丙酮红外光谱的溶剂效应

报道在20种极性或非极性溶剂中丙酮的红外光谱，研究溶质．溶剂之间相互作用．将红外谱带位移分别与溶剂参数诸如溶剂接受数AN等进行相关分析．结果表明：丙酮羰基在甲醇溶剂中红外诱导伸缩频率位移最大．一些丙酮与甲醇分子之间形成具有非线性氢键结合的六元环结构．丙酮的羰基伸缩振动频率与溶剂接受数AN值、线性溶剂自由能关系LSER均存在良好的相关性，且与LSER值的相关性更佳．在物理意义上LSER较好地解释了溶剂诱导伸缩频率位移．     

Solvent effects on infrared spectra of 2-Methyl-4,5-dimethoxy-3-oxo-2H-pyridizine: Part 2. Binary solvent systems

This research on the solvent effects of 2-methyl-4,5-dimethoxy-3-oxo-2H-pyridizine (MDOP) in binary solvent systems on the infrared spectra for MDOP in n-hexane/CHCl₃ mixture solvents showed that there were three forms of carbonyl stretching vibration band [ν(C=O)] of MPOP as the mole fraction of CHCl₃ in the binary solvents changes. In pure n-hexane solvent, the ν(C=O) of MDOP appeared at a relatively high wavenumber. With CHCl₃ added, the ν(C=O) shifted to lower wavenumbers. Two new bands were observed over a certain range of mixture solvent compositions. The origin of the bands was discussed in the terms of two kinds of hydrogen bond together with their individual dependence on mixture composition. Comparisons were drawn for the solvent sensitivities of ν(C=O) for propanone. Project supported by the Analysis and Measurement Foundation of Zhejiang Province, China.     

Copolymerization of Acrylonitrile/1-Vinyl-3-Ethylimidazolium Bromide and Rheological,Thermal Properties of the Copolymer

Acrylonitrile(AN)/1-vinyl-3-ethylimidazolium bromide(VIMB) copolymer was prepared via solution polymerization using dimethyl sulfoxide(DMSO) as a solvent and azodiisobutyronitrile as an initiator. The effects of comonomer VIMB on the polymerization, rheological properties of the polymer solution and thermal properties of the copolymer were investigated. The ionic liquid VIMB resulted in higher polymerization conversion ratio and higher average molecular weight when copolymerized with AN than itaconic acid(ITA). Rheological measurements indicated that the transition shear rate increased linearly with increasing temperature for P(AN/ITA)/DMSO solution, while an exponential growth with temperature was observed for P(AN/VIMB)/DMSO solution. The exothermic peaks of DSC curves in N_2 appeared at 276.67 and 257.34 °C for P(AN/VIMB) and P(AN/ITA), respectively. As a potential comonomer of AN for PAN carbon fibers, the VIMB resulted in about 7% higher char yield in N_2, and 23.7% less weight loss at 600 °C in air than ITA copolymer.     

3,5-二甲基苯酚的新法合成

采用5％Pd／C作为转移氢催化剂,原料3,5-二甲基-2-环己烯酮为氢给予剂,以工业双戊烯作为氢接受剂和溶剂,合成了3,5-二甲基苯酚。考察了催化剂用量、反应时间和反应温度对反应的影响,确定了合成3,5-二甲基苯酚的最佳反应条件：原料与5％Pd／C的配比为10：0．8（质量比）、反应时间30min、在回流温度下,在此条件下,3,5-二甲基苯酚的收率可达79％。对催化剂的重复使用次数进行了考察,使用5次后催化剂活性是原来的86．1％。     

The effect of the planet’s number on dynamic characteristics of planetary gear systems

Considering the effect of planet’s number on the dynamic characteristics of the planetary gear system, a translation-torsion lumped-parameter model of 2K-H spur planetary gear system was established. Through the analysis of numerical solution, the results show that 1) When the planet’s number is more than 3, the order of the natural frequency will become the same; 2) When the planet’s number increases, the natural frequencies of planet mode remain invariant, but when it comes to rotational mode and translational mode, the higher order natural frequencies increase and the lower order natural frequencies decrease; 3) The planet’s number has a great impact on the higher order natural frequencies and a little impact on the lower order natural frequencies; and 4) To avoid the resonance, we can appropriately increase or decrease the number of the planet.     

采用Gd2O2S回热填料的带预冷4K斯特林型高频脉管制冷机性能研究

研究目的：研究新型磁性回热填料Gd2O2S对液氦温区高频脉管制冷机多级回热器损失特性的影响。 创新要点：确定了不同回热填料以及运行参数（频率、平均压力）下液氦温区多级脉管制冷机的制冷温度和各级预冷量,进一步明确了4K高频回热损失机理。 研究方法：采用理论研究与实验验证相结合的方法,基于一台两级G-M型低频脉管制冷机预冷的单极斯特林型高频脉管制冷机,研究多级回热器在高频以及4K温区下的损失特性。选取新型回热填料Gd2O2S替代部分回热填料HoCu2,比较回热器采用两种填料时在不吲运行频率及平均压力下的冷端制冷温度（图10）、各级预冷量和预冷温度（图1112）。 重要结论：采用孔隙率较小的新型磁性回热填料Gd2O2S可显著改善第一级回热器内压力波与质量流的相位关系,从而减小该级回热损失。减小平均压力可以降低制冷机无负荷制冷温度并减小第二级预冷量,但制冷工质氦的体积比热容会急剧增大,从而使低温级回热器的换热对频率非常敏感。此外,频率对高温级回热器的回热特性影响不明显。该方法可以为三级斯特林型4K多级脉管制冷机提供设计依据。     

（H3O）2［Co（C2N2H8）3］2［W7O24］结构和振动光谱的实验和理论研究

采用水热法合成了新化合物（ H3O）2[ Co（ C 2N 2H 8）3]2[ W 7O 24],对其结构进行了红外光谱和X射线单晶衍射测定。通过密度泛函理论,对其红外光谱进行了计算,对吸收峰的振动模式进行了指认。结果显示,（H3O ）2[Co （C2N2H8）3]2[W7O24]的红外光谱对溶剂十分敏感。     

The impact of childhood sexual abuse in anorexia nervosa

OBJECTIVE: The aim of this study was to examine the impact of childhood sexual abuse (CSA) on clinical characteristics and premature termination of treatment in anorexia nervosa (AN). METHOD: The participants were 77 consecutive patients with AN admitted to an inpatient eating disorders unit. The patients were assessed in terms of eating disorder symptoms, general psychopathology, and CSA history at admission to hospital. RESULTS: Thirty-seven patients (48%) reported a history of CSA before the onset of the eating disorder. Individuals with a history of CSA reported significantly greater psychiatric comorbidity, including higher levels of depression and anxiety, lower self-esteem, more interpersonal problems, and more severe obsessive-compulsive symptoms. Patients with the binge-purge subtype of AN (AN-BP) were significantly more likely to report a history of CSA prior to the onset of the eating disorder as compared with patients with the restricting subtype (AN-R) of the illness (65% of the AN-BP patients vs. 37% of the AN-R patients; p<.02). Contrary to our predictions, abused patients were not significantly more likely to dropout of treatment overall. However, patients of the binge-purge subtype (AN-BP) with a history of CSA were significantly more likely to terminate treatment prematurely as compared with the other patients. CONCLUSIONS: Consistent with previous findings, the present results indicate that the prevalence of CSA is high among individuals seeking inpatient treatment for AN. A history of CSA was associated with greater psychiatric disturbance overall and a higher rate of dropout for patients of the binge-purge subtype.     

镁铝水滑石固载重铬酸钾液相活化氧气氧化醇

采用共沉淀法制得镁铝水滑石固载K2Cr2O7催化剂HT-Cr2O72-,将该催化剂在温和条件下,以分子氧为氧化剂用于催化醇的液相氧化反应,并以2-吡啶甲醇的氧化反应为模型探讨了温度、溶剂、催化剂量等条件对反应的影响。结果表明,使用苯、三氟甲苯等溶剂更有利于反应进行,2-吡啶甲醇转化率随着温度上升明显提高,该催化剂可以在温和条件下实现醇类化合物的高选择性氧化转化;和其他固体催化剂用于液相醇氧化相比,该催化剂具有更高的活性转化数(TON)。     

苦味酸锰、钴、镍、铜、锌、镉与4′─硝基苯并─15─冠─5配合物的合成与表征

在乙腈─乙醇─水（2：2：1，V／V／V）的混合溶剂中制备了六种金属（锰、钴、镍、铜、锌、镉）苦味酸盐与4′─硝基苯并─15─冠─5的固态配合物，其组成为M（pic）2·2L·XH2（M＝Mn、CU，x＝2；M＝Co，Ni，Zn，Cd，x＝4；pic＝苦味酸根；L＝4′─NO2B15CS），并通过元素分析、红外光谱、紫外光谱和摩尔电导对该系列配合物进行了表征。     

基于顺序号和确认号的TCP流标识

为了降低TCP流的处理开销,可以从TCP/IP报文中选取某些位串来作为流的标识.从位熵和随机性的角度分析了TCP流首报文的顺序号(SN)和确认号(AN)的分布,提出了一种从重尾的IP或TCP流里获得随机均匀的流标识的新方法(FIDSAN).实验结果表明,在可以接受的冲突概率下,TCP流首报文的顺序号和确认号的部分高位比特可以用来作为流标签.给定冲突概率时,该流标识的比特长度可以根据一个由观察窗口和流ID值域导出的关系式求出.与TCP五元组,CRC,Checksum等比较发现,FIDSAN具有更低的计算开销.     

Factors Influencing American Indian and Alaska Native Postsecondary Persistence: AI/AN Millennium Falcon Persistence Model

The purpose of this review of literature is to identify variables (Hart 1998), relevant to AI/AN postsecondary persistence, and to examine the relationship between findings and postsecondary persistence theories at 2 and 4-year institutions. An exhaustive review with selective citation was used to locate relevant documents. Due to the limited amount of articles found for this review, I included both qualitative and quantitative articles. The factors were organized into four emerging themes including; family support, institutional support, tribal community support and academic performance. Due to the lack of research conducted using measures important to AI/AN persistence, the understanding of factors influencing AI/AN student postsecondary persistence is still somewhat limited.     

Gd和TiO_2共掺杂的WO_3纳米粉体的制备及其光催化性能

以Na2WO4和C16H33(CH3)3NBr为原料,通过液相沉淀法制备了WO3纳米粉体,用钛酸胶体溶液浸滞法制备了TiO2掺杂的WO3纳米粉体,再用Gd(NO3)3溶液浸滞TiO2掺杂的WO3纳米粉体法制备了稀土Gd和TiO2共掺杂的WO3纳米粉体,并采用透射电子显微镜、紫外-可见漫反射吸收光谱和X-射线衍射对其结构进行了表征.实验结果表明,稀土Gd和TiO2共掺杂拓展了WO3的光响应范围,提高了对可溶性染料罗丹明B(RB)的吸附作用,使WO3对RB的光催化降解活性和光稳定性得到了显著提高.     

微波促进活性碳负载单质碘催化合成乙酰乙酸乙酯缩酮

在微波辐射下,以活性炭负载碘（I2/C）为催化剂,不用溶剂,合成了乙酰乙酸乙酯乙二醇缩酮和乙酰乙酸乙酯1,2-丙二醇缩酮。通过改变催化剂负载量、催化剂用量、微波辐射时间、微波辐射功率,研究了这四个因素对乙酰乙酸乙酯缩酮反应收率的影响。以乙酰乙酸乙酯与乙二醇缩合为模型反应进行优化,实验结果表明：I2/C是合成乙酰乙酸乙酯缩酮的良好催化剂,具有良好的催化促进作用。其优化条件是：负载量为10.9%的I2/C催化剂0.07g,乙酰乙酸乙酯5mL,乙二醇6mL,微波辐射功率400W,辐射时间2.5min,产率达100%。产物经过红外光谱表征。     

Cleaner and convenient preparation of3-(4,6-dimethoxy-pyrimidin-2-yloxy)-2-methyl-phenol

INTRODUCTION Environmental concerns have been growingfor the past two decades. High industrial density,human population density and the use of old andpolluting technologies all cause increasing levels ofpollutant emissions. This situation has highlightedthe need for cleaner technologies (Rao et al., 2003;Muthusubramanian et al., 2003). Cleaner technol-ogy has the following advantages: (a) Wasteminimization; (b) Pollution prevention; and (c)Green productivity. Implementing cleaner…     

Cleaner and convenient preparation of 3-(4,6-dimethoxy-pyrimidin-2-yloxy)-2-methyl-phenol

Environmental concerns have highlighted the need of cleaner technologies. A cleaner, convenient and selectivetechnology has been developed for the preparation of 3-(4,6-dimethoxy-pyrimidin-2-yloxy)-2-methyl-phenol (DPMP) from2-methyl-benzene-l,3-diol in water as solvent. The isolated yield of DPMP is up to 86% in good selectivity. The productstructure was characterized by conventional methods, 1H-NMR and MS. This technology belongs to the modern concept ofenvironmentally friendly low wastes or non-wastes technology (LWNWT).     

Hg2+对黄鳝外周血红细胞微核及白细胞的影响

研究了0、0.15,0.20和0.25 mg/L HgCl2溶液0、1、2、48、d对黄鳝外周血红细胞微核及白细胞的影响.结果表明,不同暴露时间、不同浓度的Hg2 不同程度地引起黄鳝红细胞微核率和核异常率等遗传指标的上升,并引起白细胞数量及各类白细胞比例的变化,与对照组相比几乎都达到显著差异(p<0.05)或极显著差异(p<0.01).     

Application of density-functional theory to studying methylation with dimethyl carbonate and dimethyl sulfate

The activities of dimethyl carbonate and dimethyl sulfate as a methylation reagent were studied by density-functional theory (DFT). B3LYP/6-31G(d, p) methods were used to optimize the structures of dimethyl carbonate and dimethyl sulfate and calculate theirs charge densities. Dimethyl sulfate is easier than dimethyl carbonate to react with a nucleophilic reagent. In dimethyl sulfate, the alkoxy carbons are the only reactive atomic nucleus because of steric hindrance. A nucleophilic reagent is more likely to react with carbonyl carbons than alkoxy carbons of dimethyl carbonate;in the presence of a Lewis acid, the phenyl nucleophilic reagent reacts with the Lewis acid first. Lewis acid increases the negative charge density of a nucleophilic reagent in polar solvent, and also incurs an accretion of steric hindrance. Polar solvent avails to ionize dimethyl carbonate and thus enables the reaction of methylation. The frequencies of transition state calculated by Gaussion 03 confirm the inferred reaction mechanism. The harvest rates of 4-methoxyphenol in the experiments of methylation reactions of hydroquinone with respectively dimethyl carbonate and dimethyl sulfate support the foregoing theortical conclusions.     

催化剂对乙二胺萃取七台河煤的影响

采用乙二胺(C2H8N2)为萃取剂,分别添加FeS2、MgCl2,MgCl2-AlCl3 3种催化剂对七台河煤进行索氏萃取,对萃取物采用气相色谱/质谱联用技术定性分析,探究了不同的催化剂对七台河煤萃取效果的影响。实验结果表明,催化剂有助于提高萃取率,增加萃取出的化合物的种类。MS分析证明,不同的催化剂可以抽提出不同的化学结构的物质,采用Cl盐作催化剂有利于含氧化合物的抽提,而FeS2有助于提高含芳环物质的抽提率,特别是对蒽系物的萃取效果良好。由试验结果推断,在煤萃取的溶剂体系里加入铁系催化剂、硫化物、卤族元素的可溶盐以及Lewis酸都可大大提高萃取效率。     

紫花苜蓿与意大利黑麦草混合青贮发酵品质研究

为研究不同比例紫花苜蓿与意大利黑麦草混合青贮的发酵品质,试验将两种牧草切割至1-2cm,按照鲜草质量比2：8、3：7、4：6和5：5等分为A、B、C、D四个处理组,充分混合后进行青贮。试验结果：各组青贮料的pH值和干物质含量均随青贮时间呈降低趋势,在青贮30d时,A、B组pH值约为4．1,显著低于C、D组的4．30左右（P〈0．05）;干物质含量B组显著高于C、D组（P〈0．05）,但与A组之间差异不显著（P〉0．05）;AN／TN的含量随着发酵天数的增加均持续升高,B组的AN／TN含量在青贮前3d稍高于其它三组,而3d后均低于其他三组,且在30d时与含量最高的D组差异显著（P〈0．05）,但与A、C组差异均不显著（P〉0．05）。青贮料中可溶性糖含量在青贮过程中均呈逐渐降低的趋势,其中在青贮前14d均以A组的WSC含量最高,青贮30d时,B组WSC含量最高,但各组之间差异均不显著（P〉0．05）。在青贮30d时,乳酸含量A、B组显著高于C、D组（P〈0．05）;与C、D组相比,B组乙酸和总挥发性脂肪酸含量低而乳画蔓／乙酸比值高,且差异均显著（P〈0．05）。结果表明：采用意大利黑麦草与紫花苜蓿混合青贮可以获得品质优良的青贮饲料。且以鲜草质量比3：7的混合青贮较为适宜。