方盒形件分块变压边力成形过程中的破裂临界压边力计算——方盒形件分块变压边力成形研究之二

在参考文献 [1]力学建模及解析的基础上 ,以分散性失稳理论为依据 ,考虑厚向异性 ,求得方盒形件分块变压边力成形过程中出现壁裂和底裂的判别条件 ,推导出两种情况下极限压边力计算公式 ,并设计算例 ,分析验证。

冷轧板数控渐进成形技术试验研究

为满足区域电机电器产业在结构调整与转型升级中对冲压件的小批量生产和新产品试制要求。以企业常用的冷轧板为研究对象,采用负板料数控渐进成形方法,加工出方锥台件和变成形角度的方锥台件,通过分析得出冷轧板的成形极限角为66°。对电机消声器外壳的成形性进行分析,得出该零件可采用单道次板料数控渐进成形方法成形,并进行了实验验证。

舰船肋骨高精度成形技术的研究

本文介绍了舰船肋骨高精度成形技术的研究内容、研究成果和成果转化 。

Combined use of Ad-hENDO-VEGI_(151) and Dexamethasone for prevention and treatment of keratoplasty rejection:an experimental study

Objective：To evaluate the probability and efficacy of endostatin-vascular endothelial growth inhibitor （VEGI） recombinant adenoviruses combined with dexamethasone on suppressing heterolamellar corneal transplantation rejection. Methods： Heterolamellar corneal transplantation models were established in 64 New Zealand rabbits, which were randomized into 4 groups of 16 rabbits each. After the transplantation, all the 64 right eyes were injected subconjunctively with 0.2 ml saline （saline group）, 0. 1 ml AdCA13-hENDO-VEGI151 plus 0. 1 ml saline （AdCA13-hENDO-VEGI151 group）, 0. 1 ml Dexamethasone （DXM） plus 0.1 ml saline （DXM group）, 0. 1 ml AdCA13-hENDO-VEGI151 plus 0. 1 ml DXM （AdCA13-hENDO-VEGI151 combined with DXM group） with one time each 3 days for 10 times. Graft survival and ocular surface were observed for 6 weeks. The fusion protein expression was detected by immunohistochemistry 6 weeks after transplantation. Results： Both the CNV index, rejection index and the xenograft rejection rate in the AdCA13-hENDO-VEGI151 combined with DXM group were statistically lower than those in other groups. AdCA13-hENDO-VEGI151 combined with DXM group： 1. 375 0±0. 500 0, 2. 750 0 ±1. 843 9 and 6.25% respectively 6 week after keratoplasty; Saline group： 3. 437 5±0. 512 3, 8. 812 5± 1. 108 7, 100. 00%; AdCA13-hENDO-VEGI151 group： 2. 312 5±0. 478 7, 5. 625 0±0. 957 4, 62.50%; DXM group： 3. 000 0±0. 816 5, 5. 562 5±1. 315 0, 56.25% （P〈0.01）. Immunohistochemical staining showed the fusion protein expressed mainly in corneal epithelium. Conclusion： The fusion protein expressed by the recombinant adenovirus has significant effect on inhibiting neovascularization after heterolamellar corneal transplantation. The topical application of AdCA13-hENDO-VEGI151 combined with DXM suppressed effectively the postoperative xenograft rejection rate of heterolamellar corneal transplantation.

Numerical study on forming complex fitting body on end of integrated stainless steel pipe without welds

It is necessary to use the integrated stainless steel pipe having two fitting bodies without welds while train travelling at high speed. In order to form this type of integrated stainless steel pipe, the method of preforming combined finish forming process is developed. The preforming process is characterized by flaring combined upsetting for left fitting body which is like a flange, and is characterized by tube axial compressive process under die constraint for right fitting body which is like a double-wall pipe. The finite element simulations of the processes are carried out by software package DEFORM, and the results indicate that: 1) left or right fitting body can be formed by a two-step forming process without folding and under-filling defects; 2) by using two-step forming, strain and stress in left fitting body are larger than those in right fitting body, and deformation in right fitting body is more homogenous than the deformation in left fitting body; 3) two or more preforming steps may be needed for left fitting body considering the distributions of strain and stress.

Researching Classroom-Based Assessment for Formative Purposes

This article aims to help teacher-researchers engage in empirical research on classroom-based assessment for formative purposes. We will first introduce the key features of classroom-based formative assessment(CBFA), and analyze the research questions asked in round-one projects funded by the Fund for Assessment Research(FAR) in Foreign Language Education in China. Next, we will illustrate how some research questions can be answered by analyzing a video-taped lesson from a round-one FAR project. We conclude by calling for more teacher-led research and argue that research on CBFA by teachers will not only produce valid interpretations and applicable findings, but also constitute a viable model for teacher professional development.

New development on additive manufacturing technology and its applications

Additive manufacturing technology has been developed in Xi＇ an Jiaotong University for almost 20 years. Up to now~ it is still attracting the attentions of the researchers or manufacturers all over the world. Some in- novative processes and frontier application research are all being conducted here to catch up with the new develop- ment of this technology. In the paper, newly developed processes, such as ultraviolet-light emitting diode （UV- LED） stereolithography, ceramic stereolithography, and direct metal forming, were described. Some results of the frontier application researches, such as indirect fabrication of ceramic casting mould, wind-tunnel-testing models, photonic crystals and metamatcrials, were also briefly reviewed.

Experiment study of forming and activation of conductive film of the surface conduction electron emitter display

The forming and activation of the conductive films are studied experimentally. The power supply, a peak-to-peak 30 V triangle profile voltage, is applied to three kinds of conductive films that contain 0.25%, 0.5%, and 1% of palladium respectively. In the experiments we contrasted the values of related parameter in different conditions, observed the lumi- nous spots on the anode panel, dealt with and analyzed the related data, and compared the positions and the amount of the luminous spots. We have gotten the conclusion that there is a threshold value Uth. The emission current Ie will increase rapidly when the device voltage Uf is greater than Uth. And the emission current Ie could be controlled by the device voltage Uf. The positions of the luminous spots on the anode panel are related with the device voltage Uf.

Bulk Glassy Alloys: Historical Development and Current Research

This paper reviews the development of current research in bulk glassy alloys by focusing on the trigger point for the synthesis of the first bulk glassy alloys by the conventional mold casting method. This review covers the background, discovery, characteristics, and applications of bulk glassy alloys, as well as recent topics regarding them. Applications of bulk glassy alloys have been expanding, particularly for Fe-based bulk glassy alloys, due to their unique properties, high glass-forming ability, and low cost. In the near future, the engineering importance of bulk glassy alloys is expected to increase steadily, and continuous interest in these novel metallic materials for basic science research is anticipated.

Recent studies on mechanical properties of recycled aggregate concrete in China-A review

Numerous experimental and theoretical studies on recycled aggregate concrete have been carried out in China in the past 10 years.This paper provides a comprehensive review of the related findings of research on the mechanical properties of RAC in China.The influences of the RCA on the strength and deformation characteristics of concrete,the statistical characteristics for the strength of RAC,fracture energy,stress-strain relationships under uniaxial compression,uniaxial tension as well as pure shear,and the residual strength of RAC after exposure to high temperatures,the bond between RAC and different kinds of steel rebar were also reviewed.Furthermore,some recent studies on the numerical simulation of the failure mechanism for RAC at the meso-structure level were discussed.

TESTING FOR LONG MEMORY IN THE ASIAN FOREIGN EXCHANGE RATES

In this paper, we use the plug-in and Whittle methods that are based on spectral regression analysis to test for the long memory property in 12 Asian/dollar daily exchange rates. The results according to the plug-in method show that with the exception of Chinese renminbi all series may have long memory properties. The results based on the Whittle method, on the other hand, show that only Japanese yen and Malaysian ringgit may have long memory properties. It is well known that inference about the differencing parameter, d, in presence of structural break in a series entails considerable difficulties. Therefore, given the financial crisis of 1997-1998 in Asia, further tests for unravelling of the memory property and presence of structural break in the exchange rate series are required.

Numerical study of ambient pressure for laser-induced bubble near a rigid boundary

The dynamics of the laser-induced bubble at different ambient pressures was numerically studied by Finite Volume Method (FVM). The velocity of the bubble wall, the liquid jet velocity at collapse, and the pressure of the water hammer while the liquid jet impacting onto the boundary are found to increase nonlinearly with increasing ambient pressure. The collapse time and the formation time of the liquid jet are found to decrease nonlinearly with increasing ambient pressure. The ratios of the jet formation time to the collapse time, and the displacement of the bubble center to the maximal radius while the jet formation stay invariant when ambient pressure changes. These ratios are independent of ambient pressure.

Studying the genetic basis of speciation in high gene flow marine invertebrates

A growing number of genes responsible for reproductive incompatibilities between species （barrier loci） exhibit the signals of positive selection. However, the possibility that genes experiencing positive selection diverge early in speciation and commonly cause reproductive incompatibilities has not been systematically investigated on a genome-wide scale. Here, I outline a research program for studying the genetic basis of speciation in broadcast spawning marine invertebrates that uses a priori genome-wide information on a large, unbiased sample of genes tested for positive selection. A targeted sequence capture approach is proposed that scores single-nucleotide polymorphisms （SNPs） in widely separated species populations at an early stage of allopatric divergence. The targeted capture of both coding and non-coding sequences enables SNPs to be characterized at known locations across the genome and at genes with known selective or neutral histories. The neutral coding and non-coding SNPs provide robust background distributions for identifying Fsm-outliers within genes that can, in principle, identify specific mutations experiencing diversifying selection. If natural hybridization occurs between species, the neutral coding and noncoding SNPs can provide a neutral admixture model for genomic clines analyses aimed at finding genes exhibiting strong blocks to introgression. Strongylocentrotid sea urchins are used as a model system to outline the approach but it can be used for any group that has a complete reference genome available.

Outcome ofJudet＇s quadricepsplasty for knee contractures and the effect of local infiltration of epinephrine on reducing blood loss

Objective： To evaluate the effectiveness ofJudet＇s quadricepsplasty for treatment of knee contractures and to identify the effect of local infiltration of epinephrine on blood loss associated with this procedure. Methods： A retrospective cohort study was conducted in which all cases of knee contractures managed with Judet＇s quadricepsplasty from 1st January 2009 to 31st December 2013 were included and were divided into two groups. The epinephrine group included patients who were infiltrated with diluted epinephrine （1：400,000） along with xylocaine, around the operative field 15 min prior to the incision time, while the control group did not receive any infiltration. Judet＇s outcome, blood loss, drop in he- moglobin and required blood transfusion were noted for all patients and compared between both groups. Results： Most common preceding pathology identified for the development of knee contractures was periarticular fracture while ilizarov application was the most common etiology. Both groups were found similar in all preoperative characteristics except preoperative flexion contracture （p = 0.02）. All func- tional outcome measures including Judet＇s outcome were similar in both groups. In contrast, duration of surgery （p = 0.01）, blood loss （p = 0.02）, drop in hemoglobin （p = 0.01） and number of transfusions （p = 0.03） were significantly reduced in epinephrine group. Conclusion： Judet＇s quadricepsplasty is a useful procedure to increase the range of motion of rigid knees and local infiltration of epinephrine is effective in decreasing the amount of subsequent blood loss and transfusion requirements.