圆齿盘变速器的设计与校核

圆齿盘变速器是一种新型齿轮式变速器,它由外齿盘和圆齿盘组成.外齿盘是齿宽很短的圆柱标准齿轮盘,圆齿盘由圆截面(端面)上若干圈轮齿形成.只有一对齿轮传动的圆齿盘变速器可以实现若干级变速.较详细介绍了圆齿盘变速器的设计与校核过程,证明它达到了一般齿轮传动的9级精度指标要求.它样式新颖、结构简单、放置灵活、制造成本低廉,特别...     

锅炉构架安装附件

锅炉构架现场安装时所需要的安装附件,可供锅炉构架设计、安装人员在工作时参考。     

风能-流体升压节流致热效应的实验研究

依据流体节流与摩擦学原理对风能致热效应进行了研究分析与实验。在800W实验装置上，取得了3小时内工质温升近50℃的实验结果，温升曲线与理论分析计算相一致。提出的能量与换热方程，可准确预测风致热装置内工质温升并可作为其换热器的设计依据。分析指出：风力致热的能量利用率高于风力发电的值；风力致热的工质应综合考虑其粘性、定压比热、密度、节流微分效应、温度—饱和蒸汽压力值等因素后优化确定；风轮、液体泵、节流器参数的确定应兼顾额定工况风能利用率及系统的变工况性能.     

基于VTK的三维地质建模方法研究

不规则三角网(TIN),广义三棱柱(GTP)和四面体(TEN)是广泛应用于钻井三维地质建模的数据模型.本文重点研究TIN-GTP-TEN混合建模方法,通过引入VTK作为可视化工具,利用VTK类库中的相关建模函数以及其自身数据结构以点索引号集合来表达任意几何体的特点,对基于钻井数据的传统三维地质建模过程作了一些改进.例如...     

开菲尔分离菌种冻干发酵剂的研究

对从开菲尔粒子中分离到的菌种进行冷冻干燥,并检测冻干后发酵效果,结果显示,当添加保护剂:10%海藻糖+5%山梨醇+10%甘油+5%低聚异麦芽糖,冷冻干燥条件为-62℃,0.03mbar冻干24h时,冻干效果较好。     

超声波处理提取葵花籽油的研究

研究了超声波强度,处理时间,溶剂用量,提取次数对葵花籽油提取率的影响,得出最佳提取参数为:超声波强度为200KW/m2,处理15min,样品与溶剂比(g押mL)1:7,提取2次,提取效果理想。     

Similarity-based online feature selection in content-based image retrieval.

Content-based image retrieval (CBIR) has been more and more important in the last decade, and the gap between high-level semantic concepts and low-level visual features hinders further performance improvement. The problem of online feature selection is critical to really bridge this gap. In this paper, we investigate online feature selection in the relevance feedback learning process to improve the retrieval performance of the region-based image retrieval system. Our contributions are mainly in three areas. 1) A novel feature selection criterion is proposed, which is based on the psychological similarity between the positive and negative training sets. 2) An effective online feature selection algorithm is implemented in a boosting manner to select the most representative features for the current query concept and combine classifiers constructed over the selected features to retrieve images. 3) To apply the proposed feature selection method in region-based image retrieval systems, we propose a novel region-based representation to describe images in a uniform feature space with real-valued fuzzy features. Our system is suitable for online relevance feedback learning in CBIR by meeting the three requirements: learning with small size training set, the intrinsic asymmetry property of training samples, and the fast response requirement. Extensive experiments, including comparisons with many state-of-the-arts, show the effectiveness of our algorithm in improving the retrieval performance and saving the processing time.     

4-乙烯吡啶在稀土钕络合物催化体系下的聚合

本文用稀土化合物的钕系催化剂〔ＮｄＣｌ３－Ａｌ（ｉ－Ｂｕ）３〕于４－乙烯吡啶单体聚合反应进行了研究。考察了Ａｌ－Ｎｄ（摩尔比）、催化剂浓度、反应时间和温度对聚合的影响。     

Experimental investigation of travelling wave power fet with coplanar slow wave electrode system

Power TW FET (travelling wave field effect transistor) models are built and tested according to a previously derived travelling wave interaction theory. The common drain and gate electrode system consisting of coplanar meander slow wave structures are employed. The active length of the device is about 3 guided wave length long. With 21 single FETs connecting between the common drain and the gate line, the output power of the model has increased by more than one order in magnitude as compared to a single FET. A bandwidth of 1:15 and low phase distortion characteristic are obtained. The electric field distribution along the common drain line is then measured and it reveals that a linear combination of a linear increasing travelling wave and a standing wave exists. The experimental results agree well with the theory. The S parameters of the model show useful results.     

镧元素对钨钴硬质合金的影响

通过正交设计实验方法分析了合金元素对钨钴硬质合金YG6性能的影响规律。结果表明镧元素能同时提高YG6硬质合金抗弯强度11％,HRA.硬度值0.2.计算确定出制备过程的最优工艺参数为:烧结温度在1396～1410℃,镧含量在0.92％～1.04％范围内。镧元素对结构的影响表现为:细化WC晶粒。