Numerical Analysis of Radio‑Frequency Inductively Coupled Plasma Spheroidization of Titanium Metal Powder Under Single Particle and Dense Loading Conditions

Jun‑Seok Nam,Eonbyeong Park,Jun‑Ho Seo 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.4

In order to allow more practical prediction of RF (radio-frequency)–ICP (inductively coupled plasma) spheroidizationresults of titanium metal powder, numerical analyses under single particle and dense loading conditions were carried outand the results were compared. First, both of the numerical results for Ar inductively coupled plasma with the power levelof 30 kW revealed that the injected particles can experience not only spheroidization by melting, but also size reduction byevaporation. In addition, this size reduction was found to strongly depend on the initial sizes of the injected particles, due tothe relatively short heating time. For example, the 100 μm Ti particles were computed to hardly experience size reduction byevaporation regardless of feeding rates. However, relatively small Ti particles < 100 μm can be rapidly heated up to boilingpoints during the short flight of plasma, resulting in the size reduction by the surface evaporation. In particular, numericalresults under dense loading condition showed that the final sizes of these small Ti particles can be changed depending onthe feeding rate. For example, a single 60 μm Ti particle was calculated to be a 51 μm spherical Ti particle due to the excessiveheating. However, with the increase of feeding rate up to 1.0 kg/h, the final sizes of the as-treated Ti powder couldbe improved to 55 μm due to the plasma temperatures decreasing through complicated plasma–particle interactions. Bypredicting the relationships between the feeding rates and the initial diameters of Ti powders at a given plasma power level,numerical modellings under single particle and dense loading conditions can help in optimizing the RF–ICP spheroidizationprocess of titanium metal powder.

품종별 감꽃 동결건조 분말의 유효성분 분석

김준한 ( Jun Han Kim ),박석희 ( Seok Hee Park ),문혜경 ( Hye Gyeong Mun ),이인선 ( In Seon Lee ),김종국 ( Jong Kuk Kim ) 한국식품저장유통학회 ( 구 한국농산물저장유통학회 ) 2006 한국식품저장유통학회지 Vol.13 No.6

감 품종별(도근조생, 고종시, 갑주백목, 차랑, 월하시, 상주둥시)로 감꽃을 개화기에 채취하여 동결건조 분말화한 감꽃분말에 함유된 유효성분을 분석, 비교하였다. 조지방 함량은 도근조생이 57.26%로 가장 높은 값을 보였으며, 유리당 조성은 fructose가 95~310 mg%, glucose는 75~281 mg%, sucrose가 7~28 mg%의 함유량을 나타내었고, 유기산 중 malic acid가 갑주백목(6월4일)에 225 mg%로 가장 많았고, tartaric acid도 189 mg%로 가장 많았다. 유리아미노산 중 hydroxy-L-proline은 월하시에 25.33 mg%, L-citrulline은 상주둥시(5월28일)가 58.83 mg%, L-threonine은 상주둥시(5월28일)가 11.88 mg%로 가장 많았다. 페놀산으로 caffeic acid는 갑주백목(6윌4일)이 1946 μg/100 g, phydroxybenzoic acid는 상주둥시(5월29일)가 417.8 μg/100 g, protocatechuic acid는 갑주백목(6월1일)이 181.1 μg/l00 g으로 가장 많았다. 따라서 감꽃에도 감이나 감잎에 못지않게 유용한 식품성분들과 기능성 성분들이 다량 함유되어 있어 새로운 식품 및 기능성 신소재로서의 가치가 매우 높다고 할 수 있다. This study was carried out to analyze useful components in freeze-dried persimmon flower powder made from six cultivars. The cultivars were Dogunjosang, Kojongsi, Kabjubaekmok, Chalang, Weolhasi and SangjuDungsi. Powder of persimmon flower was prepared by milling after freeze drying at -70℃. Crude lipid was the highest in Dogunjosang (57.26%). Major free sugars of the persimmon flowers were fructose (95~310 mg%), glucose (75~281 mg%)and sucrose (7~28 mg%). Major organic acids were malic acid (225 mg% in Kabjubaekmok (Jun. 4th)) and tartaric acid (189 mg% in Kabjubaekmok (Jun. 4th)). Predominant free amino acids were hydroxy-L-proline(25.33 mg% in Weolhasi), L-citrulline (58.83 mg% in SangjuDungsi (May 28th)) and L-threonine (11.88 mg% in SangjuDungsi (May 28th)). Major phenolic compounds in the persimmon flowers were caffeic acid (1,946 μg/100g in Kabjubaekmok (Jun. 4th)), p-hydroxybenzoic acid(418 μg/100g in SangjuDungsi (May 29th)) and protocatechuic acid(181 μg/100g in Kabjubaekmok(Jun. 1st)). The results suggest that persimmon flowers be potential materials as useful food ingredients.

Clinical usefulness of infrared thermal imaging as a non-invasive screening test for diagnosis of vascular malformations

( Chihyeon Sohng ),( Jun Hong Park ),( Won Kee Lee ),( Jun Young Kim ),( Yong Hyun Jang ),( Weon Ju Lee ),( Seok-jong Lee ) 대한피부과학회 2018 대한피부과학회 학술발표대회집 Vol.70 No.2

Background: Infrared thermal imaging (ITI), aka thermography, has been used widely in medicine, but been studied rarely its clinical application in vascular malformations (VMs). Objectives: This study investigated validity and usefulness of ITI as a new screening test to differentiate between capillary malformation (CM) and arteriovenous malformation (AVM). Methods: This study included 50 patients with VMs who conducted ITI between 2011 and 2018. They were divided into two groups; CM and AVM, and those with Parkes-Weber syndrome (PWS) were also included in AVM group. Temperature difference (ΔT) between lesional and contralateral non-lesional area was compared using ITI to calculate the maximum ΔT (ΔTmax). The receiver operating characteristic (ROC) curve was then plotted to determine optimal cutoff value of ΔTmax. Results: Of the total 50 patients, 34 were finally diagnosed with CM, and 16 AVM (12 pure AVM, and 4 PWS). AVM group had significantly higher ΔTmax (2.57±1.23°C) than CM group (0.69±0.50°C).The area under the curve of ΔTmax for diagnosis of AVM versus CM was 0.938. The sensitivity and specificity were showed 87.5% and 94.1% (LR+, 14.87; LR-, 0.13) in cutoff value of ΔTmax 1.39°C, and 81.3% and 97.1% (LR+, 27.62; LR-, 0.19) in cutoff value of ΔTmax 1.42°C. Conclusion: The value of ΔTmax measured by ITI was useful to distinguish AVM from CM, so ITI can be employed as a new non-invasive differential screening test for uncertain VMs.

21세기의 테러에 대한 동향과 대응방안

박준석 龍仁大學校 武道硏究所 2004 武道硏究所誌 Vol.14 No.2

It is that operations which centralize in national intelligence service by support of nation are cooperate with private organization public organization and academic worlds. Especially it is going to understand and public information with strengthen of systems, expansion of equipments of terror and factor of environment opposition of plans of terrors and educations are nation, private organization, academic worlds. Further, professional men with theory of terror and practical affairs are as fast as possible coming forwarded in university with security service.

한국 금융기관의 시설경비·경호 현항과 개선방안

박준석,최진영 龍仁大學校 武道硏究所 2004 武道硏究所誌 Vol.14 No.2

In this paper, examine present status of financial institution s facility in USA and Japan which are known as advanced countries of private security industry, and analyze face subject and controversial points. And then, grope improvement plan for efficient security and problems of Korean financial institution s security. As results of study, for improved self-security of financial institutions, followings are the financial institution self-security plans and confrontation plan of private security companies. First, among the financial institutions, crime is increasing to community bank which security is vulnerable relatively than major banks. This is evidence that advanced security equipments are effective to control the will of crime. Therefore, financial institution should install advanced security equipments under the sense of duty that manage customer s property safely by oneself, and cooperate with private security company for better crime prevention activities. Second, criminals are usually propel crime at opening, changing time at lunch, and at closing hour. Because, employees of financial institution are not paying much attention in those loose time. Therefore, non-window personnel s supports are must be provided to make circumstance that window personnel works at right position certainly when starting time or shifting time. Third, when crime is occurred, non-window personnel must issue alarm quickly and request cooperation of the police or private security company. Especially, one of the important suggestion by this paper is that alarm should be issued to in and out side of financial institution along with the police and private security company and establish citizen arrest system which helps arrest criminals by citizen or related agents in neighbor area. Fourth, Security must be managed as multiple system such as automatic alarm device on building walls and vault to issue the alarm when there are unusual noises or vibration of vault because in case of single alarm he, F criminals cut off the alarm line, it could be open state to crime. So, must establish multi alarm system and make criminals not to accomplish crime by delaying entry time. Fifth, to customer who withdrawal cash or check more then certain amount, escort service should be introduced and escort to destination safely as customer protection system even if customer does not ask for. And Followings are confrontation plan of private security companies. First, confrontation ability at initial stage is not enough. Under current security system, it is very hard to reach the spot with crime time even If go out as fast as possible. Therefore, manage manless automatic monitor system thoroughly and set multi-channel warning system so that alarm may issue around police station or private security' company as well as banking facilities neighborhood in case of panic button is pressed in window, and must grope plan of total citizen criminal prevention system that can request neighborhood inhabitants' cooperation. If systematic and synthetic management is accomplished in window, crime can be prevented in some degree. In other words, most of crime at window can be prevented by alarm management system at window, cooperation system with professional security agents and insuring window security agents, etc. Second, securing professionalism of professional security team is urgent. Most of private security company's manpower are not qualified, and it is that they are not much helpful when actual situation occurred. Also, it is truth that their role is limited to carry out preventive patrol activity. Therefore, professional training and education to financial facility staff is required. Moreover, should recruit specially trained manpower at military or police, and it is necessary to consider plan that confront properly in initial state of crime. And the most important thing is holding back criminal's crime wills thru security staffs periodic and systematic confrontation training abut financial facilities crime. Third, professional security school is necessity to educate and train private security staff by each fields. As a plan to this idea, utilizing education and training system of existing school or military, and newly establish professional education and training institute to cultivate professional security staffs. Especially, for financial facility, must aim at operation of the most advanced security equipments. And for cash-in transit vehicles, must used wireless transmitter equipped vehicles and bags obligatorily, so that it is possible to trace the location when it is robbed.

바렉터 다이오드를 이용한 높은 격리도를 갖는 Diplexer 스위치 설계 및 구현

박준석,강명수 국민대학교 생산기술연구소 2004 공학기술논문집 Vol.27 No.-

In this paper, using diplexer structure and varactor diode controlled by reverse bias voltage for diplexer switch gives possibilities to improve isolation and current characteristics. I have newly designed switch with high isolation by application varactor diode corresponding to capacitor of diplexer. The low-pass filter for proposed tunable diplexer passes the microwave signal in the bandwidth for wireless cellular network systems and high-pass filter passes it in the bandwidth for wireless personal communication services (PCS) network systems. As the capacitance of the low-pass filter increases, the cut-off frequency can be moved to low frequency, so that the switch is on state in cellular bandwidth and off state in the PCS bandwidth, in contrast to, as the capacitance for attenuation characteristic of high-pass filter increases, it can be moved to high frequency, so that the switch is off state and on state in the cellular bandwidth, it is possible to improve isolation and current consumption characteristics by application diplexer design methods and varactor diode. I expect that the tunable diplexer circuit and design methods should be able to find applications on MMIC and low temperature copired ceramic (LTCC).

한국 민간보안.시큐리티 산업의 발전방안

박준석 용인대학교 2006 용인대학교 논문집 Vol.24 No.-

The device for the important assignment of the healthy bringing up and the preservation of public peace should be examined, first in legal, systemic term, second the terms of quality improvement for security, guard, security guard, third the terms of cooperate important for private, security, guard, security guard, forth total security system expulsion, change of people, paradigm shift about private security , guard, crime prevention, expulsion and supporting. When considering real term, a policeman on special guard assignment system and private security guard , system's combining or unifying should be set up quickly to take a role of partner. Lastly, the access will be needed such as security industry's variety, speciality, education, guarantee of job, well fare etc like America lessen risk management system's loss, spread out. So, it is needed to access security total consulting industry, government, organization(military, police, security service, national intelligence service etc) and it is considered cooperate system of security company related area(education organization, academy world) and government organization (military, police, security service, national intelligence service) is very necessary soon. Risk management manual, D.B. expulsion should be variously developed.

스포츠 매니지먼트활동에서 매니저들의 책임 수행에 관한 연구

박준석,김정묵,정석현,조영웅,이영성 한국스포츠리서치 2004 한국 스포츠 리서치 Vol.15 No.1

Sport has taken a position as significant influence all over the world for a long time. These days, sport must exist with us in order to provide pleasure, so people have a tendency to expect it what happens to them. Therefore, a number of sport teams and competitions are able to stimulate people to be interested in sport. Sport event, information, equipment, and sport player management need systems which accompany with security and pleasure because the systematical managements establish security, and help sport players not to make an error that is a fountain of good quality game. Thus, sport players improve their ability, so the audience are willing to pay to see the game. In order to extend the power of sport influence, sport should be organized in terms of managing sport processes well. Unfortunately, the system of management for sport is not still adequate and organized in Korea. In other words, many materials must be sporadic, and newspapers or magazines have treated of sport management with fragmentary knowledge so far. Today, systematical management is essential to all segments of the sport industry, professional or amateur, school or club, private or government at any level community or individual. Hopefully, this research will be instructive as a starting point to derive a special quality of sport management which is suited to korea sport market by comparing to other management systems in order to formulate organized management industry.

풍동시험에서 사용하는 시험지지부의 동특성 해석용 툴에 관한 연구

박태민,이기석,홍준희 한국공작기계학회 2005 한국공작기계학회 춘계학술대회논문집 Vol.2005 No.-

This paper is described the program algorithm which can easily estimate dynamics of test support system by using mathematica tool based on the finite element method. We can determine the geometry, dimensions of the test support system, through tool stated in this paper for a certain test conditions. As a result of computer simulation and manufactured test support system's experiment in oder to verify suggested program, the dynamics of the test support system was well correspondent each other.

배가스 폐열회수를 위한 히트파이프 적용성 검토

전용두,박기호,고석보 公州大學校 工學硏究院 生産技術硏究所 2005 論文集 Vol.13 No.-

A Series of experiments are performed to investigate the heat transfer characteristics of sintered metal wick heat pipe especially focusing on the operational limit of maximum allowable thermal loads and the effect of inclination slope. Tested heat pipes are composed of copper tube with pure water as a working fluid. The outer diameter of the heat pipe is 6mm and the total length is 300mm, which covers the evaporator section(50mm), adiabatic section(100mm) and condenser section(150mm). respectively. Experimental data of wall temperature distribution along the axial locations are obtained to evaluate the performance of the heat pipe at different slopes. Each test is performed by changing the input thermal loads ranging from 5W to 30W.