大直径聚晶金刚石复合片的合成及表征

利用国产六面顶压机,合成出了直径为51mm的国内最大的聚晶金刚石复合片。超声波微成像分析表明,样品无大批量分层、裂纹、金刚石厚度不均等缺陷。切削试验显示,在切削硬质合金时,样品与国外同类产品性能相当。     

CVD金刚石切削工具

阐述金刚石切削工具在机加工中的重要作用和CVD金刚石的优异性能以及CVD金刚石切削工具的形式。对CVD金刚石薄膜切削工具和CVD金刚石厚膜切削工具的特点和应用范围进行了分析对比，并指出存在问题和发展前景。     

金刚石超精密切削技术探讨

金刚石超精密切削技术是超精密加工技术的重要组成部分,直接影响尖端技术和国防工业的发展。金刚石超精密切削技术涉及的方面有很多,文章对刀具的选用、刀具制造技术以及超精密加工切削用量、加工机床等是金刚石超精密切削的关键技术进行了研究与探讨。图2表1参10     

梯度硬质合金金刚石涂层刀具的切削性能研究

梯度硬质合金是金刚石涂层产品新的基体材料.现场切削实验可有效、直观地评价金刚石涂层刀具的性能。采用梯度硬质合金金刚石涂层可转位刀片车削硅铝合金,研究切削参数对加工面质量及刀具磨损的影响。结果表明,梯度硬质合金金刚石涂层刀具加工的工件面粗糙度低、光泽度好且不黏刀。切削20min后,加工面粗糙度最佳值为1.57μm,刀具后刀面磨损为0.1mm,远小于失效判据VB=0.30mm,是很好的金刚石涂层产品基体材料。     

单晶金刚石在高端技术领域的应用

阐述单晶金刚石在高端技术领域的应用,包括微型超精金刚石切削工具如加工成形随意曲率超细槽的方形立铣刀,用于三维表面微凹坑和任意曲率面加工的超精纳微型球形立铣刀,以剃削和快速切削加工直线超细槽的切削工具,此外还有人造单晶金刚石制作的高压水力喷射切割装置的喷射喉管,以及单晶金刚石制作的微型光学元件,并述及大单晶CVD金刚石的潜在用途。     

金刚石刀具化学磨损的预防

单晶金刚石刀具因其化学磨损严重,不适用于微切削加工铁基材料。为了保护金刚石刀具免受化学磨损,可将切削刀具沉积硬质涂层,以防止金刚石与工件材料直接接触。本研究则利用磁控溅射工艺在金刚石刀具上沉积T iN、T iA lN和A lN涂层。经过优化工艺参数,所沉积涂层的化学成分接近化学计量,表面非常光滑,晶粒很细,硬度高且附着强度大。虽然刃口半径因涂层略有增加,但对微切削加工来说仍可容忍。在试验切削条件下,与参比未涂层金刚石刀具相比,T iA lN涂层金刚石刀具磨损的减少高达50%。     

多晶金刚石刀具的现状及发展研究

文章介绍了多晶金刚石刀具的发展及性能特点,并简要叙述了多晶金刚石刀具的制造工艺、加工工艺参数,以及时效机理等。如今,加工制造技术的发展使刀具技术朝着高速切削,高精度,干切削和磨削的方向发展,使得超硬刀具的使用效率高,稳定性高。     

CVD金刚石薄膜与硬质合金的结合力的改善途径

化学气相沉积金刚石涂层硬质合金工具综合了金刚石和硬质合金的优异性能,可广泛应用于难加工材料的切削、电子工业等诸多领域。制造金刚石薄膜涂层工具的关键在于增强金刚石膜与硬质合金基体间的结合力。文章综述了增强化学气相沉积金刚石膜与硬质合金基体结合力的多种措施。     

UPC刀具加工不同工件材料的磨损状态差异

金刚石刀具的热化学磨损状态根据被加工材料种类的不同而有很大差异。在超精密车床上使用刀尖角130°的直线切削刃超精金刚石车刀对无氧铜和纯铝进行端面车削后,刀尖的磨损状态表明,切削无氧铜的刀具前刀面产生了月牙洼磨损,但切削刃棱线仍保持锋利状态;切削纯铝的刀具切削刃棱线磨损变为圆弧刃,但前刀面未发现月牙洼磨损。从这些磨损状态的差异可以看出各不相同的磨损机理：切削铜时,     

金刚石切削工具发展前景述评

材料科学的发展以及新材料在各工业和科技中应用领域的扩大促进了金刚石切削工具的发展。以翔实的应用实例评述不同金刚石切削工具在各种金属材料和非金属材料加工中的性能以及在某些使用中的局限性。     

牛肉肌纤维直径和结缔组织含量与嫩度相关性研究

分别选取来自安徽大明牧业牛场的18、36、54、72月龄西门塔尔杂交公牛各6头,在同一商业屠宰场进行屠宰。测定其背最长肌肌纤维直径、羟脯氨酸含量和剪切力。结果表明：背最长肌剪切力随着肌纤维直径的增大而增大,随着羟脯氨酸含量的增加而增大;背最长肌剪切力与肌纤维直径、羟脯氨酸含量有较高的相关性;剪切力与肌纤维直径和羟脯氨酸含量的相关系数r分别为0.833和0.835,为强正相关;建立的剪切力与肌纤维直径的指数回归方程为y＝1.162e0.034x,R2＝0.932,说明回归方程拟合较好;建立的剪切力与羟脯氨酸含量的指数回归方程为y＝1.793e27.430x,R2＝0.947,说明回归方程拟合较好。     

Eine alternative kontinuierliche Preßtechnologie zur Herstellung von Holzwerkstoffen

A new continuous pressing system for the manufacture of wood composites was developed by the German company Dieffenbacher, and a first plant has started production with this press at the end of 1990 and 1991 respectively. Practical experiences with the Conti Power System are referred to as well as to the main characteristics such as the particular flexibility in the adjustment of pressure, the independent set of heating circuits, an especially thick stell belt, a system of large diameter rolling rods and the very easy maintenance features.     

隧道斜井施工用钢丝绳断裂事故分析

某单位隧道斜井出碴采用的6×19+FC-24.5mm1550MPa左交互捻钢丝绳,负载运行274d后,钢丝绳发生整绳破断。分析表明钢丝绳为疲劳断裂,断裂原因是钢丝绳的直径选择不当,受力状态严重恶化造成的。选择足够安全系数的钢丝绳、加强钢丝绳维护检查和钢丝绳疲劳程度的监测,是安全运行的重要保证。     

Pig muscle fibre characteristics as a source of variation in eating quality

Despite the application of the MLC Blueprint specifications there is still unacceptable variation in meat eating quality. Evidence from the literature suggests that the intrinsic characteristics of the muscle may be an important source of variation, but there is no indication as to what extent these characteristics may explain the residual variation in eating quality. The purpose of the present study was to quantify the role of muscle fibre characteristics in accounting for eating quality variability. In the study, evaluation of samples from 125 pigs from eight breeding company populations indicated that fibre characteristics, particularly the diameter of the fast twitch oxidative glycolytic fibres, contributed to variation in instrumental texture of meat. In addition, the data suggest that there are genetic differences in fibre type distribution which can be used to segregate populations.     

Experimental assessment of the pull-out strength of single rods bonded in glulam parallel to the grain

The use of glued-in rods is a very efficient technique for connecting timber elements either in restoration or in the construction of new structures. It has been used for about 30 years in several countries all over the world. However, despite multiple research efforts, there is still a lack of consensus on a standard method to design such connections and to compute their carrying capacity. If a company wishes to include this system in its design possibilities, it has to validate it by testing. This paper reports on the results of a test program aiming at situating the glued-in rod connecting technique of the Belgian glulam company Lamcol with the main existing design methods. A total of 60 specimens of glued-in rod joints were tested in pull-pull configuration. The varying parameters were the anchoring length and the rod diameter. The rods were threaded steel bars. They were bonded into glulam Norway spruce lamellas parallel to the grain by means of an epoxy-type adhesive injection. The preparation of the specimens was kept very simple, as close as possible to the actual production technique of the company. The main difference with previously reported test results comes from the failure modes. Failure occurred mainly by splitting of the wood element along the anchorage although the standard recommendations for the distance between the rods and the edges of the specimens were respected. Two strength models are derived empirically from the analysis of the test results which are also compared with predictions from computation methods proposed in the literature.     

论家具设计公司的运作模式与发展

从2000年深圳景初家具设计有限公司成立起,中国已涌现出不少家具设计公司。本文分析了该类设计公司的职能,探讨了其在现时的两类主要运作方式,找出了家具设计是创意产生、知识型产品等观点,并找出了当前家具设计公司自我完善的几条途径。     

基于变型设计和成型工艺优化的饮料瓶模具快速设计方法

在分析饮料瓶模具设计过程的基础上,结合零部件库的构建、变型设计技术和饮料瓶成型工艺优化技术提出了饮料瓶模具快速设计方法。结合实际,开发了一个饮料瓶模具快速设计系统,并介绍了企业的应用情况。应用表明,该方法可以缩短饮料瓶模具设计周期,节约设计成本。图9参9     

天然纤维的加工设备

A．H．Meyer集团公司根据各个用户的要求并运用最新技术开发生产新设备，公司具有悠久的加工天然纤维的历史，通过与兄弟公司合作积累了许多经验，并帮助公司生产低能高效的机器设备，经济和生态学观点是公司哲学的重要组成部分。     

百年芬美意 芬芳跨世纪——访芬美意公司中国地区食用香精部总经理曾淑苹博士

<正> 瑞士是一个地处欧洲中部,永久中立的小国。然而,她的红十字国旗作为世界卫生组织的标志,却飞出国界,在不同民族、不同肤色的亿万个白衣天使的簇拥下,在我们这个星球上为人类传递着无尽的爱和福音。记者要采访的就是瑞士一家国际香精香料公司——芬美意。 瑞士向世界奉献和平,芬美意为人类酿造芬芳,和平与芬芳难道不是人类在21世纪的追求与企盼?在上海,迎接记者的是芬美意公司中国地区食用香精部总经理,高雅而不失东方神韵的曾淑苹博士。(曾:曾淑苹;记:记者)     

Prevalence of Salmonella on retail broiler chicken meat carcasses in Colombia

A cross-sectional study was performed to estimate the prevalence of Salmonella on retail market chicken carcasses in Colombia. A total of 1,003 broiler chicken carcasses from 23 departments (one city per department) were collected via a stratified sampling method. Carcass rinses were tested for the presence of Salmonella by conventional culture methods. Salmonella strains were isolated from 27 % of the carcasses sampled. Logistic regression analysis was used to determine potential risk factors for Salmonella contamination associated with the chicken production system (conventional versus free-range), storage condition (chilled versus frozen), retail store type (supermarket, independent, and wet market), poultry company (integrated company versus nonintegrated company), and socioeconomic stratum. Chickens from a nonintegrated poultry company were associated with a significantly (P < 0.05) greater risk of Salmonella contamination (odds ratio, 2.0) than were chickens from an integrated company. Chilled chickens had a significantly (P < 0.05) higher risk of Salmonella contamination (odds ratio, 4.3) than did frozen chicken carcasses.