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Fabrication and properties of MEMS compatible energetic arrays based on carbon-based copper azide

APPLIED SURFACE SCIENCE 2022年 577卷 150643-150643页

作者： Liu, xuwen hu, Yan Chen, Bingwen Wei, Hai Su, Jiaxin Yang, Caimin hu, Jiaheng Ye, Yinghua Shen, Ruiqi Nanjing Univ Sci & Technol Sch Chem & Chem Engn Nanjing 210094 Peoples R China Minist Ind & Informat Technol Micronano Energet Devices Key Lab Nanjing 210094 Peoples R China

Copper azide is a promising primary explosive with low toxicity and high energy density. However, due to the extreme electrostatic sensitivity, it does not have many practical applications in the miniaturized pyrotechnics. In this work, we constructed an energetic composite, embedding in oriented carbon nanotubes (CNTs) arrays grown on a silicon substrate, which is compatible with the micmfabrication technique of Micro-Electro-Mechanical Systems (MEMS). Since it has excellent electrical conductivity and mechanical strength, oriented CNTs, as nano-containers of Cu(N-3)(2), can availably reduce the electrostatic sensitivity and bring about the directional output of detonation energy. The oriented CNTs arrays were prepared by magnetron sputtering, anodization and chemical vapor deposition successively. Electrochemical deposition was used to deposit copper nanoparticles in the cavities of CNTs, which were converted into copper azide by subsequent in-situ azide reaction. The electrostatic sensitivity test, thermal performance analysis and laser ignition experiment were conducted on the energetic composite, respectively. The results show that the energetic composite kept safe under an electrostatic stimulation of 3.18 mJ, while original copper azide exploded when subjected to stimulation of 0.05 mJ. The energetic composite opens a new route of introducing hazardous primary explosives into micro-initiators and modern pyrotechnics.

关键词： Composite energetic materials Copper azide Oriented CNTs array Template method Electrochemical deposition Electrostatic safety

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Cation defect engineering in LaCoO3 perovskite as the "Two birds one stone" strategy to enhanced Fenton-like reaction: Regulating Co spin state and optimizing electron transfer ability

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SEPARATION AND PURIFICATION TECHNOLOGY 2024年 337卷

作者： Fang, Zhimo Feng, xuwen Zhou, Zhou Zeng, Zepeng Xia, Yuangu Li, Jihong Liu, Ji hu, Bin Li, Kai Lu, Qiang North China Elect Power Univ Natl Engn Res Ctr New Energy Power Generat Beijing 102206 Peoples R China

The reactive oxygen species (ROS) triggered by peroxymonosulfate (PMS), primarily composed of radicals and nonradicals, can deeply and selectively remove pollutants in complex wastewater. However, the low efficiency of electron transfer and insufficient surface catalytic sites remain the main obstacles to the development of efficient and selective PMS activators. Herein, we constructed ABO(3) perovskite catalysts (LaCoO3) with adjustable La vacancies (V-La) densities through urea introduction. Experiment, characterization, and theoretical calculation jointly revealed that VLa could not only induce electron delocalization in Co site to enhance the Co 3d - O 2p covalency for accelerating ROS (sulfate radicals (SO4 center dot-), singlet oxygen (O-1(2)), and high valent cobalt (Co(IV) = O)) generation, but also trigger the transition of spin-polarization configuration to form Co3+ (t(2g)(5)e(g)(1)) with the intermediate spin state as new active sites for surface-bound PMS* complexes production. The nonradical-dominated and radical-assisted system containing multi-site achieved efficient PMS utilization (95.6 %), excellent decontamination activity (0.753 min(-1)), good mineralization ability (82.7 %), satisfactory acid-base resistance (working pH range 3-11), and environmental robustness for actual water treatment. This study reveals the role of cation vacancy engineering in achieving "Two birds one stone" for PMS activation at the atomic level, which will guide the rational design of Fenton-like catalysts.

关键词： Peroxymonosulfate La vacancies Spin state Delocalization Radicals and nonradicals

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The Pararectus approach in acetabular fractures treatment: functional and radiologcial results

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BMC MUSCULOSKELETAL DISORDERS 2022年第1期23卷 370-370页

作者： Liu, Guoming Chen, Jinli Liang, Chengzhi Zhang, Chengdong Li, xuwen hu, Yanling Qingdao Univ Dept Orthoped Affiliated Hosp Qingdao 266003 Shandong Peoples R China

Background The surgical treatment of complex acetabular fractures is one of the most challenging procedures for orthopedic surgeons. The Pararectus approach, as a reasonable alternative to the existing surgical procedures, was performed for the treatment of acetabular fractures involving the anterior column. This study aimed to evaluate outcome using the Pararectus approach for acetabular fractures involving anterior columns. Methods Thirty-seven with displaced acetabular fractures involving anterior columns were treated between July 2016 and October 2019 using the Pararectus approach. The functional outcomes (using the Merle d Aubigne and Postel scoring system, WOMAC and modified Harris scoring), the quality of surgical reduction (using the Matta criteria), and postoperative complications were assessed during approximately 26 months follow-up period. Results Thirty-seven patients (mean age 53 years, range: 30-71;28 male) underwent surgery. Mean intraoperative blood loss was 840 ml (rang: 400-2000 ml) and mean operating time was 210 min (rang: 140-500 min). The modified Merle d Aubigne score was excellent and good in 27 cases (73%), fair in 6 cases (16%), and poor in 3 cases (11%). The mean score was 88.5 (range:77-96) for the modified Harris Hip scores, and 22 (range:7-35) for the WOMAC scores after operation. Postoperative functional outcomes were significantly improved compared with preoperative outcomes (P < 0.0001). The quality of reduction was anatomical in 21 cases (57%), satisfactory in 9 cases (24%), and unsatisfactory in 7 cases (19%). At follow-up, four patients developed a DVT, and heterotopic bone formation was observed in one patient. The hip osteoarthritis was not observed. Conclusion The Pararectus approach achieved good functional outcomes and anatomical reduction in the treatment of acetabular fractures involving anterior column with minimal access morbidity.

关键词： Acetabular fracture Pararectus approach Surgical exposure Outcome Radiological results

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A novel nano-thermite system with BiOF as fluorine-containing oxidant for enhanced energy release performance

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CHEMICAL ENGINEERING JOURNAL 2023年第1期468卷

作者： Li, Jingwei Liu, xuwen huang, Qian Liu, Feifan Xie, Quanmin hu, Maocong Su, Jiaxin Zhang, Chengchen Zeng, Yuyang Zhu, Chenguang Nanjing Univ Sci & Technol Sch Chem & Chem Engn Nanjing 210094 Peoples R China Jianghan Univ State Key Lab Precis Blasting Wuhan 430113 Peoples R China Shaanxi Appl Phys Chem Res Inst Sci & Technol Appl Phys Chem Lab Xian 710061 Peoples R China

The reduced diffusion distance of nano-thermite results in an exceptionally high energy release rate and intense exothermic reactions upon ignition, which has drawn significant interest from researchers in the field of energetic materials. With the deepening of research, metal fluorides are gradually favored by researchers because of their unique reaction characteristics. This paper presents the synthesis of a new fluorine-containing oxidant, BiOF, and its use in the preparation of a novel nano-thermite with n-Al. BiOF crystals exhibit a unique microscopic morphology and are interlaced into "nanoflower" microspheres, which allows for good interfacial contact between the oxidant and fuel during the recombination process. The resulting n-Al/BiOF system displays excellent ignition and combustion performance, with a combustion temperature higher than the boiling point of its main combustion products, AlF3 and Bi. Compared with n-Al/CuO and n-Al/MoO3 systems, n-Al/BiOF exhibits a higher flame propagation rate under confinement. In addition, the ignition threshold of the n-Al/BiOF system is also smaller than that of the n-Al/CuO and n-Al/MoO3 systems. Furthermore, the paper examines the reaction mechanism of the n-Al/BiOF system through thermal reaction path analysis and combustion and thermal analysis product characterization. The paper discovers a "pre-ignition" reaction mechanism before the ignition temperature, where the strongly electronegative fluorine in BiOF corrodes the Al2O3 shell, promoting the release of aluminum energy. The synergistic and effective interaction between oxygen, fluorine, and fuel aluminum in the n-Al/BiOF system results in efficient energy release performance, making BiOF a promising candidate for n-Al based reactive materials in propellants, explosives, and pyrotechnic products.

关键词： Nano-thermites Nanostructured energetic materials Conformational relationships Fluorinated oxidizing agent Pre-ignition reaction

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基于视觉传感的医疗服务机器人位姿精度测试系统的研制

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中国医疗器械杂志 2022年第2期46卷 206-210页

作者：胡晟吴贤欢陈旭雯上海市医疗器械检验研究院上海市201318 浙江谱麦科技有限公司宁波市315040

针对用于室内环境的医疗服务类机器人,提出了一种基于多目视觉传感对其工作面进行位姿精度测试的方法。该方法采用多目视觉传感器测量固定在服务机器人工作面上的靶标,通过非线性最小二乘法对测量坐标系与机器人基坐标系进行对齐,并融... 详细信息

针对用于室内环境的医疗服务类机器人,提出了一种基于多目视觉传感对其工作面进行位姿精度测试的方法。该方法采用多目视觉传感器测量固定在服务机器人工作面上的靶标,通过非线性最小二乘法对测量坐标系与机器人基坐标系进行对齐,并融合多目图像数据来实现工作面位姿精度测试。最后,将该视觉测试方案在型号为ABIR X8的医疗服务机器人上进行试验验证,依据GB/T 38124 《服务机器人性能测试方法》给出项目和精度指标。该视觉测试系统和方法满足国家标准规定的各项要求。

关键词：医疗服务机器人位姿测试视觉系统

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Time-dependent gut microbiota analysis of juvenile Oreochromis niloticus by dietary supplementation of resveratrol

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ARCHIVES OF MICROBIOLOGY 2020年第1期202卷 43-53页

作者： Zheng, Yao hu, Gengdong Wu, Wei Qiu, Liping Bing, xuwen Chen, Jiazhang Chinese Acad Fishery Sci Fishery Ecoenvironm Monitoring Ctr Lower Reaches Freshwater Fisheries Res Ctr Minist AgrLab Qual & Safety Risk Assessment Aqua 9 Shanshui East Rd Wuxi 214081 Jiangsu Peoples R China Minist Agr Key Lab Control Qual & Safety Aquat Prod Beijing 100141 Peoples R China

To evaluate the changes in bacterial diversity at various time points under resveratrol supplementation, we aimed to investigate the diversification of gut microbiota and the changes in total genetic diversity. We performed 16S rDNA gene sequencing at different time points (15, 30, and 45 days) to analyze the gut microbiota of tilapia. Fusobacteria, Proteobacteria, and Bacteroidetes (15 days) or Cyanobacteria (30 and 45 days) were found to be the three most abundant phyla. Cyanobacteria (15 and 30 days), Proteobacteria (15 days), Firmicutes and Chlamydiae (30 and 45 days), Planctomycetes (30 days), Bacteroidetes, Actinobacteria, and Fusobacteria (45 days) in the 0.05 g/kg RES group increased as compared to that in the controls. Proteobacteria and Cyanobacteria significantly decreased and increased at 30 and 45 days, respectively, while the reverse pattern was observed at 15 days. The Bacteroidetes:Firmicutes and Proteobacteria:Cyanobacteria ratios were significantly increased (15 and 45 days, P < 0.05) and decreased (30 days, P < 0.05). RES supplementation did not affect the richness and diversity of the gut microbiota in tilapia. Our findings may contribute to the development of strategies for the management of diseases.

关键词： Resveratrol GIFT Gut microbiota 16S rDNA Chinese medical herbs

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黄色的蓝藻水华

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湖泊科学 2022年第4期34卷 1384-1391页

作者：宋挺张军毅李旭文朱家民胡俊江苏省无锡环境监测中心无锡214121 江苏省环境监测中心南京210008 上海市青浦区环境监测站上海201799

随着全球气候变化和水体富营养化,在过去几十年中蓝藻水华改变了全球的淡水生态系统.蓝藻因独有的藻蓝蛋白而大多呈现蓝绿色,因此其水华也常称为蓝绿藻水华.然而随着蓝藻水华关注度的不断提升,尤其是监测和研究的不断深入,经常在水体中... 详细信息

随着全球气候变化和水体富营养化,在过去几十年中蓝藻水华改变了全球的淡水生态系统.蓝藻因独有的藻蓝蛋白而大多呈现蓝绿色,因此其水华也常称为蓝绿藻水华.然而随着蓝藻水华关注度的不断提升,尤其是监测和研究的不断深入,经常在水体中发现蓝藻水华出现黄化的现象.例如,太湖出现的黄色蓝藻水华,冬春季以长孢藻属(Dolichospermum)水华为主,夏秋季以微囊藻属(Microcystis)水华为主.即使外观看起来是蓝绿色的蓝藻水华,但仔细观察形成蓝藻水华的群体颗粒,也有部分呈现黄色,反之亦然.实际上,鉴于色素组成的差异性,也许水体中就没有两个颜色完全一致的蓝藻群体颗粒.目前对于黄色的蓝藻水华及其形成机理,国内外鲜有报道和研究.光照和氮限制被认为是最有可能的原因.在关注蓝藻水华黄化的同时,更应该关注和研究这些颜色变化给蓝藻水华及水环境所带来的风险和挑战,尤其是对水生态管理工作的启发和意义.

关键词：蓝藻水华黄色叶绿素类胡萝卜素藻胆蛋白

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Photo-electrocatalytic degradation of cyclic volatile methyl siloxane by ZnO-coated aluminum anode: Optimal parameters, kinetics, and reaction pathways

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SCIENCE OF THE TOTAL ENVIRONMENT 2020年 733卷 139246-139246页

作者： Tang, Jiawei Zhang, Chunhui Wang, Liangliang hu, Yufeng Su, Peidong Wang, Wenqian He, xuwen China Univ Min & Technol Beijing Sch Chem & Environm Engn Beijing 100083 Peoples R China Environm Protect Res Inst Light Ind Beijing 100095 Peoples R China Shenzhen Univ Coll Chem & Environm Engn Shenzhen 518060 Peoples R China Chinese Acad Sci Res Ctr Ecoenvironm Sci Key Lab Drinking Water Sci & Technol Beijing 100085 Peoples R China

Cyclic volatile methylsiloxanes (cVMSs) are widely used in industrial processes and consumer products, which have been reported to be potentially toxic to human health due to their persistence and bioaccumulation. In this study, a novel photo-catalytic zinc oxide (ZnO)-coated aluminum (ZnO@Al) anode was prepared by a facile hydrothermal epitaxial process for the purpose of degrading cVMSs in practical wastewater. Morphological data and compositional analysis showed a compact coating layer that had the characteristic peaks of ZnO. To optimize the degradation process, central composite design combined with response surface methodology was applied to acquire the optimum parameters of cVMSs removal, and results indicated the cVMSs removal efficiency was approximately 63.3% at the conditions of current density = 17.3 mA/cm(2), initial pH of electrolyte = 7.8, plate distance = 18 mm, UV intensity = 90 W, and reaction time = 80 min. Furthermore, the photo-electrocatalytic degradation of cVMSs obeys the pseudo-first order kinetic reaction, and the anode exhibited high durability as the attenuation of cVMSs removal efficiency was <6% after four times reuse. It was also observed that with the application period of the anode was extended, the electroflocculation reaction gradually occurred. The FT-IR of the generated flocs and the total ion gas chromatograms mass spectrometer analysis unraveled the methyl groups in Si-CH3 could be easily attacked by hydroxyl radicals to form the intermediates of monohydroxy substituted products (m/z = 298, 372, and 446) and eventually short-chain carboxylic acids, alkyl radical and silicate. The effective removal of cVMSs by photo-electrocatalytic process using ZnO@Al anode provide significant implication in treatment of practical wastewater.

关键词： Photo-electrocatalysis ZnO Methyl siloxanes RSM

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Preparation and Properties of Pyrotechnic Binder Encapsulated α-AlH3 Composites by Solvent/Anti-solvent Method

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CHEMNANOMAT 2023年第5期9卷

作者： Shi, Zhe Lu, Taojie hu, Yinghui Xu, Yidong Wang, xuwen Wu, Zhuo Zheng, Jian Zhang, Jian Zhu, Zhaoyang Lin, Kaifeng Yang, Yulin Harbin Inst Technol Sch Chem & Chem Engn MIIT Key Lab Crit Mat Technol New Energy Convers & Harbin 150001 Peoples R China Hubei Inst Aerosp Chemotechnol Sci & Technol Aerosp Chem Power Lab Xiangyang 441003 Hubei Peoples R China China Aerosp Sci & Technol Corp 16 Fucheng Rd Beijing 100048 Peoples R China

Alpha-aluminum hydride (a-AlH3) is an ideal energetic combustion agent, but its poor stability and safety limit its application. Therefore, we prepare different composites by using the solvent/anti-solvent method to coat different pyrotechnic binders on the surface of a-AlH3. The vacuum stability test show that the minimum outgassing of Shellac-coated a-AlH3 composite is only 1.2 mL/g at 50 ? for 6 days. Due to the good electrical insulation properties of Viton, Viton-coated a-AlH3 composite have the highest E-50 value of electrostatic sensitivity. In addition, the pyrotechnic binders coating not only protects the activity of the a-AlH3 but also effectively increases its burning rate. Viton-coated a-AlH3 composite have more gaseous products and maximum flame area during combustion. This study illustrates that a-AlH3 coated with pyrotechnic binders is a means to address its stability and safety, laying the foundation for its application in solid propellants.

关键词： Pyrotechnic binder alpha-AlH3 Stability Safety Solid propellant

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基于多尺度卷积编码器的说话人验证网络

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计算机科学 2024年第S01期51卷 75-80页

作者：刘小湖陈德富李俊周旭文胡姗周浩浙江工业大学信息工程学院杭州310023 浙江讯飞智能科技有限公司杭州310000

说话人验证是一种有效的生物身份验证方法,说话人嵌入特征的质量在很大程度上影响着说话人验证系统的性能。最近,Transformer模型在自动语音识别领域展现出了巨大的潜力,但由于Transformer中传统的自注意力机制对局部特征的提取能力较弱... 详细信息

说话人验证是一种有效的生物身份验证方法,说话人嵌入特征的质量在很大程度上影响着说话人验证系统的性能。最近,Transformer模型在自动语音识别领域展现出了巨大的潜力,但由于Transformer中传统的自注意力机制对局部特征的提取能力较弱,难以提取有效的说话人嵌入特征,因此Transformer模型在说话人验证领域的性能难以超越以往的基于卷积网络的模型。为了提高Transformer对局部特征的提取能力,文中提出了一种新的自注意力机制用于Transformer编码器,称为多尺度卷积自注意力编码器(Multi-scale Convolutional Self-Attention Encoder,MCAE)。利用不同尺度的卷积操作来提取多时间尺度信息,并通过融合时域和频域的特征,使模型获得更丰富的局部特征表示,这样的编码器设计对于说话人验证是更有效的。通过实验表明,在3个公开的测试集上,所提方法的综合性能表现更佳。与传统的Transformer编码器相比,MCAE也是更轻量级的,这更有利于模型的应用部署。

关键词：说话人验证说话人嵌入自注意力机制 Transformer编码器多尺度卷积

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