LOW MOLECULAR WEIGHT O-CARBOXYMETHYLATED CHITOSANS DERIVED FROM IRRADIATED CHITOSAN AND THEIR ANTIBACTERIAL ACTIVITY*

 Original chitosan with M_v of 2.7 × 10⁵ was degraded by irradiation with γ-rays and a series of low molecular weight O-carboxymethylated chitosans (O-CMCh) were prepared based on the irradiated chitosan. A kinetic model of the irradiation of chitosan was put forward. Results show that the irradiation degradation of chitosan obeys the rule of random degradation and the degree of deacetylation of irradiated chitosan is slightly raised. The antibacterial activity of O-CMCh is significantly influenced by its MW, and a suppositional antibacterial peak appears when M_v is equal to 2 × 10⁵.     

[Mn(NH2NHCO2C2H5)3](NO3)2的晶体结构和热分解机理

[Mn(ECZ)₃](NO₃)₂ is newly prepared by the aqueous solutions of Mn(NO₃)₂ and ethyl carbazate (ECZ). The crystal structure has been determined by X-ray crystal diffraction analysis. It belongs to monoclinic with space group of P2₁/n. The crystal parameters are: a=1.3974(2) nm, b=0.8796(2) nm, c=3.4322(7) nm, β=91.25(1) °, V= 4.2175(1) nm³, Z=8. Its molecular weight is 491.30. Mn²⁺ is located on the center of the molecular structure. Ethyl carbazate serves as a bidentate ligand which coordinates to the metal cations with its carbonyl oxygen atom and the terminal hydrazine nitrogen atom, forming five-member chelating rings, and three such rings are formed in each molecule. The coordination number of the metal ion is six and the coordination configuration of the central ion is octahedral. Specially, antimer configuration phenomenon is found in the molecule. The complex is further characterized by element analysis and IR measurements. The thermal decomposition mechanism is studied by using TG-DTG and DSC techniques. CCDC: 215675.     

Copper(II) ion-selective microelectrochemical transistor

A device has been developed for the measurement of copper(II) ions (Cu⁺⁺) in aqueous medium. The device reported here is an electrochemical transistor that consists of two platinum electrodes separated by 100-μm spacing and bridged with an anodically grown polycarbazole film. The undoped polycarbazole film is observed to be highly selective for the Cu(II) ions. In a completed device, the conductivity of the polycarbazole film changes on addition of Cu (II)ions. This change in conductivity is attributed to the conformational changes in the polymer phase on occupation of the Cu(II) ions, without affecting electron/proton transfer. The device turns on by adding 2.5×10⁻⁶ M Cu(II) ions and reaches a saturation region above a concentration of 10⁻⁴ M Cu(II) ions. In this concentration range, the plot of I _D vs log[Cu(II)] is linear. The selectivity of the device for other metal ions such as Cu(I), Co(II), Fe(II), Fe(III), Zn(II), and Pb(II) is also studied.     

ZrWO4F2的前驱物法合成和表征

Zirconium tungsten oxyfluoride, ZrWO₄F₂, was firstly synthesized with the precursor route. The composition of the compound was determined by combining the results of ICP and XPS. The indexed powder X-ray diffraction pattern of this compound indicates that it is a pure phase, orthorhombic crystal system, space group D₂²=P2₁22 and a=15.32(2)?,b=13.877(7)?,c=8.42(2)?.Combining the results of the DTA-TGA curves from room temperature to 700℃ and XRD patterns in different temperatures the mechanism was revealed during the solid precursor (1) been heated to 700℃. The zirconium tungsten oxyfluoride was considered to be a metastable com-pound. The ascertaining of annealing time and temperature is the key of handling.     

二正丁基二硫代氨基甲酸锌配合物的量子化学研究

The geometric configurations of binuclear Zinc(Ⅱ) complex Zn₂[(n-Bu)₂NCSS]₄ and the ligand Na[(n-Bu)₂ NCSS] have been optimized by B3LYP quantum chemical method. The electronic structures have been performed by density functional theory at B3LYP/6-31G^* level. The electronic spectrums of the complex and ligand were calculated by ZINDO/S-CIS method. It is indicated from the calculation that: (1) The coordination effect of bridging ligand is bigger than that of chelating one, and the bridging ligands also translate more charge to Zn than the chelating one. (2) The calculated results about electronic spectrums are similarly to experimental measurement, and farther explain that absorption band at λ=267 nm of complex is assigned to two n → π^* transitions :one arising from the bridging ligands and the another mainly arising from the chelating ligands;but absorption band at λ=236 nm of complex is assigned to π → π^* transition which the electron mainly translates from the bridging ligands to the chelating ligands. (3) By consideration of delocalization and polar effects in coordination, the charge transfer from ligand to metal decreases the π-π and p-π conjugation effects in the chromophore group NCS₂ and to increase the energy needed for the π → π^* and n → π^* transitions, and results in the absorption bands shifting towards the short wavelength direction.     

锌(Ⅱ)-氨基酸水杨醛席夫碱-α-氨基酸三元配合物的稳定性

The stability constants of binary complexes of Zn(Ⅱ)-α-amino acid and ternary complexes of Zn(Ⅱ)-N-Salicylideneaminio acid (ligand A)-α-amino acid(ligand B) at (25±0.1)℃ and in the presence of 0.1 mol·L^-1 KNO₃ have been determined by pH method. The α-amino acid(Aa) used were Glycine(Gly), L-Serine(Ser), L-Leucine(Leu), L-Proline(Pro) and L-Phenylalanine(Phe). It was found that the linear free energy relationship (LFER) exists nicely between the following parameter pairs logβ₁₀₂ and pK^B₂, logβ₁₁₁ and pK^B₂, and logβ₁₁₁ and pK^A₂. The ΔlgK was used to characterize the stability of ternary complexes related to the stability of parent binary complexes. The hydrophobic interaction between ligands in the ternary complexes was studied.     

钒催化剂选择性氧化乳酸乙酯制丙酮酸乙酯

The structure and surface acidity of vanadium oxide supported on α-Al₂O₃、TiO₂、SiO₂ have been studied by XRD、IR、TPR and adsorption microcalorimetry. The catalytic performance of the catalysts for selective oxidation of ethyl lactate to ethyl pyruvate was determined in a continuous flow fix-bed reactor. The results showed that the dispersion of vanadium oxide on the supports weakened the V=O bond and actived the terminal oxygen, which increased the reaction activity. On the otherhand, The surface acidity is harmful to the selectivity of ethyl pyruvate. V/α-Al₂O₃ exhibited a lower conversion since its dispersion is low. The low selectivity on V/SiO₂ is due to its fairly strong surface acidity. Addition of K⁺ weakened the surface acidty and enhanced selectivity of V/SiO₂. V/TiO₂ exhibited the best activity and selectivity among the catalysts studied because of its weak surface activity. The conversion of ethyl lactate and selectivity to ethyl pyruvate are 97% and 81%, respectively, over the V/TiO₂ catalyst at 473K.     

TDS and XPS study of oxygen diffusion into subsurface layers of Pd(110)

Summary The interaction of O₂with Pd(110) has been studied by TDS and XPS at T = 400 K and at pressures P_{O2 from 2.6x10}^-6to 10 Pa. At low exposures in O₂(e￡1-5 L), an adsorption layer withqof ca.0.5 and with the O1s peak at BE = 529.3 eV has been found to form on the surface. Whenegrows from 5 to 10⁸L, the position and intensity of the oxygen O1s peak remain practically constant. At the same time, as much as 5 mL of oxygen is absorbed according to the TDS data. The results obtained by TDS and XPS indicate that oxygen penetrates deep into the subsurface layers of palladium (315-20 ?) and is distributed in its bulk in a low concentration.     

LiNi1-xMxVO4的红外光谱和拉曼光谱研究

The vanadates of LiNi_1-xM_xVO₄(M=Fe,Co,Ni) containing VO₄ tetrahedrons were synthesized by soft chemical method through a new mild liquid route. The samples sintered at 450℃ for 3h and at 650℃ for 3h are named for LT-LiNiVO₄ and for MT-LiNi_1-xM_xVO₄ respectively. All of the products were measured by X-ray diffraction, IR and Raman spectra respectively. In comparison with IR spectra of V₂O₅ and NiO, the LT-LiNiVO₄ has a strong and broad IR absorption band of VO₄ tetrahedrons located at 600～850cm^-1 with three small splitting peaks corresponding to the asymmetry stretching vibrations of V-O bonds. The results of IR and Raman spectra for MT-LiNi_1-xM_xVO₄ show that the cations of Ni²⁺, Co²⁺, Fe²⁺ have the influences on the frequency shifts of the V-O vibrations.     

杂-双核配合物[CaCu(C3H2O4)2(H2O)4]n的合成、晶体结构及热稳定性

The title complex， [CaCu(C₃H₂O₄)₂(H₂O)₄]_n， with a formula of C₆H₁₂CaCuO₁₂ and M_r=379.78 has been sy-nthesized and characterized by single crystal X-ray diffraction structure analysis， elemental analysis， IR spectra and TG-DTG techniques. The results show that the crystal is Orthorhombic， space group Pbcn with a=0.669 21(5) nm， b=1.370 23(5) nm， c=1.322 39(10) nm， V=1.212 59(16) nm³， D_c=2.080 g·cm^-3， μ=2.288 mm^-1， F(000)=772 and Z=4. The final R=0.054 0 and wR=0.112 8 for 1 189 observed reflections with I>2σ(I). The structure of the title complex consists of CaO₈ polyhedra and CuO₆ elongated octahedra linked together by malonate ligands. The Ca(Ⅱ) cation， on a twofold axis， is coordinated by two water molecules and six malonate O atoms. The Cu(Ⅱ) cation， which lies in a centre of symmetry in an octahedral arrangement， is coordinated by four malonate O atoms and two water molecules. The structure comprises alternating layers along the [101] plane， with the shortest Cu…Cu distance of 0.762 46(6) nm. The whole 3D structure is maintained and stabilized by the presence of hydrogen bonds. Its thermo gravimetric analysis was determined by TG-DTG techniques. CCDC: 663184.     

SYNTHESIS AND REACTIONS OF SOME 2-THIENYL- AND 2-THENOYL-DERIVATIVES OF THIAZOLE AND THIADIAZOLINE AND THEIR SELENIUM ANALOGS

Abstract

2-(Thiocyanatoacetyl)thiophene 2 and its selenium analog 3 couple with diazotized anilines and yield 3-aryl-2-imino-5-(2-thenoyl)-2,3-dihydro-1,3,4-thiadiazoles 6 and 3-aryl-2-imino-5-(2-thenoyl)-2,3-dihydro-1,3,4-selenadiazoles 7 respectively. The reactions of both 6 and 7 with nitrous acid, acetic anhydride and benzoyl chloride are described. Azo coupling of 2-amino-4-(2-thienyl)thiazole 17 and its selenazole analog 18 with diazotized anilines yielded the arylazo derivatives 19 and 20 respectively. Reaction of the hydrazidoyl bromide 16 with potassium thiocyanate, potassium selenocyanate, thiourea and selenourea yields 6, 7, 19, and 20 respectively.     

聚壬酰胺的制备纺丝及结构与性能测定

9-氨基壬酸系从癸二酸经单酯化、氨化和Hofmann重排制得。该单体以10克规模在玻璃管中和以4公斤量在15升聚合釜中,于260℃聚合成聚壬酰胺。聚合物在288℃纺丝,120℃牵伸,得到尼龙-9纤维。测定了聚合物和纤维的结构和多种性能。     

PHOTOLYSIS AND RADIOLYSIS OF NITROMETHANE AND NITROETHANE

Abstract— Prolonged photolysis of nitromethane and nitroethane in liquid and vapour phases, with simultaneous photolysis of the nitrogen dioxide formed, was studied in the absence and presence of cupric oxide. A high-pressure quartz immersion lamp providing the full range of visible and u.v. spectrum, with a high output of radiation at 366 and 313 mμ, was employed as source of light. The products of photolysis were detected by microanalytical methods, infrared-absorption spectrum analysis and gas chromatography. Photolysis of liquid nitro-alkanes resulted in formation of many compounds; saturated hydrocarbons, and in the case of nitroethane, ethylene, were submitted to detailed examination. Photolysis in the vapour phase was carried out in a specially designed glass apparatus. The main products were nitrogen dioxide, aldehydes and polyaldehydes; hydrocarbons were not estimated.
Liquid nitromethane and nitroethane were also irradiated with γ-rays from a ⁶⁰Co source. The radiolysis products were similiar to those obtained on photolysis. The mechanism of photolytic decomposition of nitroalkanes is proposed and discussed.     

生物质热解、加氢热解及其与煤共热解的热重研究

在加压热天平上用非等温热重法进行生物质（锯末、稻壳）在Ｎ２气氛下的热解和加氢热解研究。考察了升温速率（５～２５℃／ｍｉｎ）和压力（０．１～７ＭＰａ）的影响，求取了热解动力学参数，并研究了生物质与煤在常压Ｎ２气下的共热解过程。研究结果表明：生物质在４００℃左右即完成热解反应，总失重率大于７０％（Ｗ％，ｄａｆ．），热解时仅一个峰位于３００℃左右；与煤热解行为相同，随升温速率及压力的升高，转化率下降，ＤＴＧ峰移向高温，但由于热解反应在较低温度下进行，氧气的存在对生物质热解ＴＧ和ＤＴＧ的影响远小于煤热解。证明生物质热解以其内部氢对自由基的饱和及分子重排反应为主。生物质热解可用一级反应动力学处理，主要热解阶段及表现活化能分别为：锯末，２６７～３１４℃，６９．６６ｋＪ／ｍｏｌ；稻壳，２８３～３１０℃，５３．４５ｋＪ／ｍｏｌ；生物质由于与煤的热分解温度相差很大，因而在其共热解过程中无协同作用。     

CHLOROPHYLL a AND CAROTENOID AGGREGATES AND ENERGY MIGRATION IN MONOLAYERS AND THIN FILMS

Abstract— The spectra of absorption, fluorescence and excitation of monolayers and thin films containing chlorophyll a together with a carotenoid (cis-β-carotene, trans-β-carotene, fucoxanthin, or zeaxanthin), were measured at — 196°C. The concentration ratios used, (Chl)/(Car), were 6:1, 4:1, 3:1, 2:1, 1:1 and 1:3, and the area densities, 3·70, 2·55, 1·76, 0·71, 0·37 and 0·17 nm²/pigment molecule. In dilute monolayers, (3·70 nm²/molecule), with a constant concentration ratio (Chl)/(Car) = 3:1, evidence of three β-carotene forms, with absorption bands at 460, 500 and 520 nm (C₄₆₀, C₅₀₀ and C₅₂₀), and of a chlorophyll a form with an absorption band at 669–672 (Chl_669–672) was found. On increasing the density to 0·2–0·3 nm²/molecule, a conversion of C₄₆₀ and C₅₂₀ into C₅₀₀, was observed, and several more additional (probably more strongly aggregated) chlorophyll a forms appeared, with absorption bands at 672–733 nm. With excess carotene [(Chi)/(Car) = 1:3] the forms C₄₆₀, C₅₀₀, C₅₂₀ and Chl_669–672 were present even in the most dense films (0·2–0·3 nm²/molecule). The same was found with other carotenoids: if one of the pigments was in excess, aggregated forms of the other tended to disappear. In the transfer of energy from carotenoids to chlorophyll a, C₅₀₀ was found to be the main donor. In layers with a concentration ratio (Chl)/(Car) = 3:1, the efficiency of transfer was less than 10 per cent at the lowest density used (3·70 nm²/molecule); it increased to 50 per cent, as the density was increased to 0·20 nm²/molecule. When the relative concentration of the carotenoid was increased to (Chl)/(Car) = 1:1, the efficiency of energy transfer dropped to 25 per cent even at 0·20 nm²/molecule. It seems that the efficiency of energy transfer between carotene molecules (prior to its transfer to chlorophyll a) is low, and effective transfer occurs only between β-carotene and immediately adjacent chlorophyll a molecules.     

SURFACE ENTHALPY AND ENTROPY AND THE PHYSICO-CHEMICAL NATURE OF HYDROPHOBIC AND HYDROPHILIC INTERACTIONS

The attractive Interactions between typically hydrophobic molecules such as hexane or CCl₄, and the repulsive Interactions between extremely hydrophilic molecules such as poly(ethylene oxide) (PEO), when immersed in water, as well as the interactions between these molecules and water, have been examined from a surface thermodynamic viewpoint, taking the changes in surface free energy into account, as a function of temperature. It was found that attractive hydrophobic Interactions are not, as vas generally believed up to now, invariably entropic. Hydrophobic Interactions can be mainly enthalpic or mainly entropic, or more or less equal mixtures of both, depending on each individual case; however, all hydrophobic interactions are polar (in the sense of Lewis acid-base) in nature. Repulsive hydrophilic interactions are enthalpic, and also polar in nature. The interaction between hydrophobic solutes and water is mainly enthalpic, and is apolar in nature.     

温度及pH敏感N-异丙基丙烯酰胺/β-环糊精水凝胶的合成与性能研究

用顺丁烯二酸酐 (MAH)对具有分子包结能力的 β 环糊精 (β CD)进行化学改性 ,合成出了丁烯二酸单酯化 β CD单体 (MAH β CD) .通过氧化还原自由基引发MAH β CD与N 异丙基丙烯酰胺 (NIPA)聚合 ,合成出含 β CD结构单元的新型水凝胶 .用核磁共振、红外光谱及元素分析对MAH β CD单体及共聚物的结构和组成进行了表征 .溶胀研究结果表明 ,该水凝胶具有较好的pH、温度及离子强度敏感性 ;并且水凝胶在较高羧基(—COOH)含量和弱碱环境中 ,仍能表现出明显的温敏性     

MECHANICS AND THE EVOLUTION AND FUNCTIONAL MORPHOLOGY OF CONCHOSTRACAN CARAPACE MECHANICS AND THE EVOLUTION AND FUNCTIONAL MORPHOLOGY OF CONCHOSTRACAN CARAPACE

Conchostracans, with a laterally compressed body enclosed between two symmetric valves, live swimming in fresh or brackish water. The carapace valve has a number of growth bands with various sculptures. The general trend of sculptural evolution is from smooth to punctate-minute polygon-medium reticulation-large reticulation, while these punctate, polygonal and various reticulate patterns may separately develop into various radial ridges. The development of sculpture can be well explained by mechanical principle. Functional morphology of carapace is discussed in the light of mechanics in this paper.     

N-苯基马来酰亚胺与环己烯共聚物的制备和表征

Ｎ苯基马来酰亚胺（ＰＨＭＩ）是一种很有应用价值的共聚单体,它能赋予共聚物很好的耐热性．有关ＰＨＭＩ与甲基丙烯酸甲酯、苯乙烯及乙烯基醚的二元共聚合反应已有文献报道［１～３］．而有关ＰＨＭＩ与环烯烃特别是环己烯的共聚合研究除我们所做的工作外［４］,报道甚少．作者研究了ＰＨＭＩ与环己烯在溶液中的二元共聚合反应,并对所得的共聚物进行了表征．１　原料ＰＨＭＩ,自制,ｍ．ｐ．８８－７℃;元素分析Ｃ,６９－３３;Ｈ,４－０７;Ｎ,８－１０;理论值Ｃ,６９－３６;Ｈ,４－０７;Ｎ,８－０９,１ＨＮＭＲ（δ）…