Progress of C_2-Symmetric Biphenyl Bisphosphine LigandsⅡ

手性膦配体的合成及其在手性诱导催化反应中的应用一直是不对称合成与催化研究中非常重要的研究领域之一。近十年来,大量的C2-轴对称手性双膦配体被合成出来并成功地应用于不对称催化研究,本文从C2-轴对称联苯类手性双膦配体的介绍、合成方法、C2-轴对称联苯类手性双膦配体在不对称催化氢化以及其在其他不对称诱导反应中的应用4个方面综述了相关研究进展。A vast number of biphenyl atropisomeric diphosphine ligands have been successfully applied in asymmetric catalysis.The synthesis and applications of this type of ligands are a continuous interesting theme in organic chemistry.This review describes recent progress in synthesis and application of C2-Symmetric diphosphine ligands on the asymmetric catalysis hydrogenation and other asymmetric induced reaction.国家自然科学基金(20272037); 教育部博士点基金(20080610022); 四川自然科学基金重点项目(07ZA109

Progress of C_2-Symmetric Biphenyl Bisphosphine Ligands Ⅲ

手性膦配体的合成及其在手性诱导催化反应中的应用一直是不对称合成与催化研究中非常重要的研究领域之一。近10年来,大量的C2-轴对称手性双膦配体被合成出来并成功地应用于不对称催化研究,本文从C2-轴对称联苯类手性双膦配体的介绍、合成方法、C2-轴对称联苯类手性双膦配体在不对称催化氢化、以及其在其他不对称诱导反应中的应用4个方面综述了相关研究进展,并对今后配体的合成及应用前景进行了展望。A vast number of biphenyl atropisomeric diphosphine ligands are successfully applied in asymmetric catalysis.The synthesis and applications of this type of ligands are a continuous interesting theme in organic chemistry.This review describes recent progress in synthesis and application of C2-Symmetric diphosphine ligands on the asymmetric catalysis hydrogenation and other asymmetric induced reaction,and the future ligand synthesis and application prospect.国家自然科学基金(20272037); 教育部博士点基金(20080610022); 四川自然科学基金重点项目(07ZA109

Progress of the Study on C_2-symmetric Biphenyl Bisphosphine Ligands(一)

手性膦配体的合成及其在手性诱导催化反应中的应用一直是不对称合成与催化研究中非常重要的研究领域之一。近10年来,大量的C2-轴对称手性双膦配体被合成出来并成功地应用于不对称催化研究,本文从C2-轴对称联苯类手性双膦配体的介绍、合成方法,C2-轴对称联苯类手性双膦配体在不对称催化氢化,以及其在其他不对称诱导反应中的应用4个方面综述了相关研究进展,并对今后配体的合成及应用前景进行了展望。A vast number of biphenyl atropisomeric diphosphine ligands are successfully applied in asymmetric catalysis.The synthesis and applications of this type of ligands are a continuous interesting theme in organic chemistry.This review describes recent progress in synthesis and application of C2-Symmetric diphosphine ligands in the asymmetric catalysis hydrogenation and other asymmetric induced reaction.And the future ligand synthesis and application are predicted.国家自然科学基金(20272037); 教育部博士点基金(20080610022); 四川自然科学基金重点项目(07ZA109

A Journey into the City. Migrant Workers' Relation with the Urban Space and Struggle for Existence in Xu Zechen's Early Jingpiao Fiction

In contemporary China, rural-urban migrants constitute a new urban subject with entirely new identity-related issues. This study aims at demonstrating how literature can be a valid field in investigating such evolving subjectivities, through an analysis of Xu Zechen’s early novellas depicting migrants’ vicissitudes in Beijing. Combining a close reading of the texts and a review of the main social problems characterising rural-urban migration in China, this paper focuses on the representation of the identity crisis within the migrant self in Xu’s stories, taking into account the network of meanings employed by the writer to signify the objective and subjective tension between the city and the countryside

The adsorption of As(Ⅲ) on a novel granular Fe-Cu-Mn trimetal oxide (GFCM): Behavior and mechanism

A novel sorbent of granular Fe-Cu-Mn trimetal oxide (GFCM) was fabricated by coating method,with chitosan as adhesive. The GFCM presents an incomplete spheric shape with a diameter of 0.7~ 1.0 mm. It can effectively oxidize As(Ⅲ) to As(V) and efficiently adsorb the new formed As(V). Its maximal sorption capacity on As(Ⅲ) is up to 56.5 mg&middot;g~(-1) at pH 7.0,which is superior to most of reported granular sorbents. The GFCB also shows excellent As(Ⅲ) sorption efficiency over a wide range of pH from 5.0 to 9.0,and is less affected by ionic strength. The coexisting anions would restrain the As(Ⅲ) sorption efficiency by the following order: PO~(3-)_4 &gt; SiO_3~(2-) &gt; CO_3~(2-) &gt; Cl~-&gt; SO_4~(2-). The arsenic-loaded sorbent could be effectively regenerated by using NaOH solution and reused again. During the process of As(Ⅲ) removal,Mn oxide in sorbent is mainly responsible for As(Ⅲ) oxidation,while both Fe and Cu oxides are dominant for adsorbing As(Ⅲ) and formed As(V). Moreover,Cu oxide contributes to enhance As(Ⅲ) sorption performance of the GFCM.</p

瞬间——用镜头留住长江濒危动物

本书作者经过长达28年的积累，足迹踏遍长江中下游的江河故道，镜头扫遍长江中下游的各个角落，饱受雨雪风霜，忍耐无数寂寞，日复一日、年复一年，积累了数万幅珍贵的长江濒危动物照片。经过反复挑选，优中选优，甚至不得不“忍痛割爱”，遴选出这178张照片，将长江珍稀动物的美定格下来，呈献给读者，留给后人。你也许无法在野外看到这些生灵，你也许在博物馆看到过它们的标本，而本书将会因为它们的自然美使你的视觉受到震撼，将会使你的心灵得到升华

Relationship between coping behavior and mental health of military medical laboratory scientists and technicians

目的 了解军事医学科技人员应对方式与心理健康的关系.方法 应用横断面调查研究,对325名从事军事医学科技工作的不同职称人员应用焦虑、抑郁自评量表、应对方式量表进行测量,进行组间对比分析.结果 军事医学科技人员焦虑、抑郁分(30分&plusmn;6分,37分&plusmn;8分)低于全国常模(34分&plusmn;6分,42分&plusmn;11分)且差异有统计学意义(均P＜0.01);副主任技师抑郁分(42分&plusmn;7分)高于所有其他职称,焦虑分(32分&plusmn;7分)高于研究员(28分&plusmn;4分)且差异均有统计学意义(P＜0.05),求助分(2.8分&plusmn;0.5分)除与副研究员(2.8分&plusmn;0.5分)无差异外低于所有其他职称,自责分(1.9分&plusmn;0.6分)高于助理研究员(1.0分&plusmn;0.6分)(P＜0.01)、研究员(1.6分&plusmn;0.6分)(P＜0.05)且差异均有统计学意义;相关与回归分析结果表明,积极应对方式与抑郁(r1=-0.519)、焦虑(r3=-0.348)相关,消极应对方式与抑郁(r2=0.314)、焦虑(r4=0.407)相关且差异有统计学意义(P＜0.01).结论 应对方式对军事医学科技人员心理健康有显著影响,提高求助、减少自责和幻想能够减轻医学科技人员焦虑和抑郁.</p

Effect of Preparation Methods on Phosphate Adsorption by Iron-Titanium Binary Oxide: Coprecipitation and Physical Mixing

To investigate the effect of preparation methods on surface characteristics and adsorption properties of the formed metal composite oxides,two kinds of iron-titanium binary oxides were synthesized by a coprecipitation method or a physical mixing method and were denoted as CFe-Ti and MFe-Ti,respectively. The prepared CFe-Ti and MFe-Ti were systematically characterized using SEM, XRD,BET,and FTIR techniques. Their phosphate adsorption behaviors were also studied via batch adsorption experiments. Compared with pure FeOOH and TiO_2,CFe-Ti exhibited a looser nanostructure with more pore and surface hydroxyls. Moreover,the CFe-Ti had a high maximal phosphorus adsorption capacity of 40. 6 mg·g~(-1) ,which is about 1. 5 times and 2. 4 times as high as that of pure FeOOH ( 27. 2 mg·g~(-1) ) and TiO_2 ( 16. 7 mg·g~(-1) ) ,respectively. This suggests that an obvious synergistic effect is present in the CFe-Ti system. However,the morphology and structure of MFe-Ti were not significantly different from those of pure FeOOH and TiO_2 . The maximal adsorption capacity of MFe-Ti was 22. 7 mg·g~(-1) ,which is obviously lower than that of CFe-Ti and even lower than that of pure FeOOH. Evidently,there is no synergistic effect in the MFe-Ti system. In addition,phosphate adsorption mechanisms at the surface of CFe-Ti and MFe-Ti were the same as those of their component oxides,and chemical adsorption occurred at the surface of the oxides through the formation of inner-sphere complexes. Therefore,the surface characteristics and adsorption properties of the metal composite oxides were closely related to their preparation methods. The coprecipitation method was a simpler and more economical way than the physical mixing method to fabricate a highly effective iron-titanium binary oxide for phosphate adsorptio

3种一阶偏振模色散模拟器

偏振模色散（PMD）已成为高速光通信系统的主要限制因素,为了研究它对光通信系统的影响,研制出了多种PMD模拟器代替实际光纤进行实验研究。文章介绍了3种一阶PMD模拟器的原理及其结构,并用固定分析法对其差分群时延（DGD）值进行了测量,对其性能进行了分析比较。实际操作中可根据实验目的来选择恰当的模拟器

2P3R型机器人运动学及工作空间分析

针对目前企业中存在的人工打磨大型船用螺旋桨叶面效率低、质量不均匀以及工人劳动强度大等问题，提出了一种用于加工大型船用螺旋桨叶面的2P3R型5自由度工业机器人，建立了其完整模型。将末端执行器考虑在内，采用改进D-H法建立了机器人正运动学数学模型并求得其正运动学方程。基于蒙特卡罗法，在Matlab环境下，利用机器人工具箱对机器人工作空间进行求解，描绘出该机器人末端刀具可达工作空间点云图。通过曲面拟合与空间包容对比，结果表明，所设计的2P3R型5自由度工业机器人能够实现对直径4～10 m的大型船用螺旋桨单个桨叶上表面的全部覆盖，为后续对大型螺旋桨加工机器人的运动控制与路径规划等研究奠定了基础