On the kinetics of pack aluminization

A theory of pack aluminization has been formulated by combining gaseous and solid state diffusion rates. This theory relates the surface composition of the coating, and therefore in principle the phase morphology and the growth rate of the coating, to pack operating parameters such as pack aluminum density, type of activator and temperature. Experimental data on the aluminization of unalloyed nickel in pure aluminum packs are in good agreement with the predictions of the theory.     

CO2水冷气体冷却器理论与实验研究

针对自然工质CO2热泵热水器中套管式气体冷却器进行理论分析与实验研究。选取不同的换热关联式,分析管径和流量对CO2侧和水侧换热的影响,理论分析CO2和水的温度匹配情况,设计套管式气体冷却器并进行实验研究,实验结果表明所进行的理论分析在误差允许范围内,满足设计要求,理论和实验结果对于CO2热泵热水器的产业化应用起到了很好的技术支持作用。     

Theoretical and experimental investigation of magnetotransport in iron chalcogenides

Abstract

We explore the electronic, transport and thermoelectric properties of Fe_1+ySe_xTe_1?x compounds to clarify the mechanisms of superconductivity in Fe-based compounds. We carry out first-principles density functional theory (DFT) calculations of structural, electronic, magnetic and transport properties and measure resistivity, Hall resistance and Seebeck effect curves. All the transport properties exhibit signatures of the structural/magnetic transitions, such as discontinuities and sign changes of the Seebeck coefficient and of the Hall resistance. These features are reproduced by calculations provided that antiferromagnetic correlations are taken into account and experimental values of lattice constants are considered in DFT calculations. On the other hand, the temperature dependences of the transport properties can not be fully reproduced, and to improve the agreement between experiment and DFT calculations it is necessary to go beyond the constant relaxation time approximation and take into account correlation effects.     

A modeling and experimental study of flue gas desulfurization in a dense phase tower

We used a dense phase tower as the reactor in a novel semi-dry flue gas desulfurization process to achieve a high desulfurization efficiency of over 95% when the Ca/S molar ratio reaches 1.3. Pilot-scale experiments were conducted for choosing the parameters of the full-scale reactor. Results show that with an increase in the flue gas flow rate the rate of the pressure drop in the dense phase tower also increases, however, the rate of the temperature drop decreases in the non-load hot gas. We chose a water flow rate of 0.6 kg/min to minimize the approach to adiabatic saturation temperature difference and maximize the desulfurization efficiency. To study the flue gas characteristics under different processing parameters, we simulated the desulfurization process in the reactor. The simulated data matched very well with the experimental data. We also found that with an increase in the Ca/S molar ratio, the differences between the simulation and experimental data tend to decrease; conversely, an increase in the flue gas flow rate increases the difference; this may be associated with the surface reactions caused by collision, coalescence and fragmentation between the dispersed phases.     

预应力钢拉杆的理论分析及试验研究

为了考察钢拉杆在不同受力条件下的力学性能,对10根GLG650钢拉杆试件分别进行单调受拉和低周往复拉压试验,得到钢拉杆的荷载-位移曲线、屈服承载力、最大承载力、极限承载力以及相应的变形和破坏形态。试验及分析结果表明：钢拉杆屈服强化阶段,荷载-位移曲线接近于直线;在往复拉压作用下,长细比较小的钢拉杆荷载-位移曲线出现循环软化现象。受拉屈服后,随着钢拉杆轴向变形加大,反向受压时其侧向挠曲变形随之增大,杆件中部在压弯作用下进入屈服。钢拉杆的断后伸长率约为3.4%~6.8%,远小于钢材试样的破断伸长率。钢拉杆破断多发生在加载端或固定端,受压弯累计塑性损伤的影响,长细比较小时杆件中部破断的情况增多。根据受力特征点确定的钢拉杆荷载-位移滞回规则,可供在往复荷载作用下弹塑性计算分析时应用。     

Theoretical and experimental investigation of rarefied gas flow in molecular pumps

The article presents a theoretical model for calculating the gas flow through channels with moving walls in the molecular flow regime. The analytical equations are solved by iteration techniques. The calculated data for the pumping speed and the compression ration of a molecular pump are compared with the experimental results. The agreement between calculated and measured values is good.     

Theoretical and experimental study of multi-compression particle breakage

By modifying Griffith's theory, a theoretical fatigue model was built to explain how the fatigue strength of a single particle changes under repeated compressions. The predictions of the model were validated by experimental results for two kinds of crystal particles: NaCl and MgO. We also performed experiments on granular particles whose properties were unknown. Here too the fatigue trends were similar to that of the model. The results show that as the compression stresses acting on the particles and the number of compressions increase, the fatigue compression strength decreases. In addition, fatigue trends we observed for the various particles demonstrate dependence on the material's properties.     

Theoretical and experimental study of a gas-coupled two-stage pulse tube cooler with stepped warm displacer as the phase shifter

A compact and high efficiency cooler working at liquid hydrogen temperature has many important applications such as cooling superconductors and mid-infrared sensors. This paper presents a two-stage gas-coupled pulse tube cooler system with a completely co-axial configuration. A stepped warm displacer, working as the phase shifter for both stages, has been studied theoretically and experimentally in this paper. Comparisons with the traditional phase shifter (double inlet) are also made. Compared with the double inlet type, the stepped warm displacer has the advantages of recovering the expansion work from the pulse tube hot end (especially from the first stage) and easily realizing an appropriate phase relationship between the pressure wave and volume flow rate at the pulse tube hot end. Experiments are then carried out to investigate the performance. The pressure ratio at the compression space is maintained at 1.37, for the double inlet type, the system obtains 1.1 W cooling power at 20 K with 390 W acoustic power input and the relative Carnot efficiency is only 3.85%; while for the stepped warm displacer type, the system obtains 1.06 W cooling power at 20 K with only 224 W acoustic power input and the relative Carnot efficiency can reach 6.5%.     

锥形非固结隔震结构理论与振动台试验研究

为了分析锥形非固结隔震结构的减震效果、支座耗能机理及支座受拉性能,对一缩尺1∶4的锥形非固结隔震钢框架结构模型进行了水平和竖向单向地震波输入下的振动台试验研究.分析了不同类型及强度的地震波作用下的结构上部及隔震层地震反应.试验结果表明,结构模型在8度和9度罕遇地震作用下,与其台面输入加速度峰值相比,其隔震层的加速度峰值减小10％～20％,上部结构顶层加速度峰值增加10％～50％,但和普通抗震结构相比具有明显的减震效果.在不同单向地震作用下,锥形非固结支座的滞回曲线饱满匀称;其上下盖板会在地震作用下产生错动位移,同时挤压粘弹性体消耗地震能量,耗能机理明确;地震波特性对支座受拉性能影响明显,但没有出现倾覆倒塌现象.锥形非固结隔震支座具有良好的减震性能,对低层建筑结构的减震具有明显的推广价值.     

Theoretical and experimental study of multi-impact breakage of particles

An empirical relationship between compression tests and impact tests was established for three kinds of particles: NaCl, GNP (fertilizer granule based on phosphate) and potash (fertilizer granule). As a result, the theoretical fatigue model that was previously developed for single particle strength (crushing strength) for repeated compression loads (fatigue) could be used to describe the decrease in particle strength due to repeated impact loads. The predictions of the theoretical model were validated by impact experiments for the three tested materials. In order to compare the theoretical and experimental findings, the experimental results were analyzed by tracking a defined population of particles after each impact test. The comparison showed good agreement (deviation of up to 25% for an impact number of 10). The results show that as the number of impacts and the impact velocity increase, the crushing strength decreases.     

Computer-aided and experimental study of hardness distribution in cutting tool steel body due to phase transformations during induction hardening

The paper presents the results of numerical and experimental investigations of hardness distribution in specimens of a cutting tool steel body upon induction hardening in media that essentially differ in cooling properties. The heating conditions for the tool body were chosen the same as in the case of induction brazing of a hardmetal insert to a tool body with subsequent hardening. The hardness calculations for various zones of the specimen axial section agree well with the experimental data, thus demonstrating the adequacy of the numerical procedure.     

小型恒温箱恒温性能的理论及实验研究

通过分析恒温箱内外的热量平衡，建立箱体内部温度变化的动态方程，进行理论求解，并分析箱体形状系数和内热源对箱体内部温度的影响。同时设计1台有效恒温空间为1350mm×340mm×450mm的小型恒温箱，进行不同温度波动下的恒温特性。结果表明，冷热源方式对恒温箱内温度的稳定有较大影响，较大的体型系统有利于维持恒温，另外动态方程的计算结果与实验相符。     

Theoretical and experimental study of a turbulent plasma jet

A computational technique and the results of an experimental study of a turbulent submerged plasma jet are presented.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 17, No. 3, pp. 437–446, September, 1969.     

Theoretical and experimental study of dry scroll vacuum pump

The rarefied gas flows through suction port, scroll clearance and discharge port are treated as leakage of dry scroll vacuum pump (DSVP). The models for predicting the above-mentioned leakage rate were derived in this paper. The model for predicting the heat transfer rate between rarefied gas and working chamber wall was also developed. Then, a general model for describing the working process of DSVP was set up according to the energy and mass conservation principle. This model can be applied to predict the performance of DSVP. The pumping speed for different suction pressures was obtained. Furthermore, the ultimate pressure and power consumption for different speeds were gotten. A good agreement between the theoretical results and experimental data was obtained. Finally, the volume ratio of prototype was changed and its influence on the performance was studied by experiment.     

Theoretical and experimental study of the processes of water purification in a biofilter

This paper presents the results of experimental measurements of substrate concentrations characterizing the efficiency of polluted water purification by a drop biofilter. A model describing the process of purification based on the diffusion-kinetic approach is presented. A good agreement between the experimental and theoretically calculated characteristics of the purification process has been shown. A simple semiempirical relation for estimating the operation of the drop biofilter is given. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 82, No. 2, pp. 273–282, March–April, 2009.     

Theoretical study of amplitude and phase filtering of guided waves

The design of integrated optics filters by use of refinement software based on the Abelès thin-film computation method and the film mode matching method is studied. The results obtained with the two computation methods are compared. Good agreement is obtained provided that the fill factor of the guided mode in the component is high and that modal losses between waveguide sections are simulated by absorption with the Abelès computation method. Integrated optics devices that manage either the amplitude of guided waves such as a dense wavelength division multiplexing narrow-bandpass filter and a gain-flattening filter or the phase of guided waves such as a broadband dispersion compensator are