等强度梁动应变冲击试验测试仪的控制系统

介绍了等强度梁动应变冲击试验测试仪器的控制系统设计和其中一些关键技术。动态和静态信号分别采用不同处理方法：对于动态信号，经仪表放大器、低通滤波器以及12位逐次逼近型A／D转换转换器输入中央处理单元，软件上采用平滑滤波算法来消除干扰信号；对于静态信号，经仪表放大器、直接输入12位双积分型12位A/D转换器，软件上采用平均滤波算法来消除干扰。另外还采用了最新电源监控芯片X5045既可以监控程序防止程序跑飞，又可以在掉电时保存重要参数和数据。     

折线先张法预应力工字梁受力性能试验

为克服直线先张法的预应力筋不能弯折而使桥梁跨径受限,以30 m折线先张法预应力混凝土工字梁为研究对象,研究折线先张法工字梁在弹塑性阶段的应力、变形、裂缝和承载能力,进行理论计算及静载破坏试验,并利用Midas Civil有限元软件的psc程序计算,对比静载试验与有限元模型。结果表明：在弹性阶段,荷载与混凝土应变、挠度的试验曲线均呈线性变化;跨中截面和3L/8截面为梁体应变的危险截面;加载至1～1.4倍的开裂荷载时,L/4、L/2截面挠度变化仍基本处于线性增大状态,斜率约为按弹性阶段计算的2倍;当出现第一条裂缝后,随着荷载的增加,裂缝继续向工字梁腹板延伸,跨中底板及腹板附近出现新裂缝,但未出现梁端剪切裂缝或破损现象。预应力混凝土工字梁的应力、挠度校验系数均小于1,表明折线先张法工字梁的抗弯和抗剪承载能力、强度、刚度、抗裂性均满足设计及规范要求。     

松墨天牛优良白僵菌菌株筛选

从浙江省松墨天牛１松毛虫等不同寄主上采集了６个球孢白僵菌自然菌株,并从日本及国内主要生产厂家收集６个菌株,共计１２个菌株。经过对其营养生长、产孢量、孢子活力、孢子耐热能力、孢子抗紫外线能力和室内对松墨天牛幼虫毒力等指标的研究,结果发现采自象山松墨天牛幼虫的菌株Ｂｘｓ和来自日本松墨天牛的菌株Ｆ－２６３对松墨天牛幼虫的毒力最强,并且上述各指标均表现优良。尤其是Ｂｘｓ菌株,其产孢量和抗紫外线能力大大高于     

Highly stretchable,sensitive and wide linear responsive fabric-based strain sensors with a self-segregated carbon nanotube (CNT)/Polydimethylsiloxane (PDMS) coating

Flexible strain sensors have received increasing attention with the development of wearable electronic devices. However, integrating wide strain detection range, high sensitivity while maintaining relatively wide linear response range for such sensor system still remain a challenge. A fabric based flexible sensor (S-CNT/PDMS-F) was designed and fabricated, and the sensor can simultaneously achieve high sensitivity, wide linear response and strain detection range by combining self-segregated carbon nanotube (CNT)/polydimethylsiloxane (PDMS) composites and elastic medical bandage. It has been observed that this new sensor system can achieve a high sensitivity with a gauge factor of 615, a large linear responsive range of 0–100% strain (R² ?= ?0.993) and a wide strain detection range of ～ 200%, which is superior to almost all the reported CNT/PDMS flexible strain sensors. Compared to the similar fabric based strain sensor system deploying non self-segregated structure (C-CNT/PDMS-F), our S-CNT/PDMS-F demonstrates higher electrical conductivity and lower electrical percolation threshold and response time of 55 ?ms, as well as more stable and repeatable performance under cyclic loading conditions. The capability of the sensors in monitoring physiological activities and weight distribution has also been demonstrated.     

原油价格预测：近30年研究回顾和未来展望

原油价格预测是能源经济和资产定价领域的重要研究方向，其研究热度正逐年上升。文系统梳理了30多年来原油价格预测领域的相关文献，从以下4个方面进行了现有文献的综述与讨论：(1)原油价格预测对象；(2)原油价格的影响因素、预测变量和理论基础；(3)原油价格预测方法与模型；(4)原油价格预测的实践意义。最后，结合当前热点和未来发展趋势给出值得进一步研究的方向：一是使用气候风险等新的预测信息；二是充分利用多源异构数据；三是提高机器学习等预测模型的可解释性。     

褐香椿种芽生产试验

香椿是我国人民历来喜食用的一种木本蔬菜。作者于2000年4月、5月两次采用豆芽生产方式对褐香椿种子进行种芽生产实验,取得了很好的效果,生产出来的种芽品质可口宜人,特别是不占土地、设备和技术简单,生物效率高,一年四季都可高速生产无污染的绿色保健食品,具有较高开发利用价值。