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Search Results: 1 - 10 of 68713 matches for " 闫玉奎 "
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EVA-g-MAH对CaSO4晶须/尼龙6复合材料性能的影响
Effects of EVA-g-MAH on the properties of CaSO4 whiskers/nylon 6 composites

孙文,周松,马俊辉,,珂华,张宇
- , 2017, DOI: 10.13801/j.cnki.fhclxb.20161216.001
Abstract: 采用马来酸酐接枝乙烯-醋酸乙烯酯共聚物(EVA-g-MAH)对CaSO4晶须/尼龙6(CaSO4W/PA6)增韧改性。通过双螺杆挤出机制备了CaSO4W/PA6二元、CaSO4W-(EVA-g-MAH)/PA6三元复合材料,用SEM、DSC、XRD等观察和表征了形貌、结构和结晶参数,并测试了力学性能。研究表明:添加少量CaSO4W可提高PA6的结晶速率,而高含量CaSO4W导致PA6结晶速率降低,促进γ晶型形成。添加10%(质量分数) CaSO4W可同时提高PA6的刚性和韧性;添加30% CaSO4W可进一步提高PA6的刚性,但PA6的韧性明显降低。添加2.5%和5%(质量分数) EVA-g-MAH,能使30% CaSO4W-(EVA-g-MAH)/PA6的抗冲击强度分别提高25.0%和76.7%,并使其具有较高韧性。冲击强度的提高主要源于EVA-g-MAH所产生的能量耗散、改善应力的有效传递、增强CaSO4W与PA6的界面以及EVA-g-MAH/PA6共混体系较好的相容性。 Maleic anhydride grafted ethylene-vinyl acetate copolymer (EVA-g-MAH) was used to toughen the calcium sulfate whiskers (CaSO4W)/nylon6 (PA6) composites. The CaSO4W/PA6 and CaSO4W-(EVA-g-MAH)/PA6 composites were prepared using by a twin screw extruder, and analyzed by means of SEM, DSC, XRD and mechanical testing. The results indicate that addition of small amounts of CaSO4W can increase the rate of crystallization, however, higher CaSO4W contents lead to a decreased rate of crystalization and promotion of forming γ-crystals of PA6. Adding 10% (mass fraction) CaSO4W increases both the stiffness and toughness of PA6. Adding 30% CaSO4W can further improve the stiffness but significantly decreases the fracture toughness of PA6. With 2.5% and 5% mass fraction of EVA-g-MAH, the impact strength of 30%CaSO4W-(EVA-g-MAH)/PA6 increases by 25.0% and 76.7%, respectively, thus imparting the higher toughness to the 30%CaSO4W/PA6. The improvement of impact strength of the composites mainly results from energy-absorption process, effective stress transfering, the increasing in interfacial adhesion between CaSO4W and PA6 in the presence of EVA-g-MAH as well as good miscibility of EVA-g-MAH/PA6 blend system.
基于等温滴定量热技术表征的中药注射剂临床联合用药相容性评价
冯雪,鄢丹*,,任永申,张萍,,,肖小河*
药学学报 , 2011,
Abstract: 为建立一种快速评价中药注射剂临床联合用药相容性的方法,采用等温滴定量热法(isothermaltitrationcalorimetry,itc),考察模式药益气复脉冻干粉针(yqfm)与常用联合用药维生素c注射液(vc)及5%葡萄糖注射液(5%gs)的相容性,以热力学参数吉布斯自由能(δg)、焓变(δh)、熵变(δs)判断溶合反应类型,以反应活性谱判断反应热量变化,辅以化学特征色谱法进行佐证。结果显示,yqfm与vc溶合过程中│δh│>t│δs│,为焓驱动反应,且反应活性谱显示两者溶合放出大量热,即溶合过程中化学反应起主导作用,活性成分发生质变;与5%gs溶合过程│δh│
水泥乳化沥青混合料施工和易性评价方法及影响因素
Evaluation method and influencing factors for construction workability of cement-emulsified asphalt mixture

张翠红,焦生杰,曹学鹏,,陈小雪,齐彦秋
- , 2018,
Abstract: 为了研究水泥乳化沥青混合料的施工和易性及其对压实性能的影响,基于沥青表面自由能理论,采用拌和扭矩表征该混合料的施工和易性。通过拌和和易性测试设备和旋转压实仪分别测定混合料的拌和扭矩和压实性能。通过抗压强度极差分析法确定常温下混合料的最优配合比方案,提出该混合料的拌和和易性评价方法及影响因素;根据拌和状态和拌和扭矩值确定10 ℃、25 ℃、40 ℃时混合料的最佳含水率与拌和时间的推荐值,并分析3种温度下不同摊铺模拟初压次数时的摊铺和易性对压实性能的影响。研究结果表明:含水率对混合料的拌和和易性有显著影响,10 ℃、25 ℃、40 ℃时的最佳含水率(质量分数)分别为5.25%、6%、6.5%,3种温度下混合料的推荐拌和时间均为12 s;整体上随着温度的增加,试件空隙率随扭矩的增加逐渐下降,抗压强度随扭矩的增加而逐渐增大,最佳施工温度为40 ℃;10 ℃、25 ℃时的最佳初压次数为20,相应的试件密实度分别为84.3%和85%;40 ℃时最佳初压次数为30,相应的试件密实度为85.7%。采用给出的水泥乳化沥青混合料拌和和易性评价方法可为路面拌和施工工艺提供参考,最佳初压次数对应的密实度可对摊铺机振捣梁和熨平板频率参数的选择与优化组合提供参考。
In order to study the construction workability of cement-emulsified asphalt mixture and its effect on the compaction properties, the mixing torque value of cement-emulsified asphalt mixture was employed to represent construction workability on the basis of the surface free energy theory of asphalt. By employing the test equipment of mixing workability and superpave gyratory compactor (SGC), mixing torque value and compaction performance of the mixture were respectively measured. The optimal mix ratio scheme of the mixture at normal temperature was determined by the range analysis of compressive strength, and evaluation method and influencing factors for mixing workability of the mixture were proposed. According to the mixing states and mixing torque values, the optimum moisture content and recommended value of mixing time were determined for the mixture at 10 ℃,25 ℃ and 40 ℃. Analysis was did about the effect of paving workability on compaction performance for the mixtures at different initial compaction times under the three temperatures. The results show that moisture content has a significant effect on mixing workability of the mixture. The optimum moisture contents of the mixture are 5.25%, 6% and 6.5% at 10 ℃, 25 ℃ and 40 ℃, respectively. The recommended mixing time of the mixture at three temperatures is 12 s. As a whole, with the increase of temperature, the void fraction of specimen decreases and the compressive strength increases with the increase of torque value. The best construction temperature is 40 ℃. The optimal initial compaction times are 20 at 10 ℃ and 25 ℃, and the corresponding specimen compactness are 84.3% and 85%, respectively. The optimal initial compaction times are 30 at 40 ℃, and the corresponding specimen compactness is 85.7%. The evaluation method for mixing workability of the cement-emulsified asphalt mixture is able to offer reference for the mixing technology of pavement construction. The compactness value corresponding to the optimal initial compaction times can provide reference for the
基于DEA方法的吉林省农业生产效率的实证分析
Empirical Analysis on Agricultural Production Efficiency in Jilin Province Based on DEA Method
 [PDF]

, 于卓熙
Statistics and Applications (SA) , 2013, DOI: 10.12677/SA.2013.23009
Abstract:

本文利用DEA方法分析了自社会主义新农村政策提出以来吉林省县级市的农业生产效率,包括规模效率、纯技术效率及全要素生产力指数的变化。本文认为吉林省县级市的规模效率处于递增状态,即依靠外界投入改变产出生产规模效益的方法取得了很好的效果。社会主义新农村政策提出以后,促进了吉林省县级市的全要素生产力指数快速增加,农村农业生产率有了显著提高。纯技术效率初期递增而后处于递减状态,说明吉林省的农业生产效率的提高除了依赖扩大生产规模,在技术层次上的投入也需进一步加强。
Based on the method of Data Envelopment Analysis, we analyzed the changes of agricultural pro- duction efficiency in county-level cities of Jilin Province, including scale efficiency, pure technical efficiency and the total factor productivity index, since the New Socialist Countryside policy was put forward. This arti- cle suggests that the scale efficiency of the county-level cities in Jilin Province shows a tendency of increas- ing, which reveals that changing the output production scale efficiency by depending on outside inputs has achieved remarkable success. New Socialist Countryside policy promotes the rapid increase of total factor productivity index in the county-level cities of Jilin Province and helps to increase the agricultural productiv- ity in rural areas. The initial increase and later decrease of pure technical efficiency illustrates that the effi- ciency of agricultural production in Jilin Province mainly relies on the expansion of production scale, and the technical inputs should be further strengthened.

·问题讨论·固氮酶催化还原C2H2和N2的探讨

生物化学与生物物理进展 , 1986,
Abstract:
固氮酶催化乙炔还原的色谱测定

生物化学与生物物理进展 , 1984,
Abstract: 一般认为(15)~N_2同位素示踪技术是研究固氮作用最可靠的方法。Dilworth 1965年发现乙炔也是固氮微生物的一种底物,报道了巴氏梭菌粗提液能还原乙炔为乙烯。Hardy和Knight最先用氢火焰离子化气相色谱法测定了还原反应的产物。此后,这一方法便成了研究固氮活性的有效方法。由于气相色谱法较之(15)~N_2同位素示踪法具有简单、迅速,灵敏等优点,并能适应江河、湖泊、土壤测定的需要,得到了广泛的应用。 (一) 在固氮研究中,无论是土壤肥力调查,固氮资源开发以及对于固氮酶分子水平的结构与功能,底物反应动力学等的研究,都是一项工作量
用于北京地铁模拟的BSSS系统

系统工程理论与实践 , 1984,
Abstract: 系统模拟是进行系统研究的重要手段,已开始应用于社会、经济、科学研究、军事等领域。各种通用和专用模拟语言的出现为模拟方法更广泛地应用提供了有力的工具。 我们在Burroughs B6810大型计算机上,应用GPSS语言(这是对离散系统进行模拟的、面向问题的高级程序设计语言)及其它软件资源,开发了北京地铁系统模拟软件——BSSS系统。利用此软件系统对现行的北京地铁系统进行了模拟,取得了满意的结果。 一 问题的提出
几种微机故障诊断排除方法

计算机系统应用 , 1995,
Abstract: 本文是作者近几年在计算机科研工作中处理微机故障的经验小结。它给出了处理微机故障的四种方法及相应实例,这对于从事计算机工作的同仁会有一定的参考价值。
细内径高效液相色谱柱的联接

科学通报 , 1982,
Abstract: 从七十年代后期开始研究的细内径高效液相色谱柱目前已有了令人瞩目的发展。为在保持高效的基础上减小柱内径,我们曾系统地研究了柱外效应对柱效的影响,并在此基础上发展出了K-1型细内径高效液相色谱柱以及为充分发挥细内径高效柱的柱效而专门设计的K-2型高效液相色谱仪。使2毫米内径,柱长为100毫米、150毫米和250毫米的吸附型柱以及150毫米的键合相柱分别达到了6000、9000、20000和7000以上的理论塔板数,
液相色谱、毛细管电泳及质谱用于蛇毒蛋白的分离与鉴定

科学通报 , 1994,
Abstract: 现代分析技术的发展为生物大分子的分离鉴定提供了强有力的手段,因而大大加速了生命科学的研究进展.近几年,毛细管区带电泳和飞行时间质谱在分离和鉴定生物大分子方面显示了快速、简便、高效等特点,本文采用毛细管区带电泳和飞行时间质谱,对常压色谱分离得到的蛇毒蛋白中的某些活性组分进行了分离和鉴定,并讨论了三种技术在分离蛇毒蛋白上的差异.
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