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Verification on Spray Simulation of a Pintle Injector for Liquid Rocket Engine

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Journal of Thermal Science 2016年第1期25卷 90-96页

作者： min Son Kijeong Yu Kanmaniraja Radhakrishnan Bongchul Shin Jaye koo Korea Aerospace University GoyangRepublic of Korea School of Aerospace and Mechanical Engineering Korea Aerospace UniversityGoyangRepublic of Korea

The pintle injector used for a liquid rocket engine is a newly re-attracted injection system famous for its wide throttle ability with high efficiency. The pintle injector has many variations with complex inner structures due to its moving parts. In order to study the rotating flow near the injector tip, which was observed from the cold flow experiment using water and air, a numerical simulation was adopted and a verification of the numerical model was later conducted. For the verification process, three types of experimental data including velocity distributions of gas flows, spray angles and liquid distribution were all compared using simulated results. The numerical simulation was performed using a commercial simulation program with the Eulerian multiphase model and axisymmetric two dimensional grids. The maximum and minimum velocities of gas were within the acceptable range of agreement, however, the spray angles experienced up to 25% error when the momentum ratios were increased. The spray density distributions were quantitatively measured and had good agreement. As a result of this study, it was concluded that the simulation method was properly constructed to study specific flow characteristics of the pintle injector despite having the limitations of two dimensional and coarse grids.

关键词： Spray characteristics Pintle injector Simulation Experiment Liquid rocket engine

Photocatalytic degradation of organic pollutants using green oil palm frond-derived carbon quantum dots/titanium dioxide as multifunctional photocatalysts under visible light radiation

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Chinese Journal of Chemical Engineering 2022年第11期51卷 21-34页

作者： Zeng Wei Heng Woon Chan chong Yean Ling Pang Lan Ching Sim Chai Hoon koo Lee Kong Chian Faculty of Engineering and Science Universiti Tunku Abdul RahmanSungai Long CampusJalan Sungai LongCheras43000 KajangSelangorMalaysia Centre for Photonics and Advanced Materials Research Universiti Tunku Abdul RahmanSungai Long CampusJalan Sungai LongCheras43000 KajangSelangorMalaysia

The present work suggested the use of waste oil palm frond as an alternative precursor for nitrogendoped carbon quantum dots(NCQDs)and proposed a straightforward in-situ hydrothermal method for the preparation of NCQDs/TiO_(2)*** elemental composition,morphological,structural and optical characteristics of NCQDs/TiO_(2)nanocomposites have been comprehensively *** successful grafting of NCQDs on TiO_(2)matrix was confirmed by the formation of Ti AOAC bond and the electronic coupling between theπ-states of NCQDs and the conduction band of TiO_(2).For the first time,the oil palm frond-derived NCQDs/TiO_(2)was adopted in the photodegradation of methylene blue(MB)under visible-light *** a result,the photocatalytic efficiency of NCQDs/TiO_(2)nanocomposites(86.16%)was 2.85 times higher than its counterpart TiO_(2)(30.18%).The enhanced performance of nanocomposites was attributed to the pivotal roles of NCQDs serving as electron mediator and visiblelight ***,the optimal NCQDs loading was determined at 4 ml while the removal efficiency of NCQDs/TiO_(2)-4 was the highest at a catalyst dosage of 1 g.L^(-1)under alkaline *** research work is important as it proposed a new insight to the preparation of biomass-based NCQDs/TiO_(2)using a facile synthetic method,which offers a green and sustainable water remediation technology.

关键词： Oil palm frond biomass N-doped carbon quantum dots Titanium-dioxide In-situ hydrothermal Visible light photocatalysis Methylene blue

A new rotation method for constructing orthogonal Latin hypercube designs

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Science China Mathematics 2023年第4期66卷 839-854页

作者： chong Sheng Jinyu Yang min-Qian Liu National Key Laboratory for Complex Systems Simulation Beijing 100101China School of Statistics and Data Science LPMC&KLMDASRNankai UniversityTianjin 300071China

Latin hypercube designs(LHDs)are very popular in designing computer *** addition,orthogonality is a desirable property for LHDs,as it allows the estimates of the main effects in linear models to be uncorrelated with each other,and is a stepping stone to the space-filling property for fitting Gaussian process *** the available methods for constructing orthogonal Latin hypercube designs(OLHDs),the rotation method is particularly attractive due to its theoretical elegance as well as its contribution to spacefilling properties in low-dimensional *** paper proposes a new rotation method for constructing OLHDs and nearly OLHDs with flexible run sizes that cannot be obtained by existing ***,the resulting OLHDs are improved in terms of the maximin distance criterion and the alias matrices and a new kind of orthogonal designs are *** properties as well as construction algorithms are provided.

关键词： computer experiment factorial design Latin hypercube design maximin distance orthogonality

系统化全程心理干预联合配偶健康教育对乳腺癌患者术后情绪及生活质量的影响

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临床心身疾病杂志 2024年第2期30卷 88-91页

作者：袁敏常静张冲徐升新乡市中心医院河南新乡453000

目的探讨系统化全程心理干预联合配偶健康教育对乳腺癌患者术后情绪及生活质量的影响。方法将86例行乳腺癌手术的患者按照随机数字表法,分为研究组43例,对照组43例。对照组患者给予常规干预。研究组患者在对照组基础上,给予系统化全... 详细信息

目的探讨系统化全程心理干预联合配偶健康教育对乳腺癌患者术后情绪及生活质量的影响。方法将86例行乳腺癌手术的患者按照随机数字表法,分为研究组43例,对照组43例。对照组患者给予常规干预。研究组患者在对照组基础上,给予系统化全程心理干预联合配偶健康教育。于干预前、术后2周末、随访3个月末,采用焦虑自评量表(SAS)、抑郁自评量表(SDS)评定两组患者焦虑及抑郁情绪状况。干预前及随访3个月末,采用生活质量指数问卷(QL-Index)评定两组患者生活质量。随访3个月末,比较两组治疗依从性和护理满意度。结果术后2周末及随访3个月末,两组患者SAS、SDS评分均较干预前降低,且研究组低于对照组(P<0.05或0.01)。随访3个月末,两组患者QL-Index总分及各维度评分均较干预前升高,且研究组高于对照组(P<0.01)。随访3个月末,研究组患者治疗总依从率、护理总满意率均高于对照组(P<0.05或0.01)。结论系统化全程心理干预联合配偶健康教育对乳腺癌患者的干预效果显著,可以有效缓解乳腺癌患者术后的焦虑抑郁情绪,提高患者生活质量、治疗依从性及护理满意度。

关键词：乳腺癌系统化全程心理干预配偶健康教育情绪生活质量

Semisolid A356 alloy feedstock poured through a serpentine channel

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International Journal of minerals,Metallurgy and Materials 2009年第5期16卷 603-607页

作者： Xiao-rong Yang Wei-min Mao chong Gao School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China School of Materials Science and Engineering Taiyuan University of Science and Technology Taiyuan 030024 China

Fine spheroidal and equiaxed nondendritic microstructures required for semisolid casting can be formed through a serpentine pouting channel. Effects of the pouring temperature and the vertical section length of the serpentine pouring channel were studied. The results indicate that both favorable semisolid microstructures of A356 aluminum alloy can be generated by a serpentine pouring channel, and the solid shell inside the channel can be avoided when the pouting temperature is in the range from 660 to 680℃. It is also shown that the vertical section length of the serpentine pouting channel has a significant influence on the microstructure of the feedstock, namely both the microstructure of the feedstock and the microstructure uniformity in the radial direction get worse when the vertical section length is shortened; moreover, the pouring temperature for obtaining the feedstock with suitable microstructure decreases. The relevant mechanisms were discussed.

关键词： semisolid microstructure serpentine channel primary α-A1

A Dynamic Analysis of Body's Mechanism and Physique of Chinese Students of Han Nationality between 1985 and 2005 Investigation and Research Group of Chinese Students' Physique and Health

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中国体育科技 2009年第1期45卷 6-14页

作者： Jiang chong-min China Institute of Sport Science Beijing China

1 Foreword Teenage and adolescence is a critical period for one's physical and mental and the development of his/her *** refers to the capability of body's activity,which in fact is a combined physical capacity of s... 详细信息

关键词：青春期体质体育运动敏捷性

An investigation of the CH_(3)OH and CO selectivity of CO_(2)hydrogenation over Cu-Ce-Zr catalysts

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Frontiers of Chemical Science and Engineering 2022年第6期16卷 950-962页

作者： Weiwei Wang Xiaoyu Zhang min Guo Jianan Li chong Peng School of Life Science and Chemistry MinNan Science and Technology UniversityQuanzhou 362332China Sinochem Quanzhou Petrochemical Co. Ltd.Quanzhou 362100China School of Resources and Environmental Engineering East China University of Science and TechnologyShanghai 200237China Department of Instrument Science and Engineering School of Electronic Information and Electrical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

A series of Cu-Ce-Zr catalysts with different Ce contents are applied to the hydrogenation of CO_(2)to CO/CH3OH *** Cu-Ce-Zr catalyst with 2 wt%Ce loading shows higher CO selectivity(S_(CO)=0.0%-87.8%)from 200-300℃,while the Cu-Ce-Zr catalyst with 8 wt%Ce loading presents higher CO_(2)conversion(X_(CO_(2))=5.4%-15.6%)and CH3OH selectivity(S_(CH_(3)OH)=97.8%-40.6%).The number of hydroxyl groups and solid solution nature play a significant role in changing the reaction *** solid solution enhances the CO_(2)adsorption *** the CO_(2)adsorption step,a larger number of hydroxyl groups over the Cu-Ce-Zr catalyst with 8 wt%Ce loading leads to the production of H-containing adsorption *** the CO_(2)hydrogenation step,a larger number of hydroxyl groups assists in encouraging the further hydrogenation of intermediate species to CH_(3)OH and improving the hydrogenation ***,the Cu-Ce-Zr catalyst with 8 wt%Ce loading favors CH3OH selectivity and CO_(2)activation,while CO is preferred on the Cu-Ce-Zr catalyst with 2 wt%Ce loading,a smaller number of hydroxyl groups and a solid solution ***,high-pressure in situ diffuse reflectance infrared Fourier transform spectroscopy shows that CO is produced from formate decomposition and that both monodentate formate and bidentate formate are active intermediate species of CO_(2)hydrogenation to CH3OH.

关键词： CO_(2)hydrogenation Cu-Ce-Zr hydroxyls CO/CH3OH selectivity

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基于多尺度特征融合的恒星光谱分类方法

光谱学与光谱分析 2024年第8期44卷 2284-2288页

作者：韩博冲宋轶晗赵永恒中国科学院国家天文台北京100101 中国科学院大学北京100049

近年来,随着各大光谱巡天项目的陆续实施,观测得到的天体光谱数据急剧增长。大型光谱巡天项目对光谱的自动分类和分析提出了更高的要求。采用多尺度特征融合模块来获取光谱在不同尺度上的光谱特征,结合CNN网络在分类任务上的优势,提出... 详细信息

近年来,随着各大光谱巡天项目的陆续实施,观测得到的天体光谱数据急剧增长。大型光谱巡天项目对光谱的自动分类和分析提出了更高的要求。采用多尺度特征融合模块来获取光谱在不同尺度上的光谱特征,结合CNN网络在分类任务上的优势,提出了一种基于多尺度特征融合的恒星光谱分类模型(MSFnet),对恒星光谱进行光谱型预测。主要包含多尺度特征融合模块和一个含4个卷积层,2个最大池化层,1个全连接层的卷积神经网络。为了防止出现过拟合的问题,添加了dropout,添加dropout后可以使得模型不依赖某些局部特征,防止过拟合,优化网络的鲁棒性。实验中的数据集均来自LAMOST DR9数据库,在输入到模型进行训练之前,需要对光谱数据进行预处理:重新对光谱进行均匀采样,之后进行最大最小值归一化。该实验的编程语言为python 3.9,引入了Pytorch深度学习框架来构建网络。实验部分为两部分:第一部分是研究卷积神经网络的层数、特征图个数与准确率的关系;第二部分将本文提出的MSFnet模型和Resnet18模型的结果对比实验,从精准率P、召回率R、调和平均值F1、准确率A、运行时间等指标来对两个模型进行对比评估。两个模型所采用的训练集、验证集和测试集均按6∶2∶2的比例进行分配,保证了两个模型的训练样本一致。结果表明,采用4个卷积层、特征图数量为16的卷积神经网络的准确率最高。基于此结论,本文提出了特征融合模块与卷积神经网络的组合MSFnet模型,相对于18层的残差神经网络模型,该模型的结构更简单,在上述指标的表现上也与Resnet18模型相当,并且在A、F、K型光谱的分类效果更好,速度更快。MSFnet模型在测试集上的准确率接近97%,比传统的CNN和Resnet18模型的准确率更高,表明了MSFnet模型有助于提升光谱自动分类的准确性。

关键词：恒星光谱深度学习模型自动分类卷积神经网络

微波法超快制备泡沫镍负载的Co/Zn氧化物增强硫离子氧化反应活性

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化学研究与应用 2024年第9期36卷 2056-2063页

作者：刘崇菠杨茗安琪唐相民虞淑敏高涛涛陈渝赵虔成都大学机械工程学院四川成都610106 重庆新天地环境检测技术有限公司重庆401120 成都大学高等研究院四川成都610106

本文通过微波法超快速制备了泡沫镍(NF)负载的Co/Zn复合氧化物(Co-Zn/NF)。XRD测试表明生成的Co/Zn复合氧化物具有低结晶度。采用线性扫描伏安法(LSV)测试了Co-Zn/NF在碱性条件下的电催化硫离子氧化性能。与泡沫镍负载的单金属氧化物(Co... 详细信息

本文通过微波法超快速制备了泡沫镍(NF)负载的Co/Zn复合氧化物(Co-Zn/NF)。XRD测试表明生成的Co/Zn复合氧化物具有低结晶度。采用线性扫描伏安法(LSV)测试了Co-Zn/NF在碱性条件下的电催化硫离子氧化性能。与泡沫镍负载的单金属氧化物(Co/NF和Zn/NF)相比,Co-Zn/NF表现出更好的催化性能。在含有1 mol·L^(-1)Na2S和1 mol·L^(-1)NaOH的电解液中,Co-Zn/NF达到100 m A·cm^(-2)的电流密度所需的电位仅为0.28 V vs RHE,并且在恒定100 m A·cm^(-2)的电流密度下,长时间工作35小时后仍保持高的催化性能。此外,组装非对称电解槽(阳极:硫离子氧化反应(sulfion oxidation reaction,SOR)用1 mol·L^(-1)Na2S和1mol·L^(-1)NaOH为电解质,阴极:析氢反应(hydrogen evolution reaction,HER)用1 mol·L^(-1)Na OH为电解质)进行双电极硫氧化辅助电解水制氢测试,与传统的碱性电解水相比,达到100 m A·cm^(-2)电流密度所需的能耗降低了46%。本工作为低能耗电化学制氢提供了一种新思路,并证明了SOR耦合HER电解水制氢具有实际应用的可行性。

关键词：微波加热钴/锌复合氧化物硫氧化反应低能耗制氢