An Analysis of Michael Long＇ s Interaction Hypothesis in Second Language Acquisition

The Interaction Hypothesis, which was first advanced by Michael Long, is considered as a further supplement or extension of the Input Hypothesis in the field of second language acquisition. This paper explains the main claims of Michael Long＇s Interaction Hypothesis, the three steps to study how input and interaction affect the acquisition of a second language, and the importance of the interactional modifications applied by both participants of the interaction. Emphasis is placed on the evaluation of the theory as well as its relation to second language teaching, with many researchers＇ findings and arguments discussed as supporting evidence. It aims to help the effective application of this theory in second language teaching.     

KF-Al2O3试剂在Michael加成反应中的新应用

芳亚甲基丙二腈和硝基甲烷在KF-Al2O3的作用下发生双Michael加成，继而发生环化反应生成2-氨基-1，3，3-三氰基-5-硝基-4，6-二芳基环己烯，该反应的研究为此类化合物的合成提供了一种方便的方法。     

1-(3-巯基-2-甲基丙酰基)吡咯-2-羧酸的合成

碱性离子液体[bmim]OH能有效地促进硫代乙酸和甲基丙烯酸乙烯酯的迈克尔加成反应,反应在室温条件下进行,在30 min内可以取得定量收益率的2-甲基-3-乙酰硫基丙酸乙烯酯.以甲基丙烯酸乙烯酯为起始原料,提出了一种合成卡托普利的新方法.     

2-[2-(3-氨基丙氧基)乙氧基]乙醇的合成

以二甘醇为起始原料,经羟基保护,Michael加成,催化加氢反应合成目标化合物2-[2-(3-氨基丙氧基)乙氧基]乙醇;优选Michael加成催化剂为LiOH·H_2O;优选加氢催化剂为Sponge Co,反应压力为6.0 MPa,反应温度为80℃,总收率46%.     

聚氧乙烯单甲醚改性聚酰胺-胺的造纸助留增强性能

采用Michael加成反应制备了聚氧乙烯单甲醚(MPEO-A-1000)改性的聚酰胺一胺树形聚合物(MnG,n=4.0,5.0),研究了该MnG及其与阴离子聚丙烯酸钠、丙烯酸钠改性的聚酰胺-胺树形聚合物复配的助留增强体系在阔叶木浆料中所起到的助留和增强效果.结果表明:M4.0G及其与丙烯酸钠改性的聚酰胺-胺树形聚合物复配的双元助留体系的纸样助留率和物理强度均比空白纸样明显提高.     

理论研究H2S与羟基和Cl在没有水分子和有水分子条件下的反应机理

本文用量子化学计算方法研究没有水分子和有水分子条件下对Cl+H2S和OH+H2S这两个反应产生的影响.在wb97xd/aug-cc-pvtz水平下的计算结果表明,单个水分子加到反应中会使Cl+H2S和OH+H2S这两个反应的能垒分别减小3.0kal/mol和2.2kal/mol.同时两个反应的速率常数在水分子影响下也分...     

叶色草蛉对绣线菊蚜的捕食功能反应和搜寻效应

作者研究了叶色革蛉成虫捕食绣线菊蚜的功能反应和寻找效应,组建了其捕食功能模式:1/Na=0.0037+2.1137 1/N,处理时间(Th)为0.0037d,瞬时攻击率为0.4731,从中可看出叶色草蛉成虫的日最大理论捕食蚜量为270.3头(即N为无限大时),此模式表明这种天敌昆虫对绣线菊圩有明显地控制作用,并有保护利用价值,其寻找效应随着蚜虫密度增加而降低.     

Theoretical study of spin-orbit coupling and zero-field splitting in the spin-forbidden two-state reaction between cobaltacyclopentadiene and isocyanate

The two-state reaction mechanism of CpCo(C_4H_4)with isocyanate on the triplet and singlet potential energy surfaces has been investigated at the B3LYP level.A study is described for the computation of spin-orbit coupling of triplet state of the minimal energy crossing point(CP)with their singlet states and of the zerofield splitting(ZFS)parameters of the triplet states,including the full one-and two-electron terms of the BreitPauli Hamiltonian.There are two key crossing points along this two-state reaction pathway.The first crossing point—CP2 exists near~1B.The reacting system will change its spin multiplicity from the triplet state to the singlet state near this crossing region.Although the spin-orbit coupling interaction and ZFS D-tensor of the CP2 region are very strong,the reaction system will occur the reverse intersystem crossing from T_1 to S_0.Therefore,its spin-flip efficiency may be lower.The second crossing point,CP3will again change its spin multiplicity from the singlet state to the triplet state in the Co-Cr bond activation pathway,leading to a decrease in the barrier height of~1TS(CF)from19.5 to 9.5 kcal/mol(1cal=4.182 J),and the efficiency of intersystem crossing from S_0 to T_1 is high because the larger spin-orbit coupling(SOC)matrix elements will result in the overpopulations of the three sublevels of T_1(3.30×10~(-1),3.32×10~(-1),and 3.38×10~(-1),respectively).     

Control of four stereocentres in a triple cascade organocatalytic reaction

Efficient and elegant syntheses of complex organic molecules with multiple stereogenic centres continue to be important in both academic and industrial laboratories. In particular, catalytic asymmetric multi-component 'domino' reactions, used during total syntheses of natural products and synthetic building blocks, are highly desirable. These reactions avoid time-consuming and costly processes, including the purification of intermediates and steps involving the protection and deprotection of functional groups, and they are environmentally friendly and often proceed with excellent stereoselectivities. Therefore, the design of new catalytic and stereoselective cascade reactions is a continuing challenge at the forefront of synthetic chemistry. In addition, catalytic cascade reactions can be described as biomimetic, as they are reminiscent of tandem reactions that may occur during biosyntheses of complex natural products. Here we report the development of an asymmetric organocatalytic triple cascade reaction for the synthesis of tetra-substituted cyclohexene carbaldehydes. This three-component domino reaction proceeds by way of a catalysed Michael/Michael/aldol condensation sequence affording the products with good to moderate yields (25-58 per cent). During this sequence, four stereogenic centres are formed with high diastereoselectivity and complete enantioselectivity. In addition, variation of the starting materials can be used to obtain diverse polyfunctional cyclohexene derivatives, which can be used as building blocks in organic synthesis.     

叔胺类化合物的合成新方法

提出了一种由仲胺合成叔胺的新方法，胺与丙烯腈的Michael加成产物与卤代烃发生季铵化，生成的季铵盐完成Hoffmann型消除反应，合成了系列叔胺类化合物3a，3b，6，其结构经IR，^1HNMR，Ms谱证实，本文还就反应温度、溶剂、反应物结构等对反应的影响做了详细探讨，确定了最佳反应条件。     

微波辐射下碘催化水相合成2,2′-二(3-羟基-5,5-二甲基-2-环己烯基)甲苯

在微波条件下,以为水介质,碘为催化剂,使芳醛与5,5-二甲基-1,3-环己二酮发生Michael加成反应,合成2,2′-二(3-羟基-5,5-二甲基-2-环己烯基)甲苯.该法具有反应时间较短,操作简单,安全,产率高和环境友好等特点.     

双马来酰亚胺树脂增韧改性研究进展

 综述了双马来酰亚胺树脂的基本性能,分析了增韧改性的意义。目前双马来酰亚胺树脂增韧改性的主要方法包括与烯丙基化合物共聚、二元胺增韧、环氧树脂增韧、热塑性树脂增韧、氰酸酯增韧、合成新型双马来酰亚胺树脂单体、橡胶增韧改性、无机填料增韧改性、液晶增韧改性、纳米材料增韧改性及柔性材料增韧改性等。双马来酰亚胺树脂增韧改性的机理包括加成反应、Diels-Alder 反应、齐聚反应、Michael 加成反应、共聚反应、裂纹钉锚机制及半互穿网络机制等。论述了国内外对于双马来酰亚胺树脂增韧改性的研究现状,探讨了该方向的研究趋势。     

手性环丁内酯取代的氨基噻二唑的合成研究

探讨了手性源(R)-(-)-5-[(1R)-孟氧基]-2(5H)-呋喃 酮与氨基噻唑类化合物的不对称Michael加成反应,并利用该反应合成了6个新型手性环丁内酯取代的氨基噻二唑类化合物,所有产物均经过1HNMR、 IR、旋光度和元素分析等给予确证. 结果显示氨基噻唑中的氨基主要是从孟氧基所在位置的反面进攻β-碳原子 .     

离子液体[bmim]OH中硫醇和丙烯酸酯的快速共轭加成反应

碱性离子液体[bmim]OH有效地促进硫醇和α,β-不饱和羰基化合物的迈克尔加成反应.反应在室温条件下进行,在2~15 min内可以取得良好的收益率,离子液体也可以循环回收利用.     

新型手性杂环并环丁内酯的合成研究

研究5－（l-孟氧基）－3－溴－2－（5H）－呋喃酮与硝基烷烃之间的Michael不对称加成反应和取代反应，通过该串联反应得到了一系列其他方法无法得到的新型多手性杂环并环化合物；丰富了5－（l－孟氧基）－3－溴－2－（5H）－呋喃酮的反应，通过IR，^13CNMR，^1HNMR，Ms等确证了新型多手性杂环并环化合物的结构和构型。     

OXO(X=Cl,Br)自由基与CO和NO自由基反应机理的理论研究

对CO和NO自由基与OXO(X=Cl,Br)自由基反应机理进行了理论研究.在MP2/6-311 +G(d,P)水平下优化了反应物、产物、中间体和过渡态的几何构型,并对所有平衡构型进行了简谐振动频率分析.在相同的计算水平下以过渡态为出发点,利用内禀反应坐标(IRC)理论得到了反应的最小能量路径(MEP),能量信息的进一步校正在较高的MCQCISD//MP2/6-311+G(d,p)水平下完成.研究结果表明,该反应体系可发生氧抽提反应,其中NO与OClO的反应是最具有动力学优势的.     

微生物絮凝剂MBFA9去除水中Pb~(2+)的机理

从土壤中筛选得到一株类芽孢杆菌A9,所产微生物絮凝剂MBFA9对水中Pb2+具有较高的去除作用,并进一步考察了MBFA9对Pb~(2+)的吸附动力学和热力学过程.结果表明:当水中初始Pb2+质量浓度为56.20 mg/L,MBFA9吸附25 min后的去除率最高可达92.73%;MBFA9捕集Pb2+的理论最大值为196.08 mg/g,吸附速率常数k2为0.019 g/(mg·min),动力学特征符合准二级动力学模型,其等温吸附模型与Langmuir方程拟合较好,相关系数R2=0.96;结合红外光谱检测、场发射扫描电镜和能谱分析,探讨了M BFA9去除Pb2+的机理为其表面的官能团如羟基、酰胺基、羧基等在捕集Pb2+过程中与之发生配合作用,对Pb2+的去除贡献了重要作用.     

MGB probe assay for rapid detection of mtDNAl1778 mutation in the Chinese LHON patients by real-time PCR

Objective： Leber＇s hereditary optic neuropathy （LHON） is a maternally inherited degeneration of the optic nerve caused by point mutations of mitochondrial DNA （mtDNA）. Many unsolved questions regarding the penetrance and pathophysiological mechanism of LHON demand efficient and reliable mutation testing. This study aims to develop a minor groove binder （MGB） probe assay for rapid detection of mtDNA11778 mutation and heteroplasmy in Chinese LHON patients by real-time polymerase chain reaction （PCR）. Methods： Forty-eight patients suspected of having LHON and their maternal relatives underwent a molecular genetic evaluation, with 20 normal individuals as a control group at the same time. A real-time PCR involving two MGB probes was used to detect the mtDNA 1 1778 mutation and heteroplasmy. A linear standard curve was obtained by pUCmLHONG and pUCmLHONA clones. Results： All 48 LHON patients and their maternal relatives were positive for rntDNA11778 mutation in our assay, 27 heteroplasmic and 21 homoplasmic. Eighteen cases did not show an occurrence of the disease, while 9 developed the disease among the 27 heteroplasmic mutation cases. Eleven did not show an occurrence of the disease, while 10 cases developed the disease among 21 homoplasmic mutation cases. There was a significant difference in the incidence between the heteroplasmic and the homoplasmic mutation types. The time needed for running a real-time PCR assay was only 80 min. Conclusion： This real-time PCR assay is a rapid, reliable method for mtDNA mutation detection as well as heteroplasmy quantification. Detecting this ratio is very important for predicting phenotypic expression of unaffected carriers.     

Chiral pyrrolidine-azole conjugates: Simple and efficient asymmetric organocatalysts for Michael addition to nitrostyrenes

Simple pyrrolidine-azole conjugates have been synthesized and found to be efficient catalysts for asymmetric Michael addition to nitrostyrenes. The identified optimal catalysts, pyrrolidine-azoles 2, 8 and 13, could catalyze the asymmetric Michael addition of a range of Michael donors and nitrostyrenes in high yields (up to 99%) and excellent stereoselectivities (up to 99:1 dr and 97% ee).     

200 MeV内p+60Ni核反应的计算与分析

以现有p+60Ni核反应的实验数据为基础,利用自行研制的大型程序MEND从理论上系统地计算了200MeV能区内p+60Ni核反应的反应截面、弹性散射角分布、能谱和6种轻粒子(n、p、α、d、t、3He)出射的双微分截面.与实验数据及ENDF/B6评价库比较发现,文章理论计算的结果与实验数据基本一致;与ENDF/B6相比,文章增加了3He的计算,将能区上推到了200 MeV,结果更接近实验敷据、更全面.