2519-T87装甲板焊缝抗弹规律及抗应力腐蚀性能初探

以2519-T87板材为基材,采用MIG焊、电子束焊和搅拌摩擦焊焊接工艺焊接成平板对接结构,对其焊缝及热影响区进行抗弹和应力腐蚀性能研究。试验结果表明:在安全角测试条件下计算焊缝及热影响区的抗弹性能可以达到母材的80%以上,其中采用MIG焊和电子束焊的板材焊缝抗弹性能可达到母材的90%以上;C形环焊缝应力腐蚀性能好于母材,在温度±35℃,5%NaCl盐雾箱内连续喷雾760 h以上不开裂。     

Efficient implementation of a spatial light modulator as a diffractive optical microlens array in a digital Shack-Hartmann wavefront sensor

A traditional Shack-Hartmann wavefront sensor (SHWS) uses a physical microlens array to sample the incoming wavefront into a number of segments and to measure the phase profile over the cross section of a given light beam. We customized a digital SHWS by encoding a spatial light modulator (SLM) with a diffractive optical lens (DOL) pattern to function as a diffractive optical microlens array. This SHWS can offer great flexibility for various applications. Through fast-Fourier-transform (FFT) analysis and experimental investigation, we studied three sampling methods to generate the digitized DOL pattern, and we compared the results. By analyzing the diffraction efficiency of the DOL and the microstructure of the SLM, we proposed three important strategies for the proper implementation of DOLs and DOL arrays with a SLM. Experiments demonstrated that these design rules were necessary and sufficient for generating an efficient DOL and DOL array with a SLM.     

The self-directed learning with technology scale (SDLTS) for young students: An initial development and validation

Research has found self-directed learning to have a significant impact on the long-term societal demands on our future workforce and our perspective on learning. Over the years, many measures have been developed to examine self-directed learning. However, few, if any, were developed for use by young students (age 10–12). In addition, none have included technology as an element in supporting self-directed learning. The aim of this study is to develop and validate a Self-Directed Learning with Technology Scale (SDLTS) for young students. Using two studies, a proposed 6-item SDLTS was piloted with 558 students, aged 10–12 years (mean = 10.18; SD = 0.38) and subsequently tested to establish the validity and reliability of the scale using a separate sample (n = 545). Applying principal component and confirmatory factor analyses, the results of these studies supported a 6-item, two-factor Self-Directed Learning with Technology Scale (SDLTS): Self-Management and Intentional Learning.     

What Has Come out from Phytomedicines and Herbal Edibles for the Treatment of Cancer?

Several modern treatment strategies have been adopted to combat cancer with the aim of minimizing toxicity. Medicinal plant‐based compounds with the potential to treat cancer have been widely studied in preclinical research and have elicited many innovations in cutting‐edge clinical research. In parallel, researchers have eagerly tried to decrease the toxicity of current chemotherapeutic agents either by combining them with herbals or in using herbals alone. The aim of this article is to present an update of medicinal plants and their bioactive compounds, or mere changes in the bioactive compounds, along with herbal edibles, which display efficacy against diverse cancer cells and in anticancer therapy. It describes the basic mechanism(s) of action of phytochemicals used either alone or in combination therapy with other phytochemicals or herbal edibles. This review also highlights the remarkable synergistic effects that arise between certain herbals and chemotherapeutic agents used in oncology. The anticancer phytochemicals used in clinical research are also described; furthermore, we discuss our own experience related to semisynthetic derivatives, which are developed based on phytochemicals. Overall, this compilation is intended to facilitate research and development projects on phytopharmaceuticals for successful anticancer drug discovery.     

Integrated Biorefinery Design with Techno-Economic and Life Cycle Assessment Tools in Polyhydroxyalkanoates Processing

To support and move toward a sustainable bioeconomy, the production of polyhydroxyalkanoates (PHAs) using renewable biomass has acquired more attention. However, expensive biomass pretreatment and low yield of PHAs pose significant disadvantages in its large-scale production. To overcome such limitations, the most recent advances in metabolic engineering strategies used to develop high-performance strains that are leading to a new manufacturing concept converting biomass to PHAs with co-products such as amino acids, proteins, biohydrogen, biosurfactants, and various fine chemicals are critically summarized. This review article presents a comprehensive roadmap that highlights the integrated biorefinery strategies, lifecycle analysis, and techno-economic assessment for sustainable and economic PHAs production. Finally, current and future challenges that must be addressed to transfer this technology to real-world applications are reviewed.     

Palm oil‐based unsaturated polyester: Activation energy and swelling properties

In this study, unsaturated polyester (UP) resin based on palm oil was synthesized. Palm oil monoglyceride (POMG) was obtained by alchoholysis process of palm oil at 230°C for 3 h. Then, POMG was treated with maleic anhydride (MA) at different ratio of POMG:MA to produce UP resin. The products were then characterized using Fourier transform infrared (FTIR) spectrometer and proton nuclear magnetic resonance (¹H‐NMR) spectrometer. FTIR and ¹H‐NMR spectrum analyses confirmed that the unsaturated group of MA was chemically attached to POMG. The activation energy of POMG/MA reaction was also studied. The results showed that the ratio of reactants and the presence of 2‐methylimidazole influenced the activation energy of reaction. The prepared UP resin was mixed with 35% of styrene, 0.3% of cobalt naphthenate, and 1% of methyl ethyl ketone peroxide before it was subjected to curing process. The effect of POMG/MG ratio on swelling properties of the cured UP was studied, and the result indicated that toluene and cured UP resin were compatible. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Antioxidant Activity of Sesamin in Canola Oil

The present study presents the antioxidant activity of sesamin in canola oil compared with that of butylated hydroxytoluene (BHT) by monitoring the oxygen consumption and the decrease in linoleic acid and α-linolenic acid. The oxidation of canola oil was conducted at 35, 60, 90, 120 and 180 °C with addition of 50–400 ppm sesamin. Results from the oxygen consumption test showed that sesamin dose-dependently inhibited the oxidation of canola oil at concentrations of 50–200 ppm at temperatures of 60–180 °C, however, sesamin lost its antioxidant activity at a low temperature of 35 °C. The fatty acid analysis also demonstrated that sesamin at 50, 100 and 200 ppm dose-dependently prevented the oxidation of linoleic acid and α-linolenic acid in canola oil. Both the oxygen consumption and the fatty acid analysis demonstrated sesamin was less effective than BHT as an antioxidant at temperatures of 60–180 °C. It was therefore concluded that sesamin could prevent the lipid oxidation of frying fats and oil, however, its antioxidant activity was not as potent as that of BHT.     

智能化油井套管阴极保护脉冲电源系统设计

脉冲电流阴极保护相比于传统的直流阴极保护具有更均匀的电流密度,更深的穿透性,较小的电流需求等优点,应用脉冲电流阴极保护技术可有效延长油井套管保护深度,使一些深井或超深井的套管得到有效的全线保护。设计了基于双核微控制器SH99F100的智能化油井套管脉冲电流阴极保护电源系统,该系统采用二次逆变电路结构形式作主功率单元,充分利用SH99F100的双核结构及强大的运算能力并结合三层自学习闭环控制算法及自适应数字滤波算法,实现了脉冲电源系统的智能化,同时提升系统的稳定性以及对油井套管的保护效果,实验表明,该系统可输出参数可调的脉冲电流,并可在无人值守的情况下实现自适应控制,可有效促使被保护金属达到保护电位,同时基于三层自学习闭环控制策略可以有效调节脉冲电源的输出参数,使其达到最佳匹配值,并有效降低电能消耗。     

变频调速在精矿回水再利用中的应用

本文介绍了永平铜矿精矿回水泵运用变频器进行调速改造的控制系统、原理、参数设置及应用效果。实践证明 ,变频调速在精矿回水利用中是可行的 ,具有一定的推广价值