Selective oxidation of unsaturated alcohols catalyzed by sodium nitrite and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone with molecular oxygen under mild conditions

We have developed a simple and practical process for the oxidation of alcohols to the corresponding carbonyl compounds by using a low catalytic amount of DDQ, NaNO(2) as a cocatalyst, and molecular oxygen as terminal oxidant. Nitric oxide generated in situ by NaNO(2) in the presence of AcOH is essential for the realization of the catalytic cycle at room temperature. The practical utility of this catalytic process has been demonstrated in the gram-scale oxidation of cinnamyl alcohol.     

Exact quantum scattering study of the H + HS reaction on a new ab initio potential energy surface H2S (3A")

We present an exact quantum dynamical study and quasi-classical trajectory (QCT) calculations for the exchange and abstraction processes for the H + HS reaction. These calculations were based on a newly constructed high-quality potential energy surface for the lowest triplet state of H(2)S ((3)A"). The ab initio single-point energies were computed using complete active space self-consistent field and multi-reference configuration interaction method with a basis set of aug-cc-pV5Z. The time-dependent wave packet (TDWP) method was used to calculate the total reaction probabilities and integral cross sections over the collision energy (E(col)) range of 0.0-2.0 eV for the reactant HS initially at the ground state and the first vibrationally excited state. It was found that the initial vibrational excitation of HS enhances both abstraction and exchange processes. In addition, a good agreement is found between QCT and TDWP reaction probabilities at the total momentum J = 0 as a function of collision energy for the H + HS (v = 0, j = 0) reaction.     

含运动变形物体流场的数值模拟

基于含拓扑结构改变、可变形运动网格生成技术及动边界条件下的数值处理方法,对爆炸波通过有限入口进入建筑物内部的透射(infiltration)现象进行直接模拟.系统研究入口处门板不同运动、变形、脱落方式下,爆炸波在建筑物内部的传播过程和内壁面上的爆炸载荷,直接模拟门与挡板的碰撞、门的断裂及破片的抛洒过程.结果表明,所发展的用于含拓扑结构改变的运动可变形物体流场计算方法对该类问题的直接模拟行之有效.     

输尿管开口囊肿、狭窄及膀胱颈部挛缩的HO:YAG激光治疗

目的利用HOYAG激光的软组织切割及止血作用,对输尿管开口囊肿、狭窄及膀胱颈部挛缩的患者行激光治疗,并观察疗效.方法采用HOYAG激光对6例输尿管开口囊肿,15例输尿管开口狭窄(其中3例合并输尿管结石),32例膀胱颈部挛缩进行治疗,观察术中出血、术后并发症、膀胱挛缩患者手术前后Qmax.结果总计53例患者通过HOYAG激光治疗,均获得满意临床疗效,术中几乎无出血,输尿管开口囊肿及狭窄患者,术毕能顺利留置F7双猪尾巴导管.膀胱颈部挛缩患者术后最大尿流率提高了7.6ml/s(7.2～14.8ml/s).结论HO;YAG激光对输尿管开口囊肿、狭窄及膀胱颈部挛缩是一种行之有效的治疗方法,且无出血,易于操作、安全、恢复快.尤其是输尿管结石合并输尿管开口狭窄患者,可通过HOYAG激光一次手术解决.     

酵母菌立体专一性还原的研究

微生物可应用于不对称合成中,微生物法具有光学纯度高,环境污染少,成本低等优点,对一些具有生物活性的化合物的合成具有独到的作用。探讨了微生物中的酶在β－酮酸酯立体专一性还原反应中的作用机理。     

PLC提高性实验的实验教学改革探索

介绍PLC即可编程序控制器在实验教学中进行的提高性实验,提高性实验之一是PLC对三台鼠笼异步电动机的自动与手动控制,PLC指令的灵活应用及实现。     

Synthesis of hexagonal monocrystal AlN microtubes and nanowires at low temperature

This paper reports that pure hexagonal aluminium nitride microtubes and nanowires growing along the [0001] direction have been successfully synthesized by directly reacting AlClh-AlN, microtubes, nanowires,h-AlN, microtubes, nanowiresProject supported by the National Natural Science Foundation of China (Grant No 10474078) and the Science Foundation of the Education Office of Shanxi Province, China.2006-11-23This paper reports that pure hexagonal aluminium nitride microtubes and nanowires growing along the [0001] direction have been successfully synthesized by directly reacting AlCl3 with NaN3 at low temperature （450℃） under condition of non-solvent system. The grey-white powder of reacting product was characterized by high-resolution transmission electron microscope （HRTEM）, which shows that the powder is long straight-wire morphology with outer diameter from 40nm to 300 nm and length up to several micrometres. The results of both electron diffraction （ED） and x-ray diffraction （XRD） indicate that the AlN microtubes have a pure hexagonal monocrystal tubular structure with the combination of the curled AlN nanobelts. Room-temperature photoluminescence spectrum of the synthesized sample showed an emission peak, which is closely related to the small size of the microtubes.     

应用于5 V电压电路的新型闩锁免疫LVTSCR

传统低压触发可控硅(LVTSCR)维持电压过低,应用于片上ESD防护时存在闩锁风险。文章提出了一种嵌入分流路径的LVTSCR。基于0.18 μm CMOS工艺,使用Sentaurus-TCAD软件模拟人体模型,对器件准静态特性进行了分析。结果表明,新型器件在保持触发电压、ESD防护性良好的情况下,有效提高了维持电压。对关键尺寸D6进行优化,该器件的维持电压提高到5.5 V以上,器件可安全应用于5 V电压电路,避免了闩锁效应。     

Identification of functionally key residues in maltose transporter with an elastic network model-based thermodynamic method

Periplasmic binding protein-dependent maltose transport system (MBP-MalFGK₂) of Escherichia coli, an important member of the Adenosine triphosphate-binding cassette transporter superfamily, is in charge of the transportation of maltoses across cellular membrane. Studies have shown that this transport processes are activated by the binding of maltose and are accompanied by large-scale cooperative movements between different domains which are mediated by a network of important residues related to signal transduction and allosteric regulation. In this paper, the functionally crucial residues and long-range allosteric pathway of the regulation of the system by substrate were identified by utilising a coarse-grained thermodynamic method proposed by our group. The residues whose perturbations markedly change the binding free energy between maltoses and MBP-MalFGK₂ were considered to be key residues. In result, the key residues in 62 clusters distributed in different subdomains were identified successfully, and the results from our calculation are highly consistent with experimental and theoretical observations. Furthermore, we explored the long-range cooperation within the transporter. These studies will help us better understand the physical mechanism of the effects of the maltose on MBP-MalFGK₂ by long-range allosteric modulation.