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A 2-Dimensional Micro Flow Sensor with Wide Range Flow Sensing Properties

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稀有金属材料与工程 2006年第A3期35卷 590-594页

作者： tae-Yong kim Division of Computer and Information Engineering Dongseo UniversityBusan 617-716Korea

A new silicon micro flow sensor with multiple temperature sensing elements was proposed and numerically simulated in considering wide range flow measuring *** micro flow sensor has three pairs of temperature sensing elements with a central heater compared with typical sensor which has only a temperature sensing element on each side of a central heater.A numerical analysis of the micro flow sensor by Finite Difference Formulation for Heat Transfer Equation was *** nearest pair of temperature sensor showed very good linear sensitivity between 0 to 0.4m/s flow and saturated from 0.75m/s *** the furthest pair of temperature sensor showed some flow sensitivity even though the flow rate of 2.0m/***,this suggested new micro flow meter with multiple temperature sensing elements could be used as a thermal mass flow sensor which has accuracy sensitivity for very wide flow range.

关键词： micro sensor silicon sensor flow sensor 2-D micro flow sensor thermal simulation FDM

A case study of environmental characteristics on urban road-surface and air temperatures during heat-wave days in Seoul

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Atmospheric and Oceanic Science Letters 2019年第4期12卷 261-269页

作者： kim Yoo-Jun kim Baek-Jo SHIN Yoon-Sook kim Hui-Won kim Geon-tae kim Seon-jeong High Impact Weather Research Center National Institute of Meteorological Sciences

High road-surface temperature due to heat waves can lead to dangerous driving conditions such as tire blowouts and deformation induced by thermal stress on the roads. In this study, a Mobile Observation Vehicle dataset, with high spatial and temporal resolutions for the heat-wave episode that occurred on 16–17 August 2018, is used to understand environmental characteristics on urban road-surface and air temperatures in Seoul. This study demonstrates that the magnitude of urban road-surface temperature is dependent on the differences in incoming solar radiation due to screening of high-rise buildings in the Gangnam area, and is associated with the topographical features in the Gangbuk area. The road-surface temperature in the section of darker-colored asphalts was higher than that of lighter-colored asphalts, with a mean difference of 6.8°C, and both surface and air temperatures on the iron plate were highest, with means of 51.7°C and 35.1°C,respectively. In addition, during the water-sprinkling period, road-surface temperature was cooled by about 8.7°C(19%) compared with that in the period without water-sprinkling, but there was no significant change in air temperature. The current results could be practically used to improve roadsurface temperature prediction models for civil engineers or road managers.

关键词： Heat wave road-surface temperature mobile observation vehicle Seoul

Integrated guidance and control for damping augmented system via convex optimization

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Chinese Journal of Aeronautics 2022年第7期35卷 30-39页

作者： Bong-Gyun PARK tae-Hun kim The 1^(st)R&D Institute-4 Agency for Defense DevelopmentDaejeon 34186Republic of Korea

In this paper,an integrated guidance and control approach is presented to improve the performance of the missile *** approach includes damping augmented system with attitude rate feedback to decrease the oscillation during the homing phase for missiles with low *** addition,physical constraints,which can affect the performance of the missile interception,such as acceleration limit,seeker’s look angle,and look angle rate constraints are *** integrated guidance and control problem is formulated as a convex quadratic optimization problem with equality and inequality constraints,and the solution is obtained by a primal–dual interior point *** performance of the proposed method is verified through several numerical examples.

关键词： Convex optimization Damping augmented system Integrated guidance and control Physical constraint Primal-dual interior point method

Association between preoperative high sensitive troponin I levels and cardiovascular events after hip fracture surgery in the elderly

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Journal of Geriatric Cardiology 2018年第3期15卷 215-221页

作者： Bum Sung kim tae-Hoon kim jeong-Hwan Oh Chang Hee Kwon Sung Hea kim Hyun-Joong kim Heung Kon Hwang Sang-Man Chung in-gu Seoul Republic of Korea Department of Orthopedic surgery Konkuk University Medical Center 120-1 Neungdong-ro Hwayang-dong Gwangjin-guSeoulRepublic of Korea

Objective Cardiovascular complications contribute to postoperative morbidity and mortality in elderly hip fracture patients. Limited data are available regarding which preoperative risk factors predict cardiovascular course following hip fracture surgery （HFS）. We used high sensitive troponin I （hs-TnI） assays and clinical parameters to identify preoperative risk factors associated with major adverse cardiac events （MACE） in elderly hip frac^u＇e patients. Method From August 2014 to November 2016, 575 patients with hip fracture were enrolled in a retrospective, single-center registry. A total of 262 of these patients underwent HFS and hs-TnI assays. MACE was defined as postoperative all-cause deaths, heart failure （HF）, new-onset atrial fibrillation （AF）, myocardial infarction （MI） and cardiovascular re-hospitalization that occurred within 90 days postoperative. Results Of 262 HFS patients, MACE developed following HFS in 65 （24.8%）. Patients with MACE were older and had higher rates of renal insufficiency, coronary artery disease, prior HF, low left ventricular ejection fraction and use of beta blockers; higher levels of hs-Tnl and N-terminal pro-brain natriuretic peptide （NT-proBNP） and higher revised cardiac risk index. A preoperative hs-TnI≥ 6.5 ng/L was associated with high risk of postoperative HF, new-onset AF and MACE. In multivariable analysis, pre-operative independent predictors for MACE were age 〉 80 years [adjusted hazard ratio （HR）： 1.79, 95% confident interval （CI）： 1.03-3.13, P = 0.04], left ventricular ejection fraction （LVEF）〈 50% （adjusted HR： 3.17, 95% CI： 1.47-5.82, P 〈 0.01） and hs-TnI 〉 6.5 ng/L （adjusted HR： 3.75, 95% CI： 2.09~5.17, P 〈 0.01）. Conclusion In elderly patients with hip fracture who undergo HFS, a preoperative assessment of hs-TnI may help the risk refinement of cardiovascular complications.

关键词： Cardiovascular complication High sensitive troponin I Hip fracture surgery

Flexible thermocells for utilization of body heat

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Nano Research 2014年第4期7卷 443-452页

作者： Hyeongwook Im Hyung Geun Moon jeong Seok Lee In Young Chung tae June Kang Yong Hyup kim School of Mechanical and Aerospace Engineering Seoul National University Seoul 151-742 Republic of Korea Department of Electronics and Communications Engineering Kwangwook University Seou1139-701 Republic of Korea Department of Nanofusion Technology Pusan National University Busan 609-735 Republic of Korea

Plastic thermo-electrochemical ceils （thermocells） involving aqueous potassium ferricyanide/ferrocyanide electrolyte have been investigated as an alternative to conventional thermoelectrics for thermal energy harvesting. Plastic thermocells that consist of all pliable materials such as polyethylene terephthalate （PET）, fabrics, and wires are flexible enough to be wearable on the human body and to be wrapped around cylindrical shapes. The performance of the thermocells is enhanced by incorporating carbon nanotubes into activated carbon textiles, due to improved charge transfer at the interface. In cold weather conditions （a surrounding temperature of 5 ℃）, the thermocell generates a short-circuit current density of 0.39 A/m2 and maximum power density of 0.46 mW/m2 from body heat （temperature of 36℃）. For practical use, we have shown that the thermocell charges up a capacitor when worn on a T-shirt by a person. We also have demonstrated that the electrical energy generated from waste pipe heat using a serial array of the thermocells and voltage converters can power a typical commercial light emitting diode （LED）.

关键词： wearable thermocell body heat waste heat recovery carbon nanotubes activated carbon textile porous electrode

Clinical usefulness of transpapillary removal of common bile duct stones by frequency doubled double pulse Nd:YAG laser

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World Journal of Gastroenterology 2008年第18期14卷 2863-2866页

作者： tae Hyeon kim Hyo jeong Oh Chang-Soo Choi Dong Han Yeom Suck Chei Choi Department of Internal Medicine and Digestive Disease Research Institute Wonkwang University School of Medicine Iksan 570180 Korea

AIM: To study the efficacy and the safety of laser lithotripsy without direct visual control by using a balloon catheter in patients with bile duct stones that could not be extracted by standard technique. METHODS: The seventeen patients (7 male and 10 female; mean age 67.8 years) with difficult common bile duct (CBD) stones were not amenable for conventional endoscopic maneuvers such as sphincterotomy and mechanical lithotripsy were included in this study. Laser wavelengths of 532 nm and 1064 nm as a double pulse were applied with pulse energy of 120 mJ. The laser fiber was advanced under fluoroscopic control through the ERCP balloon catheter. Laser lithotripsy was continued until the fragment size seemed to be less than 10 mm. Endoscopic extraction of the stones and fragments was performed with the use of the Dormia basket and balloon catheter. RESULTS: Bile duct clearance was achieved in 15 of 17 patients (88%). The mean number of treatment sessions was 1.7 ± 0.6. Endoscopic stone removal could not be achieved in 2 patients (7%). Adverse effects were noted in three patients (hemobilia, pancreatitis, and cholangitis). CONCLUSION: The Frequency Doubled Double Pulse Nd:YAG (FREDDY) laser may be an effective and safe technique in treatment of difficult bile duct stones.

关键词： Bile duct stones Frequency doubled double pulse Nd:YAG laser Transpapillary removal Mechanical lithotripsy Balloon catheter

Avoiding heating interference and guided thermal conduction in stretchable devices using thermal conductive composite islands

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Nano Research 2021年第9期14卷 3253-3259页

作者： Seung Ji Kang Haeleen Hong Chanho jeong Ju Seung Lee Hyewon Ryu Jae-hun Yang Jong Uk kim Yiel Jae Shin tae-il kim School of Chemical Engineering Sungkyunkwan University(SKKU)Suwon 16419Republic of Korea Department of Biomedical Engineering Sungkyunkwan University(SKKU)Suwon 16419Republic of Korea Biomedical Institute for Convergence(BICS) Sungkyunkwan University(SKKU)Suwon 16419Republic of Korea

The miniaturization and high integration of devices demand significant thermal management *** technologies for the thermal management of electronics show some limitations in the case of multiple chip arrays.A device in multiple chip array is affected by heat from adjacent devices,along with thermal conductive *** address this problem,we present a nano composite of aligned boron nitride(BN)nanosheet islands with porous polydimethylsiloxane(PDMS)foam to have mechanical stability and non-thermal *** islands of tetrahedrally-structured BN in the composite have a high thermal conductivity of 1.219 W·m^(-1)·K^(-1) in the through-plane direction(11.234W·m^(-1)·K^(-1)in the in-plane direction)with 16 wt.%loading of *** the other hand,porous PDMS foam has a low thermal conductivity of 0.0328W·m^(-1)·K^(-1) in the through-plane direction at 70%*** pathways are then formed only in the structured BN islands of the *** porous PDMS foam can be applied as a thermal barrier between structured BN islands to inhibit thermal interference in multiple device ***,this composite can maintain selective thermal dissipation performance with 70%tensile *** beauty of the work is that it could have guided heat dissipation by assembling of multiple layers which have high vertical thermal conductive islands,while inhibiting thermal *** selective heat dissipating composite can be applied as a heatsink for multiple chip arrays electronics.

关键词： selective thermal conduction non-thermal interference thermal conductive composite island stretchable electronics structured boron nitride nanosheet(s-BN) porous polydimethylsiloxane(p-PDMS)

A combination strategy of functionalized polymer coating with Ta ion implantation for multifunctional and biodegradable vascular stents

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Journal of Magnesium and Alloys 2021年第6期9卷 2195-2207页

作者： Kwang-Hee Cheon Cheonil Park Min-Ho Kang Suhyung Park Jinyoung kim Seol-Ha jeong Hyoun-Ee kim Hyun-Do Jung tae-Sik Jang Department of Materials Science and Engineering Seoul National UniversitySeoul 08826Republic of Korea Department of Chemical and Biological Engineering Seoul National UniversitySeoul 08826Republic of Korea Department of Biomedical-Chemical Engineering Catholic University of KoreaBucheon-si 03083Republic of Korea Department of Biotechnology The Catholic University of KoreaBucheon-si 14662Republic of Korea Department of Materials Science and Engineering Chosun UniversityGwangju 61452Republic of Korea

Biodegradable stents made of magnesium(Mg)and its alloys have been developed to minimize persistent inflammation or in-stent restenosis,which are the main problems for permanent ***,their rapid corrosion behavior under physiological conditions leads to poor vascular compatibility and premature structural failure,which remains an important unsolved clinical ***,we demonstrate a new strategy for solving this problem by combining poly(ether imide)(PEI)coating and subsequent tantalum(Ta)ion *** PEI coating covers the whole surface of the Mg stent uniformly via a spray coating technique and provides Mg with superior corrosion resistance and stable sirolimus-carrying *** ion implantation is conducted by a sputtering-based plasma immersion ion implantation technique only onto the luminal surface of the PEI-coated Mg *** extremely short processing time(<30 s)permits preservation of the PEI coating’s corrosion protection ability and sirolimus loading *** addition,a Ta-implanted skin layer that forms on the topmost surface of the PEI coating plays an effective role in not only preventing a rapid release of sirolimus from the surface but also improving the PEI coating’s surface *** on in vitro cellular response and blood compatibility tests,Ta ion implantation leads to the improvement of endothelial cell adhesion/proliferation and suppression of platelet adhesion/activation regardless of sirolimus *** results indicate that the combination of PEI coating and Ta ion implantation has significant innovative potential to provide excellent vascular compatibility and prevent in-stent restenosis and thrombosis.

关键词： Magnesium stent Biodegradability Tantalum Plasma immersion ion implantation Multifunctionality

Adult intussusception caused by cystic lymphangioma of the colon:A rare case report

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World Journal of Gastroenterology 2006年第13期12卷 2130-2132页

作者： tae Oh kim Jung Hyun Lee Gwang Ha kim jeong Heo Dae Hwan Kang Geun Am Song Mong Cho Division of Gastroenterology Department of Internal Medicine College of MedicinePusan National University College of MedicineBusanKorea

We experienced a case of intussusception caused by cystic lymphangioma of the colon in a 32 years old female who was admitted to our hospital for the chief complaint of bloody stool. In the colonoscopic examination, cystic mass with stalk which had smooth mucosal surface was noted at the descending colon. Abdominal ultrasonography and computed tomography revealed left colon intussusception with a multilocular cystic tumor as a leading point. Emergent operation was performed. On the histopathologic examination, the cystically dilated spaces lined by endothelium and septated by fibrous septa were present. The pathological diagnosis was cystic lymphangioma of the colon. Although intussusception due to lymphangioma in an adult are rare, it should be taken into consideration that it is possible diagnosis.

关键词： Cystic lymphangioma of the colon Adult intussusception