22 research outputs found

    离子液体在稀土萃取分离中的应用

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    稀土元素萃取分离是获得高纯单一稀土的关键步骤之一,开发对稀土元素具有高效分离能力的新材料和新过程是全球科技工作者研究的热点。离子液体作为一类代表性的新材料,因具有不挥发、不易燃、稳定性好、结构性质可调等独特的物理化学性质,近年来在稀土元素萃取分离领域的应用受到广泛关注。在稀土元素萃取分离过程中,离子液体不仅可用作萃取剂,也可作为稀释剂、协萃剂或同时作为萃取剂和稀释剂。系统评述了离子液体在稀土元素萃取分离中的研究进展,对非功能化离子液体和功能化离子液体在稀土元素萃取分离中的萃取行为和萃取机理进行了分析。同时,对该领域的发展所面临的主要问题和进一步的研究工作进行了探讨

    Individual and Organizational Factors Affecting Chinese Civil Aviation Safety: Event Analysis Based on HFACS Framework

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    主要通过民航事故征候(事件)的分析,对影响飞行安全的人的因素进行研究。数据分析主要采用编码分析的方法,结果发现:在个体层面,对事故征候影响顺序是技能差错、决策差错与知觉差错;机组内部的沟通与协调不畅在各个飞行阶段都存在;在组织层面,监督、资源管理、文化与氛围是比较有影响的组织因素;组织内部与外部的信息界面是飞行安全的隐患之一。与此同时,分析了该项目研究的不足之处,提出改善民航飞行安全的建并指出今后研究的方向

    离子液体在稀土萃取分离中的应用

    No full text
    稀土元素萃取分离是获得高纯单一稀土的关键步骤之一,开发对稀土元素具有高效分离能力的新材料和新过程是全球科技工作者研究的热点。离子液体作为一类代表性的新材料,因具有不挥发、不易燃、稳定性好、结构性质可调等独特的物理化学性质,近年来在稀土元素萃取分离领域的应用受到广泛关注。在稀土元素萃取分离过程中,离子液体不仅可用作萃取剂,也可作为稀释剂、协萃剂或同时作为萃取剂和稀释剂。系统评述了离子液体在稀土元素萃取分离中的研究进展,对非功能化离子液体和功能化离子液体在稀土元素萃取分离中的萃取行为和萃取机理进行了分析。同时,对该领域的发展所面临的主要问题和进一步的研究工作进行了探讨

    利用两种模型预测多孔介质中气体水合物平衡分解条件

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    分别利用两种热力学方法(基于逸度相等的方法与基于活度相等的方法)预测了不同多孔介质中气体水合物的平衡分解条件,对于非水合物相,逸度方法采用Trebble—Bishnoi(TB)方程,而活度方法则使用Soave—Redlich—Kwong(SRK)方程,对于水合物相,两种方法都利用了van der Waals—Platteeuw模型结合Llamedo等关于毛细管力作用模型来模拟.两种方法的预测结果与实验结果吻合,逸度方法的预测效果要好于活度方法

    Studies on Hydrogenase from Rhizobium japonicum and Rhizobium arachis

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    根瘤菌在共生固氮过程中因放 H2 所消耗的能量约占固氮总能量的 4 0 %~ 6 0 % .吸氢酶则能回收和利用固氮过程所放的 H2 ,减少能量损失 ,从而提高共生固氮效率 .在厌氧条件下 ,加入防止酶蛋白聚合的试剂 ,利用 DEAE-纤维素和 Sephacryl S- 2 0 0柱层析 ,从自养性大豆根瘤菌和花生根瘤菌类菌体中分离并提纯膜结合态氢酶 .纯化的两种氢酶表现相近的分子特征 :均含有大 (6 0 k D,6 5k D)、小 (30 k D,35k D)两个亚基 ;均为 Ni Fe-氢酶 ,并具有较高的吸 H2 活性 .大豆根瘤菌氢酶的纯酶组分不含 Cyt b559.花生根瘤菌 L8- 3菌株能进行化能自养生长 ,诱导出高吸 H2 活性 .根瘤菌的吸H2 能明显提高固氮活性 .从具有高吸 H2 活性的花生根瘤菌中分离并克隆吸氢基因 ,采用 PCR和探针杂交技术 ,获得含有吸氢基因的质粒 p Z- 55.利用多种限制性内切酶构建了质粒 p Z- 55的物理图谱 .通过三亲本杂交 ,将含吸氢基因的重组质粒转移到不吸 H2 的花生和毛豆根瘤菌中 ,所获得的结合株在自生和共生条件下均表达吸 H2 活性 .以结合株接种大田花生 ,获得的共生根瘤的吸 H2 活性比接种受体株提高 4倍 ,花生叶片和种子的含 N量、产量分别提高 1.7%、8.9%和 9.6 % .Hydrogen produced by nitrogenase consumed 40~60% of energy of symbiotic nitrogen fixation. Hydrogenase can uptake and reuse the H 2 produced by nitrogenase, which results in decreasing the loss of energy and increasing the efficiency of nitrogen fixation. The membrane bound hydrogenase from autotrophical cultured Rhizobium japanicum and from the bacteroids of peanut nodule have been purified and characterized. The hydrogenase from R.japonicum consists of two subunits (60 kD, 30 kD). The molecular weight of large and small subunits of hydrogenase from R.arachis is about 65 kD and 35 kD. Both hydrogenases are NiFe hydrogenase. No cytochrome b(559) could be detected in the fractions with the highest specific activity of hydrogenase from R. japonicum. R. arachis L8 3 strains(hup +) expressed high hydrogenase activity when grow autotrophicully in mineral salt vitamins medium and gas mixture containing H 2 and CO 2. It is evident that H 2 uptake by hydrogenase significantly increased the dinitrogen fixation either in free living cultures or in symbiotic nodules. A genomic library of R. arachis L8 3(hup +) has been constructed. Four clones(pZ 27, pZ 55, pZ 60, pZ 61) containing hup gene were screened by PCR and hydrogenase probe. The fragment of insert DNA of recombinant cosmid pZ 55 was about 19.6 kb. When the cosmid pZ 55 was transferred into the hup - strain of R.arachis and hup - strain of R.japonicum by triparental matting, the transconjugants showed high levels of H 2 uptake activities in free living state. Inoculating test was carried out in the field by using the transconjugant containing pZ 55. The result indicated that H 2 uptake activity of nodules inoculated with hup + transconjugant was 4 fold high than those of nodule inoculated with recipient (hup -). The total nitrogen content of peanut leaves and seed increased by 17% and 8.9% respectively. The peanut yield inoculated with transconjugant increased by 9.6% in comparison with that inoculated with recipient.国家自然科学基金!(39370 0 6 2 ;39770 0 70 );; 福建省自然科学基金!(B9910 0 0 1)资助项
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