Electrooxidation Mechanism of Methanol at Pt-Ru Catalyst Modified GC Electrode in Electrolytes with Different pH Using Electrochemical and SERS Techniques

The electrochemical and in-situ surface-enhanced Raman spectroscopy （SERS） techniques were used to investigate the electrooxidation behavior of methanol in acidic, neutral and alkaline media at a Pt-Ru nanoparticle modified glassy carbon （Pt-Ru/GC） electrode. The results showed that methanol could be dissociated spontaneously at the Pt-Ru/GC electrode to produce a strongly adsorbed intermediate, CO. It was found that CO could be oxidized more easily in the alkaline medium than in the acidic and neutral media. The peak potential of methanol oxidation was shifted from 0.663 and 0.708 V in the acidic and neutral media to -0.030 V in the alkaline medium, which is due to that the adsorption strength of CO on the Pt surface in the alkaline medium is weaker than that in the acidic and neutral media. The final product of the methanol oxidation is CO2. However, in the alkaline medium, CO2 produced would form CO3^2- and HCO3^- resulting in the decrease in the alkaline concentration and then in the decrease in the performance of DMFC. Therefore, the performance of the alkaline DMFC is not Stable.     

由水杨醇衍生的二苯并冠醚的合成和构型

将水杨醇在ＤＭＦ中与ＮａＨ和二甘醇或三某醇二对甲苯磺酸酯反，合成了２个新的二苯并冠醚（１和２），其结构由元素分析和波谱分析所表征，１ 射线衍射分析确定为反位构型，提出了合成反应的机理。     

C28X4（X=H,Cl）,CX4（X=H,Cl）的结构和电子光谱的理论研究

用ＩＮＤＯ法对Ｃ２８Ｘ４（Ｘ＝Ｈ，Ｃｌ）和ＣＸ４（Ｘ＝Ｈ，Ｃｌ）进行几何构型优化，得到Ｔｄ对称性的构型Ｃ２８Ｘ４有４种键、４种不等同原子，基态为稳定的闭壳层分子，以此构型为基础计算了上述分子的电子光谱，并预测Ｃ２８Ｘ４的电子光谱。     

Total synthesis of methyl protodioscin: a potent agent with antitumor activity

Methyl protodioscin (1), otherwise known as 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-[alpha-L-rhamnopyranosyl-(1-->4)]-beta-d-glucopyranosyl]-26-O-[beta-D-glucopyranosyl]-22-methoxy-25(R)-furost-5-ene-3 beta,26-diol, has been synthesized for the first time from diosgenin through nine steps in an overall yield of 7.8%.     

ISOLATION,CHARACTERIZATION AND EXPRESSION OF THE COMPLEMENTARY DNA FOR HUMAN TUMOR NECROSIS FACTOR (TNF-α)

A cDNA for human TNF-α (615bp) was isolated by means of polymerase chain reaction (PCR) using first strand cDNA from PMA-induced HL-60 cells as template. The result from sequencing the 615 bp cDNA fragment indicated that it corresponded to the entire sequence of mature human TNF coding region. Direct expression of mature human TNF was achieved using a plasmid pHT-1 constructed by ligation of the cDNA and a synthetic DNA. The IPTG-induced bacterial product (hTNF) showed cytotoxicity to mouse L-929 cells. The TNF activity was further identified by neutralization of a specific monoclonal antibody against human TNF-α. Approximately 80,000 units of activity were detected per ml of culture at A600=2.     

1－苯基－3－甲基－4－苯甲酰基－5－吡唑啉酮（HPMBP）与金属离子配合物的结构研究──（Ⅲ）La（pmbp）_3（H_2O）_2的合成与晶体结构

报道标题化合物Ｌａ（ＰＭＢＰ）_３（Ｈ_２Ｏ）_２，Ｈｐｍｂｐ＝Ｃ_（１７）Ｈ_（１４）Ｎ_２Ｏ_２的合成及晶体结构，晶体属于单斜晶系，空间群Ｃ２／ｃ，晶体学数据：ａ＝２４．７４４（５），ｂ＝１６．３２５（６），ｃ＝２５．８７１（５），β＝１０５．４４（３）°，Ｖ＝１００７３（２）３，Ｍ_ｒ＝１００６，Ｚ＝８，Ｄ_ｘ＝１．３２８ｇ／ｃｍ~（－３），μ＝９．０４２ｃｍ~（－１），Ｆ（０００）＝４０９４。最终偏离因子Ｒ＝０．０４９，Ｒ_ｗ＝０．０５９。分子中Ｌａ（Ⅲ）与８个氧原子配位形成三角十二面体构型，Ｌａ－Ｏ平均键长为２．４９６（２）。     

甲烷生物催化氧化制甲醇——几种化学物质对Methylosinus trichosporium 3011甲醇累积的影响

本文报导了在 Methylosinus trichosporium 3011细胞反应液中加入一些化学物质对甲醇累积的影响。结果表明,Na~+抑制甲烷单加氧酶的活性。当 M.trichosporium 3011细胞反应液中含高浓度磷酸根时,只有很少量甲醇累积下来。EDTA 和 Na_2EDTA 甲醇累积的促进作用小于甲酸钠或甲酸的作用。但由于 EDTA 不仅可以抑制甲醇脱氢酶的活性,而且可以螯合 Na~+,而甲酸则可使 NADH 辅酶再生。因此,反应液中含有2mM EDTA 和20mM 甲酸时甲醇累积量最高。     

CuCrAl和CuCrZr低温液相合成甲醇催化剂的研究

 用络合共沉淀法制备了CuCrAl和CuCrZr复合氧化物液相合成甲醇催化剂，其比表面分别达到119和116m2／g．在5．0～5．5MPa和383K条件下，分别用间歇式和流动式反应釜考察了催化剂的活性和稳定性．结果表明：CuCrAl和CuCrZr的活性均明显高于CuCr；CuCrAl的活性略高于CuCrZr，但甲酸甲酯（MF）的选择性明显低于CuCrZr；两者在12h内未见活性明显下降．甲醇钠在反应过程中部分转化为甲酸钠和NaOH．CuCrAl和CuCrZr有较高的氢解活性可抑制甲醇钠与MF生成甲酸钠，从而有较低的甲酸钠浓度．但是，Al2O3和ZrO2的酸性有利于甲醇脱水，引起甲醇钠水解生成NaOH．溶剂对CuCr基催化剂的活性和选择性有明显影响．对反应机理进行了讨论．     

Mg0.9-xTi0.1PdxNi(x=O.04～0.1)贮氢合金电极腐蚀行为研究

研究了Pd部分替代Mg对Mg0.9-xTi0.1PdxNi(x=0.04～0.1)贮氢合金腐蚀性能的影响.利用机械合金化方法制备了Mg0.9-xTi0.1PdxNi(x=0.04～0.1)贮氢合金.XRD和TEM分析表明经120 h球磨后该合金完全非晶化.循环充放电测试结果表明,Pd的替代有效地延长了Mg0.9-xTi0.1PdxNi(x=0.04～0.1)合金的循环寿命.采用开路电位测量,阳极极化,电化学阻抗和X射线光电子能谱研究了该合金的腐蚀行为.结果表明,随着Pd含量增加,合金腐蚀电位正移,初始腐蚀电流下降,腐蚀电流增加的速度变缓.采用本文提出的等效电路模型较好地拟合了合金的电化学阻抗谱.分析表明,随着Pd含量的增加,合金表面钝化膜厚度和电阻逐渐增大.X射线光电子能谱分析表明,Pd的加入减弱了合金在充放电过程中的氧化程度.当Pd含量达到0.1时,Mg0.9-xTi0.1PdxNi(x=0.04～0.1)合金的耐腐蚀性能最好,其放电容量保持率最高.     

微波干法催化芳香醛与绕丹宁及N－苯基绕丹宁的缩合反应

利用微波辐射和固体碱性载体试剂催化绕丹宁及Ｎ－苯基绕丹宁和芳香醛的缩合反应合成了１４个绕丹宁衍生物并研究了影响反应的因素。