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71.
Hydrogenation of CO2 to form methanol utilizing green hydrogen is a promising route to realizing carbon neutrality. However, the development of catalyst with high activity and selectivity to methanol from the CO2 hydrogenation is still a challenge due to the chemical inertness of CO2 and its characteristics of multi-path conversion. Herein, a series of highly active carbon-confining molybdenum sulfide (MoS2@C) catalysts were prepared by the in-situ pyrolysis method. In comparison with the bulk MoS2 and MoS2/C, the stronger interaction between MoS2 and the carbon layer was clearly generated. Under the optimized reaction conditions, MoS2@C showed better catalytic performance and long-term stability. The MoS2@C catalyst could sustain around 32.4% conversion of CO2 with 94.8% selectivity of MeOH for at least 150 h.  相似文献   
72.
The uncontrolled formation of lithium (Li) dendrites and the unnecessary consumption of electrolyte during the Li plating/stripping process have been major obst...  相似文献   
73.
74.
Objective: The aim of our study was to investigate the effect of Cinobufacini injection on the proliferation and cell cycle of human hepatoma HepG-2 cells. Methods: Cell proliferation was assessed by MTT assay, cell cycle distributionwas detected by the flow cytometry (FCM). The expression of Cyclin A, CDK2 mRNA levels were examined by RT-PCR.Quantitative colorimetric assay was used to analyze Cyclin NCDK2 activity in HepG-2 cells. Results: Cinobufacini injection significantly inhibited HepG-2 cells proliferation in dose- and time-dependent ways; FCM analysis showed Cinobufacini injection induced cell cycle arrest at S phase; RT-PCR assay showed Cinobufacini injection down-regulated Cyclin A, CDK2expression at mRNA levels; Quantitative colorimetric assay showed Cinobufacini injection deceased Cyclin A/CDK2 activity in HepG-2 cells. Conclusion: Cinobufacini injection can inhibit human hepatoma HepG-2 cells growth, induce cell apoptosis and induce cell cycle arrest at S phase, the mechanism of which might be partly related to the down-regulation of Cyclin A,CDK2 mRNA expression and inhibition of Cyclin A/CDK2 activity.  相似文献   
75.
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.  相似文献   
76.
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.  相似文献   
77.
王芳  崔丹丹  李林 《电子测量技术》2021,44(20):162-167
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...  相似文献   
78.
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 (PTool) and specific energy (Es) 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 PTool and Es on ω and v and the relationship between Es and the processing zone temperature will be discussed.  相似文献   
79.
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.  相似文献   
80.
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。  相似文献   
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