A Ti3C2Tx-carbon black-acrylic epoxy coating for 304SS bipolar plates with enhanced corrosion resistant and conductivity

A conducting and anticorrosive coating is crucial for the application of metal bipolar plates (BP) in proton exchange membrane fuel cell (PEMFC). In this work, a Ti₃C₂T_x (T)-carbon black (C)-acrylic epoxy (AE) coating is prepared on 304 stainless steel (SS) with enhanced corrosion resistance and conductivity. The corrosion resistance of the T-C-AE coating is investigated in a 0.5 M H₂SO₄ solution as compared to the AE, T, and T-AE coatings. The T-C-AE coated 304SS exhibits the strongest corrosion resistance with the most positive corrosion potential and the lowest corrosion current density of 0.00673 μA cm^?2 in all the samples, while retaining intact and compact surface morphology with the lowest metal ion dissolution even after immersed for 720 h. The addition of Ti₃C₂T_x and carbon black into the AE matrix greatly decreases interfacial contact resistance (ICR), and the T-C-AE coating achieves a low ICR of 15.5 mΩ cm^?2 under 140 N cm^?2 compaction force. The excellent anticorrosion performance is mainly attributed to the physical barrier and the cathodic protection provided by the stacked Ti₃C₂T_x (MXene) nanosheets in the T-C-AE coating. This eco-friendly, conducting, and anticorrosive T-C-AE coating has a good application prospect on SS BP of PEMFC.     

非径向管板焊接接头的超声检测

对AP1000压水堆核电站安全壳贯穿件的非径向管板焊接接头结构特点进行了介绍,并分析其超声检测工艺的重点和难点。通过建立统一的缺陷定位坐标系并结合被检构件的几何特点进行综合分析,推导得出了h值(缺陷回波最高点距套管外壁的距离)的计算方法。为超声检测对这类焊接接头缺陷的准确识别和定位提供了行之有效的方法,为解决这类焊接接头的超声检测技术受限区提供了行之有效的措施。     

Ag nanoparticles-polypyrrole-carbon black/mesoporous TiO2 novel nanocomposite as ultrafast visible-light-driven photocatalyst

Effective design and fabrication of novel visible light-oriented photocatalysts is an existing challenging task that requires further dedicated efforts, and it has been always a main concern among the scientific community. This study deals with the design and fabrication of an extremely active and ultrafast ternary photocatalyst based on Ag nanoparticles, polypyrrole doped carbon black (PPy-C) and mesoporous TiO₂ (m-TiO₂). Sol-gel methodology along with sonication and photodeposition routes have been employed for the successful creation of the ternary framework. Ternary photocatalyst composed of uniform spherical titania nanoparticles (10–15 nm in size) perfectly intermingled with the polymeric linkage of PPy-C. Fruitful creation of unique trio photocatalyst between AgNPs, PPy-C and m-TiO₂ was confirmed by XPS and XRD. FTIR analysis further supports the development of nanocomposite photocatalyst. TEM analysis showed uniform spherical m-TiO₂ nanoparticles (10–15 nm in size) covered by PPy-C with compact nodes like appearance interlocked very well among each other. The newly developed Ag@PPy-C/m-TiO₂ ternary photocatalyst exhibited band gap energy in desired visible range of spectra. The photocatalytic efficiency for all created photocatalysts has been evaluated taking Imidacloprid (insecticide derivative) and methylene blue (MB) dye as target pollutants. The novel Ag@PPy-C/m-TiO₂ photocatalyst produced astonishing results with ultrafast removal of both Imidacloprid as well MB dye under visible light irradiation. The newly created ultrafast Ag@PPy-C/m-TiO₂ photocatalyst has removed 96.0% of the insecticide Imidacloprid in only 25 min with almost ? 2.65 times more efficient than bare m-TiO₂ towards the removal of insecticide derivative. The present report offers a highly encouraging and vastly talented Ag@PPy-C/m-TiO₂ ternary photocatalyst, enabling the ideal management of extremely lethal and notorious chemicals.     

大足黑山羊不同部位肌肉脂肪酸比较研究

为研究大足黑山羊不同部位肌内脂肪、脂肪酸含量和组成方面的差异，以处于相同饲喂条件且体质量相近的6 只5 月龄大足黑山羊为研究对象，分别利用索式抽提法和气相色谱-质谱联用法测定背最长肌和臂三头肌肌内脂肪含量和脂肪酸组成。结果表明：大足黑山羊背最长肌中肌内脂肪含量为3.2%，臂三头肌为3.0%，背最长肌略高于臂三头肌；大足黑山羊背最长肌和臂三头肌各检测出33 种脂肪酸，2 个部位各脂肪酸含量基本一致，但与背最长肌相比，臂三头肌反油酸（C18:1 n-9t）含量较高，而介子酸（C22:1）含量较低；16 种饱和脂肪酸中，仅十七碳酸（C17:0）含量背最长肌极显著高于臂三头肌（P＜0.01）；17 种不饱和脂肪酸中，4 种脂肪酸在不同部位间存在显著差异，背最长肌二十碳烯酸（C20:1）含量极显著高于臂三头肌（P＜0.01），油酸（C18:1 n-9c）含量显著高于臂三头肌（P＜0.05），臂三头肌反油酸（C18:1 n-9t）含量极显著高于背最长肌（P＜0.01）；臂三头肌和背最长肌中不同种类脂肪酸相对含量：单不饱和脂肪酸＞饱和脂肪酸＞多不饱和脂肪酸＞中链脂肪酸，臂三头肌和背最长肌中饱和脂肪酸和单不饱和脂肪酸相对含量之和分别为88.4%和86.3%；臂三头肌和背最长肌中n-3/n-6值相近且均在3.0左右；背最长肌多不饱和脂肪酸与饱和脂肪酸含量比值（P/S）为0.45，臂三头肌P/S值为0.41，背最长肌高于臂三头肌。说明不同部位大足黑山羊肉脂肪酸含量及组成存在差异，并可能在一定程度上影响肉的风味及营养价值。     

Investigation of the influence of iron-containing abrasives on the corrosion behaviour of the aluminium alloy AlSi1.2Mg0.4

The corrosion resistance of aluminium surfaces is closely linked to the surface state after a grinding process. For years, iron-containing abrasive materials were suspected to lead to increased corrosion susceptibility after processing of aluminium surfaces. To prove a possible correlation between the iron content of an abrasive and the corrosion behaviour of aluminium components, scientific investigations and experimentally practical corrosion tests are necessary. For the current investigation, specimens of a technical Al-Si alloy from the same batch were used. The test specimens were mechanically ground with various resin-bonded model abrasives containing different iron contents. The performed corrosion tests did not reveal a negative influence of the different iron-containing abrasives on the corrosion behaviour of the Al–Si alloy. However, the most sensitive measuring method (electrochemical noise) showed differences in the surface activity depending on the type of abrasive.     

基于LDRA TBrun软件集成测试的研究

Integration testing is to ensure that each functional module is correct and performs well, so that these modules can be as- sembled together to work well. The manual testing method of the tester alone cannot effectively evaluate the tested aviation soft- ware, and the use of advanced automated testing tools can overcome these difficulties. This paper introduces the method and process of integration testing with Testbed suite tool TBrun through a practical test project.     

起重机械防碰装置试验系统的设计

防碰装置是起重机械重要的安全防护装置,其性能质量直接关系到人员和设备安全。常规的防碰装置性能试验方法难以保证试验数据的精度和可靠性。针对防碰装置的工作特点和试验要求,从试验原理、系统结构、运行逻辑等方面入手,设计一套能模拟防碰装置实际运行工况,自动进行性能试验和数据采集处理,精度高、重复性好的试验系统,可以有效提升防碰装置检测能力。     

饮料中柠檬黄的测定能力验证情况分析

目的了解和评价全国食品检验系统实验室对人工合成着色剂柠檬黄的检测能力,促进各参加实验室在人工合成着色剂检测方面能力的提高。方法在全国食检系统内组织开展饮料中柠檬黄的测定能力验证项目。制备阳性及空白考核样品,完成均匀性稳定性实验,确保样品满足能力验证发样要求,向167家参加实验室随机发放样品,并在规定时间内回收有效数据,采用稳健(Robust)统计进行分析并给出结论。结果在反馈结果的163家实验室中,16家实验室的检测结果为不满意,8家实验室的检测结果为可疑,139家实验室的检测结果为满意,满意率为85.3%。结论本次能力验证活动中,85.3%的满意率表明绝大部分实验室具备饮料中柠檬黄的检测能力。但依然存在部分实验室的评价结果为可疑或不满意的情况,应分析原因并进一步提高实验室的检测能力。