Electrochemical fabrication of single-crystalline and polycrystalline Au nanowires: the influence of deposition parameters

We report the electrochemical growth of gold nanowires with controlled dimensions and crystallinity. By systematically varying the deposition conditions, both polycrystalline and single-crystalline wires with diameters between 20 and 100 nm are successfully synthesized in etched ion-track membranes. The nanowires are characterized using scanning electron microscopy, high resolution transmission electron microscopy, scanning tunnelling microscopy and x-ray diffraction. The influence of the deposition parameters, especially those of the electrolyte, on the nanowire structure is investigated. Gold sulfite electrolytes lead to polycrystalline structure at the temperatures and voltages employed. In contrast, gold cyanide solution favours the growth of single crystals at temperatures between 50 and 65 degrees C under both direct current and reverse pulse current deposition conditions. The single-crystalline wires possess a [110] preferred orientation.

Bi同位素链上原子核α衰变性质的理论研究；Theoretical Study on α Decay Properties for Bi Isotopes

采用结团模型(clustermodel)计算了从10752Te到292116共443个核素α衰变的半衰期,所得结果与实验值符合得很好,显示了结团模型可以成功地应用于研究原子核α衰变的性质。同时研究了Bi同位素链上奇A核α衰变的半衰期,计算结果与已有的实验值的偏差一般在3倍以内,进而对实验上未知α衰变半衰期的原子核的性质进行了预言。这有助于将来在实验室探测与鉴别这些原子核以及研究它们的α衰变性质。理论与实验的比较将加深人们对原子核结构的认识。

~(12)C与~(209)Bi反应中Au同位素的产额与Q_(gg)的关系；Q_(gg)-Yield Dependence of Au Isotopes in Interaction of 47 MeV/u ~(12)C With ~(209)Bi

用47MeV/u12C离子轰击天然铋靶,通过炮弹和靶核之间的核子转移反应产生Au同位素。使用放射化学方法从大量Bi和复杂反应产物中分离、纯化Au,并制备Au的γ射线测量源。使用HPGe探测器测量放射性Au同位素的γ活性。根据照射结束时Au同位素的活度和其他相关数据,确定每个Au同位素的产生截面。分析发现,缺中子Au同位素的产生截面与Qgg值之间不遵从指数依赖关系,这可用重离子碰撞中的次级过程加以解释。

47MeV/u~(12) C轰击~(197)Au和~(209)Bi引起的裂变关联测量

本论文的工作：利用两体裂变角关联技术，辅之以飞行时间测量，测定了47MeV/u的~(12)C轰击~(197)Au和~(209)Bi靶中心碰撞对应的线性动量转移（LMT），得到了关联裂片出射的共面歧离分布，同时还发现了关联角很小且共面歧离很大的裂变事件，并得到了其相对速度分布。从测到的LMT分布中，得到中心碰撞对应的最可几线性动量转移约占入射动量的65％，相应于单核子线性动量转移约为192MeV/c.A，进而还估算出了所形成热核的激发能上限。在对关联裂片出射的共面歧离效应研究中，发现了共面歧离宽度是热核激发能的较好量度之一。并给出了共面歧离宽度跟热核单核子激发能的经验关系；还用简化的裂片级联蒸发模型估算了蒸发中子、质子和α粒子的平均多重性

25MeV/u~(40)Ar~(15+)+~(209)Bi反应的裂变研究

本文首先回顾了重离子物理学的发展简史，并介绍了当前的一些关于重离子反应的理论方法，同时对于现在核物理的研究热点，热核的特性进行了概括性的叙述．由于裂变是作者工作的重点，因此在文章中，对裂变反应的理论也进行了介绍．为了能够清楚全面的说明我们的工作，本文对于实验装置和探测器也给出了详细的描述．最后，文章对25 MeVu Ar+Bi反应中的裂变进行了讨论．在这些讨论中，我们分析了反应中与裂变相关的数据，得到了碎片的质量，动能分布。同时运用与碎片相关联的4He粒子能谱提取了核温度和裂前裂后的4He粒子多重性，并利用这一数据计算了不同初始激发能下的裂点激发能和裂变时标.

Heat capacity and thermodynamic properties of crystalline ornidazole (C7H10ClN3O3)

The molar heat capacities of 1-(2-hydroxy-3-chloropropyl)-2-methyl-5-nitroimidazole (Ornidazole) (C7H10CIN3O3) with purity of 99.72mol% were measured with an adiabatic calorimeter in the temperature range between 79 and 380K. The melting-point temperature, molar enthalpy Delta(fus)H(m), and entropy, Delta(fus)S(m), of fusion of this compound were determined to be 358.59 +/- 0.04K, 21.38 +/- 0.02 kJ mol(-1) and 59.61 +/- 0.05 J K-1 mol(-1), respectively, from fractional melting experiments. The thermodynamic function data relative to the reference temperature (298.15 K) were calculated based on the heat capacities measurements in the temperature range from 80 to 380 K. The thermal stability of the compound was further investigated by DSC and TG. From the DSC curve an intensive exothermic peak assigned to the thermal decomposition of the compound was observed in the range of 445-590 K with the peak temperature of 505 K. Subsequently, a slow exothermic effect appears when the temperature is higher than 590 K, which is probably due to the further decomposition of the compound. The TG curve indicates the mass loss of the sample starts at about 440K, which corresponds to the decomposition of the sample. (C) 2003 Elsevier B.V. All rights reserved.

Calorimetric study and thermal analysis of crystalline nicotinic acid

As one primary component of Vitamin B-3, nicotinic acid [pyridine 3-carboxylic acid] was synthesized, and calorimetric study and thermal analysis for this compound were performed. The low-temperature heat capacity of nicotinic acid was measured with a precise automated adiabatic calorimeter over the temperature rang from 79 to 368 K. No thermal anomaly or phase transition was observed in this temperature range. A solid-to-solid transition at T-trs = 451.4 K, a solid-to-liquid transition at T-fus = 509.1 K and a thermal decomposition at T-d = 538.8 K were found through the DSC and TG-DTG techniques. The molar enthalpies of these transitions were determined to be Delta(trs)H(m =) 0.81 kJ mol(-1), Delta(fus)H(m) 27.57 kJ mol(-1) and Delta(d)H(m) = 62.38 kJ mol(-1), respectively, by the integrals of the peak areas of the DSC curves.

Low-temperature heat capacity and thermodynamic properties of crystalline carboxin (C12H13NO2S)

Carboxin was synthesized and its heat capacities were measured with an automated adiabatic calorimeter over the temperature range from 79 to 380K. The melting point, molar enthalpy (Delta(fus)H(m)) and entropy (Delta(fus)S(m)) of fusion of this compound were determined to be 365.29 +/- 0.06K, 28.193 +/- 0.09 kJ mol(-1) and 77.180 +/- 0.02 J mol(-1) K-1, respectively. The purity of the compound was determined to be 99.55 mol% by using the fractional melting technique. The thermodynamic functions relative to the reference temperature (298.15 K) were calculated based on the heat capacity measurements in the temperature range between 80 and 360 K. The thermal stability of the compound was further investigated by differential scanning calorimetry (DSC) and thermogravimetric (TG) analysis. The DSC curve indicates that the sample starts to decompose at ca. 290degreesC with the peak temperature at 292.7degreesC. The TG-DTG results demonstrate the maximum mass loss rate occurs at 293degreesC corresponding to the maximum decomposition rate. (C) 2003 Elsevier B.V All rights reserved.

Low-temperature heat capacity and thermodynamic properties of crystalline 2-chloro-5-trichloromethylpyridine

The low-temperature heat capacities of 2-chloro-5-trichloromethylpyridine were measured with a high-precision automated adiabatic calorimeter in the temperature range from 80 K to 345 K. A solid-liquid phase transition was observed from 318.57 K to 327.44 K with peak temperature 324.67 K; the molar enthalpy and entropy of phase transition, DeltaH(m) and DeltaS(m), were determined to be 14.50 +/-0.02 kJ mol(-1) and 44.66 +/- 0.07 kJ K-1 mol(-1), respectively. The thermal stability was investigated through thermogravimetric analysis (TG). The TG and DTG results reveal that 2-chloro-5-trichloromethylpyridine starts to lose mass at 332 K due to evaporation and completely changes into vapour at 483 K under the present experimental conditions.