西加毒素(CTX)的电子结构及构效关系研究

应用ＭＮＤＯ方法对ＣＴＸ衍生物进行了量子化学计算,得到了它们的电子结构信息,根据构象分析研究了它们的空间结构,推测出它们的活性部位,探讨了与受体结合时的作用方式,讨论了结构－活性关系,解释了活性差异的原因,研究结果表明该类化合物的Ｄ、Ｅ、Ｆ环和Ａ环及其支链等部位的不饱和键对活性有重要影响。     

西加毒素(CTX)的电子结构及构效关系研究

应用MNDO方法对CTX衍生物进行了量子化学计算 ,得到了它们的电子结构信息.根据构象分析研究了它们的空间结构.推测出它们的活性部位 ,探讨了与受体结合时的作用方式 ,讨论了结构 -活性关系 ,解释了活性差异的原因.研究结果表明该类化合物的D、E、F环和A环及其支链等部位的不饱和键对活性有重要影响     

Au@Gen (n=2-9)团簇的几何结构和电子性质的理论研究

本文选用密度泛函B3LYP方法在Lan L2DZ基组上对Au Gen+(n=2~9)团簇的几何结构和电子性质进行了理论研究,其中包括结构优化、平均键能、HOMO-LUMO能隙和电荷转移等。结果表明,随着锗原子数的不断增加,这些掺杂团簇逐渐形成了三维立体结构,并发现Au Ge7+和Au Ge9+两个掺杂团簇是相对稳定的,而且这些掺杂团簇的电荷转移主要是由金原子到锗原子骨架上。此外,还模拟了这些掺杂团簇的红外光谱,为以后实验研究提供有价值的理论参考。     

多晶顺磁共振谱的拟合

对电子自旋1/2≤S<3.5,核自旋1/2≤I<4.5和配体少于10个的顺磁体系的多晶EPR谱的拟合进行研究。在VAX-11/785计算机上用FORTRAN语言建立EPR谱模拟程序包,计算了多个例子,获得较为满意的结果。     

Size Dependence of Electronic Excitation Energy in Linear C_(2n)H and C_(2n-1)N

IntroductionCarbon chains are among the most attractivecandidates as the carriers of the diffuse interstellarbands ( DIBs) [1] .To detect the carbon chains indark clouds and carbon stars[2 ] ,itis very importantto understand their electronic spectra.Maier andhis coworkers have measured the polyacetylenicradicals C2 n H( n=1— 4) and C2 n-1H( n=2— 6) bythe rotational spectroscopy[3 ,4] and the species n≤ 4have been detected in dark interstellar clouds[5,6] .In neon matrices,the B2 Π← X2…     

C60O2可能异构体的结构,电子光谱和NMR谱的理论研究

用ＩＮＤＯ系列方法研究Ｃ６０Ｏ２可能异构体的结构，两个氧原子分别加在两个六元环相邻边或五六元环相邻边形成环氧结构，为Ｃｓ对称性，得６种可能构型，计算表明，两个氧原子加在同个六元环的六六元环相邻边所形成环氧结构Ｃｓ构型最稳定，环氧处Ｃ－Ｃ键不断开，与实验结果一致，其电子光谱计算结果亦与实验值相吻合，这种Ｃｓ构环氧结构所在六元环上的另一个Ｃ－Ｃ键有大的键序，为高活性位置，因此Ｃ６０Ｏ２可能有较好的化学     

Studies on the Electronic Structures and Spectra of C78（CH2）3

The structures and spectra of 20 possible isomers of C78(CH2)3 have been studied by using AM1,INDO/CIS and DFT methods. The results show that the most stable isomer is 1,2,3,4,5,6-C78(CH2)3 (A) with annulene structures,where three -CH2 groups are added to the 6/6 bonds located at the same hexagon passed by the shortest axis of C78 (C2v). Compared with that of C78 (C2v),the first absorption in the electronic spectrum of C78(CH2)3 (A) is blue-shifted because of its wider LUMO-HOMO energy gap. While the IR frequencies of the C–C bonds on the carbon cage are red-shifted owing to the formation of annulene structures and the extension of the conjugated system. The chemical shifts of the carbon atoms in 13C NMR spectra are moved upfield upon the addition.     

(NiV13O38)7-的电子结构和催化性质的探讨

使用SCC－DV－Xα方法研究了高钒杂多化合物（NiV13O38）7-的电子结构，并探讨了它的催化性质·结果表明，（NiV13O38）7-是一种比Keggin结构更强的催化剂。分析了该阴离子中的键的强弱关系，认为配位数越少的氧与V形成的键越强．并分析了前线轨道HOMO，LUMO的组成，从而得出它的催化活性中心是Ni，V、一配位端氧，二、三配位桥氧，五配位中心氧的结论。     

马来腈二硫纶·邻菲咯啉镍(II)配合物的电子光谱和理论研究

测量了标题配合物Ni(mnt)(phen)在多种介质中的电子吸收光谱和发射光谱, 使用密度泛函理论的B3LYP方法和分子轨道理论的PM3方法研究了其气态分子几何构型、电子结构和成键, 用ZINDO/S方法通过多组态的组态相互作用(CI)计算解释了实验光谱. 结果表明: 该配合物分子为平面结构, 对称性属于点群C_2v, 基态为自旋三重态, 配位键Ni—N和Ni—S为典型的共价结合, Ni的3d电子反馈效应较显著; 可见区的吸收带和发射带(对应于基态电子组态到较低能量激发态组态的跃迁)本质上属于配体phen到mnt^2－的荷移跃迁(LL'CT), 紫外区的吸收带本质上属于配体的π→π*跃迁.     

Evaluation of Pomegranate (Punica Granatum L.) Pulps for the Removal of Copper(II) Ions: Kinetic,Equilibrium, and Desorption Studies

Pomegranate pulp has been used as novel adsorbent for removing Cu(II) ions from aqueous solution. The optimum conditions for removal of Cu(II) ions were found to be pH 5.32, biosorbent dose 0.1 g, contact time 120 minutes, initial concentration 50 mg/L, and temperature 30°C. The kinetic data were well fitted to the pseudo-second-order model. The biosorption process agreed with the Langmuir isotherm model. Maximum monolayer biosorption capacity was 7.30 mg/g. Thermodynamic parameters suggest that the biosorption process is spontaneous and exothermic. Desorption studies were carried out with different desorbing agents.      

Simultaneous Determination of Gallium(III) and Indium(III) in Urine and Water Samples with Cloud Point Extraction and by Inductively Coupled Plasma Optical Emission Spectrometry

A simple, sensitive, and selective method for the determination of gallium and indium in different samples at trace levels is presented. This method was based on complexation of analyzes with 2-(5-bromo-2- pyridylazo)-5-diethylaminophenol (5-Br-PADAP) in the presence of t-octylphenoxy-polyethoxyethanol (Triton X-100). After phase separation, the analyzed concentrations were determined by inductively coupled plasma optical emission spectrometry. Quantitative extraction of gallium and indium was performed at pH 7.0, 1.7 mmol L^?1, 5-Br-PADAP, 1.3% (w/v) Triton X-100 and at 75°C. The relative standard deviations (RSD) of this method were between 0.3% and 1.6% (C = 20 ng mL^?1, n = 9). The calibration curve is linear over the concentration range 6–200 ng mL^?1 for gallium and 2–200 ng mL^?1 for indium, respectively. The limits of detection (LOD) for gallium and indium were 0.72 and 0.28 ng mL^?1, respectively. The results showed the developed method was not susceptible to matrix effects, providing recoveries between 98% and 102%. The accuracy of the developed method was evaluated by the analysis of spiked certified reference materials. The developed method was successfully applied to gallium and indium determination in urine and lake water with satisfactory results.     

Studies on Effect of Tri(2-hydroxypropyl), Tri(2-hydroxybutyl) and Tri(hydroxythiodiethylene) Borates on Thermal and Heat Properties of Rigid Polyurethane-Polyisocyanurate Foams

Effect of tri（2-hydroxypropyl）, tri（2-hydroxybutyl）and tri（hydroxythiodiethylene） borates （BT2HB, BT2HP and BTHET） on the thermal and heat properties of the rigid polyurethane-polyisocyanurate （PUR-PIR） foams was investigated： Increasing amounts of BT2HB and BT2HP in the foam composition, from 0.05 to 0.4 of chemical equivalent, caused increases in the softening point, the temperature of the first mass loss, the extrapolated tempera- ture of the main mass loss foam and temperature of the highest rate of the mass loss. In the case when BTHTE was added to the foam compositions, the lower increase in the mentioned above characteristic temperatures was observed as compared to those of standard foam （without borate added）.     

测定晶体结构的系统试差法的研究(III) SYSTEM 90程序系统和应用

介绍最近研究的系统试差法的基本公式和它的程序系统ＳＹＳＴＥＭ９０的构成，应用该程序系统对收集到的５个难解结构进行了成功的测定，实验结果显示了ＳＹＳＴＥＭ９０程序系统的威力，最后在分析的基础上，提出了系统试差法程序系统不同于其它直接法的四个特点。     

Enhanced general analytical equation for the kinetics of the thermal degradation of poly(lactic acid) driven by random scission

An enhanced general analytical equation has been developed in order to evaluate the kinetic parameters of the thermal degradation of poly(lactic acid) (PLA) at various linear heating rates and at constant rate conditions. This improvement consisted of replacing the n-order conversion function by a modified form of the Sestak-Berggren equation f(α) = c(1?α)ⁿα^m, which led to better adjustment of experimental data, and also adequately represented the conventional mechanisms for solid-state processes. The kinetic parameters so obtained have been compared to those determined by conventional differential and isoconversional methods. Given that the thermal degradation of PLA has been argued to be caused by random chain scission reactions of ester groups, the conversion function (α) = 2(α^1/2?α), corresponding to a random scission mechanism, has been tested.     

测定晶体结构的系统试差法的研究(II)系统位相超解方程得改进

本文证明了|E(k)E(h-k)|的大小是由结构决定的。与原点无关, 在这种认识的基础上, 提出了用归一化结构振幅|E|估量它的三种模式。特别是通过四位相结构不变量的二级Noighborhood~[1,2]原理解决三位相不变量间的匹配问题而算出的|E(k)E(h-k)|_(QE), 这是在没有位相数据的情况下对它的理想的估量。予期它能改进系统试差法中位相超解方程的功能, 提高测得位相的准确性。     

α—氨基膦（次膦）酸类衍生物的合成及其性质

采用8种合成方法,合成了38种α-氨基膦(次膦)酸类衍生物。发现部分α-氨基膦酸化合物中含有1个结晶水。测定了化合物的pK_α值。所有化合物都具有一定除草和杀菌活性。     

Development of Azo Dye Immobilized Sulfonated Poly (Glycidyl Methacrylate) Polymer Composite as Novel Adsorbents for Water Treatment Applications: Methylene Blue Immobilization Isotherm,Kinetic, Thermodynamic,and Simulations Studies

Methylene blue (MB) immobilized onto a sulfonated poly(glycidyl methacrylate) (SPGMA) polymer composite has been developed as a novel adsorbent for water treatment applications. The MB adsorptions onto sulfonated poly(glycidyl methacrylate) polymer characters have been studied. The adsorption isotherms, namely Langmuir and Freundlich, have been investigated. Other isotherm models. As a compromise between the Freundlich and Langmuir isotherm models, such as the D–R isotherm and the Temkin isotherm, have been compared. The results indicated that the adsorption process followed the Freundlich isotherm model, indicating heterogeneous surface site energies and multi-layer levels of sorption. This study selected three linear kinetic models, namely pseudo-first order, pseudo-second order, and Elovich, to describe the MB sorption process using SPGMA negatively charged nanoparticles (430 nm). The obtained data revealed that the adsorption process obeyed the pseudo-second-order kinetic model, suggesting that the rate-limiting step in these sorption processes may be chemisorption. Furthermore, the thermodynamic parameters have been evaluated. Moreover, the interaction of the MB molecules with SPGMA nanoparticles has been simulated using the governing equation that describes ion exchange resin derived from Nernst—Plank equations between two ion species. Finally, the developed MB-SPGMA composite adsorbent (27 mg/g) wastested for the first time for the removal of Cr⁶⁺ ions and Mn⁷⁺ metal ions from dichromate and permanganate-contaminated waters under mild adsorption conditions, opening a new field of multiuse of the same adsorbent in the removal of more than one contaminant.     

次甲基硅SiH与H2X(X=O,S)反应的热力学及动力学性质研究

在量子化学对SiH与H₂O和H₂S反应计算的基础上,运用统计热力学和Wigner校正的Eyring过渡态理论,计算了上述两反应在200～2000 K温度范围内的热力学函数、平衡常数、频率因子A和速率常数随温度的变化。计算结果表明,两反应在低温下具有热力学优势,而在高温下具有动力学优势。比较两反应的计算结果发现,在相同的温度下,SiH与H₂O反应比SiH与H₂S反应放热较多,但速率常数却较小。SiH与H₂O反应和前文报道的SiH与HF反应的比较表明,SiH与H₂O反应放热较少,而且在相同温度下,速率常数也较小。     

Sol-Gel Microsphere Pelletisation Process for Fabrication of (U,Pu)O2, (U,Pu)C and (U,Pu)N Fuel Pellets for the Prototype Fast Breeder Reactor in India

A “dust-free” sol-gel microsphere pelletisation (SGMP) process has been developed for fabrication of (U,Pu)O₂, (U,Pu)C and (U,Pu)N fuel pellets containing around 15% plutonium for the forthcoming prototype fast breeder reactor (PFBR) in India. The objective was to produce homogeneous sintered pellets of ∼85% T.D. with a predominantly open-pore structure. Hydrated gel-microspheres of UO₃+PuO₂ and UO₃+PuO₂+C have been prepared from nitrate solutions of uranium and plutonium by the “ammonia internal gelation” process, using hexamethylene tetramine (HMTA) as an ammonia generator and silicone oil at 90±1°C as gelation bath. For oxide fuel pellets, the hydrated UO₃+PuO₂ gel-microspheres were calcined at around 700°C in Ar+8% H₂ atmosphere to produce “non-porous”, “free-flowing” and coarse (around 400 micron) microspheres which could be directly pelletised at 550 MPa to green pellets. The mixed oxide pellets were subjected either to low temperature (∼1100°C) oxidative sintering (LTS) in N₂+air containing ∼1500 ppm O₂ or to high temperature (1650°C) sintering, (HTS) in Ar+8% H₂. For monocarbide and mononitride pellets, hydrated gel-microspheres of UO₃+PuO₂+C were subjected to carbothermic synthesis in vacuum (∼1 Pa) and flowing nitrogen (flow rate: 1.2 m³/h) in the temperature range of 1450–1550°C respectively. The monocarbide and mononitride microspheres thus produced were relatively hard and required higher compaction pressure (∼1200 MPa) for making reen pellets which could be sintered to 85% T.D. in Ar+8% H₂ at 1700°C. The sintered oxide, monocarbide and mononitride pellets had a “blackberry” “open” pore microstructure with fine grain size. The microspheres retained their individual identity in the sintered pellets because during sintering densification took place mainly within and not between the microspheres.     

Structural,Electronic and Optical Properties of Multifunctional Iridium(III) and Platinum(II) Metallophosphors for Organic Light‐Emitting Diodes

An elaborated theoretical investigation on the optical and electronic properties of three fluorene‐based platinum(II) and iridium(III) cyclometalated complexes Pt‐a , Ir‐a and Ir‐b is reported. The geometric and electronic structures of the complexes in the ground state are studied with density functional theory and Hartree Fock approaches, while the lowest triplet excited states are optimized by singles configuration interaction (CIS) methods. At the time‐dependent density functional theory (TD‐DFT) level, molecular absorption and emission properties were calculated on the basis of optimized ground‐ and excited‐state geometries, respectively. The computational results show that the appearance of triphenylamino (TPA) moiety at the 9‐position of fluorene ring favors the hole‐creation and leads to red‐shifts of absorption and emission spectra. Moreover, Pt‐a and Ir‐b are nice hole‐transporting materials whereas Ir‐a has good charge‐transfer balance, which render them useful for the realization of efficient OLEDs (Organic Light‐Emitting Diodes).