粉末冶金从动齿轮的高频淬火

摩托车离合器粉末冶金齿轮(见图1),是采用粉末冶金工艺无切削加工成形的,且具有径向尺寸大,高度尺寸小,中心7孔位置度要求高等特点,以往只能依赖进口。1993年,我们协同有关单位共同开发该齿轮,以实现国产化。经过近几年的攻关,取得了重大突破。由于粉末冶金齿轮存在孔隙,使导热性降低,影响淬硬层深度、硬度,也易于出现裂纹和变形。因此,该摩托车齿轮对高频淬火热处理要求较高,既要一定的表面硬度和淬硬层深度,又要防止齿轮变形和开裂。我们经过从材料到工艺的不断探索,已稳定了该齿轮的高频淬火工艺,其淬火质量达到或超过同类日本FCC公司的标准,且高频废品率明显降低。

Separation of Ions from Volatile Organic Compounds Using High-Field Asymmetric Waveform Ion Mobility Spectrometry-Mass Spectrometer

A combination of high-field asymmetric waveform ion mobility spectrometry （FAIMS） with mass spectrometer （MS） was analyzed. FAIMS separates ions from the volatile organic compounds in the gas-phase as an ion-filter for MS. The sample ions were created at ambient pressure by ion source, which was equipped with a 10.6 eV UV discharge lamp （A=116.5 nm）. The drift tube of FAIMS is composed of two parallel planar electrodes and the dimension is 10 mm×8 mm×0.5 mm. FAIMS was investigated when driven by the high-filed rectangular asymmetric waveform with the peak-to-peak voltage of 1.36 kV at the frequency of 1 MHz and the duty cycle of 30%. The acetone, the butanone, and their mixture were adopted to characterize the FAIMS-MS. The mass spectra obtained from MS illustrate that there are ion-molecular reactions between the ions and the sample neutral molecular. And the proton transfer behavior in the mixture of the acetone and the butanone is also observed. With the compensation voltage tuned from -30 V to 10 V with a step size of 0.1 V, the ion pre-separation before MS is realized.

A Capacitor-Free CMOS Low-Dropout Regulator for System-on-Chip Application

A stable CMOS low drop-out regulator without an off-chip capacitor for system-on-chip application is presen- ted. By using an on-chip pole splitting technique and an on-chip pole-zero canceling technique, high stability is achieved without an off-chip capacitor. The chip was implemented in CSMC＇s 0.5μm CMOS technology and the die area is 600μm×480μm. The error of the output voltage due to line variation is less than -＋ 0.21% ,and the quiescent current is 39.8μA. The power supply rejection ratio at 100kHz is -33.9dB, and the output noise spectral densities at 100Hz and 100kHz are 1.65 and 0.89μV √Hz, respectively.

可靠性技术在民品制造过程中的应用

本文针对JS55T摩托车在试制阶段出现的离合器动皮带盘卡死故障，根据ETA故障树分析系统的各种失控状态，对导致这些元件换效的特殊原因进行分析，找出了系统的薄弱环节，从而提高了系统的可靠性，通过生产实践证明，即耗费用小，又能保证不产生故障，满足了可靠性的经济效益，是行之有效的。

Numerical Simulation of Fluid Flow and Oil-Water Separation in Hydrocyclones

The fluid flow and oil-water separation were simulated using a Reynolds stress transport equation model of turbulence in water flow and a stochastic model of oil droplet motion. Simulation results give the axial and tangential velocity components, the pressure and turbulence intensity distribution and droplet trajectories for a hydrocyclone of F type and a hydrocyclone proposed by the present authors. The flow field predictions are in qualitative agreement with the LDV measurements. The results show that the proposed hydrocyclone has better performance than the hydrocyclone of F type due to creating stronger centrifugal force and lower axial velocity.

Visualization of the Precessing Vortex Core in a Cyclone Separator by PIV

The precessing vortex core (PVC) in a cyclone separator plays an important role in the separation performance and in further understanding of the general law of periodic unsteady flow therein. In this paper, the unsteady flow field is investigated with particle image velocimetry (PIV), and the instantaneous velocity, vorticity, tangential velocity, and radial velocity are acquired by analyzing the images of instantaneous flow. It is for the first time reported that there is a centrifugal flow region close to the dust discharge zone and its maximum value is higher than the mean radial velocity. This discovery is very important for understanding the principle of separation of particles in the area of dust discharge. Determination of the frequency and amplitude of PVC was conducted in the region where the phenomenon of PVC is remarkable. Results agree well with those obtained by hot wire anemometry. The observations of the center of vortex core and the bimodal distribution of the amplitude of the PVC indicate the vortex core precesses around the geometric axis of the cyclone in its own way.

Efficiency of Plate Separators for Dispersed Liquid-Liquid Systems

The basic flow model of laminar flow field and the trajectory model of dispersed phase drops are derived. Based on the comparable volumetric flow rate, the dispersed flow rate can be linearly discretized. Consequently, the trajectory of a droplet in the channel can be tracked, and the trajectories of all drops are observed in order to statistically analyse the drops for capture or entrainment. Therefore, in terms of theoretical model of motion, the stratified two phase flow systems are studied in the mixture of nitrobenzene and concentrated sulfuric acid. The analytical results indicate that the trajectories of droplets of different diameters are different at the same location. The larger droplets can help to promote the efficiency of plate separators. The thickness of trickling film has a significant influence on the efficiency of numerical simulation when the concentration of the dispersed phase is greater than 10%. So the modification of thickness of trickling film can help to get the real flow field efficiency. The low flow rate lowers the average Renolds number so that the lighter phase droplets have sufficient time to interact with the trickling film. It is an indispensable factor for predicting efficiency that coalesced drops flow off inclined plates together with trickling films. A comparison confirms that the simulation results are in good agreement with the experiment results.

Application of Electrical Capacitance Tomography to the Concentration Measurement in a Cyclone Dipleg

Accurate solid concentration measurement plays a key role in the process industry. Measurements analyzed offline can be used to estimate process efficiencies, to identify problems in a flow, and to validate computational models. Online measurements can be used for active control. Electrical capacitance tomography （ECT） is a unique measuring technique with great potential in multiphase flow measurement. Experimental studies are carried out on a solid concentration measurement in a cyclone separator dipleg, using ECT. In this experiment eight electrodes are selected for the ECT sensor that is placed on the straight tube of the dipleg. The fluctuating characteristics according to the screw feeder and the effect of the airflow rate from the top of the cyclone are analyzed. The feasibility andreliability of the method are verified by the experimental results.

Beneficiation study of Eshidiya phosphorites using a rotary triboelectrostatic separator

This study was performed to investigate the feasibility of applying a Rotary Triboelectrostatic Separator（RTS） to the beneficiation of Eshidiya phosphate minerals.RTS separation tests were carried out on phosphatic bed A_1,phosphatic bed A_3 and slime samples.The bed A_1 and slime samples were tested without desliming.Two sets of tests were performed using the A_3 sample： one was performed without desliming and the other with the A_3 sample deslimed.RTS separation tests as initially performed on the bed A_1 and slime samples gave products that had essentially the same P_2O_5 content.This indicated that adsorbed clay particles on the phosphate surface are responsible for the poor separation of un-deslimed phosphates.Better triboelectrostatic separation was observed with the undeslimed A_3 phosphate sample;these tests resulted in a highest product grade of 26%P_2O_5.The deslimed A_3 sample showed far more effective separation than the undeslimed A_3 one.In fact,a concentrate of 34%P_2O_5 was obtained from the triboelectrcstatic separation of deslimed A_3.The results indicate that with deslimed A_3 P_2O_5 recovery was about 65%for a concentrate of 28%P_2O_5 and about 45%for a concentrate of 30%P_2O_5.These results clearly show the importance of desliming for effective beneficiation of phosphate by the RTS.A more efficient separation can be expected from optimized operating conditions and circuit configuration.

Numerical Simulation and Experimental Study on the Performance of Gas/liquid Spiral Separator

The gas/liquid spiral separator, a key component in the compressed air system, was used to remove liquid and oil from gas stream by centrifugal and gravitational forces. To optimize the design of the separator,the relationship between the performance and structural parameters of separators is studied. Computational fluid dynamics (CFD) method is employed to simulate the flow fields and calculate the pressure drop and separation efficiency of air-liquid spiral separators with different structural parameters. The RSM (Reynolds stress model)turbulence model is used to analyze the highly swirling flow fields while the stochastic trajectory model is used to simulate the traces of liquid droplets in the flow field. A simplified calculation formula of pressure drop in spiral structures is obtained by modifying Darcy's equation and verified by experiment.

Modularized dry coal beneficiation technique based on gas-solid fluidized bed

A 40-60 t/h modularized dry coal beneficiation process with a novel method to control the bed was designed around a gas-solid fluidized bed separator. Furthermore, the hydrodynamics of medium-solids consisting of wide-size-range magnetite powder （0.3-0.06 ram） and 〈1 mm fine coal were numerically studied. The simulation results show that the fluidization performance of the wide-size-range medium-solid bed is good. The separation performance of the modularized system was then investigated in detail using a mixture of 〈0.3 mm magnetite powder （mass fraction of 0.3-0.06 mm particles is 91.38 %） and 〈1 mm fine coal as solid media. The experimental results show that at separation densities of 1.33 g/cm^3 or 1.61 g/cm^3, 50-6 mm coal can be separated effectively with probable error, E, values of 0.05 g/cm^3 and 0.06 g/cm^3, respectively. This technique is beneficial for saving water resources and for the clean utilization of coal.

A new technique of combining accretion by cyclone separator and scattertube for tailings dams

A new technique of combining accretion by cyclone separator and scattertube for tailings dams was developed according to laboratory experiment, model experiment and spot experiment technology. Three tailings dams were successfully constructed by the new technique. The results of engineering geological exploration, static and dynamic test and stability analysis on Baizhishan tailings dams prove that the new technique improves structure and stability of the dams and working conditions compared with the traditional technique. The thin layers of fine-grained soils are greatly reduced, fine tailings sand is solid to make the dam stable and seepage conditions are well improved; the immersing line of the dam descends. In addition, the stability and liquefaction resistance of tailings dams are strengthened remarkably. The interior stress is compressive stress, stress level of every element is less than 1.0 and safety coefficient of every element is greater than 1.0. The safety coefficient against liquefaction of every element of tailings dams is greater than 1.5 according to the analysis of seismic response by finite element method.

Dry coal fly ash cleaning using rotary triboelectrostatic separator

More than 80 million metric tons of fly ash is produced annually in the U.S. as coal combustion by-product. Coal fly ash can be converted to value-added products if unburned carbon is reduced to less than 2.5%. However, most of fly ash is currently landfilled as waste due to lack of efficient purification technologies to separate unburned carbon from fly ash. A rotary triboelectrostatic separator has been developed and patented recently at the University of Kentucky with unique features. Several fly ash samples have been used to understand the effects of major process parameters on the separation performance. The results show that compared to existing triboelectrostatic separators, the rotary triboelectrostatic separator has significant advantages in particle charging efficiency, solids throughput, separation efficiency, applicable particle size range.

Mixed refrigerant composition shift due to throttle valves opening in auto cascade refrigeration system

Auto cascade refrigeration(ACR) cycle with phase separators is widely used in the cryogenic system. The composition of mixed refrigerant has a great effect on the performance of the system. Based on the assumption of infinite volume of phase separator, ACR system with one phase separator is simulated in this paper. The variation of refrigerant composition under different valves opening is obtained. A related experimental system is set up to verify the variation. The result shows that when the valve opening connected to the evaporator increases or the valve opening under the phase separator decreases, the low-boiling component concentration of the working mixture passing through the compressor and condenser increases, while the high-boiling component concentration decreases. Furthermore, the variations of condensation pressure and evaporation pressure under different valves opening are also observed. This paper is helpful to deepen the understanding of ACR system.

Triboelectrostatic Separation-an Efficient Method of Producing Low Ash Clean Coal

At present, coal is mainly consumed as fuel. In fact, coal is also a kind of precious raw material in chemical industry on the premise that some harmful minerals should be removed from coal. The paper presents the results of the research on producing low ash (<2%) coal with triboelectrostatic separator used for producing high-grade active carbon. The test is conducted in bench-scale system, whose capacity is 30～100 kg/h. The results indicate that: 1) the ash content of clean coal increases with the increase of solid content of feedstock, on the contrary, the yield of clean coal is declining; 2) a high velocity may result in a good separation efficiency; 3) for the same solid content, the reunion caused by intermolecular force makes the separation efficiency drop down when the ultra-fine coal is separated; 4) the separation efficiency is improved with the increase of electric field intensity, but there is a good optimized match between the electric field intensity and yield of clean coal; 5) a low rank coal is easy-to-wash in triboelectrostatic separation process; 6) the yield of clean coal can be enhanced and the ash decreased through adapting optimized conditions according to various coals.

Droplets Turbulence Effect of Gas-Water Separator with Corrugated Plates

Droplet turbulence effect on gas-water separator with corrugated plates is explored using the Eulerian-Lagrangian two-way coupled multiphase approach of FLUENT. It is concluded that the inertial force is dominant in separating large droplets, while droplet turbulence dispersion plays a decisive role in separating fine droplets. Good agreement exists between calculations and air-water experiments. The numerical method developed provides a rea-sonable description of the droplet trajectories and separating efficiency, and it can be applied to predicting the performance of gas-water separator with corrugated plates.

Theoretical Study on Dynamic Filtration with the Membrane in Simple Harmonic Motion

A simple harmonic motion is proposed to make the membrane move in a simpleharmonic way so as to enhance the membrane filtration, and minimize the membrane fouling andconcentration polarization. The velocity distribution and pressure distribution are deduced from theNavier-Stokes equation on the basis of a laminar flow when the membrane rotates at the speed of Asin(αt). And then the shear stress, shear force, moment of force on the membrane surface and powerconsumed by viscous force are calculated. The velocity distribution demonstrates that the phase ofmembrane velocity does not synchronize with that of shear stress. The simple harmonic motion canresult in self-cleaning, optimize energy utilization, provide the velocity field with instability,and make the feed fluid fluctuation. It also results in higher shear stress on the membrane surfacethan the constant motion when they consume the same quantitative energy.

A new gravity ＆ flotation separator with double-tailing discharge and its beneficiation performance

Introduced a new gravity and flotation separator with double-tailing dtsctaarge tor nne coat~, u,u ,,,~,.~ cation and cyclone scavenging with flotation in an original way. The beneficiation performance of it was good. The results show that the gravity and flotation separator with double-tailing discharge can produce high-quality clean coal of 10.46% ash from free coal of 35.56% ash. It can discharge the fine and coarse tailings separately.

Multi-mode Coherent-Entangled State Representation and Its Applications

We introduce the so-called coherent-entangled state (CES) in the four-mode Fock space,which makesup a new quantum mechanical representation owing to completeness relation and orthogonal property.Its standardSchmidt decomposition and experimental generation using beam-splitter (BS) are proposed.In addition,its applicationsin quantum optics are presented.Finally,we extend it to multi-mode case and discuss some applications,too.

Simulation of clinker grinding circuits of cement plant based on process models calibrated using GA search method

Particle size distributions of obtained samples from several sampling campaigns were determined and raw data were mass balanced before being used in simulation studies.After determination of breakage function,selection function,Bond work index,residence time distribution parameters,and Whiten's model parameters for air separators and diaphragms between the two compartments of tube ball mills,performance of the circuits was simulated for given throughputs and feed particle size distribution.Whiten's model parameters were determined by GA(genetic algorithm) toolbox of MATLAB software.Based on implemented models for modeling and simulation,optimization of circuits was carried out.It increased nearly 10.5% and 15.8% in fresh feed capacity input to each tube ball mill.In addition,circulating load ratios of circuits are modified to 118% and 127% from low level of 57% and 22%,respectively,and also cut points of air separators are adjusted at 30 and 40 μm from high range of 53 and 97 μm,respectively.All applications helped in well-operation and energy consumption reduction of equipments.