A combined pseudoreplica-immunochemical technique for research and diagnostic virology.

Pseudoreplica and immunochemical techniques were combined in a single protocol for identification of virus in research and clinical specimens. Stock preparations of vesicular stomatitis virus (VSV), cytomegalovirus (CMV), and herpes simplex virus (HSV) were used to develop the technique. Traditional pseudoreplicas of viral stock solutions were prepared but not negatively stained. The virus was then immunolabeled in two stages. Virus-specific polyclonal antisera were used in the first stage; colloidal gold conjugated antibodies were used as indicator antibody in the second stage. After immunolabeling, the grids were negatively stained. As a demonstration of the clinical usefulness of this approach, it was employed to antenatally identify human parvovirus B19 particles in ascites from a 22 week gestational fetus with nonimmune hydrops fetalis. The combined pseudoreplica-immunochemical approach offers several advantages over both the pseudoreplica and immunochemical methods when used in isolation. Advantages include relative purification of samples, concentration of virus, morphological preservation, and enhanced diagnostic specificity.     

Effects of B100 Biodiesel on Injector and Pump Piston

In this study, the effects of biodiesel use in a diesel engine on an injector and fuel injection pump piston were experimentally analyzed. To this end, two engines with the same technical specifications were used; petroleum diesel was used in one of the engines and 100% (B100) biodiesel was used in the other engine. After the engines were run for 200 h, their injectors and pump pistons were examined and compared by performing scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis measurements. SEM and EDX analyses showed significant structural changes on the surfaces of the injector nozzle and pump piston in the event that B100 is used.     

钢包回转台液压旋转接头渗漏原因分析及改进

通过对钢包回转台液压旋转接头工作原理和结构的研究,分析其液压油渗漏的原因,采用角接触球轴承替代原使用的深沟球轴承,以及采用新型孔用回转方形圈替代原使用的孔用格莱圈,对液压旋转接头进行了改造,减少了钢包回转台液压旋转接头的渗漏油对环境的污染,提高了使用可靠性.     

Performance of Used Engine Oil as Gear-Cutting Oil

In Japan, the lubricating oil used for the internal combustion engine of passenger cars is usually exchanged for fresh oil after running a distance in the range from 3,000 to 10,000 km. Refining of the used engine oil is very costly because friction-reducing additives containing sulfur, phosphorus, etc., are included in the oil. Therefore, wasted engine oil (used engine oil) is burned in many cases. This investigation was conducted to effectively re-use wasted engine oil without chemical refining. Performance of used engine oil as a gear-cutting oil was examined by conducting five kinds of experiments: (a) chemical analyses of the oils, (b) measurements of friction coefficients on the four-ball tester, (c) tool wear tests using a lathe, (d) tool life tests using a gear-cutting machine, and (e) accuracy and surface finish of the cut gears. In contrast to general expectations, longer tool lives were obtained when the used engine oils were used instead of a high-grade gear-cutting oil. The reason for this was discussed and it was concluded that used engine oil may be used as a high-performance gear-cutting oil if health risks for workers are removed.     

Surfaces of cryosections: is cryosectioning ‘cutting’ or ‘fracturing’?

In order to determine if cryosectioning involves ‘fracturing’ or ‘cutting’ we examined the surfaces obtained in cryosectioning by a metal-replicating procedure commonly used in freeze-fracture microscopy. Platinum-carbon replicas were made of the surfaces of both the sections and the complementary surfaces of the sample stubs from which the sections were cut. When samples of frozen red cells were sectioned at ?120°C with large knife advancements (1 μm), the chips produced did not resemble sections. Membrane fracture faces, produced by splitting of the lipid bilayer, were found in electron micrographs of replicas of the sample stubs. This demonstrates that a cryomicrotome can be used to produce large intact replicas. When dull knives were used with small knife advancements, both smooth and fractured regions were found. The sections produced with dull knives had a snowflake appearance in the light microscope. When sharp knives were used with small advancements (0·1 μm), replicas of the surfaces were free of fracture faces and the sections had a cellophane-like appearance in the light microscope. Therefore, in cryosectioning a different process other than ‘fracturing’ is responsible. This ‘cutting’ process may be micromelting of a superficial layer by the mechanism of melting-point depression from the pressure exerted by the sharp edge of the knife.     

浅谈用于汽车生产中不同轻量化材料的加工工艺

阐述了常用汽车生产轻量化材料的加工工艺方法,并详细介绍了其工艺分类、工艺原理以及工艺特点,指出了加工工艺的技术难点,最后提出了汽车轻量化研究的热点和发展趋势,对轻量化设计具有一定的参考作用。     

基于组合神经网络的风机轮毂处短期风速预测

综合考虑风电机组轮毂处历史风速规律和近期数值气象预报风速变化,对时间尺度为6 h以内的风电机组轮毂处风速进行预测。为提高风速骤变情况下短期风速预测精度,提出一种新的组合神经网络。针对信号分解后的不同频率子序列特点,采用深度卷积神经网络和门控循环递归单元对趋势项子序列进行预测,用建立的Elman循环递归神经网络对细节项子序列进行预测。利用降尺度后的数值气象预报风速来判断风速骤变拐点,采用广义自回归条件异方差模型对非拐点风速预测值进行修正。最后,利用新疆某风电场实际风速数据进行实验,以平均绝对误差、均方误差及平均绝对百分比误差计算确定性预测精度,以覆盖率和区间宽度计算不确定性预测精度,结果验证了所提算法的有效性。     

湿法测定矿石中金的分析方法和措施探讨

本文结合笔者在长期的生产实践中遇到的影响各种矿石中金测定的因素,提出了一些提高分析质量的方法及措施。对如何提高氢醌滴定分析中试样均匀性进行研究,认为机械摩擦的时间有利于提高试样的均匀性,对不同种类的矿石试样采取不同方法进行分解,对矿石试样的富集与分离采用活性炭和聚氨脂泡沫塑料来进行,滴定过程的控制采用温度法,对溶液的保存也提出了一些措施。     

Measurement by vertical scanning profilometry of resorption volume and lacunae depth caused by osteoclasts on dentine slices

The resorption pit assay is classically used to evaluate osteoclast activity on bone or dentine slices that can be eroded by these cells. Two different types of cells were generated from peripheral blood mononuclear cells cultured in the presence of M-CSF + sRANKL or with M-CSF + LPS. At the end of the culture period (21 days), cells were discarded and the dentine slices stained with toluidine blue and examined with an NT9100 Wyco vertical scanning profilometer. The images of the dentine surface were corrected for tilt and the eroded volume was calculated on the whole images. The depth of the eroded pits was determined. The data files were used to reconstruct the surface of the slices by standardizing the ground level to compare both conditions. Osteoclasts generated with M-CSF + sRANKL were capable of resorbing a more important volume than those generated with M-CSF + LPS. In addition, the formers were able to resorb the dentine matrix more deeply. Data provided by the microscope were used to reconstruct three-dimensional images of the dentine slices with pseudo colours varying with the depth of erosion. Vertical scanning profilometry, a technique used to measure the roughness of polished or etched surfaces in metallurgic industry, can be used to accurately measure the eroded volume and the mean erosion depth done by osteoclasts in the resorption pit assay.     

Numerical simulation of vapor volume fraction in a vertical channel under low-pressure conditions

This numerical study involved investigating void behavior under low-pressure subcooled flow boiling by using an Eulerian approach (two-fluid model). In the simulation, a vertical pipe with a length of 0.15 m and diameter of 0.01229 m was considered. Different levels of uniform wall heat flux, mass flux, and inlet subcooling temperature were applied although a constant pressure of 1.65 bar was used for all the simulations. A sensitivity study of the empirical coefficients used to access the predictive capacity of the existing mass transfer models was conducted. Thus, the k-epsilon model was used for the turbulence of the fluid. The axial vapor volume fraction profile, liquid temperature is compared at the operating pressure. Furthermore, the most sensitive flow characteristics of the channel were identified. The results indicated that the predictions of numerical phase evolution relative to the experimental observations were in good qualitative agreement with those obtained in extant studies. Additionally, the changes in drag coefficients were helpful in precisely predicting the void fraction. A commercial CFD solver was used for the implementation of the model.     

产品总体设计方案评价与优选的组合决策

为了使决策者在产品总体设计方案评价与优选过程中可以充分表达各种主观决策信息,提出了一种基于模糊优选和证据推理的组合决策模型.在该决策模型中,针对评价中的完全决策信息,尽可能地利用模糊优选中的属性相对优属度进行处理;针对定性评价中不确定和不完全决策信息,采用分布式评价的方式进行决策意见表达,然后用基于证据的推理方式进行处理.在此基础上,利用模糊优选中的决策相对优属度进行方案优选.最后给出了实例.     

Effects of work hardening models on low-cycle fatigue evaluations of coiled tubing with CT-100 steel

In the present study, low-cycle fatigue life of a coiled tubing (CT) with a CT-100 steel was evaluated by using various work hardening models. Tensile and low-cycle fatigue tests were performed, and experimental results were used to calibrate material model constants. A nonlinear finite element model was constructed in the ABAQUS program by using a CT fatigue test machine. During the test cycles, bending and straightening conditions were repeated and histories of strains were collected. The multiaxial low-cycle fatigue life was calculated by using Manson–Coffin relation and Tresca criterion. The kinematic and combined hardening models can be used to evaluate the fatigue life of CT, and their results are conservative compared with the fatigue test results. Results of the present study can be used as the basic data in establishing CT fatigue analysis.     

材料多轴疲劳破坏准则回顾

对多轴疲劳载荷作用下材料的疲劳破坏准则作了系统的回顾，按照用于描述材料疲劳破坏的参量，将多轴疲劳破坏准则划分为三类，应力准则、应变准则、能量准则。分别对这三种准则按多轴比例加载及多轴非比例加载两种情况进行阐述，并进行简单的评述。     

Design and Development of a Miniature Digital Delay Generator for Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is widely used for atomic emission spectroscopy. The delay time is a significant factor that affects the selection of the optimal plasma conditions. In this study, a miniature digital delay generator was designed and built for time-resolved LIBS with a widely adjustable time delay with 0.1 ns resolution. Experimental observations were used to examine and perform a diagnosis study of the delay time accuracy and a series of time-resolved LIBS spectra with satisfactory signal-to-noise ratios were obtained. Therefore, this delay generator is suitable for replacing the widely used delay generators in LIBS instrumentation and may have widespread application in portable instrumentation.     

Tribological Testing of Hemispherical Titanium Pin Lubricated by Novel Palm Oil: Evaluating Anti-Wear and Anti-Friction Properties

In this study, the properties of hip implant material and lubricants were examined using a pin on disc apparatus, to compare the effect of metal-on-metal(Mo M)contact with a bio-lubricant derived from palm oil. The behaviour of the lubricants was observed during the experiments, in which a hemispherical pin was loaded against a rotating disc with a groove. A titanium alloy was used to modify the hemispherical pin and disc. Before and after the experiments, the weight and surface roughness were analysed, to detect any degradation. The results were compared according to the different kinematic viscosities.The wear rates and level of friction with each lubricant were also examined. The lubricant with the highest viscosity had the lowest frictional value. Therefore, developing suitable lubricants has the potential to prolong the lifespan of prostheses or implants used in biomedical applications. The experiments collectively show that lubricants derived from palm oil could be used as efficient bio-lubricants in the future.     

套索驱动空心杆机器人结构设计

介绍了套索传动特性,确定了套索驱动空心杆机器人传动系统。根据不同使用场合和不同需要确定了两套结构方案,并用SolidWorks三维绘图软件分别进行结构设计建模。该机器人连续细长、结构简单轻便,可用于灾后废墟中的搜救、大型结构和设备检测检修等需要在狭小空间内作业的场合。     

A reaming test for cutting fluid evaluation

As an alternative to tapping torque measurement and thread finish evaluation, a reaming test is suggested for the evaluation of the lubricating efficiency of cutting fluids. An investigation was carried out where results from tapping torque measurements were compared with those from measuring torque, feed force, and surface roughness in reaming. Two different tap geometries and two different reamer geometries were used. Technically-pure aluminium was used as the workpiece material and four laboratory water-based cutting fluids as well as a commercial cutting oil were investigated. The results show that lubricants have a significant and similar effect with respect to both tapping torque and reaming torque, when tools with straight flutes are used. In reaming, a more comprehensive picture of lubrication can be obtained if torque measurement is accompanied by determination of the surface roughness. In a subsequent investigation, the reaming torque and roughness test was used to evaluate two different water-based cutting fluids and a neat oil, using austenitic stainless steel as the workpiece material.     

Bearing fault detection utilizing group delay and the Hilbert-Huang transform

Vibration signals measured from a mechanical system are useful to detect system faults. Signal processing has been used to extract fault information in bearing systems. However, a wide vibration signal frequency band often affects the ability to obtain the effective fault features. In addition, a few oscillation components are not useful at the entire frequency band in a vibration signal. By contrast, useful fatigue information can be embedded in the noise oscillation components. Thus, a method to estimate which frequency band contains fault information utilizing group delay was proposed in this paper. Group delay as a measure of phase distortion can indicate the phase structure relationship in the frequency domain between original (with noise) and denoising signals. We used the empirical mode decomposition of a Hilbert-Huang transform to sift the useful intrinsic mode functions based on the results of group delay after determining the valuable frequency band. Finally, envelope analysis and the energy distribution after the Hilbert transform were used to complete the fault diagnosis. The practical bearing fault data, which were divided into inner and outer race faults, were used to verify the efficiency and quality of the proposed method.     

一种针对概率与非概率混合结构可靠性的敏感性分析方法

基于概率与非概率混合不确定模型,提出了一种用于不确定结构的可靠度敏感性分析方法。混合不确定模型中,使用随机分布描述不确定性变量,并给定某些关键分布参数变化区间而非精确值,通过混合可靠性分析方法,获得结构可靠性指标或失效概率区间。给出了六种敏感性指标,定量描述了可靠性区间对区间分布参数的敏感程度。该方法被用于一悬臂梁结构及一实际车门结构的可靠性分析中。