• Title/Summary/Keyword: Thermal regeneration

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The Implementation of TMM test phantom for evaluating the thermal performance in High Intensity Focused Ultrasound system (강력 집속 초음파 시스템의 열적 성능 평가를 위한 팬텀 개발에 관한 기초연구)

  • Yu, Woo-Jin;Noh, Si-Cheol;Park, Moon-Kyu;Min, Hae-Ki;Park, Jae-Hyun;Choi, Heung-Ho
    • Proceedings of the KIEE Conference
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    • 2008.10b
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    • pp.484-485
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    • 2008
  • 초음파는 의학적 진단 및 치료의 목적으로 널리 사용되어 왔다. 일반적으로, 초음파 조사의 생물학적 무해성은 많은 연구를 통하여 보고되었으나, 최근 초음파 집속을 통한 강력 초음파의 사용에 대한 열적 안전성 평가가 중요한 요소로 대두되고 있다. 이에 본 연구에서는 강력 집속 초음파의 전달 에너지와 열적 분포를 측정하여 안전성 평가에 활용 가능한 초음파 열분포 팬텀을 제안하였다. 온도 분포 측정용 팬텀은 초음파 조직유사 팬텀 재료인 한천을 이용하였으며, 음향학적 특성의 유사성을 평가하였다. 온도 효과를 측정하기 위하여 $3{\times}3$의 형태로 온도 센서를 팬텀 내부에 배열하여 초음파 조사에 따른 온도 분포를 측정하였고 온도 측정을 위한 시스템을 개발하여, 초음파 가열 실험을 수행하였다. 본 연구에서 제안된 초음파 온도 분포 측정용 팬텀의 유용성을 확인하였으며, 온도 분포용 팬텀을 통한 강력 집속 초음파 장비의 열적 성능 평가에 적용 될 수 있을 것으로 사료되었다.

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A Study on Heavy-Duty Diesel Engine Performance with a CR-DPF and Cooled-EGR (CR-DPF와 Cooled-EGR 적용한 대형디젤기관 성능에 관한 연구)

  • Moon, Byung-Chul;Oh, Yong-Suk;Oh, Sang-Ki;Kang, Kum-Won;Ahn, Kyun-Jae
    • Transactions of the Korean Society of Automotive Engineers
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    • v.14 no.3
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    • pp.75-80
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    • 2006
  • Since air pollution has become a globally critical issue and exhaust emissions from automobiles cause a major source of air pollution, many countries including advanced countries have stipulated stringent emission regulations. Particularly in diesel vehicles, NOx and particulate matters exhaust in significant amounts even though diesel vehicles provide merits in aspects of higher thermal efficiency and lower $CO_2$. To reduce Particulate matters and NOx, after-treatment technology such as filter trap, oxidation catalysts and EGR has been applied. This test was conducted on the effect of continuous regeneration diesel particulate filter and cooled-EGR, and 15ppm low sulfur diesel was used as a test fuel. Exhaust emissions, PM, NOx, CO, HC and Soots were measured and compared under D-13 and D-3 modes.

Functionalized Poplar Powder as a Support Material for Immobilization of Enoate Reductase and a Cofactor Regeneration System

  • Li, Han;Cui, Xiumei;Zheng, Liangyu
    • Journal of Microbiology and Biotechnology
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    • v.29 no.4
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    • pp.607-616
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    • 2019
  • In this study, functionalized poplar powder (FPP) was used as a support material for the immobilization of enoate reductase (ER) and glucose-6-phosphate dehydrogenase (GDH) by covalent binding. Under optimal conditions, the immobilization efficiency of ER-FPP and GDH-FPP was 95.1% and 84.7%, and the activity recovery of ER and GDH was 47.5% and 37.8%, respectively. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis indicated that FPP was a suitable carrier for enzyme immobilization. ER-FPP and GDH-FPP exhibit excellent thermal stabilities and superior reusability. Especially, ER-FPP and GDH-FPP enable the continuous conversion of 4-(4-Methoxyphenyl)-3-buten-2-one with $NAD^+$ recycling. While the immobilization strategies established here were simple and inexpensive, they exploited a new method for the immobilization and application of ER and its cofactor recycling system.

The Effects of Dokhwalgisaeng-tang(Duhuoqisheng-tang ) and Jungsongouhyul Pharmacopuncture on Pain Control and Nerve Regeneration in the Crush-induced Sciatic Nerve Injury of the Rat Model (독활기생탕(獨活寄生湯) 및 중성어혈약침(中性瘀血藥鍼)이 좌골신경 압좌손상 백서의 통증과 신경 재생에 미치는 영향)

  • Lee, Sang-Gyu;Won, Jae-Kyun;Yeom, Seung-Ryong;Lee, Su-Kyung;Song, Yung-Sun;Kwon, Young-Dal
    • Journal of Korean Medicine Rehabilitation
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    • v.19 no.3
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    • pp.15-32
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    • 2009
  • Objectives : The purpose of this Study was to identify the effect of Dokhwalgisaeng-tang(Duhuoqisheng-tang) and Jungsongouhyul pharmacopuncture on pain control and nerve regeneration after crush injury in rat sciatic nerve. Methods : Neuropathic pain was induced by crush-induced model of right sciatic nerve. Animal groups were divided as follows; Group I: no treatment control group, Group II : experimental group treated with Dokhwalgisaeng-tang(Duhuoqisheng-tang), Group III : experimental group treated with Jungsongouhyul pharmacopuncture, and Group IV : experimental group treated with Dokhwalgisaeng-tang(Duhuoqisheng-tang) and Jungsongouhyul pharmacopuncture. To evaluate pain intensity, each group was observed paw withdrawal threshold and immunoreactivity on the c-fos before and after respective treatments in five hours, first, third, and fifth day. To evaluate nerve regeneration, those were observed SFI(Sciatic Functional Index) and GAP-43(Growth Associated Protein 43) after each treatment in seventh and thirteenth day. Results : 1. Paw withdrawal threshold to the mechanical stimuli made the significant difference between group IV and the control group after five days of the experiment. 2. Paw withdrawal threshold to the thermal stimuli made the significant difference between group I and III, I and IV, II and IV. 3. In immunohistochemical response of c-fos, as time passes, the immunoreactivity of all groups was decreased gradually. Especially, group IV was observed the lowest after three days. 4. The differences of sciatic function indexes in each group were significantly between group I and III, I and IV, II and IV after 14 days, and between group I and III, I and IV, II and IV, III and IV after 21 days. 5. In immunohistochemical response of GAP-43, all groups had higher GAP-43 immunoreactivity at the 14 days from post-injury and group IV showed highest immunoreactivity. Conclusions : Based on above the results, it is proposed that Dokhwalgisaeng-tang(Duhuoqisheng-tang) and Jungsongouhyul pharmacopuncture may be helpful as a treatment in neuropathic pain and nerve regeneration in rat model.

The Clinical Study on the Thermal Temperature Changes after Hominis Placenta Acupuncture Therapy (자하차약침(紫何車藥鍼)이 체표온도변화(體表溫度變化)에 미치는 영향(影響))

  • Yook, Tae-Han;Sin, Min-Seop
    • Journal of Acupuncture Research
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    • v.19 no.3
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    • pp.88-94
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    • 2002
  • Objective : This study was done to observe the effects on the themal changes of Hominis Placenta acupuncture therapy. The objectives are as follows; If there are remarkable local thermal changes between pre- and post- Hominis Placenta acupuncture therapy on D.I.T.I. or not. If there are those, we examine how long its changes are maintained, the adequate interval and clinical applications of therapy. Methods : To study the local thermal changes in therapy, D.I.T.I. was used. Thermal temperatures were measured pre- and post-therapy (1 hour, 1st day, 2nd day, and 7th day). The study group was divided into two groups. One was HP(Hominis Placenta) group(N=20), the other was NS(Normal Saline) group. The Hominis Placenta acupuncture was injected into 4 points (Fengmen(風門: $B_{12}$), Feishu(肺兪: $B_{13}$), Fufen(附分: $B_{41}$), Pohu(魄戶: $B_{42}$)) by 0.05ml. Results : The following results were obtained. 1. PLACENTA HOMINIS is the dried placenta of a healthy woman, used to warm the kidney for impotence, infertility, lack of lactation, and replenish Gi(氣), blood, vital essence for emaciation, hectic fever, night sweating in consumptive diseases. 2. Hominis Placenta acupuncture therapy has effects on invigoration of vital energy (補氣, 益氣), nourishing blood (養血), and tonifying the essence (補精). 3. Hominis Placenta acupuncture therapy is effective at tissue regeneration, antibody formation, increasing immunity, hormone-like effects. So, it is clinically used in osteoporosis and facial nerve paralysis. 4. There was no significant dermatothermal changes at NS group, but HP group had remarkable changes between operated and non-operated area in post-therapy 1hour. But there were not any change on 1, 2, and 7th day.

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Performance Characteristics Analysis of Combined Cycle Using Regenerative Organic Rankine Cycle and LNG Cold Energy (LNG 냉열과 재생 유기 랭킨 사이클을 이용한 복합 사이클의 성능 특성 해석)

  • KIM, KYOUNG HOON;JUNG, YOUNG GUAN;HAN, CHUL HO
    • Transactions of the Korean hydrogen and new energy society
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    • v.31 no.2
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    • pp.234-241
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    • 2020
  • This paper presents a thermodynamic performance analysis of a combined cycle consisting of regenerative organic Rankine cycle (ORC) and liquefied natural gas (LNG) Rankine cycle to recover low-grade heat source and the cold energy of LNG. The mathematical models are developed and the system performances are analyzed in the aspect of thermodynamics. The effects of the turbine inlet pressure and the working fluid on the system performance such as the mass flow rates, heat transfers at heat exchangers, power productions at turbines, and thermal efficiency are systematically investigated. The results show that the thermodynamic performance of ORC such as net power production and thermal efficiency can be significantly improved by the regenerative ORC and the LNG cold energy.

Cycle Simulation of a Desiccant Cooling System with a Regenerative Evaporative Cooler (재생형 증발식 냉각기를 이용한 제습 냉방시스템의 성능해석)

  • 이재완;이대영;강병하
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.16 no.6
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    • pp.566-573
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    • 2004
  • Comparison of the cooling performance is provided between the desiccant cool-ing systems incorporating a direct evaporative cooler and a regenerative evaporative cooler, respectively. Cycle simulation is conducted, and the cooling capacity and COP are evaluated at various temperature and humidity conditions. The COP of the system with a regenerative evaporative cooler and the regeneration temperature of 6$0^{\circ}C$ is evaluated 0.65 at the outdoor air condition of 35$^{\circ}C$ and 40% RH. This value is found about 3.4 times larger than that of the system with a direct evaporative cooler. Furthermore, incorporating a regenerative evaporative cooler eliminates the need for deep dehumidification in a desiccant dehumidifier that is necessary to achieve low air temperature in the system with a direct evaporative cooler. Subsequently, the regenerative evaporative cooler enables the use of low temperature heat source to regenerate the dehumidifier permitting the desiccant cooling system more beneficial compared with other thermal driven air conditioners.

Graphene: an emerging material for biological tissue engineering

  • Lee, Sang Kyu;Kim, Hyun;Shim, Bong Sup
    • Carbon letters
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    • v.14 no.2
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    • pp.63-75
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    • 2013
  • Graphene, a carbon crystal sheet of molecular thickness, shows diverse and exceptional properties ranging from electrical and thermal conductivities, to optical and mechanical qualities. Thus, its potential applications include not only physicochemical materials but also extends to biological uses. Here, we review recent experimental studies about graphene for such bioapplications. As a prerequisite to the search to determine the potential of graphene for bioapplications, the essential qualities of graphene that support biocompatibility, were briefly summarized. Then, direct examples of tissue regeneration and tissue engineering utilizing graphenes, were discussed, including uses for cell scaffolds, cell modulating interfaces, drug delivery, and neural interfaces.

Hydrogen Evolution Properties of Alanate-based Hydrogen Storage Materials (알라네이트 계 수소 저장 물질의 수소 방출 특성)

  • JEONG, HEONDO
    • Transactions of the Korean hydrogen and new energy society
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    • v.28 no.4
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    • pp.361-368
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    • 2017
  • Alanate-based materials, which were known to have high hydrogen storage capacity, were synthesized by mechanochemically metathesis reaction of metal chloride and sodium alanate without solvent. XRD patterns of synthesized materials showed that metathesis reaction of cations between metal chloride and sodium alanate was progressed favorably without any solvent. Magnesium alanate showed that 3.2 wt.% of hydrogen was evolved by the thermal decomposition. The addition of a small amount of Ti to the magnesium alanate greatly reduced hydrogen evolution temperature. Also, Ti doped magnesium alanate had a good regeneration property. Both the calcium and lithium-magnesium alanate showed the lower starting temperature of the two step hydrogen evolution and fast kinetics for the hydrogen evolution.

DNS of turbulent heat transfer in a concentric annulus (동심 환형관 내 난류 열전달의 직접 수치 모사)

  • Chung Seo Yoon;Sung Hyung Jin
    • Proceedings of the KSME Conference
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    • 2002.08a
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    • pp.827-830
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    • 2002
  • A direct numerical simulation is performed for turbulent heat transfer in a concentric annulus at $Re_{Dh}=8900\;and\;Pr=0.71$ for two radius ratios ($R_{1}/R_{2}=0.1\;and\;0.5$) and $q^{\ast}=1.0$. Main emphasis is placed on the transverse curvature effect on near-wall turbulent thermal structures. Near-wall turbulent structures close to the inner and outer walls are scrutinized by computing the lower-order statistics. The fluctuating temperature variance and turbulent heat flux budgets are illustrated to confirm the results of the lower-order statistics. The present numerical results show that the turbulent structures near the outer wall are more activated than those near the inner wall, which may be attributed to the different vortex regeneration processes between the inner and outer walls.

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