FORMATION OF MANGANESE SILICIDE THIN FILMS BY SOLID PHASE REACTION

1. IntroductionThe transition metal silicides have attraeted much attention because of their potentialapplicatiOIl in very large scale integration (VLSI) de.ice[1]. Near-noble metal silicides canbe used as Schottky al1d ohn1ic col1tacts in silicon-based d…     

Diluent effects on carbonate mobility in bisphenol-A polycarbonate in the solid state

The effect of miscible low molecular weight additives on the mobility of the carbonate group in bisphenol-A polycarbonate (BPAPC) has been studied using n.m.r. and dielectric relaxation experiments in the solid state. Proton-enhanced dipolar-decoupled carbon-13 n.m.r. spectra of BPAPC, isotopically enriched at the carbonate position, are obtained without magic-angle sample spinning. The resolved chemical shift anisotropy allows study of nuclear spin relaxation for the carbonate groups in the polymer that have different orientations relative to the static magnetic field in the laboratory frame. The spin-lattice relaxation time in the rotating frame (T_1?) is measured at a motional-probe frequency of 50 kHz for the undiluted polymer and for BPAPC-diluent blends containing either dibutylphthalate or dinitrobiphenyl. The T_1? exhibits some dependence on orientation in all systems studied. In the blend containing dibutylphthalate (DBP), T_1? is decreased by a factor of two for all orientations of the carbonate group. This implies that DBP substantially increases the spectral density of 50 kHz motions in the carbonate region of the polymer at ambient temperature. In contrast, dinitrobiphenyl does not significantly alter the Fourier component of thermal fluctuations at 50 kHz. Dielectric relaxation measurements at 10 kHz reveal that the primary (T_g) and secondary (β) motional processes in BPAPC are affected by low molecular weight additives. An intermediate relaxation process appears in the temperature interval between the glass transition temperature (T_g) and the sub-T_g β-relaxation (T_β) in the polymer-diluent blends. The n.m.r. spin-lattice relaxation rate in the rotating frame, T^?1_1?, correlates well with the relative magnitude of the dielectric dissipation factor (tan δ_ε) between T_g and T_β.     

利用ADCP回波强度估算河流悬移质含沙量的应用研究

通过简要介绍利用声学多普勒水流剖面仪(ADCP)回波强度估算悬移质含沙量的基本原理,结合梧州水文站的应用实例,利用ADCP的回波强度数据和现场采集的水样含沙量建立相关关系,根据相关关系由回波强度反演估算的水体悬移质含沙量验证了利用ADCP的回波强度估算悬移质含沙量的可行性。应用于梧州水文站的实践表明,左河道推算的系统误差为-0.1%,右河道推算的系统误差为1.5%。这种方法具有不扰动流场、测量剖面同步性较好、数据空间分辨率较高的优点,与传统的取样过滤称量法相比,计算效率显著提高。     

汽轮发电机组负荷波动的原因分析及解决措施

详细分析了汽轮发电机组在运行过程中出现电负荷波动和瞬间突降的原因，重点介绍了如何调节、维持汽轮发电机组的经济运行以及解决电负荷波动的措施，从而保证汽轮发电机组的稳定运行。     

SO_4~（2－）／ZrO_2固体超强酸的失活与再生

初步探索了ＳＯ_４~２－／ＺｒＯ２固体超强酸的失活机理．并着重研究了催化剂的两种再生方法：灼烧法和溶剂洗涤法。催化剂主要是因结焦而失活，高温灼烧能基本恢复催化剂原有活性．且再生效果与灼烧温度有关。溶剂洗涤法有一定的再生能力，但不显著．     

新型层状表面相锆基固体酸催化酯化反应研究

将所研制的层状表面相锆基固体酸催化剂用于一元、二元醇醋酸酯和其他羧酸酯类产品的合成 ,考察了其催化性能。研究发现 :层状表面相锆基固体酸催化剂对所考察的酯化反应具有很好的普遍适用性 ,但其酯化率与醇的性质和结构密切有关。催化反应动力学研究表明乙酸与丁醇、戊醇、己醇的酯化反应均为二级反应 ,且反应活化能均较低 ,分别为 47 4kJ/mol、2 3 3kJ/mol和 19 8kJ/mo     

Ignition and Combustion of Dust-Gas Suspensions

The ignition and combustion of dust-gas suspensions are considered. It is shown that the ability of these systems to accumulate heat is determined not only by their kinetic and thermal properties but also by the relation between their reaction surface and the heat-removal surface (f). Experimental information on flame temperatures, ignition delays, and flame propagation over gas suspensions is processed using the parameter f, and the postulate on the stimulating role of the developed reaction surface in activating these processes is validated. It is shown that during overall burning, diffusion combustion of particles occurs only for rather small values of f. The ambiguous effect of the parameter f on the ignition and combustion processes leads to the necessity of optimizing the fuel size distribution and concentration for the effective operation of the power devices. The role of the macroparameters of two-phase flames of refractory metals in the synthesis of combustion nanoproducts is analyzed. __________ Translated from Fizika Goreniya i Vzryva, Vol. 41, No. 6, pp. 3–14, November–December, 2005.     

半参数广义线性模型惩罚似然估计的几个性质

本文在给出了半参数广义线性模型惩罚似然估计及惩罚准似然估计的基础上,得到了下面几个性质:(Ⅰ)极小惩罚似然估计及惩罚准似然估计等价于惩罚加权最小二乘估计;(Ⅱ)估计的收敛性及加速收敛法;(Ⅲ)估计的一种 Bayes 解释。     

固体酸催化合成苯甲酸正丁酯

论述了利用对甲苯磺酸，磺化苯磷酸锆，六水三氯化铁，氧化亚锡，十二水合硫酸铁铵，一水硫酸氢钠，固体超强酸和杂多酸等各种固体催化剂催化合成苯甲酸正丁酯的方法。研究发现：各种催化剂的催化效果良好，酯收率达74％以上，有的甚至达97.8％。同时对各种催化剂的催化机理进行了初步探讨，对各种固体酸的催化效果也进行了比较。