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Internal Flow Simulation of High-Performance Solid Rockets using a k-ω Turbulence Model

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Journal of Thermal Science 2005年第2期14卷 114-119页

作者： V.R.SANAL KUMAR H.D.kim B.N.RAGHUNANDAN T.SETOGUCHI S.RAGHUNATHAN Andong National University Andong 760-749 KoreaAndong National University Andong 760-749KoreaIndian Institute of Science Bangalore-560 012IndiaSaga University Honjo-machiSaga 840-8502JapanThe Oueen's University of Belfast Northern IrelandUK

For technological reasons many high-performance solid rocket motors are made from segmented propellant grains with non-uniform port geometry. In this paper parametric studies have been carried out to examine the geometric dependence of transient flow features in solid rockets with non-uniform ports. Numerical computations have been carried out in an inert simulator of solid propellant rocket motor with the aid of a standard k-ω turbulence model. It was seen that the damping of the temperature fluctuation is faster in solid rocket with convergent port than with divergent port geometry. We inferred that the damping of the flow fluctuations using the port geometry is a meaningful objective for the suppression and control of the instability and/or pressure/thrust oscillations during the starting transient of solid rockets.

关键词： solid rockets pressure spike instability thrust oscillation turbulent separation.

Study of Commercial Wheat Flour Milling Process:Relation of Flour Yield,Ash and Protein Contents of Flour Mill and Characteristics of Wheat Blend

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食品科学 2006年第11期27卷 146-152页

作者： Y S kim C W Deyoe O K Chung E Haque Department of Grain Science and Industry Kansas State University (KSU) Manhattan 66506 Kansas StateU.S. Key Laboratory ofFood Science and Safety Ministry of Education School of Food Science and Technology Southern YangtzeUniversity Wuxi 214036 China Department of Grain Science and Industry Kansas State University (KSU) Manhattan 66506 Kansas StateU.S. Hard Winter Wheat Quality Laboratory Grain Marketing and Production Research Center AgriculturalResearch Service U.S. Department of Agriculture Manhattan 66502 Kansas State U.S.

The profit margin in the flour milling industry is quite narrow,so high-quality raw materials and efficiency of milling operations are crucial for every company. Many flour mills,especially those which import wheat from other countries and have limited storage space for the different varieties or classes of wheat,can not afford to buy low quality wheat. Consequently,a mathematical model which can test the impact and interactions of raw materials,in technical point of view,would be a useful decision-making tool for the milling industry. A flour miller tests wheat for physical and chemical characteristics,cleanness and soundness. The miller also performs experimental milling,if available,to have some idea how the given wheat will behave during commercial milling. Based on these test results,the miller can only guess the commercial milling results such as flour yields and flour ash and protein contents. Thus,the objective of this study was to develop empirical equations to estimate commercial milling results,using the physical,chemical and experimental milling data of the given wheat blend and also,additionally,flour ash and protein specifications of the end-user. This was done by using the actual commercial milling procedures and their wheat physical,chemical,experimental milling data,and other vital data. Data were collected from a commercial mill located in East Asia that had four production lines and used wheat blend combinations from five different wheat classes,i.e. Hard Red Winter (HRW),Dark Northern Spring (DNS),Soft White (SW),Australian Soft (AS),and Australian Standard White (ASW) wheat to produce over 40 different products. The wheat physical and chemical characteristics included test weight,thousand kernel weight,ash and protein contents. The experimental milling data were straight-grade and patent flour yields,along with patent flour ash and protein contents from a Buhler experimental mill. The commercial milling results included the flour yields of paten

关键词： Study of Commercial Wheat Flour Milling Process SFA BPP

Energy-efficient digital and wireless IC design for wireless smart sensing

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Journal of Semiconductors 2017年第10期38卷 30-38页

作者： Jun Zhou Xiongchuan Huang Chao Wang Tony Tae-Hyoung kim Yong Lian University of Electronic Science and Technology of China Broadcom Singapore University of Technology and Design Nanyang Technological University Shanghai Jiao Tong University

Wireless smart sensing is now widely used in various applications such as health monitoring and structural *** conventional wireless sensor nodes,significant power is consumed in wirelessly transmitting the raw *** sensing adds local intelligence to the sensor node and reduces the amount of wireless data transmission via on-node digital signal *** the total power consumption is reduced compared to conventional wireless sensing,the power consumption of the digital processing becomes as dominant as wireless data *** paper reviews the state-of-the-art energy-efficient digital and wireless IC design techniques for reducing the power consumption of the wireless smart sensor node to prolong battery life and enable self-powered applications.

关键词： energy-efficient digital IC wireless IC wireless smart sensing

Nanowire encapsulation with polymer for electrical isolation and enhanced optical properties

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Nano Research 2017年第8期10卷 2657-2666页

作者： Tuomas Haggren Ali Shah Anton Autere Joona-Pekko Kakko Veer Dhaka Maria kim Teppo Huhtio Zhipei Sun Harri Lipsanen Department of Micro- and Nanosciences Micronova Aalto University P.O. Box 13500 Fl-00076 Aalto Finland

Light management and electrical isolation are essential for the majority of optoelectronic nanowire （NW） devices. Here, we present a cost-effective technique, based on vapor-phase deposition of parylene-C and subsequent annealing, that provides conformal encapsulation, anti-reflective coating, improved optical properties, and electrical insulation for GaAs nanowires. The process presented allows facile encapsulation and insulation that is suitable for any nanowire structure. In particular, the parylene-C encapsulation functions as an efficient antireflection coating for the nanowires, with reflectivity down to 〈1% in the visible spectrum. Furthermore, the parylene-C coating increases photoluminescence intensity, suggesting improved light guiding to the NWs. Finally, based on this process, a NW LED was fabricated, which showed good diode performance and a clear electroluminescence signal. We believe the process can expand the fabrication possibilities and improve the devices. performance of optoelectronic nanowire

关键词： antireflection GaAs parylene-C metallo-organic vapor phase epitaxy (MOVPE) annealing light emitting diode (LED)

还原性气氛制备Zr-B-N纳米复合涂层的结构及性能分析

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表面技术 2022年第9期51卷 83-90,101页

作者：张纪福刘艳梅张涛柯培玲张翔宇丁洋 kim Kwang Ho 王铁钢天津职业技术师范大学天津市高速切削与精密加工重点实验室天津300222 中国科学院宁波材料技术与工程研究所中国科学院海洋新材料与应用技术重点实验室浙江宁波315201 Global Frontier R&D Center for Hybrid Interface Materials Pusan National UniversityBusan 609-735South Korea

目的制备高纯度、超硬、高耐磨的Zr-B-N纳米复合涂层。方法在反应气体中掺入还原性气体H_(2),利用氢元素强还原性去除真空室以及反应气氛中残留的O杂质,采用脉冲直流磁控溅射技术,通过调节N_(2)+H_(2)混合气体流量制备高纯度Zr-B-N涂层... 详细信息

目的制备高纯度、超硬、高耐磨的Zr-B-N纳米复合涂层。方法在反应气体中掺入还原性气体H_(2),利用氢元素强还原性去除真空室以及反应气氛中残留的O杂质,采用脉冲直流磁控溅射技术,通过调节N_(2)+H_(2)混合气体流量制备高纯度Zr-B-N涂层。利用扫描电镜、纳米压痕仪、摩擦磨损试验机等设备对涂层的微观结构、力学性能和摩擦性能进行测试,并分析其变化机理。结果随着N_(2)+H_(2)流量的增加,Zr-B-N涂层内N含量在N_(2)+H_(2)流量为10 mL/min时达到最高。从截面形貌可以看出,涂层结构由粗大的柱状晶逐步转变为玻璃状细小柱状晶结构,涂层更加致密,呈现典型的纳米复合结构。微量H元素的掺入,减少了涂层制备过程中O相关化学键的生成,制备出的Zr-B-N涂层晶粒的生长环境得到改善。在N_(2)+H_(2)流量为10 mL/min时,涂层的硬度和弹性模量达到最大值40.26 GPa和532.98 GPa,临界载荷最大约为60.1 N,摩擦系数较小,为0.72,磨损率在此时最低,为1.12×10^(–5)mm^(3)/(N·m)。结论当N_(2)+H_(2)流量为10 mL/min时,制备出了超硬Zr-B-N纳米复合涂层。适量氢元素的掺入,充分去除真空室内氧杂质,改善了涂层中晶粒的生长环境,有效地提高涂层的硬度及摩擦磨损性能。

关键词：还原性反应气氛 Zr-B-N涂层磁控溅射纳米复合涂层微观结构力学性能

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Alternating current electrolysis:A photoredox catalysis mimic and beyond

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Green Synthesis and Catalysis 2022年第1期3卷 4-10页

作者： Junsong Zhong Chenglin Ding Hyunwoo kim Terry McCallum Keyin Ye Institute of Pharmaceutical Science and Technology College of ChemistryFuzhou UniversityFuzhou 350108China Department of Chemistry and Nanoscience Ewha Womans UniversitySeoul 03760South Korea The Canadian Bank Note Company OttawaOntario 91758Canada State Key Laboratory of Physical Chemistry of Solid Surfaces Xiamen UniversityXiamen 361005China

Alternating current electrolysis(ACE)is an emerging powerful synthetic tool,which principally resembles photoredox catalysis *** periodically alternating polarity feature allows oxidation and reduction processes to take place on the same electrode surface in a well-controlled manner via the fine-tuning of current frequency along with other reaction ***,many challenging transformations in typical direct electrolysis,including constant current electrolysis or constant potential electrolysis,could be achieved via *** recent advances in the organic synthesis using this emerging technology and its advantages over direct electrolysis are highlighted.

关键词： Electrochemistry Photoredox catalysis Alternating current electrolysis Green chemistry Selectivity

Oxyntic gland adenoma endoscopically mimicking a gastric neuroendocrine tumor: A case report

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World Journal of Gastroenterology 2015年第16期21卷 5099-5104页

作者： Tae-In Lee Jae-Young Jang Seungmin kim Jung-Wook kim Young-Woon Chang Youn-Wha kim Division of Gastroenterology Department of Internal MedicineCollege of MedicineKyung Hee University Department of Pathology College of MedicineKyung Hee University

Gastric adenocarcinoma is one of the most common malignancies *** and immunohistologic analyses classify the phenotypes of gastric adenocarcinoma into several groups based on the variable clinical and pathologic features.A new and rare variant of gastric adenocarcinoma with chief cell differentiation(GA-CCD)has recently been *** reporting the distinct clinicopathologic characteristics proposed the term oxyntic gland polyp/adenoma because of the benign nature of the ***,GA-CCD is a solitary mucosal lesion that develops either in the gastric cardia or ***,this lesion is characterized by tightly clustered glands and anastomosing cords of chief ***,GA-CCD is diffusely positive for mucin(MUC)6 and negative for MUC2and ***,other gastric tumors such as a gastric neuroendocrine tumor or fundic gland polyp have been difficult to *** GA-CCD tends to be endoscopically misdiagnosed as a neuroendocrine tumor or fundic gland polyp,comprehensive assessment and observation by an endoscopist are strongly ***,we report a rare case of oxyntic gland adenoma endoscopically mimicking a gastric neuroendocrine tumor that was successfully removed by endoscopic mucosal resection.

关键词： Chief cell differentiation Gastric carcinoma Mucin 6 Neuroendocrine tumor Oxyntic gland adenoma

Hierarchical Linear Modeling in International Marketing Research： A Review with an Application on Innovation and Export in China

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Frontiers of Business Research in China 2015年第2期9卷 135-160页

作者： Kiaohui yuan Ziliang Deng Ruer-Jer Bryan Jean Daekwan kim School of Business Renmin University of China Beijing 100872 China Department of International Business National Chengchi University Taipei 11605 TaiwanChina College of Business Florida State University Tallahassee FL 32306-1110 USA

While much of international marketing research involves two or more levels, limited work in the international marketing literature uses hierarchical linear modeling to examine different level effects. This study conducts a thorough literature review on hierarchical linear modeling （HLM） in 28 international marketing papers that employed HLM from 2005-2014 and evaluates the use of HLM in these papers on the objects, operating levels, and other issues. We call for more applications of HLM in international marketing research, particularly for research on emerging markets with significant sub-national and institutional variations. The paper provides an illustrative empirical study that employs HLM to test the moderating role of industry-level government subsidies in the relationship between firm innovation and exporter performance in China.

关键词： hierarchical linear modeling (HLM), multilevel modeling,international marketing, China, innovation export subsidy

Congenital retinal macrovessel with intracranial venous malformation in a pediatric patient: a case report

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International Journal of Ophthalmology(English edition) 2022年第7期15卷 1214-1216页

作者： Hyeon Jin Park Sook Hyun Yoon Sook Young kim donghun Lee Department of Ophthalmology Daegu Catholic University School of MedicineDaegu 42472Republic of Korea

Dear Editor,Congenital retinal macrovessel (CRM) is defined as an abnormal large retinal vessel that encircles the foveal avascular zone (FAZ).Since the first description of a large aberrant vessel crossing the macula by Mauthnerin 1868,there have been several case reports about *** recently,Pichi et alreported clinical manifestations and multimodal retinal imaging of 49 eyes with *** their study,they had identified an association between macrovessel in the retina and venous anomalies of the brain and they emphasized the importance of systemic workups including brain magnetic resonance imaging (MRI).

关键词： venous Congenital malformation