1—取代苯基—1,4—二氢—6—甲基—4—哒嗪酮—3—酰胺的合成

用杂交方法培育新作物品种是农业增产的重要措施。与常规杂交育种方法相比,采用化学杀雄法(Chemical induction lf male sterility)育种具有程序简单,节省劳力,时间缩短等优点,可以诱导产生非遗传性的雄性不育母本,与另一品种的文本杂交而得优化组合的良种,国外在小麦上已试验成功但在水稻上尚在探索,美国Rohm and Haas公司曾报道一些哒嗪酮类     

Pressurized gradient capillary electrochromatographic separation of eighteen amino acid derivatives

A pressurized gradient capillary electrochromatography (pCEC) instrument was developed to separate 18 amino acid derivatives. A reversed-phase C18 column (3 microm, 130 mm x 75 microm I.D.) and an acetate buffer (50 mmol/l NaAc, pH 6.4) with an ion-pair reagent (1% N,N-dimethylformamide) were used to separate derivatized amino acids from a standard solution (2 microg/ml), and the wavelength of the UV-Vis detector was 360 nm. The pressure on the capillary column was kept at approx. 70 Pa and 3 kV positive voltage was added on the outlet end of column. The effect of voltage on the eluting order of amino acids and the resolution of separation were studied, and it was found that when the voltage was higher than 3 kV, the adsorption of amino acids in the porous C18 column occurred. The effect of salt concentration, injection volume, and column length on the separation of amino acids was determined. The amino acid sample was separated by pCEC, and RSDs of the migration times of each amino acid were all less than 2.5%.     

Folding, conformational changes, and dynamics of cytochromes C probed by NMR spectroscopy

NMR spectroscopy has become a vital tool for studies of protein conformational changes and dynamics. Oxidized Fe(III)cytochromes c are a particularly attractive target for NMR analysis because their paramagnetism (S = (1)/(2)) leads to high (1)H chemical shift dispersion, even for unfolded or otherwise disordered states. In addition, analysis of shifts induced by the hyperfine interaction reveals details of the structure of the heme and its ligands for native and nonnative protein conformational states. The use of NMR spectroscopy to investigate the folding and dynamics of paramagnetic cytochromes c is reviewed here. Studies of nonnative conformations formed by denaturation and by anomalous in vivo maturation (heme attachment) are facilitated by the paramagnetic, low-spin nature of native and nonnative forms of cytochromes c. Investigation of the dynamics of folded cytochromes c also are aided by their paramagnetism. As an example of this analysis, the expression in Escherichia coli of cytochrome c(552) from Nitrosomonas europaea is reported here, along with analysis of its unusual heme hyperfine shifts. The results are suggestive of heme axial methionine fluxion in N. europaea ferricytochrome c(552). The application of NMR spectroscopy to investigate paramagnetic cytochrome c folding and dynamics has advanced our understanding of the structure and dynamics of both native and nonnative states of heme proteins.     

Differential pulse voltammetric determination of arsenic(III,V) and antimony (III,V) in glasses

Summary Analytical methods based on differential pulse voltammetry (DPV) have been described for the determination of total As, As(III), As(V), total Sb and Sb(III) as trace to minor constituents in complex glasses. For total As, the sample is decomposed with HF-H₂SO₄-KMnO₄. The As(V) is chemically reduced to As (III) by hypophosphite and a DPV scan is carried out at the dropping mercury electrode from –0.2 to –0.7 Vvs. SCE (E _p –0.41V). As(V) is determined by decomposing the sample in HF-H₂SO₄ and volatilizing the As(III) as AsF₃. The chemical reduction of As(V) and the DPV scan are then applied. If the glass can be decomposed with cold HF, the As(III) present in the glass can be determined by applying the DPV scan after cold sample-dissolution. For Sb(III), the sample is decomposed with HF-H₂SO₄, diluted, and adjusted to 1M in HCl. A DPV scan is conducted from –0.03 to –0.5 V (E _p –0.15 V). Sb(V) is not reduced in the 1M HCl supporting electrolyte. Total Sb is determined by using an aliquot of the sample solution adjusted to 6M in HCl. The DPV sweep is carried out from –0.5 to –0.1 V [E _p for Sb(V) and Sb(III) is –0.30 V]. The methods have been applied to a wide range of glass compositions and the results compared with values obtained by spectrophotometry and coulometric titration.

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Bestimmung von Arsen(III, V) und Antimon(III, V) in Gläsern mit Hilfe der Differential-Puls-Voltammetrie

Zusammenfassung Analytische Methoden auf der Grundlage der Differential-Puls-Voltammetrie (DPV) für die Bestimmung des gesamten Arsens, As(III), As(V), des gesamten Antimons und Sb(III) als Spuren in komplexen Gläsern wurden beschrieben. Zwecks Bestimmung des Gesamt-As wird die Probe mit Flußsäure +Schwefelsäure + Permanganat aufgeschlossen. As(V) wird mit Hypophosphit reduziert und die DPV wird an einer Quecksilber-Tropfelektrode zwischen –0,2 und –0,7V gegen eine ges. Kalomelelektrode (E _p =–0,41V) durchgeführt. Zur Bestimmung von As(V) wird die Probe mit HF-H₂SO₄ unter Verflüchtigung des As(III) als AsF₃ aufgeschlossen. Dann erfolgt die Reduktion des As(V) und die DPV. Wenn sich das Glas mit kalter HF lösen läßt, wird anwesendes As(III) mittels DPV in dieser Lösung bestimmt. Zur Bestimmung des Sb(III) wird die Probe mit HF-H₂SO₄ zersetzt, verdünnt und bis zur 1-Molarität mit HCl versetzt. Dann wird mit DPV zwischen –0,03 und –0,5V gemessen (E _p =–0,15V). Sb(V) wird in 1M salzsaurer Lösung nicht reduziert. Das Gesamt-Sb wird in einem Aliquot der Probelösung bestimmt, das dazu mit HCl bis zur 6fachen Molarität versetzt wird. Der DPV-Bereich wird von –0,5 bis –0,1 V ausgenützt (E _p f:ur Sb(V) und Sb(III) ist –0,30 V). Das Verfahren wurde für Gläser verschiedenster Zusammensetzung angewendet. Die Ergebnisse wurden mit den Resultaten der Spektrophotometrie und der coulometrischen Titration verglichen.

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Presented at the 8th International Microchemical Symposium, Graz, August 25–30, 1980.     

Theoretical study on the reaction mechanism of CH4 with CaO

The reaction pathways and energetics for the reaction of methane with CaO are discussed on the singlet spin state potential energy surface at the B3LYP/6-311+G(2df,2p) and QCISD/6-311++G(3df,3pd)//B3LYP/6-311+G(2df,2p) levels of theory. The reaction of methane with CaO is proposed to proceed in the following reaction pathways: CaO + CH₄ → CaOCH₄ → [TS] → CaOH + CH₃, CaO + CH₄ → OCaCH₄ → [TS] → HOCaCH₃ → CaOH + CH₃ or [TS] → CaCH₃OH → Ca + CH₃OH, and OCaCH₄ → [TS] → HCaOCH₃ → CaOCH₃ + H or [TS] → CaCH₃OH → Ca + CH₃OH. The gas-phase methane–methanol conversion by CaO is suggested to proceed via two kinds of important reaction intermediates, HOCaCH₃ and HCaOCH₃, and the reaction pathway via the hydroxy intermediate (HOCaCH₃) is energetically more favorable than the other one via the methoxy intermediate (HCaOCH₃). The hydroxy intermediate HOCaCH₃ is predicted to be the energetically most preferred configuration in the reaction of CaO + CH₄. Meanwhile, these three product channels (CaOH + CH₃, CaOCH₃ + H and Ca + CH₃OH) are expected to compete with each other, and the formation of methyl radical is the most preferable pathway energetically. On the other hand, the intermediates HCaOCH₃ and HOCaCH₃ are predicted to be the energetically preferred configuration in the reaction of Ca + CH₃OH, which is precisely the reverse reaction of methane hydroxylation.     

CeO2和Pd在Ni/γ-Al2O3催化剂中的助剂作用

采用脉冲微反技术研究了添加n型半导体氧化物CeO2及贵金属Pd对Ni/γ Al2O3催化剂上CH4积炭/CO2消炭反应性能的影响,并运用BET、TPR、CO2 TPSR及氢吸附等技术对催化剂进行了表征.结果表明, n型半导体氧化物CeO2的添加可以降低Ni/γ Al2O3催化剂上CH4裂解积炭活性,提高CO2消炭活性,添加少量贵金属Pd可以进一步改变载体Al2O3、助剂CeO2和活性组分Ni之间的相互作用,从而改善Ni/γ Al2O3催化剂的抗积炭性能.通过Ni Ce Pd/γ Al2O3催化剂上CH4积炭/CO2消炭模型对上述作用机制作出了新的解释.     

新型镍催化剂催化乙烯聚合的阳离子机理

含氮氧配位原子的镍催化剂是一类新型催化剂.文章以配体为[NH=CH－CH=CH－O]的镍催化剂为模型,用密度泛函方法（DFT）在B3LYP/LANL2MB水平上研究了该类乙烯聚合催化的反应机理.计算结果表明,催化的反应过程中,中心原子镍最先形成带空位的四边形阳离子配合物,乙烯以垂直于催化剂平面的方式占据空位,然后旋转到催化剂平面内以利于插入反应的进行；插入反应发生后,在催化剂中Ni和β-C之间形成一种氢桥键,协助新空位的形成,实现链的增长.     

纳米Y2O3/钴基合金激光熔覆层的组织

利用5 kW CO2激光器,在Ni基高温合金表面,熔覆纳米稀土氧化物(Y2O3)/钴基合金复合材料,制备了涂层.利用光学显微镜、扫描电镜及透射电镜分析了熔覆层的组织结构.结果表明: 熔覆层的主要相组成为γ-Co,ε-Co,Cr23C6和Y2O3;加入纳米Y2O3,凝固组织由细长的柱状树枝晶转变为较短的树枝晶;纳米Y2O3含量增大至1%时整个断面获得等轴晶组织;纳米Y2O3作为异质形核的核心,细化了组织;纳米Y2O3在熔覆层中分布不均匀,促进了γ-Co向ε-Co的转变;熔覆层的亚结构为堆跺层错.对熔覆层等轴组织形成机制进行了分析.     

填料对硅橡胶化学应力松弛的影响

二氧化硅填充的硅橡胶在250—300℃作连续化学应力松弛时相对应力的变化是先衰减到一最低值而后增长。它近似地符合下列式子 f(t)/f(0)=A_1e~(-k_1l+A_2e~(-k_2l)+k_3t+A3f(t)、f(0)分别为t时和起始时的应力。k_1和k_2为应力松弛常数,分别代表与填料相连之链的断裂和胶相断裂的反应速度,k_3为应力增长常数,代表受力链的交联速度。     

Quantum chemical study on the abstraction reaction of alkylidenegermylene with oxirane and thiirane

The mechanisms of theion reaction of alkylidenegermylene with oxirane and thiirane have been characterized detail in using density functional theory, as well as ab initio method, including geometry optimization and vibrational analysis for the involved stationary points on the potential energy surface. Energies were calculated by CCSD(T)/6-311G(d)//B3LYP/6-311G(d,p) method for the involved conformations. The results show that the reaction pathways for both reactions consist of two ways: (1) the reactants can yield bent products (P1; P4) by syn-isomers; (2) the reactants can also yield three-membered products (P2; P5) by anti-isomers, which then further react with oxirane and thiirane to form the ultimate products (P3-1, P3-2; P6). Furthermore, a comparison with alkylidenecarbene, oxirane, and thiirane was done.