神木半焦粉末萃取物的组成特征

依次用石油醚、CS₂、CH₂Cl₂、丙酮和甲醇在索氏萃取器中萃取了神木半焦粉末,得到了五级萃取物(E_1-5)和最终的萃余物,总萃取率为1.76%。分别用气相色谱/质谱联用仪(GC/MS)、大气压固体探针/飞行时间质谱仪(ASAP/TOF-MS)和电喷雾电离/飞行时间质谱仪(ESI/TOF-MS)分析了各级萃取物。用GC/MS分析的结果表明,在E₁中C_15-24的直链烷烃和E₂中3与4环的芳烃比较丰富,在E_3-5中含杂原子有机化合物较丰富,特别是E₄和E₅中含氧有机化合物的含量最高。与用GC/MS分析的结果相比,用ASAP/TOF-MS和ESI/TOF-MS从E_3-5中检测出更多的含杂原子有机化合物。     

氟喹诺酮C-3均三唑衍生物抗增殖活性的QSAR研究

基于拓扑化学理论,用原子类型的电性拓扑状态指数(E_A)描述了48个氟喹诺酮C-3均三唑衍生物分子的化学微环境。基于E_A和最佳变量子集回归,建立上述化合物对人白血病细胞(HL60)的抗增殖活性(pH)的定量构效关系(QSAR)模型。其最优四元(E₈、E₁₃、E₁₉、E₄₂)模型的判定系数(R²)和逐一剔除法交叉验证系数(R_cv²)分别为0.853和0.813。经R²、R_cv²、F_IT、A_IC、F、V_IF等统计指标检验,所建模型具有良好的稳定性、相关性和预测能力。结果显示影响氟喹诺酮C-3均三唑衍生物对人白血病细胞(HL60)的抗增殖活性的主要因素是与靶标形成氢键,以及配位和疏水作用。     

三元混配络合物形成的极谱研究——Cd-Bipy-Gly体系的稳定常数测定

用般谱法研究了Cd(Ⅱ)-2,2′-联吡啶(bipy)、Cd(Ⅱ)-甘氨酸(Gly)二元体系及cd(Ⅱ)-bipy-Gly三元体系的配合物的形成条件,用极谱法测定了不同浓庹配体的E_1/2(a)、E_1/2(c)、ΔE_1/2、(i_d)_s和(i_d)_c值,利用Lrden函数作图,外推求得各级稳定常数。     

新型卤代3-芳基香豆素的合成及其抗癌活性

以卤代芳基乙酸和2,3,4-三羟基苯甲醛为主要原料,经Perkin缩合和关环反应制得12个含卤素的7,8-二乙酰氧基-3-芳基香豆素化合物（D₁~D₁₂）; D₁~D₁₂经水解反应合成了12个含卤素的7,8-二羟基-3-芳基香豆素化合物（E₁~E₁₂）,除D₂, D₄~D6, E₂, E₄~E₆外均为新化合物,其结构经¹H NMR和MS（EI）表征。采用MTT法研究了D₁~E₁₂对人肺癌细胞株(A549)的体外细胞毒性。结果表明：D₁~E₁₂均表现出不同程度的肿瘤细胞增殖抑制活性（IC₅₀≥192.74 μmol·L^-1）。     

BeSO4-Al2(SO4)3-Na2SO4三元熔盐体系相图的研究

热分析法研究了BeSO₄-Al₂(SO₄)3-Na₂SO₄三元熔盐体系的状态图。体系中存在三元转熔(包晶)点P,温度490℃,组成为BeSO₄18.8Wt%,Al₂(SO₄)₃15.0%,Na₂SO₄66.2%;三元低共熔(共晶)点E₁,温度为476℃,组成为BeSO₄20.0%,Al₂(SO₄)₃11.2,%,Na₂SO₄68.8%。另一低共熔点E₂温度为595℃,组成未能确定。体系中无三元化合物生成。     

极谱法研究金属络合物时滴汞电极表面络合剂浓度的表达式

在极谱学中,各作者得到的从半波电位E_1/2求络合物稳定常数的公式中,都要用到半波电位E_1/2和汞滴表面络合剂X^b-的平衡浓度[X]₀这两个最基本的量^[1-11].其中,E_1/2这个量不但可以从实验上直接测定,而且它与标准电极电位、稳定常数、活度系数、扩散系数以及汞滴表面络合剂的平衡浓度等的关系式已由许多学者^[1-6]从理论上进行了推导.     

用密度泛函理论研究一种新型有机硅化合物异构体的振动光谱

在B3LYP/6-31＋G(d)的水平上, 对两种含有手性Si原子的新型有机硅单体Si₂(CH₃)₂H₂N₂(C₂H₅)₄和Si₄(CH₃)₄H₄N₂(C₆H₅)₂的几种异构体进行了研究, 在全参量几何构型优化的基础上, 进行了简谐振动频率计算, 同时对所研究的体系进行了热力学性质和低能激发态的含时密度泛函理论(TDDFT)计算. 理论计算表明, 构象异构体之间的红外光谱差异不大, 热力学和低能激发态性质也相似; 顺/反结构相似的异构体之间红外光谱差异不大, 但热力学和低能激发态性质却呈现差异; 旋光异构体或顺/反结构相差较大的异构体之间, 红外光谱和热力学及低能激发态性质有明显的差异. 从理论上解释了实验红外光谱中Si—H振动峰的裂分是由异构体的存在所致, 并找到裂分峰所对应的异构结构. Si—H键振动频率与其键长相关.     

LaNi4M(Ni,Cu,Fe)-H2体系的量热研究

本文用量热法测定了氢在LaNi₅,LaNi₄Cu,LaNi₄Fe中溶解的相对偏摩尔焓△H_Hα→β和偏摩尔自由能△G_Hα→β,并计算了偏摩尔熵△S_Hα→β。用X光衍射分析计算了LaNi₅,LaNi₄Cu,LaNi₄Fe的晶胞体积V,发现了△H_Hα→β和△G_Hα→β)与V存在线性关系。     

基于第一性原理计算的铁电材料BaTiO3相关振动光谱指认

通过固相反应烧结法在1400 ℃下烧结4 h合成了BaTiO₃陶瓷, 并用X衍射确定了其为四方晶系. 进行了拉曼谱和红外谱的测量, 并采用洛仑兹函数以及四参数方法分别对上述光谱进行了拟合. 基于第一性原理的计算, 并考虑了横模纵模劈裂, 对拉曼和红外光谱进行了指认. 为了更好地分析振动模式, 所有振动模用群论的对称坐标进行了分解. 在12个光学模中, 仅具有拉曼活性的B₁模式是O4和O5沿着z轴的相对运动. A₁模式和E₁软模式是从立方BaTiO₃相的F_1u模式劈裂出来的, 对于四方相BaTiO₃的铁电性有着重要作用, 其体现在A₁⁽¹⁾模式造成了铁电z轴的极化, E₁模式导致了大介电常数. 这两个模式都可以看成是Ti 原子相对于O₆八面体笼子沿着z轴或者是xy平面的振动.     

硝酸铕和穴醚配合物的电化学研究

用循环伏安法在二氯甲烷、二氯乙烷、乙腈、丙酮,苯腈、吡啶、二甲基甲酰胺、二甲基亚砜等不同溶剂中,研究了稀土穴醚配合物Eu(NO₃)₃(2,2)和Eu₂(NO₃)₆(2,2,2)的电化学行为。测定了其氧化还原反应的半波电位及电子转移速度常数,讨论了E_1/2、k_s与溶剂及支持电解质的关系。     

An analysis of the adhesion strength between polyethylene and paper

Composites of polyethylene with paper were studied in order to determine the influence of the surface energy of the paper on their cohesive strength. The papers used in this study had the same roughness, but fifferent surface energy owing to treatment with different sizing agents. The surface energies were determined by the contact angle method with various liquids, and the variations of the cohesive strength were followed by the energy of peeling at 180 °C. It was shown that the peeling energy decreases linearly when the reversible energy of adhesion decreases, and becomes negligible when the paper surface energy is approximately equal the surface energy of polyethylene.     

外电场下氮化铝分子结构和光谱研究

以6-311＋G(2DF)为基函数, 采用密度泛函B3P86的方法研究了外电场作用下氮化铝(AlN)基态分子的几何结构、HOMO能级、LUMO能级、能隙及谐振频率. 结果表明, 外电场的大小和方向对AlN分子基态的这些性质有明显影响. 在所加的电场范围内, 随着外电场的增大分子键长减小, 谐振频率增大, 总能量升高, 在F＝0.02 a.u.时能量达到最大, 为－297.4217 a.u., 此后继续增大电场强度, 系统总能量则开始降低; EH 和EL 随着电场的增加均逐渐增大, 在 F＝0.01 a.u.时, EH 和EL均取得最大值, 分别为－0.2776和－0.0828 a.u., 随着电场的继续增大, 能级EH和EL均逐渐减小, 而能隙在外电场增大的过程中始终处于减小趋势.     

镧系元素f-f跃迁光谱计算

运用不可约张量算符方法,建立了f-f超灵敏跃迁光谱的计算模型,编制了计算f离子^2s+1L~J能级、约化矩阵元、晶体场Stark能级、晶体场态-态跃迁振子强度及模拟吸收光谱的计算机程序.其中,自由f离子能级计算采用包括双电子与叁电子组态相互作用的二三参数模型,晶体场Stark分裂计算采用单电子轨道近似,用Newman角叠加模型计算晶体场参数.f-f跃迁振子强度计算包括静电诱导偶极跃、配体极化偶极跃、振动诱导电偶极跃迁及磁偶极跃迁的贡献.     

Energetics of phase transformations in polyethylene

The molecular mechanisms involved in the orthorhombic-to-monoclinic phase transformation in polyethylene were investigated by the computer simulation of a structure–energy map based on empirically justified intermolecular potential functions. Stable packing structures for the orthorhombic and monoclinic form were isolated as relative minima, cohesive energies were determined from the energy minima, specific chain motions involved in the transformation were identified by the minimum energy path connecting the packing minima, and the activation energy for the transformation was determined from the energy barrier along the minimum energy transformation path. The packing structure parameters predicted from the energy map were in excellent agreement with unit cell dimensions observed near 0°K. The activation energy predicted for the transformation is relatively low (～0.5 kcal/mole of ethylene at 0°K and 0.25 kcal/mole of ethylene near the melting point, 411°K). Monoclinic packing was predicted to be slightly more stable than orthorhombic. Since this result is inconsistent with a large body of observations, we propose that the intramolecular energy of chain folds plays a dominant role in establishing chain-packing geometry. The inclusion of fold-transition energetics could give rise to transformation mechanisms which differ in details from those proposed in this work.     

定量能谱CT多参数成像诊断多发性骨髓瘤价值及临床意义

本文探讨能谱CT多参数成像定量分析对多发性骨髓瘤(MM)的诊断价值及与实验室指标、疾病分期的关系。选取MM患者62例作为研究组,另随机选取同期健康者62例作为对照组,均行能谱CT检查。结果发现,研究组40 keV、50 keV、60 keV、70 keV、80 keV、90 keV、100 keV能量水平的CT值、能谱曲线斜率均低于对照组(P<0.05);上述能量水平的CT值、能谱曲线斜率联合诊断的AUC为0.875;40~100 keV能量水平的CT值、能谱曲线斜率与Hb呈正相关,与CREA、BUN、β2-MG、疾病分期呈负相关(P<0.05)。因此能谱CT多参数成像定量分析在MM诊断方面具有较高价值,且与患者Hb、CREA、BUN、β2-MG水平、疾病分期密切相关。     

Application of the Monte Carlo method to modeling of kinetic processes with the participation of polyatomic molecules and clusters: 1. Kinetics of energy transfer during collisions of polyatomic molecules

The Monte Carlo method was used to model the collisional energy transfer for polyatomic molecules within the framework of the statistical theory of reactions. A model describing energy transfer through the formation of a statistical collisional complex was suggested. It was assumed that the total energy of the complex was randomized in the course of collisions and statistically distributed among the internal and translational degrees of freedom. The method was verified by comparing the equilibrium distribution functions for the vibrational, rotational, and total energies of the molecule. The mean energy portion and the root-mean-square energy portion transferred per collision, as functions of the total molecular energy, were determined. The relaxation parameters of the population distribution over energy after a sharp increase in the bath-gas temperature were calculated.     

Prediction of granule physical property by a novel compression energy of wet powder

Wet granulation is a very important process and a reliable evaluation method for formulation study; thus it requires appropriate process control. In this study, a novel and effective method that involves a compression test of wet powder is proposed. Here, the compression energy, which could predict the capability of the wet powder for extrusion granulation as well as the physical properties of the final products, is used as a novel characteristic of wet powder. The compression energy was defined as the energy consumption derived from the compression speed and the transmission loss during the compression test. Lactose monohydrate was mixed with various additives such as hydroxypropylcellulose in the mass ratio of 0-10%. Various amounts of water were fed into the mixtures, which were kneaded in a planetary motion mixer to prepare the kneaded wet powders. The characteristics of these powders were evaluated by the compression energy. The kneaded wet powders were then extruded through an extrusion granulator, the electrical loads of the granulator during the operation were analyzed as the extrusion energy, and the physical properties of extruded granules were investigated. As a result, the granule strength and granule size distribution showed a good correlation with the compression energy. A good correlation was also observed between the compression energy of the kneaded wet powder and the extrusion energy regardless of the different additives and water contents. It was concluded that the compression energy of the wet powder could be used for the formulation study and the process control of wet granulation.     

Allostery of the two-state model of hemoglobin studied by ECEPP energy minimization

Recently, a powerful parallel-vector processor became available for molecular science. A new FORTRUN program was coded to treat the whole hemoglobin molecule with twofold symmetry. Using the X-ray coordinates of deoxyhemoglobin and oxyhemoglobin, minimum energy conformations were obtained for both the T-state and the R-state on the two-state model of allostery. From them, further energy minimization was performed with simple perturbation to bring the proximal region close to the heme group instead of oxygen binding, and the structural changes and energy changes were investigated. The difference of calculated energy changes between T and R was semiquantitatively in agreement with the experimental value 2.7 kcal/mol for one oxygen binding. When the perturbation was exerted on the alpha-subunits, the energy change within the perturbed alpha-subunits in the T-state gave a main contribution, and in the R-state, the structural changes of the alpha-subunits were specifically large. When the perturbation was exerted on the beta-subunits, the intersubunit interaction energy between alpha1 and beta2 (alpha2 and beta1) was dominant in the difference of the energy changes between T and R.     

Measurement of force components for ink detachment of newsprints

Ink detachment tests were carried out using a Couette device. During the test, the energy supplied to the operation of the device partially dissipated as heat. The fraction of energy dissipated increased with pulp consistency. The fraction of energy for peeling and pulling the ink from the printed samples were calculated. At 4% consistency, the energy for pulling was much higher than for peeling, while at higher consistencies, the peeling effect became more significant. The ink detachment was highly dependant on how the pulp interacted with the printed surface. This interaction was influenced by pulp consistency and the energy applied to the rotor of the Couette device. Copyright © 2008 John Wiley & Sons, Ltd.     

Construction of database of effective energy‐loss functions

Effective energy‐loss functions for Al, Cu, Ag and Au were derived from the reflection electron energy‐loss spectroscopy (REELS) spectra for 1 keV electrons using extended Landau theory. Features of the obtained effective energy‐loss functions are close to those of optical surface energy‐loss functions, revealing the significant contribution of the low energy loss below a few tens of electron‐volts in the REELS spectrum for Cu, Ag and Au. The REELS spectra were reproduced using the newly derived effective energy‐loss functions, leading to the confirmation that this type of database of the effective energy‐loss function is very useful not only for more comprehensive understanding of the measured spectrum of surface electron spectroscopies but also for practical background subtraction in surface electron spectroscopy. Copyright © 2003 John Wiley & Sons, Ltd.