Numerical simulation on the rheo-diecasting of the semi-solid A356 aluminum alloy

The effect of injection pressure, piston velocity, and the forming temperature of semisolid slurry on the filling behavior of the semi-solid A356 aluminum alloy was investigated by simulation methods. The simulation results show that these processing parameters have an important effect on the filling behavior of the semi-solid A356 aluminum alloy. The slurry flows steadily in the cavity when the injection pressure, the piston velocity, and the forming temperature are low, but it is prone to turbulent flow w...     

微粒群优化和区域生长结合的彩色图像分割算法

提出了一种微粒群优化和区域生长相结合的彩色图像分割算法,以彩色图像直方图中自适应搜索到的峰值作为像素种子。由于搜索像素种子点是按密度进行,计算量小,大幅度提高了算法的计算速度,同时克服了传统区域生长方法不能自动选择种子且容易导致过分割的局限性。实验表明：该方法提高了图像分割速度,并可以准确地分割出目标,是一种有效的图像分割方法。     

压实填土随浸水时间增长强度降低规律研究

水利、交通、建筑等土木工程建设中,压实填土是经常遇到的建设内容,压实填土遇降雨、水浸时,含水率逐渐增大,颗粒间结合水逐渐增厚,结晶盐类逐渐溶解,压实填土粘聚力逐渐减小,土体强度逐渐降低,严重时导致工程破坏.使用不同级配土体,按各自最优含水率击实,制备多组试样,分批次在不同条件下浸水,测定土体强度随浸水时间的变化数值,分析其变化规律、土体级配与土体强度随浸水时间降低的关系、产生原因,给出了较好的压实土种类,为水利、交通、建筑工程压实填土浸水后预防工程事故提供参考.     

新型就仓干燥技术处理高水分玉米种子的实仓应用效果分析

应用低温缓速均匀通风基本原理设计的设备系统,对堆高2 m的58 t散装高水分玉米种子(籽粒,入仓平均水分20.2%)进行就仓干燥处理.经过累计301.5 h的间断式处理,按预定降水目标12.5%,结果以40多个固定和临时取样点的跟踪检测,实际降低到平均12.4%(最高12.9%,最低11.7%);对水分检测结果的离散性分析表明,在无霉变、无损伤、无抛洒、不影响种子活性的前提下,能够达到精确控制调节粮食水分的要求.     

麻疯树籽粕中毒蛋白的提取

研究了溶剂浸提法提取麻疯树籽饼粕中麻疯树毒蛋白时的各影响因素,考察了提取时间、提取温度、pH值、缓冲液浓度和无机盐浓度对麻疯树毒蛋白溶出的影响.结果表明:提取液pH值是影响麻疯树毒蛋白溶出的最重要因素,提取时间、缓冲液浓度及盐浓度对提取也有一定影响.通过正交试验获得最佳提取条件:提取时间3 h,提取温度25℃,提取液为浓度0.4 mol/L的NaCl溶液,pH=7.在此条件下得到的毒蛋白占去壳种仁的质量分数的0.39%.     

Biodiesel development from high acid value polanga seed oil and performance evaluation in a CI engine

Non-edible filtered high viscous (72 cSt at 40 °C) and high acid value (44 mg KOH/gm) polanga (Calophyllum inophyllum L.) oil based mono esters (biodiesel) produced by triple stage transesterification process and blended with high speed diesel (HSD) were tested for their use as a substitute fuel of diesel in a single cylinder diesel engine. HSD and polanga oil methyl ester (POME) fuel blends (20%, 40%, 60%, 80%, and 100%) were used for conducting the short-term engine performance tests at varying loads (0%, 20%, 40%, 60%, 80%, and 100%). Tests were carried out over entire range of engine operation at varying conditions of speed and load. The brake specific fuel consumption (BSFC) and brake thermal efficiency (BTE) were calculated from the recorded data. The engine performance parameters such as fuel consumption, thermal efficiency, exhaust gas temperature and exhaust emissions (CO, CO₂, HC, NO_x, and O₂) were recorded. The optimum engine operating condition based on lower brake specific fuel consumption and higher brake thermal efficiency was observed at 100% load for neat biodiesel. From emission point of view the neat POME was found to be the best fuel as it showed lesser exhaust emission as compared to HSD.     

Chinese melon (Momordica charantia L.) seed: Composition and potential use

Chinese melon (Momordica charantia L.), also known as bitter gourd, is a tropical crop, grown throughout Asian countries for use as food and medicinals. In 1993, four cultivars of Chinese melon were grown in Mississippi and the seeds were collected. Oil contents of the seeds ranged from 41 to 45% and the oils contained 63–68% eleostearic acid and 22–27% stearic acid. Industrially important tung oil, a “fast-drying oil” used in paints and varnishes, contains 90% eleostearic and 2–3% stearic acid. The ratio of stearic to eleostearic in Chinese melon seed oil is ten times greater than that in tung oil. The higher ratio should reduce the rate of drying and crosslinking and could be advantageous in the paint industry. The defatted meals contained 52–61% protein and would be a good source of methionine.     

基于计数排序的最小种子集贪心算法

网络最小种子集问题与网络影响最大化问题相关,研究的是对于具有节点阈值的网络,构造网络的最小节点子集,使得如果这个子集中的节点是活的,则在给定的影响传播模型下整个网络都受到影响。为此提出了新的贪心算法,以节点的度与阈值的差为关键值对网络节点进行计数排序,然后取值最小的节点进行处理。新算法在时间复杂度上改进了基于最小堆的种子点选取算法。在简单多数阈值模型上针对经典的无标度网络得到了所构造的种子集规模上界。实验在随机生成网络和一些实际网络数据集上进行,结果表明所提方法的有效性,特别在无标度网络上生成的种子集具有比相关算法更小的规模。     

低成本聚丙烯压滤机过滤板的研制

通过对聚丙烯（PP）进行各种改性的探讨，分析了各种改性PP用作压滤机过滤板的优缺点，重点考察了碳酸钙的表面处理，含量及粒径对材料性能的影响。从而确定了用填充改性PP帛备压滤过滤板的最佳方法。并以PP为基体，超细重质碳酸钙为填料，帛备了压滤机过滤板，所研制的压滤机过滤板不但性能可靠，而且大大降低了生长成本，具有显著的经济效益。     

基于意图—槽位注意机制的医疗咨询意图理解与实体抽取算法

自然语言理解作为医疗对话中的关键组成部分,包含意图识别和槽位填充两个重要的子任务。为建立意图和槽位的相互促进关系,实现语义层次上的建模,提出了基于意图—槽位注意机制的医疗咨询意图理解与实体抽取算法。首先,收集医疗信息网站上用户的医疗健康提问文本,基于医学知识归纳总结了24类医疗意图和5种槽位,构建了中文医疗健康咨询数据集（CMISD-UQS）;然后,引入槽位选通机制来建模意图和槽位向量之间的显式关系,设计了意图—槽位注意机制层,构建了意图上下文信息以意图标签向量方式嵌入到槽位的方式。在公共数据集ATIS和SNIPS上与八种代表性算法的对比实验结果表明,所提算法优于所比较的八种算法;在CMISD-UQS数据集上的测试结果表明,所提算法的医疗意图识别准确率、语义槽填充F1值、句子级语义框架准确率分别为78.1%、94.9%和73.2%,均优于其他对比算法。