排序方式： 共有114条查询结果，搜索用时 31 毫秒
21.
研究了双水杨醛邻苯二胺(SALOPHEN)与Fe(III)的显色反应,试验表明,在pH=2.21的氨基乙酸-盐酸缓冲介质中,在阴离子表面活性剂十二烷基磺酸钠(SDS)存在下,Fe(III)与双水杨醛邻苯二胺(SALOPHEN)形成1:1稳定的棕色配合物。其最大吸收峰位于462nm处,表观摩尔吸光系数为4.1'104。铁浓度在0-4.5mg/ml范围内符合比尔定律。方法具有较高的灵敏度和选择性。应用于食品样品中微量铁的测定,结果满意。 相似文献
22.
Scrubbing of NO
x
from the gas phase with Fe(II)EDTA has been shown to be highly effective. A new biological method can be used to convert
NO to N2 and regenerate the chelating agent Fe(II)EDTA for continuous NO absorption. The core of this biological regeneration is how
to effectively simultaneous reduce Fe(III)EDTA and Fe(II)EDTA-NO, two mainly products in the ferrous chelate absorption solution.
The biological reduction rate of Fe(III)EDTA plays a main role for the NO
x
removal efficiency. In this paper, a bacterial strain identified asKlebsiella Trevisan sp. was used to demonstrate an inhibition of Fe(III)EDTA reduction in the presence of Fe(II)EDTA-NO. The competitive inhibition
experiments indicted that Fe(II)EDTA-NO inhibited not only the growth rate of the iron-reduction bacterial strain but also
the Fe(III)EDTA reduction rate. Cell growth rate and Fe(III)EDTA reduction rate decreased with increasing Fe(II)EDTA-NO concentration
in the solution.
Project (No. 20176052) supported by the National Natural Science Foundation of China and the Scientific Research Foundation
for Returned Overseas Chinese Scholars, Ministry of Education 相似文献
23.
采用CiteSpace V可视化研究工具，以量化的方式梳理和总结国外军事体能训练领域的研究热点及演进脉络，以期为促进我国军事体能训练理论体系建设与发展。研究表明，从年发文量来看，军事体能训练研究在2011年和2015年发文量骤增。从地区来看，美国发文量最多，澳大利亚和英国的影响力最大；军事体能训练研究涉及体育学、医学等多个学科领域，呈现多学科交叉融合的特点；军事体能训练研究的热点人群包括新兵、男性和军人等，热点内容涉及训练伤及其预防和训练表现等；军事体能训练的演变过程可分为萌芽阶段、初步的训练优化阶段和深入的训练优化阶段，研究主题、研究手段和研究人群日益丰富。 相似文献
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为了解我国近10年压力容器研究的发展现状，理清该研究领域的热点问题。通过中国知网数据库，检索了2008-2017年关于压力容器研究者的文章4669篇，应用热点分析方法，借助文献可视化软件Citespace得出可视化图谱。通过Citespace得到我国压力容器研究关键词发展趋势图和知识图谱。我国压力容器研究经历了活跃成长和稳步增长两个时期；目前关于压力容器研究热点分别是锅炉压力容器、反应堆压力容器、压力容器、压力面积法、固定式、焊接接头、有限元共7个研究热点；我国压力容器设计从常规设计正逐步转移到分析设计；我国压力容器研究组织和领军人物主要集中在相关研究院，研究组织机构较单一。 相似文献
26.
在国际技术掣肘加剧和国内创新人才供需失衡的现实背景下,优化创新人才培养政策成为实现经济高质量发展的基础。基于中国情境,运用文献计量分析法梳理了中国1996—2019年创新人才培养政策的现状、问题并提出政策方向。研究发现：我国创新人才培养的支持政策力度逐年加大,并经历了“统包统揽-高度集中-主导”三个阶段的政策演变,呈现出线性沉降、区域分化、融合推进、初形集成的形式特征,以及集中于创新价值链中后端、多元不饱和、统分联动却高度自由裁量、开放的形式化的内容特征,在前瞻性、协同性、引导性、规范性、功能性等方面存在不足,导致培养对象的识别不准与结构失衡、政策工具效率损失、组织保障逆向失配及考评结果二维异化等问题。对此,未来政策的优化,需转变重术轻学的观念,加大对基础研究的支持和供给型政策的供应,并辅之以规范和约束;强化知识产权保护,提供保护性或兜底性需求型政策;推动政府职能由主导向引导转变。本文补充了现有相关研究对全局定量分析、中国情境考察的不足。 相似文献
27.
Xiaohua Li David Demers 《Journal of Interlibrary Loan, Document Delivery & Electronic Reserve》2013,23(4):263-269
To improve the efficiency of Ryan-Matura Library's electronic reserve (e-reserve) service, the staff of the library and the Office of Instructional Technology at Sacred Heart University codeveloped and implemented a system that streamlined the request and delivery of e-reserves for faculty and students. This system utilizes the institution's integrated course/content management system (Blackboard) along with a custom-built Web application that facilitates the request, retrieval, digitization, and delivery of e-reserve materials directly to students within their Blackboard courses. 相似文献
28.
目的：构建2004－2013年糖尿病领域高被引论文主体的合作网络知识图谱,揭示主要作者、机构和国家,分析其合作模式。方法：用可视化软件Citespace绘制2004－2013年糖尿病领域高被引论文的作者、机构、国家合作网络图谱。结果：核心作者是Graham Nichol、SM Grundy和Hertzel C．Gerstein等,团体内部合作密切,团体间合作极少。核心研究机构是Harvard Univ、Brigham＆Womens Hosp、Univ Sydney等,大学成为科研的主要力量。最有影响力的发文国家是美国、英国和加拿大,合作十分密切。结论：2004－2013年糖尿病领域高被引论文主体合作模式有单点型、双核型、发展型和完备型4种。基于地缘和机构属性的合作还处于摸索与探索阶段,应进一步加强地域间,高校、医疗机构、事业单位和科研机构间的合作与交流。 相似文献
29.
This short notice provides a novel and preliminary analysis of the source for the first Arabic history of the crusades, and contributes to the understanding of the penetration of the crusades as a distinct phenomenon into the Islamic world. The Arabic history, Min Ta?rīkh al-?urūb al-muqaddasa fī l-mashriq al-mad?ūwa ?arb al-?alīb was published in Jerusalem in 1865 under the authorship of the (late) Melkite patriarch, Maximos III Mazloum (d. 1855). The book was a modified translation of the French Les Guerres saintes d’Outre-Mer, ou tableau des croisades, retracé d’après les chroniques contemporaines, published in 1840 by Maxime de Montrond, who was heavily inspired by Michaud's Histoire des croisades. Though created in a Christian Francophile milieu, it seems clear that the Arabic translation was intended not only for a Christian audience, but also for a Muslim readership, as evidenced by examples, provided here, of the modifications of the French original. 相似文献
30.
Emma Kate Zadow Cecilia Marie Kitic Sam Shi Xuan Wu James William Fell Murray John Adams 《European Journal of Sport Science》2018,18(3):367-375
Exercise has been demonstrated to have considerable effects upon haemostasis, with activation dependent upon the duration and intensity of the exercise bout. In addition, markers of coagulation and fibrinolysis have been shown to possess circadian rhythms, peaking within the morning (0600–1200?h). Therefore, the time of day in which exercise is performed may influence the activation of the coagulation and fibrinolytic systems. This study aimed to examine coagulation and fibrinolytic responses to short-duration high-intensity exercise when completed at different times of the day. Fifteen male cyclists (VO2max: 60.3?±?8.1?ml?kg?1?min?1) completed a 4-km cycling time trial (TT) on five separate occasions at 0830, 1130, 1430, 1730 and 2030. Venous blood samples were obtained pre- and immediately post-exercise, and analysed for tissue factor (TF), tissue factor pathway inhibitor (TFPI), thrombin–anti-thrombin complexes (TAT) and D-Dimer. Exercise significantly increased plasma concentrations of TF (p?p?p?p?p?=?.004) and TFPI (p?=?.031), with 0830 greater than 1730 (p .001), while 1730 was less than 2030?h (p?=?.008), respectively. There was no significant effect of time of day for TAT (p?=?.364) and D-Dimer (p?=?.228). Power output, TT time and heart rate were not significantly different between TTs (p?>?.05); however, percentage VO2max was greater at 1730 when compared to 2030 (p?=?.04). Due to a time-of-day effect present within TF, peaking at 0830, caution should be applied when prescribing short-duration high-intensity exercise bout within the morning in populations predisposed to hypercoagulability. 相似文献