• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.11
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• pp.2150-2158
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• 1992

This study was carried out to investigate the flow structure and mixing process of a cross mixing flow formed by two round jets with respect to the ratio of mass flow rate. This flow configuration is of great practical relevance in a variety of combustion systems, and the flow behaviour of a cross jet defends critically on the ratio of mass flow rate and the cross angle. The mass flow rate ratios of two different jets were controlled as 1.0, 0.8, 0.6, and 0.4, and the crossing angle of two round jets was fixed at 45 degree. The velocities issuing from jet nozzle with an exit diameter of 20mm were adjusted to 40m/s, 32m/s, 24m/s, and 16m/s, and the measurements have been conducted in the streamwise range of $1.1X_0$to $2.5X_0$ by an on-line measurement system consisted of a constant temperature type two channel hot-wire anemometry connected to a computer analyzing system. The original air flow was generated by a subsonic wind tunnel with reliable stabilities and uniform flows in the test section. For the analysis of the cross mixing flow structure in the downstream region after the cross point, the mean velocity profiles, the resultant velocity contours, and the three-dimensional profiles depending upon the mass flow rate ratio have been concentrately studied.

• Applied Chemistry for Engineering
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• v.10 no.4
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• pp.581-585
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• 1999

The surface treated hydroxypropyl methylcellulose(HPMC) which could adjust the soluble time was synthesized when 40 wt % glyoxal solution and $KH_2PO_4$ were sprayed and reacted. And also, the solution dynamic at different ratios of two adding agents were identified If the surface of HPMC was treated with only glyoxal, the dispersion characteristics at different ratios of two adding agents were identified If the surface of HPMC was treated with only glyoxal, the dispersion was observed in the neutral solution and the viscosity was increased after directly dissolved as the solution become alkali condition. But the fine-powder type of HPMC which reacted with glyoxal and $KH_2PO_4$ was dispersed regardless of pH of solution and observed that it was dissolved and its viscosity increased after elapsing some time. With increasing amount of glyoxal and $KH_2PO_4$, the soluble time was delayed. The reaction condition was about 60 min at $75{\sim}85^{\circ}C$. Especially, the removal process of organic solvent after reaction was not required due to reaction under water solution without organic during glyoxal and $KH_2PO_4$ treatment. And also, the HPMC which could adjust the soluble rate in water or organic solvent by changing the degree of substitution of HPMC was synthesized.

• Journal of the Korean Ceramic Society
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• v.45 no.12
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• pp.839-844
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• 2008

$TiO_2$ is an environment-friendly semiconducting material, and it has photocatalytic and hydrophilic effect. There are a lot of reports on the photocatalytic characteristics of $TiO_2$, such as organic pollutants resolving, anti-bacterial, and self-purification material. In this paper, $TiO_2$ micron-sized powders were deposited on the glass by room temperature powder spray in vacuum process, so called aerosol deposition (AD), and nano-grained $TiO_2$ photocatalytic thin films were fabricated. The thickness of the films were controlled by changing the number of deposition cycle. Morphologies and characteristics of the AD-$TiO_2$ thin films were examined by SEM, TEM, XRD, and UV-Visible Spectrophotometer. As the thickness of $TiO_2$ films increased, surface roughness increased. By this increment, the reaction area between film and pollutant was enlarged, resulting in better photocatalytic property.

• Journal of Korean Medical classics
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• v.13 no.1
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• pp.146-183
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• 2000

통과이상적연구(通過以上的硏究), 장상한학술적성숙기(將傷寒學術的成熟期), 칙지명대여청대관여상한의학사적내용정리(則至明代與淸代關與傷寒醫學史的內容整理) 여하(如下). 1. 명청시대적시대배경사상한학적내용갱풍부(明淸時代的時代背景使傷寒學的內容更豊富), 촉진상한학술적발전(促進傷寒學術的發展) 병차출현료흔다관여상한적저작(幷且出現了?多關與傷寒的著作), 단실제상야출현료상한론내용적중복여지론술일반부분(但實際上也出現了傷寒論內容的重複與只論述一般部分), 혹저자립안조잡적처방지폐단(或著者立案粗雜的處方之弊端). 차기우출현각종상한학파적리유(此期又出現各種傷寒學派的理由), 시인위당시류행적사조(是因爲當時流行的思潮), 칙정주리학적영향여명대문단부고(則程朱理學的影響與明代文壇復古), 의고적추향(擬古的趨向), 환유금원시대적백가쟁오등(還有金元時代的百家爭嗚等), 성료형성상한학파적기초(成了形成傷寒學派的基礎). 2. 위료불실거상한론적본래의식(爲了不失去傷寒論的本來意識), 주장정리화고정원문회부왕숙화이전모양적착간중정파시왕안도기료개단(主張整理和考訂原文恢復王叔和以前模樣的錯簡重訂派是王安道起了開端), 방유집확대료기의식(方有執擴大了其意識). 유창여침명종시대표저학파학자(喩昌與沈明宗是代表這學派學者), 장로(張?) 정응모(程應?) 주양준(周揚俊) 오겸등수료저학설(吳謙等隨了這學說). 3. 주장(主張)'존왕(尊王)(숙화(叔和))찬성(贊成)(무기(无己))'적유호구론파(的維護舊論派), 주장료불능수변개상한론삼음삼양편적배렬여순서(主張了不能隨變改傷寒論三陰三陽篇的排列與順序), 문자(文字), 구문(句文), 문장(文章), 고세식(高世?), 진념조등인(陳念祖等人). 4. 주장상한론적정수재어변증론치(主張傷寒論的精髓在於辨證論治), 선우운용칙능득상한핵심리론적학파시변증론치학파(善于運用則能得傷寒核心理論的學派是辨證論治學派). 저학파분사개계통(這學派分四?系統), 이처방수집증상적의가유허굉(以處方收集證狀的醫家有許宏), 가금(柯琴), 서대춘(徐大椿); 이치법수집증상적의가유오인구(以治法收集證狀的醫家有吳人駒), 우이(尤怡); 이분유륙경찰증상적의가유진념조(以分有六經察證狀的醫家有陳念祖), 포성(包誠); 이증상분류증후적의가유류순(以證狀分類證候的醫家有劉純), 왕긍당(王肯堂), 진지정(秦之楨), 침금오등인(沈金鰲等人). 5. 회통파유량종류형(?通派有兩種類型), 일시수통상한여온병적학파(一是誰通傷寒與溫病的學派), 간칭회통파(簡稱?通派), 대표의가유도화(代表醫家有陶華), 오정(吳貞), 유근초등인(兪根初等人), 령일개유회통중의여서의적립장상해석상한적의가당종해(?一?有?通中醫與西醫的立場上解釋傷寒的醫家唐宗海). 6. 경전학파시이상한론위보귀적경전래인식(經典學派是以傷寒論爲保貴的經典來認識), 병차지유숭상차경여사상적학파(幷且持有崇尙此經與思想的學派), 차리분량개편우원문적고증래연구적경전고증파(此里分兩?偏于原文的考證來硏究的經典考證派), 화인위지유상한론(和認爲只有傷寒論), 재능총괄치료외감병(才能總括治療外感病), 부정온병학설병배척적경전림상파(否定溫病學說幷排斥的經典臨床派).

• Clean Technology
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• v.19 no.4
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• pp.437-445
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• 2013

To develop SEWGS (sorption enhanced water gas shift) system using dry $CO_2$ absorbent for pre-combustion $CO_2$ capture, hydrodynamic characteristics of $CO_2$ absorbents were measured and investigated. The minimum fluidization velocity of $CO_2$ absorbent was measured and the effects of the operating conditions were investigated to operate the system at bubbling fluidized bed condition. The minimum fluidization velocity decreased as pressure and temperature increased. Moreover, the minimum fluidization velocity decreased as column diameter increased. The effects of operating conditions on the solid circulation rate were measured and investigated to select appropriate operating conditions for continuous $CO_2$ capture and regeneration. The measured solid circulation rates were ranged between 10 and 65 kg/h and increased as the solid injection velocity, gas velocity in the regeneration reactor, and solid height increased.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.5
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• pp.455-461
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• 2015

A high-pressure fuel pump is a key component in a gasoline direct injection (GDI) engine; thus, understanding its flow characteristics is essential for improving the engine power and fuel efficiency. In this study, AMESim, which is a hydraulic analysis program, was used to analyze the performance of the high-pressure fuel pump. However, since AMESim uses a one-dimensional model for the system analysis, it does not accurately analyze the complicated flow characteristics. Thus, Fluent, computational fluid dynamics (CFD) software, was used to calculate the flow rates and net forces at the intake and discharge ports of the high-pressure fuel pump where turbulent flow occurs. The CFD analysis results for various pressure conditions and valve lifts were used as look-up tables for the AMEsim model. The CFD analysis results complemented the AMEsim results, and thus, improved the accuracy of the performance analysis results for the high-pressure fuel pump.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.1
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• pp.116-123
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• 2019

Thermal batteries are also called molten-salt batteries as the electrolyte is mainly composed of molten salt. The molten-salt electrolyte is a solid that does not conduct electricity at room temperature, but when it is melted by a pyrotechnic heat source, it becomes an excellent ionic conductor. Thermal batteries are a kind of pyrotechnic battery because they operate only when the solid electrolyte is melted by the heat energy provided by pyrotechnic materials. Pyrotechnic components used in a thermal battery include heat sources, fuse strips, and an igniter. The reliability of these pyrotechnic components critically affects the reliability and performance of the battery that must supply electricity stably to guided munitions even under extreme environmental conditions. Different igniter types offer different advantages: notch-type igniters offer improved ignition probability, whereas film-type igniters offer improved safety. The addition of metal oxides to the heat paper could improve the burn rate, and the ignition reliability could be greatly improved by using it with a flame igniter at the same time. Using a two-step reduction process, high-purity Fe particles in coral form can be safely obtained.