二氮双环阳离子游离基中N，N′—三电子键

用从头算HF/3-21+G*优化了二氮双环[m,n,l]游离基阳离子(m,n,l≥2～5).分子[4,4,4]和[2,2,2]+,[3,3,3]+,[4,4,4]+游离基阳离子的优势构型有D3对称性,而其它游离基阳离子的优势构型为非对称性.通过比较这些阳离子几何构型,HOMO和NHOMO(即Next HOMO和HOMO-1),和由MNDO计算确定的原子对作用能,表明当二氮双环游离基阳离子的桥链(CH2)n的n≥3时,桥头氮原子通过空间相互作用形成了一个弱的N,N＇-三电子σ-键.形成的三电子键强度不随环的扩大而增强.而三电子键强度被两个因素影响:一个是桥头氮原子间的p轨道重叠的取向;另一个是它们相应p轨道成分.

一些球蛋白可解离基的相互作用特征

球状蛋白质的结构分析有助于蛋白质三维结构的认识.维持蛋白质三维结构的作用力至少有3种类型,即氢键、盐桥(亦称盐键或静电键)和疏水键.维持三维结构的作用力可以看作是可解离基和非解离基各自间的以及两者之间的相互作用.

失去弹性的“之间”:埃克哈特与存在的离基

在亚里士多德主义经院哲学与基督教神学的融合过程中,神与存在的关系成为焦点之一。对于这一问题,埃克哈特一方面发展了托马斯主义,认为存在就是上帝,并由此建构了创造论的形而上学;另一方面提升了上帝超越性,揭示出神深处的神性,并将神性理解为寂静虚无的离基深渊。神性与神的差异,又以两者作为纯粹的一为前提。然而埃克哈特因为固守永恒视角,遵循多明我会的理智主义传统,取消了新柏拉图主义的层级结构,遵循更为直接性的思想取向,从而有意去除了神性与神、存在与无之间转变的弹性,造成了“失去弹性的‘之间’”状态。这种直接性的同一性及其遗留下来的问题,为后世德意志神秘主义思想与德国绝对唯心论的发展,提供了重要的思想动力。而他对存在与离基关系的揭示,又与海德格尔哲学产生了内在的亲缘性。

无端的开端——笛卡尔与非根据的双重复现

哲学的开端问题,伴随着笛卡尔我思的建立,成为近现代哲学的重要主题,而其分歧也大多能追溯到笛卡尔哲学中的多种开端。在《指导天赋的规则》中,笛卡尔曾以心灵的直观活动作为开端。《指导天赋的规则》的失败使笛卡尔提出了超越理性秩序的离基性上帝作为新的开端,并随后将心灵改造为我思,它通过离基性的自我证成制约和平衡了上帝的离基性,从而成为第一哲学的真正开端。不过我思和上帝都应有先于两者分化的非根据状态,正是这一无分别且绝对自由的原始状态,通过意志的决断将自身双重复现为我思与上帝,并形成了两者的对生关系,从而成为一种“无端的开端”。笛卡尔在为近代形而上学进行奠基的同时,也揭示了这一奠基的限度,预示了它的终结。

Mechanisms of surface charge development of serpentine mineral

The electrokinetic behavior and surface dissolution of serpentine mineral were studied through Zeta potential measurements, dissolution experiments and X-ray photoelectron spectroscopy. The results show that serpentine has an iso-electric point （IEP） of 11.9, which is higher than that of other phyllosilicate minerals. Dissolution experiments show that the hydroxyl is easy to dissolve with respect to the magnesium cations in the magnesium oxide octahedral sheet. As a result of hydroxyl dissolution, the magnesium ions are left on serpentine surface, which is responsible for serpentine surface charge. The removal of magnesium ions from serpentine surface by acid leaching results in a decrease of serpentine IEP. Therefore, it has been clearly established that the surface charge developed at the serpentine/aqueous electrical interface is a function of the serpentine surface incongruent dissolution.

不同氮水平下盐胁迫对大麦幼苗中某些氮化物积累的影响(简报)

在土培条件下,提高氮素供应水平和NaCl处理浓度后大麦幼苗地上部和根中的全氮,蛋白质氮和游离氨基酸总量增加;蛋白质氮占全氮的比值亦因NaCl处理浓度的增大而提高。在盐胁迫下,游离脯氨酸占氨基酸总量的百分比明显增加,而谷氨酸所占比例则下降。

FAA Composition and Content Variation in Different Pyropia yezoensis Cultivar in Harvest Period

The contents of 16 kinds of free amino acids （FAAs） in 7 Pyropia yezoensis cultivars were determined by pre-column derivatization high performance liquid chromatographyin early, middle and late harvest period.The results showed that the total FAA content ranged from 48.71 to 62.05 mg/g among the 7 test ma- terials. Among the 16 kinds of FAAs, Ala, Arg, Glu and Asp, four kinds of flavor amino acids, showed the highest contents, and their total content ranged from 36.05 to 53.96 mg/g, accounting for 69.11%-86.47% of the total FAA content. The total contents of flavor amino acids and FAAs all reached the peaks in all the test ma- terials, except the control cultivar, at middle harvest period. The essential amino acid content was trended to be increased in all the test materials with the extended harvest period, and it reached the peak at the late harvest period. Sutong showed the highest flavor amino acid content and FAAs content, followed by Y-H002, Suyan and Sulian, while the control cultivar showed the lowest contents.

SOD-like Activities of Fifteen Constituents from Rhubarb

It is important to search for the ingredients with SOD—like activity present in Chinese traditional drugs.Four classes of constituents including fifteen compounds isolated from Chinese rhubarb were studied for their SOD-like activity by determining the percentage of scavenging effect of the superoxide radical anion (O2),(S％),The results showed that the SOD-like activities of four tanninoid compounds were stronger among which(—)-epi- catechin has the strongest SOD-like activity at lower concentrations:the activity of five stil- bene compounds is weaker:while chrysophanol-8-glucoside and desoxyrhaponticin have no SOD-like activity and,on the contrary.may promote the production of O_2^-

Cloning and Differential Expression of a 1-Aminocyclopropane-1-Carboxylate Synthase cDNA from Peach

The ACC synthase is the key enzyme in ethylene biosynthesis and fruit ripening. To study the mechanism of ACC synthase in peach Prunus persica (L.) Batsch) fruit ripening, we cloned a full_length cDNA of ACC synthase pacs from peach using 5′/3′ RACE PCR. The nucleic acid sequence of pacs was 1 848 bp, containing 177 bp of 5′untranslated sequence, 1 449 bp of an open reading frame, and 219 bp of 3′untranslated sequence (excluding the stop codon TAA). The pacs open reading frame encoded a 483_amino acid polypeptide with a predicted size of 54 kD and a calculated PI of 6.43. The deduced protein from ACC synthase cDNA pacs had 65%, 70%, 75%, and 90% homology with the other deduced proteins from tomato (S19677), plum (AB031026), papaya (U68216) and apple (AB034993), which contained the active site of ACC synthase SLSKDMGFPGFR conserved among these plant ACC synthases. RNA_based PCR amplification combined with hybridization analysis with pacs and another ACC synthase cDNApacs12 (AF467782) cloned by us before as probes, indicated that expression patterns of both clones were very similar. mRNAs of both clones expressed in the alabastrum and petal, and were induced after ethylene treatment. Wounding and IAA treatments could induce ACC synthase expression of both clones in the leaves. However, the wounding treatment of leaves has induced more abundant pacs ACC synthase expression than that ofpacs12. Pacs mRNA expressed in both green mature and ripening fruit, whilepacs12mRNA was little or undetectable in green mature fruit, but apparent in ripening fruit. Both clone mRNAs accumulated more in leaves (following wounding and IAA treatments) and flowers than in fruits.

Cloning and Expression Analysis of Two Wheat cDNAs Encoding Cinnamoyl-CoA Reductase

Cinnamoyl-CoA reductase (CCR) is responsible for the first committed reaction in monolignol biosynthesis, which diverts phenylpropanoid-derived metabolites into the biosynthesis of lignin. To gain a better understanding of the lion biosynthesis in wheat development, two cDNAs encoding CCR were identified from wheat (Triticum aestivum L. cv. H4564). DNA sequence analyses indicated that the two cDNAs represent two classes of CCR. RT-PCR and Northern blot hybridization demonstrated that one of them, W-cr6, was expressed actively in stem and leaf tissue, the other one, W-cr19, was expressed in root and stem tissue. The results suggested that there are at least two genes encoded for CCR existing in wheat genome.

Tribological properties of Ni-base alloy composite coating modified by both graphite and TiC particles

In order to reduce the friction coefficient of Ni-base alloy coating and further improve its wear resistance,Ni-base alloy composite coatings modified by both graphite and TiC particles were prepared by plasma spray technology on the surface of 45 carbon steel.The results show that friction coefficient of the composite coating is 47.45% lower than that of the Ni-base alloy coating,and the wear mass loss is reduced by 59.1%.Slip lines and severe adhesive plastic deformation are observed on the worn surface of the Ni-base alloy coating,indicating that the wear mechanisms of the Ni-base alloy coating are multi-plastic deformation wear and adhesive wear.A soft transferred layer abundant in graphite and ferric oxide is developed on the worn surface of the composite coating,which reduces the friction coefficient and wear loss in a great deal.The main wear mechanism of the composite coating is fatigue delamination of the transferred layer.

Influence of copper ions and calcium ions on adsorption of CMC on chlorite

The effects of copper ions and calcium ions on the depression of chlorite using CMC（carboxymethyl cellulose） as a depressant were studied through flotation tests,adsorption measurements,ζ potential tests and co-precipitation experiments.The results show that the electrostatic repulsion between the CMC molecules and the chlorite surfaces hinders the approach of the CMC to the chlorite while the presence of copper ions and calcium ions enhances the adsorption density of CMC.The action mechanisms of these two types of ions are different.Calcium ions can not adsorb onto the mineral surfaces,but they can interact with the CMC molecules,thus reducing the charge of the CMC and enhancing adsorption density.Copper ions can adsorb onto the mineral surfaces,which facilitates the CMC adsorption through acid/base interaction.The enhanced adsorption density is also attributed to the decreased electrostatic repulsion between the CMC and mineral surfaces as copper ions reduce the surface charge of both the mineral surfaces and the CMC molecules.

Nano-porous Composites Based on Liquid： Synthesis, Characterization, Esterification Heteropolyacid Functionalized Ionic and Catalytic Performance in

Fhnctionalized ionic liquid samples （bmim-PW12） were synthesized by 1-butyl-3-methyl- imidazolium bromide （bmimBr） and 12-phosphotungstic heteropolyacid （PW12）. The samples were annealed at 100-450 ℃ and were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscope, thermal gravity-DTG, brunauer emmett teller, and NHa-temperature programmed desorption. The results showed that the bmim-PW12 samples were crystal and maintained intact Keggin structure. The organic parts of those samples were partly decomposed at a temperature more than 350 ℃. The sample annealed at 400 ℃ exhibited nano-porous structure, strong acidity, and excellent catalytic activity on the esterification of n-butanol with acetic acid. The higher ester yield was obtained when the mass ratio of catalyst over the reactants amount was 5% for bmim-PW12 catalyst annealed at 400 ℃.

Effects of graphite content on microstructure and tribological properties of graphite/TiC/Ni-base alloy composite coatings

In order to reduce the friction coefficients and further improve the anti-wear properties of Ni-base alloy coatings reinforced by TiC particles,graphite/TiC/Ni-base alloy（GTN） coatings were prepared on the surface of 45 carbon steel.The effects of graphite content on the microstructure and tribological properties of the GTN coatings were investigated.The results show that the addition of graphite to the GTN coatings may greatly reduce the friction coefficients and improve their wear resistance.The 6.56GTN and 12.71GTN coatings exhibit excellent integrated properties of anti-friction and wear resistance under low and high loads,respectively.Under a low load,the wear mechanisms of the GTN coatings are mainly multi-plastic deformation with slight abrasive wear and gradually change into mixture of multi-plastic deformation,delamination and micro-cutting wear with the increase of graphite fraction.As the load increases,the main wear mechanisms gradually change from micro-cracks,micro-cutting and adhesive wear to micro-cutting and micro-fracture with the increase of graphite fraction.

Research on Thermodynamic Properties of Polybrominated Diphenylamine by Neural Network

Based on the location of bromine substituents and conjugation matrix, a new substituent po- sition index ~X not only was defined, but also molecular shape indexes Km and electronega- tivity distance vectors Mm of diphenylamine and 209 kinds of polybrominated diphenylamine （PBDPA） molecules were calculated. Then the quantitative structure-property relationships （QSPR） among the thermodynamic properties of 210 organic pollutants and 0X, K3, M29, M36 were founded by Leaps-and-Bounds regression. Using the four structural parameters as input neurons of the artificial neural network, three satisfactory QSPR models with network structures of 4：21：1, 4：24：1, and 4：24：1 respectively, were achieved by the back-propagation algorithm. The total correlation coefficients R were 0.9999, 0.9997, and 0.9995 respectively and the standard errors S were 1.036, 1.469, and 1.510 respectively. The relative mean deviation between the predicted value and the experimental value of Sθ, AfHe and △fGθ- were 0.11%, 0.34% and 0.24% respectively, which indicated that the QSPR models had good stability and superior predictive ability. The results showed that there were good nonlinear correlations between the thermodynamic properties of PBDPAs and the four structural pa- rameters. Thus, it was concluded that the ANN models established by the new substituent position index were fully applicable to predict properties of PBDPAs.

Optimization of Plasma Etching Parameters and Mask for Silica Optical Waveguides

Optical waveguides in silica-on-silicon are one of the key elements in optical communications.The processes of deep etching silica waveguides using resist and metal masks in RIE plasma are investigated.The etching responses,including etching rate and selectivity as functions of variation of parameters,are modeled with a 3D neural network.A novel resist/metal combined mask that can overcome the single-layer masks’ limitations is developed for enhancing the waveguides deep etching and low-loss optical waveguides are fabricated at last.

Separation and Identification of Differentially Expressed Proteins in Pistillate Flowers between Different Mulberry Cultivars

[Objective] This study aimed to explore the proteins related to pistillate flower development in different mulberry cultivars. [Method] The total proteins of the pistillate flowers of two mulberry cultivars Dal0 （Morus atropurpurea Roxb.） and SG01 （Morus muIticaulis Perr.） were extracted, separated and detected through two- dimensional electrophoresis （2-DE） and mass spectrometry. [Result] There was sig- nificant difference in the expression of proteins from the pistillate flowers of different mulberry cultivars. From the 2-DE images of Dal0 and SG01, 445_＋17 and 425_＋12 protein spots were respectively detected. The expression levels of 75 protein spots differed significantly. Thirteen spots those were expressed at high levels and well separated were analyzed by mass spectrometry, and nine of them were identified successfully. The nine proteins are involved in the glycometabolism, protein and amino acid metabolism and defense responses during the development of mulberry pistillate flower after they were pollinated. [Conclusion] The findings will provide reference for further study on the molecular mechanism of mulberry pistillate flower de- velopment.

Theoretical Study of the C-CI Bond Dissociation Enthalpy and Electronic Structure of Substituted Chlorobenzene Compounds

Quantum chemical calculations were used to estimate the bond dissociation energies （BDEs） for 13 substituted chlorobenzene compounds. These compounds were studied by the hybrid density functional theory （B3LYP, B3PW91, B3P86） methods together with 6-31G^＊＊ and 6-311G^＊＊ basis sets. The results show that B3P86/6-311G^＊＊ method is the best method to compute the reliable BDEs for substituted chlorobenzene compounds which contain the C-C1 bond. It is found that the C-C1 BDE depends strongly on the computational method and the basis sets used. Substituent effect on the C-C1 BDE of substituted chlorobenzene compounds is further discussed. It is noted that the effects of substitution on the C-C1 BDE of substituted chlorobenzene compounds are very insignificant. The energy gaps between the HOMO and LUMO of studied compounds estimate the relative thermal stability ordering are also investigated and from this data we of substituted chlorobenzene compounds.

Changes of Amino Acid Content in Leaves of Agropyron cristatum Under Grazing Pressure

By measuring and comparing the contents of amino acids in Agropyron cristatum under grazing pressure, this study showed that the contents of total and each of the amino acids in A. cristatum changed little under grazing pressure. How- ever, the contents of free glycine （Gly） and proline （Pro） were very sensitive to grazing. Glycine content in grazing population was higher than that in non-grazing population at flowering stage; the content of free proline in non-grazing population was higher than that in grazing population at tillering, heading and especially flower- ing stage; the content of free proline under grazing pressure at maturity stage was higher than that of non-grazing population.

Triterpenes and Other Constituents from Rhaponticum uniflorum

From the roots of Rhaponticum uniflorum a new triterpene was isolated together with ursolic acid(2), 3-oxo-19a-hydroxyurs-12-en-28-oic acid (3), pomolic acid (4), 2a,3a,19a-trihydroxyurs-12-en-28-oic acid (5), arctic acid (6), catechin (7) and b-sitosterol (8). The structure of the new compound was elucidated as 2a,3a,19a,25-tetrahydroxyurs-12-en-23,28-dioic acid (1) on the basis of spectral and chemical methods.