Structural design and mechanical performance test of densely drilled glass fiber reinforced plastics pipelines

Densely drilled glass fiber reinforced plastic (GFRP) pipelines are thought to be of prosperous future in sand control in oilfield. However, due to the fact that the mechanical properties of the perforated GFRP pipelines are always lowered remarkably, some structural design work must be done. Several key factors, including the winding angle of the glass fibers, the mechanical properties of the matrix resin were considered carefully in advance. The tensile strength, compressive strength and the screw-crushing properties of the GFRP pipelines were measured subsequently. Most of the test results were coincided with what had been expected during structural design. The winding angle was proved to be an important factor in improving the mechanical performance of perforated GFRP pipelines. Mechanical property of the matrix resin was another important factor in determining the performance of the GFRP pipelines. The effect of the hole-size and distribution on the mechanical performance of the heavily perforated GFRP pipelines always depended on the winding angle and matrix resin. In the screw-crushing test, the GFRP pipelines showed to be easily destroyed by the slowly rotating drill head.     

Effects of phospholipid hydroperoxide glutathione peroxidase mRNA expression on meat quality of <Emphasis Type=Italic>M. longissimus dorsi</Emphasis> in pigs

Antioxidant enzymes protect muscle tissues against oxidation from reactive oxygen species and increase the stability of the muscle. Phospholipid hydroperoxide glutathione peroxidase (GPx4) is an important antioxidant enzyme in muscle tissue. So the aim of this study was to identify the effects of mRNA expression level of GPx4 gene on meat quality properties in Longissimus dorsi of three pig breeds. Total 36 pigs (12 pigs for each breed) were used to measure the meat quality properties and to analyze the expression levels of GPx4 gene by quantitative real-time PCR. The results showed that meat quality, GPx4 activity, and GPx4 mRNA levels were affected by pig breeds. There were the lowest expressible moisture, drip loss, and cooking loss in Laiwu Pig among the three breeds, and also there were the highest GPx4 activity and the expression levels of GPx4 gene in Laiwu Pig compared with the other two pig breeds. Analysis of meat samples divergent for water-holding capacity identified highly negative associations between expressions levels of GPx4 gene and expressible moisture, drip loss and cooking loss. These results suggest that the higher mRNA expression level of GPx4 gene up-regulate the water-holding capacity and the activity of GPx4, and the expression of GPx4 gene plays an important role in physiological changes related to the meat quality properties and the mechanisms of the antioxidant ion of meat.     

基于深度学习的采摘机器人目标识别定位算法

为了提升采摘机器人对果实的识别准确率以及定位定精度,提出一种基于深度学习Faster-RCNN框架的采摘机器人目标识别和定位算法.首先采用卷积神经网络VGG16模型提取输入图像的特性信息,并利用区域提议网络RPN生成含有目标的候选框,通过引入自适应候选框数的方法有效提升了算法性能,然后利用多任务损失函数对目标进行分类识...     

A model relating tool torque and its associated power and specific energy to rotation and forward speeds during friction stir welding/processing

Torque (M) is a very important quantity in the friction stir welding (FSW) process but a satisfactory model relating M to the two major FSW parameters, rotation speed (ω) and forward speed (v), has not been well developed. In this work, a better model of the form, M=f(ω, v), was sought. Experimentally, FSW of an aluminium alloy was conducted over a wide range of ω and v values and M was measured. An exponential decay function has been found to fit all the M versus ω data well and is meaningful for any ω value. The effect of v on M can approximately be accounted for through linearly relating the model parameters to v. The model allows for a detailed evaluation of the sensitivity of M to changes in ω and v. The model decay and the pre-exponential parameters need to be adjusted to make predictions for different aluminium alloys in the low ω range. Both the model and experimental data demonstrate a diminishing alloy effect on material flow resistance as ω increases. Furthermore, models of tool power (P_Tool) and specific energy (E_s) can be derived from the model for M and give predictions that are also meaningful over the entire range of ω values. Finally, the dependences of P_Tool and E_s on ω and v and the relationship between E_s and the processing zone temperature will be discussed.     

High response organic ultraviolet photodetector based on bis (2-methyl-8-quinolinato)-4-phenylphenolate aluminum

We report highly efficient visible-blind ultraviolet photodetectors based on 1,3,5-tris(3-methylphenyl-phenylamino)-triphenyamine (m-MTDATA) as donor and bis(2-methyl-8-quinolinato)-4-phenylphenolate aluminum (BAlq) as acceptor. Strong photoluminescence quenching of m-MTDATA by BAlq is observed manifesting the efficient photoinduced charge transfer occurs between m-MTDATA and BAlq. The optimized device exhibits a photocurrent of 172 μA/cm² at ?14 V under an illumination of 365 nm UV light irradiation with an intensity of 0.691 mW/cm², corresponding to a responsivity of 248 mA/W. We attribute the high response to the efficient electron transfer from the donor to the acceptor, the feasible level alignment match and the high carrier mobility of photoresponsive materials.     

国内外己内酰胺的供需现状及发展前景

分析了国内外己内酰胺的生产消费现状及发展前景,提出了发展我国己内酰胺生产的建议。     

塑料小盖注射模设计

通过对塑料小盖的工艺分析,合理地确定了模具中的浇注系统、脱模机构以及冷却系统等结构形式。并介绍了该模具的工作过程以及模具制造和装配过程中的要点。     

特产的定位路径

<正>北京的糖葫芦,涪陵的榨菜,山西的陈醋,金华的火腿,黄岩的蜜橘……这些驰名中外的特产可谓数不胜数,但都是产地品牌,而不是产品品牌。目前全国的特产有很多生产厂家,大厂、小厂、手工作坊均有,但是品牌鱼龙混杂,产品质量良莠不齐,让消费者很难辨认。一旦一个厂家出现问题,会对整个产地品牌产生伤害。2003年金华的毒火腿事件就是证明。     

加强行业标准化工作 促进煤炭工业科学发展

总结了近5年来煤炭行业标准制定修订情况,分析了煤炭行业标准在煤炭工业快速稳定发展中的地位和作用。探讨了煤炭行业标准化工作中存在的主要问题,并有针对性地提出今后煤炭行业标准化工作重点的建议。