高耐磨化学共沉积复合材料的组成与耐磨性能研究

采用化学沉积方法，制备镍合金－碳化硅，氧化铝，金刚石复合材料，研究了金属基体与硬质非金属粒子复合材料的组成与耐磨性能，硬质粒子相随着镍合金的还原反应沉积而复合，二者复合界面不产生反应系机械结合；随着硬质粒子相添加量的提高，复合材料晶化倾向加大，与镍合金相比，复合材料的硬度和耐磨性能显著上升，金刚石复合材料为最高；经过４００℃时效处理，复合材料基体析出磷化物Ｎｉ３Ｐ，进一步得以强化，表现为硬度升高，     

第六届西太平洋地区声学会议(WESTPRAC Ⅵ97)

为了推进西太平洋地区的声学工作，加强学术交流，西太平洋地区声学委员会每三年举行一次学术会议．迄今为止，已举行过五次会议，分别在新加坡、香港、上海、布里斯班（澳大利亚），和汉城举行．由于1997年香港将回归中国，西太平洋地区声学委员会同意1997年第六届西太平洋地区声学会议在香港举行·会议的内容是广泛的，包括：有源噪声和振动控制，建筑声学，声学计量技术，电声学，环境噪声控制，测量和仪器，物理声学，语言与听觉，信号处理，交通噪声，超声学和水声学．会议上将有美国Wilson，Ihvig巳ASSOC，Inc．的GeorgeWilson博士，加拿大国家研究署的GeorgeWong博士和日本东京大学的Ta     

有机同系物性质递变的基本规律

发现了有机同系性质递变的两个基本规律：等差递变和等比递变，它们可分别表示为Ｐ＝ａ＋ｂｎ和Ｐ＝ｃ＋ｄａ，式中Ｐ同系物的某种性能，ｎ的同系物的重复结构单元数，ａ，ｂ，ｃ，ｄ和α为系数，研究结果表明，同系物的加和型性能一般遵守等差递变规律，如标准生成焓和临界体积等，结构型性能通常遵守等中比递变规律，如电离能，电子亲和能，密度，沸点，粘度与表面张力等。     

激光辐照下固体材料的温度分布理论研究

 考虑到有限厚介质的表面热对流，利用格林函数方法理论计算了强激光作用下介质材料的3维温度分布，给出了温升与材料尺寸的关系式及其关系曲线。以单晶硅材料为例进行了模拟计算，结果表明：温升不仅与材料本身的性质（热容，热导率，密度）密切相关，而且还与材料的吸收系数，激光加热参数（功率密度，能量分布，光斑大小，作用时间），以及对流换热系数有关。在激光照射的初始阶段，材料表面温度迅速增加；其后，随着激光照射时间的增加，温度增加量逐步变缓。     

姜科植物长柄山姜及茴香砂仁精油原位拉曼光谱研究

常温下，将制备好的长柄山姜及茴香砂仁的水装片放在显微拉曼光谱仪的载物台上，寻找油细胞，并分析其中精油。长柄山姜油细胞上获得的拉曼光谱，较强峰出现在1 638，1 600，1 555，1 203和1 001 cm-1，次强峰出现在1 716，1 577，1 496，1 407，1 346，1 307，1 273，1 181，1 156，1 029，958，618和218 cm-1共获得26条光谱线，与肉桂酸甲酯拉曼光谱的29条谱线比较，长柄山姜油细胞有22条谱线与之有对应关系；茴香砂仁油细胞上获得的拉曼光谱较强峰出现在1 648，1 639，1 607，1 174，842和836 cm-1，次强峰出现在1 292，1 244，1 235，1 204和631 cm-1共获得24条光谱线，与4-烯丙基苯甲醚的拉曼光谱在300～1 700 cm-1区间内的29条谱线比较，茴香砂仁油细胞有23条谱峰与之有对应关系。说明长柄山姜挥发油的主要成分是肉桂酸甲酯，茴香砂仁挥发油的主要成分为4-烯丙基苯甲醚。用密度泛函理论计算了肉桂酸甲酯、4-烯丙基苯甲醚的拉曼光谱，并对谱线进行了初步的归属。姜科植物油细胞中精油不需提取就可直接快速的检测，用此方法可对姜科植物精油的提取进行质量控制及开发研究。     

气固界面氧化学吸附物种的动态研究

用自编的傅里叶变换红外（ＦＴ－ＩＲ）动态谱批处理程序，在２０－６５０℃对Ｂｅ，Ｍｇ，Ｃａ，Ｌａ，Ｃｅ，Ｓｍ，Ｔｉ，Ｚｒ，Ｖ，Ｎｂ，ｃＲ，Ｍｏ，Ｗ，ＭＮ，Ｆｅ，Ｎｉ，Ｃｕ，Ｚｎ和Ｓｎ等一系列金属氧化物上的氧化学吸附物种进行了原位动态三维谱学研究，就所观测到的超氧（Ｏ＾－２）和过氧（Ｏ＾２－２）物种随温度的变化情况以及甲烷氧化偶联催化反应中的活性氧物种进行了讨论。     

高指数稳定硅表面的低能电子衍射图分析

报道了在系统搜寻稳定硅表面的过程中对四个稳定高指数表面Si(1，1，11)，(1，0，8)，(2，1，2)和(15，1，17)的低能电子衍射(LEED)图进行的分析和结果.这些表面经充分退火后都能给出属于各自表面的LEED图，而不是小面化的，说明它们都是稳定的.从它们的LEED斑点强度分布特征不仅可以推断(15，1，17)是主稳定表面，而(1，1，11)，(1，0，8)和(2，1，2)则是副稳定表面，还能知道这些副稳定表面的原胞结构特征，甚至许多重要细节.从原胞结构特征来看，这些副稳定表面有可能用作生长周期量子线的模板.     

基于OBE教学理念的大学物理实验线上线下混合式教学实践

近年来，线上线下混合式教学模式逐步兴起，但该模式未用数据充分分析学生的学情，为改善这一不足，教改组基于OBE教学理念，结合课堂派在线课堂管理平台，挑选线上部分及线下建设教育资源，获得学生学情，反向设计线下教学环节，建设基于OBE教学理念，从学情出发的大学物理实验线上线下混合式教学模式，满足学生核心需求的同时调动学生兴趣，提升教学质量。通过教学实践及学生期末笔试成绩表明，该教学模式能精准服务教学目标，有利于学生深入理解实验原理，灵活运用所学知识，有助于逐步提升学生实践、创新能力，提高教学质量。     

徐霞客（Xu Xia-Ke，1587-1641）中国地理学家和旅行家（Geographer and Explorer,China）

徐霞客，名宏祖，字振之，号霞客，江苏省江阴县人。他的祖父和父亲都是当地有名的隐居学者，经济富裕，藏书丰富。徐霞客自幼喜欢看历史、游记、探险记一类的书籍，萌发了遍游五岳的志愿。公元1607年，22岁的他毅然背起行囊，告别父母，开始了他一生艰苦的旅行探险生涯，直到56岁病逝前半年为止。     

灵武长枣VC含量的高光谱快速检测研究

采用可见-近红外高光谱成像技术结合化学计量学方法检测灵武长枣维生素C(VC)含量，探究一种全新的水果内部成分的快速无损检测方法。采用高效液相色谱法(HPLC)测得长枣的VC含量化学值，可见-近红外高光谱成像系统采集164个灵武长枣400～1 000 nm的高光谱图像，利用ENVI4.8软件提取图像的感兴趣区域(region of interest，ROI)，计算其平均光谱，获得光谱值，将化学值与光谱值通过The UnsecramblerX 10.4软件建立模型。利用蒙特卡洛交叉验证法剔除异常值，采用光谱理化值共生距离法(sample set partitioning based on joint x-y distance，SPXY)进行样本划分以提高模型的预测性能；对光谱采用移动平滑(moving average)、中值滤波(median filter)、归一化(normalize)、基线校准(baseline)、多元散射校正(multiple scattering correction，MSC)、去趋势(detrending)和标准正态变量变换(standard normal variate，SNV)等7种方法进行预处理；为进一步减少数据量，降低维度，提高运算速度，使用竞争性自适应加权算法(competitive adaptive reweighted sampling，CARS)、无信息变量消除算法(uninformative variable elimination ，UVE)和连续投影算法(successive projections algorithm，SPA)提取特征波长，以期实现以少数波段代替全波段；将全波段光谱(full spectrum，FS)以及CARS, UVE和SPA三种方法提取的特征波长分别建立偏最小二乘(partial least squares wavelength regression，PLSR)和支持向量机(support vector machine，SVM)模型，从而确定最优的建模模型。利用蒙特卡洛交叉验证法共剔除7个异常样本，采用SPXY法将剔除异常样本后的157个数据区分为校正集和预测集，校正集中样本个数为117，预测集中样本个数为40。将未经光谱预处理的建模结果与分别经过七种光谱预处理的建模结果相比，选择未经光谱预处理的数据进行后续分析；将未经光谱预处理的光谱值采用CARS，UVE，SPA方法进行提取特征波长，CARS共优选出406，415，487，631，636，655，660，665，670，684，689，694，723，732，747和881 nm下的光谱变量16个，利用CARS提取出的特征波长占总波长的12.8%；UVE共优选出406，415，627，631，636，651，655，660，665，670，675，679，684，689，694，699，703，708，742，747，751，756，761，766，771，775，780，785，790，795，919和924 nm下的32个特征波长，利用UVE提取出的特征波长占总波长的25.6%；SPA共优选出401，665，684 nm三个特征波长，利用SPA提取出的特征波长占总波长的2.4%。将全波段光谱与提取出的特征波长建立PLSR模型和SVM模型，对比模型结果显示UVE-SVM模型最优，其R2_c为0.847 1，R2_p为0.714 9，说明UVE有效地对光谱进行降维，简化了数据处理过程。本研究对高光谱成像技术在水果领域的应用进行了有益探索，探究了一种全新的灵武长枣VC含量的无损检测方法，相应建立的可见-近红外高光谱模型为其他水果成分的快速检测提供了理论基础。     

An Improved Time-Saving Synthesis for [11CMethyl] Iodide

[¹¹]CMethyliodide is a key to a large scale of ¹¹C-PET-radiopharmaceuticals. A method was devised for its efficient production in a yield between 85 and 90% within 7 minutes only. The use of tetrahydrofuran (THF) opens the possibility to absorb the starting [¹¹C]CO₂ at room temperature. The methyl iodide generation from its precursor can be achieved in THF directly or in aqueous solution.

Es wird die Mögliclikeit gezeigt, [¹¹C]Mthyliodid, einer Schlüssclverbindung der ¹¹C-Chemie, innerhalb von nur 7 Minuten in Ausbeuten zwischen 85 und 90% herzustellen. Die Verwendung von Tetrahydrofuran als Lösungsmittel anstelle von Diethylether ermöglicht die vollständige Absorption des Ausgangs- [¹¹C]C0₂ bei Raumtemperatur. Die Umsetzung des Vorproduktes zum Alelhyliodid kann wahlweise direkt in Tetrahydrofuran oder in wäβriger Lösung vorgenommen werden.     

氢键效应对2,3-二氢-3-酮基-1H-吡啶并[3,2,1-kl]吩噻嗪光物理性质的影响

利用含时密度泛函理论(TDDFT)方法和飞秒时间分辨的瞬态吸收光谱技术对2,3-二氢-3-酮基-1H-吡啶并[3,2,1-kl]吩噻嗪(PTZ4)和3-酮基-1H-吡啶并[3,2,1-kl]吩噻嗪(PTZ5)这两种荧光探针分子的光物理性质进行了研究. TDDFT结果表明PTZ4和PTZ5在甲醇溶液形成了氢键络合物导致它们吸收峰的红移. PTZ4分子在基态有四种稳定构型,其在四氢呋喃溶液中的双荧光峰正是来自于四种构型下的内部电荷转移态. PTZ4分子在四氢呋喃和甲醇溶液中的瞬态吸收光谱表明,从局域态到转移态的弛豫时间常数在四氢呋喃中为16.0 ps,在甲醇中为7.5 ps;PTZ4分子在甲醇中的激发态寿命为53.8 ps,而这种超短的寿命可能是由于PTZ4分子在激发态时形成的面外型氢键络合物导致的.     

Preferential interactions in the formamide/ tetrahydrofuran/dioxane system: a study by Raman spectroscopy

Significant changes observed in the Raman spectra of formamide (FA)–tetrahydrofuran (THF)–dioxane (DX) mixtures have been interpreted in terms of preferential interactions. The Gutmann's donor (DN) and acceptor (AN) number values of these solvents give a good interpretation for the differences observed. In the ternary system, THF behaves as a stronger base than DX and the band at ∼442 cm⁻¹, recently assigned to the FA–DX adduct is only observed at the highest FA concentration. Quantitative analyses performed at the C (FA) and C O (THF) stretching regions show that the extent of the association for the [FA]_n adduct is significantly larger than for the FA THF adduct. Electrostatic parameters, such as dipole moment and dielectric constant, are also regarded as a better interpretation of these associations. The good correlation between DN and electrostatic parameters indicates that the basic strength increases in the order DX < THF < FA. Copyright © 2008 John Wiley & Sons, Ltd.     

在N2中[VnCr3—n（μ3—O）（μ—O2CCH3）6（THF）3]X[n=0—3,X=Cl^—1,ClO4^—,（VO5）0.5^—]及[VnFe3—n（μ3—O）（μ—O2CCH3）6（THF）3]X（n=0—3,X=Cl^—1）

The reaction behavior of the title complexes have been investigated by means of in situ IR in nitrogen atmosphere. It has been found that they enabled the acetic acid to convert to acetone and methane in different temperatures. The results indicate that the sequence of the ketonization reaction activity for the clusters was [V3OAT] > [VFe2OAT], [V2CrOAT] > [Fe3OAT], [VCr2OAT] > [Cr3OAT] [OAT = (mu 3-O) (mu-O2CCH3)6 (THF)3], and the sequence of the methanation reaction activity for the clusters was [Cr3OAT] > [VCr2OAT], [V2CrOAT] > [V3OAT] > [VFe2OAT], [Fe2OAH]. The ketonization reaction activity of [Fe3OAT] were obviously lower than that of [Fe3OAH] [OAH = (mu 3-O) (mu-O2CCH3)6 (H2O)3] and the methanation reaction activity of [Cr3OAT] were also much lower than that of [Cr3OAH]. The difference between [Fe3OAH], [Cr3OAT] and [Fe3OAH], [Cr3OAH] mentioned above were discussed.     

A facile one-pot ultrasound assisted for an efficient synthesis of 1H-spiro[furo[3,4-b]pyridine-4,3′-indoline]-3-carbonitriles

A convenient one-pot protocol was developed for the synthesis of 1H-spiro[furo[3,4-b]pyridine-4,3′-indoline]-3-carbonitrile derivatives. This reaction was carried out through a three component condensation reaction of isatins, malononitrile, and anilinolactones in the presence of a catalytic amount of Et₃N as an inexpensive and available basic catalyst in THF under ultrasound irradiation. The products were obtained in high yields and short reaction times. The main advantage of this synthetic method is that the obtained products in ultrasonic irradiations are different from classical heating.     

DFT study on coupling reaction of carbon dioxide with ethylene oxide catalyzed by 1,4,6-triaza-bicyclo[3.3.0]oct-4-enium bromide (TBO.HBr)

ABSTRACT

Chemical fixation of CO₂ with epoxides catalyzed by organic-base salts were found to be efficient among the various catalysts tested due to synergetic effects of HBDs and halide-ions for ring-opening. In this study, 1,4,6-Triaza–bicyclo[3.3.0]oct-4-enium bromide catalyzed conversion of CO₂ and epoxide into cyclic-carbonate has been studied by using DFT method to understand the reaction mechanism and the catalytic performance of TBO.HBr. Two hypothetical reaction mechanisms were proposed for the coupling reaction. Thermodynamic and kinetic parameters were computed for each steps to determine the more favorable route. Mechanism II is more favorable path whereby Br^- ion first interacts with epoxide to form bromo-alcohol, which directed to form carbonate-ion and finally ring-closure step yielded cyclic-carbonate with catalyst-regeneration. Cyclization step is rate-determining step with reaction barrier of 22.696?kcal/mol in gas phase. Ensuing the favorable mechanism, solvent-effects on the reaction barrier has been investigated using water and THF. Mechanism II is still more favorable reaction path in both THF and water. However, the rate-determining step is found to be ring-opening of the epoxide with reaction barrier of 22.658?kcal/mol (wate) and 21.969?kcal/mol (THF). In this study, TBO.HBr exhibited good catalytic activity for the title reaction investigated in both gas phase and solvents.     

Triblock copolyampholytes from 5-(N,N-dimethylamino)isoprene, styrene, and methacrylic acid: Synthesis and solution properties

ABC triblock copolymers of the type poly[5-(N,N-dimethylamino)isoprene]-block-polystyrene-block-poly(tert-butyl methacrylate) (AiST) were synthesized and hydrolyzed to yield poly[5-(N,N-dimethylamino)isoprene]-block-polystyrene-block-poly(methacrylic acid) (AiSA) triblock copolyampholytes. Due to a complex solubility behavior the solution properties of these materials had to be investigated in THF/water solvent mixtures. Potentiometric titrations of AiSA triblock copolyampholytes showed two inflection points with the A block being deprotonated prior to the Ai hydrochloride block thus forming a polyzwitterion at the isoelectric point (iep). The aggregation behavior was studied by dynamic light scattering (DLS) and freeze-fracture/transmission electron microscopy (TEM). Large vesicular structures with almost pH-independent radii were observed. Received 15 March 2000     

Förster-type energy transfer mechanism in PF2/6 to MEH-PPV conjugated polymers

Energy transfer mechanism between Poly[9,9-di-(2′-ethylhexyl)fluorenyl-2,7-diyl] (PF_2/6) as a donor and poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) as an acceptor in different solvents has been studied using steady-state emission measurements. Four different solvents namely, tetrahydrofuran (THF), toluene, chlorobenzene (C.B) and benzene have been used in this study. The absorption and luminescence behaviors of the samples are measured at a fixed concentration of donor (0.1 μM) while the concentrations for acceptor are kept in the range of 0.1–1.0 μM. Based on these measurements, the energy transfer properties namely quenching rate constant (k_SV), energy transfer rate constant (k_ET), energy transfer probability (P_DA), transfer efficiency (η) and critical distance of energy transfer (R_o) are calculated. The use of THF resulted in the highest energy transfer. Long range dipole–dipole interaction between the excited donor and ground state acceptor molecules is the dominant mechanism responsible for the energy transfer as proven by the large values of R_o.     

Laser properties of a conjugate polymer (MEH-PPV) in the liquid-excimeric state

We have studied the amplified spontaneous-emission characteristics (ASE) of conjugated poly[2-methoxy-5-(2-ethylhexyloxy)1,4-phenylenevinylene] MEH-PPV in a few organic solutions. The ASE of MEH-PPV appears to arise from its excimeric state. This is perhaps the first report, to the best of our knowledge, on an excimeric-liquid state laser. MEH-PPV in solutions of benzene or tetrahydrofuran (THF) was pumped by the second and third harmonics of an Nd:YAG (532 and 355 nm) for different pump-pulse energies. The ASE of MEH-PPV was compared with the conventional laser dyes Rhodamine B (Rh B) and Rhodamine 6G (Rh 6G). The most important and distinguishing features are: (a) MEH-PPV has a four-times better photochemical stability than Rh B or Rh 6G; (b) the threshold and concentration for the laser action in MEH-PPV is far less than Rh B or Rh 6G.     

Synthesis,solution properties,and chain flexibility of poly (methyl dodecyl itaconate)

The dilute solution behavior of poly(methyl dodecyl itaconate) (PMeDoI) has been studied in THF and n-butanol at 298 K, by intrinsic viscosity, light scattering, and size-exclusion chromatography (SEC) measurements. The Kuhn-Mark-Houwink-Sakurada relationships were established. The flexibílity factors [sgrave] and C_∞ and the thermodynamic parameters B were calculated using the Stockmayer-Fixman equation. The A₂ and the B values are indicative of the presence of the excluded volume effect. The results obtained are compared with those previously found for poly(mono dodecyl itaconate) (PMDoI) and discussed in terms of specific influence of the free carboxylic group in the poly(monoester).