切削介质对微细铣刀磨损影响的试验研究

在微细铣削加工中,尚缺乏切削介质对刀具磨损影响的研究.在干切削、浇灌切削液、微量切削液和低温冷风介质下,对6061铝合金进行了微细铣削试验,研究了刀具的磨损形式和机理、不同切削介质对刀具磨损、切削力和表面粗糙度Ra的影响规律.同时,确定出能减小刀具磨损和切削力,提高加工质量的最佳切削介质.结果表明:四种切削介质下刀具磨损的形式不完全相同,粘结磨损与磨粒磨损是造成刀具磨损的主要机理;切削力和表面粗糙度Ra的变化趋势可以辅助判断刀具磨损情况;相比于其它切削介质,微量切削液介质下刀具磨损小,切削力低,工件表面质量好,是微细铣削6061铝合金的最佳切削介质.为深入研究微细铣削刀具磨损和实际加工中选择切削介质有一定的参考价值.     

临近钱塘江大型深基坑支护案例分析

杭州钱塘江北岸钱江新城区块土层渗透性强,深基坑开挖对防渗止水要求较高.在此介绍了地处钱江新城的标志性建筑--浙江财富金融中心基坑的设计方案的确定过程,结合监测资料,得出了一些对类似工程有一定参考意义的结论.     

腐蚀极化曲线的微机测试系统

从腐蚀极化曲线测试的特点及要求出发,用微机和普通恒电位仪组成其测试系统,由计算机通过Ｄ／Ａ转换产生所需的波形电压,代替波形发生器工作,然后用两路Ａ／Ｄ分别采集腐蚀电流和腐蚀电位,并同步显示腐蚀极化曲线,本研究在提高腐蚀极化曲线测试水平方面进行了成功的尝试。     

坡耕地黑土不同密度的土壤有机碳组分的空间分布特征

以东北黑土区一典型漫岗坡耕地为研究对象,通过测定不同侵蚀程度地形部位的轻组、重组有机碳含量,分析土壤侵蚀和沉积过程对土壤不同密度组分有机碳的影响.研究结果表明:在各地形部位,表层土壤(0～20 cm)轻组有机碳(LF-C)含量显著高于亚表层土壤,介于45.3～65.8mg kg-1之间,占土壤总有机碳(TOC)的2.91%～5.87%.侵蚀严重的坡肩部位LF-C、重组有机碳(HF-C)和TOC分别比侵蚀微弱的坡顶部位减少了27.4%、17.2%和18.1%,表明LF-C对土壤侵蚀和沉积过程的响应比土壤总有机碳更为强烈,土壤TOC的减少是土壤LF-C和HF-C减少共同作用的结果.LF-C/TOC的变化和LF-C的变化相似,说明土壤侵蚀优先导致LF-C的损失.各地形部位表层土壤LF-C和微生物量碳显著正相关,在沉积部位富集的LF-C的最终归宿问题还有待于进一步研究,沉积部位仍以惰性的HF-C为主.     

Y2O3加入量对SiCw／ZrO2（Y2O3）复合材料力学性能的影响

采用热压法制备出２０Ｖｏｌ％ＳｉＣ晶须增强的具有不同Ｙ２Ｏ３含量的ＺｒＯ２基复合材料。试验结果表明,含有２ｍｏｌ％Ｙ２Ｏ３的ＳｉＣｗ／ＺｒＯ２（Ｙ２Ｏ３）复合在断过程中有２９％和ｔ－ｍ相变增量,由于ＺｒＯ２相变与ＳｉＣ晶须的共同补强增韧,能获得较佳的力学性能。晶须增韧机制为晶须拔出,晶须桥接与裂纹偏转 。     

Rare Earths, Niobium and Tantalum Minerals in Bayan Obo Ore Deposit and Discussion on Their Genesis

Bayan Obo ore deposit is endowed with and lie hidden in the Proterozoic strata. The localities and occurfences of the minerals in the ore deposit were described. It is obviously that some minerals are strata minerals and some are post-strata minerals. The rare earths, niobium and tantalum minerals are exactly the post-strata minerals. In these minerals the hydrothermal metasomatic phenomena distinctly reveal their metallogenic characteristics. According to tectonic movement, magma activity, mineral paragenesis, hydrothermal metasomatism, geological age and lasting time-scale of metallogenesis, and some other factors, it is supposed that genesis of rare-earths, niobium and tantalum minerals in Bayan Obo ore deposit are closely related with hydrothermal metallogenic solution which is differentiated from silica acid and carbonic acid magma and derived from deep seated source, and then intruded into Proterozoic strata and metasomatized. It is recognized that the metallogenesis of Bayan Obo ore deposit is undergoing a long geological period and many episodes.     

Geochemical Characteristics of Rare Earth Elements in Guposhan Granite Complex and Their Petrogenetic Implication

In this paper the geochemical characteristics of rare earth elements in Guposhan granite complex in NanlingArea,South China,is systematically studied,and the balance of REE distribution in rock-forming minerals,which contain only 21.47～29.71 wt% of total REE in granites,is calculated.The petrogenetic relationship be-tween three different stages of the granites in the complex is discussed,and a geochemical model is suggested forthe formation of granitic magma in early stage by partial melting of the crustal basement rocks containing moreREE than that in the late stage.It shows that a ion-adsorption type of REE deposit could ocuur in the weath-ering crust on the early stage granite.Rb-Sr isotope isochron dating of the first stage medium-coarse-grainedK-feldspar granite shows that its age is 146.5 Ma and initial ~(87)Sr/~(86)Sr ratio is 0.71198.     

信息交换平台设计中交换模式的融合研究

通过分析和比较数据交换平台的几种常用数据交换模式,对交换平台的系统架构、技术实现模式,设计理念和策略进行探讨分析,提出了一种基于XML的数据交换模式,阐述了XML在平台数据交换的数据表示、数据格式转换、数据传输等方面的应用。定义和实现了基于XML的交换数据封装方法相关类接口。给出的方法在广东省航标遥测遥控系统的数据集成与交换中得到了实际应用。     

几种矿物中稀土元素激活剂的阴极发光发射光谱及其地质含义

目前,越来越多的关于阴极发光发射光谱(CES)在研究地质样品上的应用充分说明CES正成为矿物学研究的重要手段,并将迅速扩展到地质研究的各个领域。CES在检测矿物中稀土元索激活剂方面显示其独特的地位,它可以灵敏地给出在可见光     

基于信号强度测距的最小均方误差定位算法

针对室内视距（LOS）和非视距（NLOS）混合环境下的定位精度不高的问题,提出基于信号强度测距的最小均方误差定位（Strength Ranging-based Minimum Mean Square Error localization,SRMSL）算法。SRMSL算法先建立基于超宽带（ultra wide band,UWB）的测距模型,并分别构建在LOS和NLOS环境下的最小均方误差函数,再估计未知节点位置。利用中值函数滤除异常的抽样值,有效辨识NLOS环境下的测距信息。仿真和实验结果表明,提出的SRMSL算法在定位精度方面优于M估计和最小中值平方估计。