corner-sharing-corner(CSC) chain. Through P sites, the CSC chains link with an unusual edge-sharing dimmer, Ga2F4(H2O)2, giving rise to a 4,10-membered ring net layered structure of JGP-7. On excitation at 254 nm, JGP-2 can emit strong blue light at ,λmax=388 rim. JGP-7 presents a strong fluorescence emission band centered at 394 nm(λex=340 nm), the emission energy of JGP-7 is red-shifted comoared with that of JGP-2. 展开更多
关键词 Inorganic-organic hybrid GALLOPHOSPHATE Hydrothermal synthesis CRYSTAL PHOTOLUMINESCENCE
下载PDF
Compound Ceramic Coatings Grown by Micro-plasma Oxidation on Ti-6Al-4V Alloy
5
作者 XUE Wei YAO Zhong-ping jiang zhao-hua 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2006年第B12期126-129,共4页
Compound ceramics coatings on the Ti-6Al-4V alloy were prepared by the direct current micro-plasma oxidation (MPO) in NaAlO2 solution. The composition and morphology of the coatings were studied with the X-ray diffr... Compound ceramics coatings on the Ti-6Al-4V alloy were prepared by the direct current micro-plasma oxidation (MPO) in NaAlO2 solution. The composition and morphology of the coatings were studied with the X-ray diffraction (XRD) and the scanning electron microscopy (SEM), respectively. Inductively coupled plasma atomic emission spectrometer technique was used to analyze the solution features of Ti-6Al-4V alloy in the process of preparation. The results reveal that Al2TiO5 forms in the coatings at the initial stages of MPO reaction, and its content changes rapidly with the reaction continuing: after 20 min, the ceramics coatings are composed of α-Al2O3, 7-Al2O3 and Al2TiO5, but after 40 min, its main composition is of α-Al2O3. The content of Ti in the solution will increase when the MPO time extends, and as will Al in the anode area until, after 30 min, it reaches the maximum and keeps constant from then on. Both substrata of Ti and Al in the electrolyte join the MPO reaction at the initial stage, where the formation of Al2TiO5 happens; but as the MPO reaction prolongs, more and more Al in the electrolyte will take part in the reaction, leading to the appearance of a large amount ofAl2O3. 展开更多
关键词 micro-plasma oxidation ceramic coatings composition inductively coupled plasma atomic emission spectrometer technique (ICP-AES)
下载PDF
荧光定量PCR检测女性HPV-DNA的临床价值
6
作者 姜赵华 肖勇武 《中国社区医师》 2022年第3期82-84,共3页
目的:评价荧光定量PCR技术在女性生殖道人乳头状瘤病毒(HPV-DNA)中的检测价值。方法:收集2016年10月-2021年5月体检中心26630例健康体检者、门诊12521例及住院患者5576例的宫颈分泌物,采用PCR荧光探针法进行HPV-DNA检测,对检测结果进行... 目的:评价荧光定量PCR技术在女性生殖道人乳头状瘤病毒(HPV-DNA)中的检测价值。方法:收集2016年10月-2021年5月体检中心26630例健康体检者、门诊12521例及住院患者5576例的宫颈分泌物,采用PCR荧光探针法进行HPV-DNA检测,对检测结果进行统计分析。结果:门诊患者与住院患者HPV感染率均高于健康体检者,差异有统计学意义(P<0.05)。健康体检者、门诊及住院患者荧光定量PCR法检出HPV感染7860例,阳性率为17.57%;其中高危型2542例(32.34%)、低危型5318例(67.66%);与病理活检结果比较,荧光定量PCR法检测高危型HPV阳性符合率为93.30%,阴性符合率为93.59%,总符合率为93.55%。结论:荧光定量PCR法是HPV-DNA有效的临床检测技术,在检测常见的高危型HPV方面有较好结果,可用于女性大规模体检初筛。 展开更多
关键词 荧光定量PCR技术 人乳头状瘤病毒 宫颈肿瘤
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部