• Title/Summary/Keyword: Hwang Yong-Ha

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A Study on the Optimization of New Renewable Energy Systems in Public-Purpose Facilities (공공용 업무시설의 신재생에너지시스템 최적화 연구)

  • Lee, Yong-Ho;Seo, Sang-Hyun;Cho, Young-Hum;Hwang, Jung-Ha
    • Journal of the Korean Solar Energy Society
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    • v.33 no.5
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    • pp.95-104
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    • 2013
  • This study set out to devise an optimized system to take into account life cycle cost(LCC) and ton of carbon dioxide($TCO_2$) by applying the weighted coefficient method(WCM) to "public-purpose" facility buildings according to the mandatory 5% and 11% of new renewable energy in total construction costs and anticipated energy consumption, respectively, based on the changes of the public obligation system. (1) System installation capacity is applied within the same new renewable energy facility investment according to the mandatory 5% of new renewable energy in total construction costs. Both LCC and $TCO_2$ recorded in the descending order of geothermal, solar, and photovoltaic energy. The geothermal energy systems tended to exhibit an excellent performance with the increasing installation capacity percentage. (2) Optimal systems include the geothermal energy(100%) system in the category of single systems, the solar energy(12%)+geothermal energy(88%) system in the category of 2-combined systems, and the photovoltaic energy(12%)+solar energy(12%)+geothermal energy(76%) system and the photovoltaic energy(12%)+solar energy(25%)+geothermal energy(63%) system in the category of 3-combined systems. (3) LCC was the highest in the descending order of photovoltaic, geothermal and solar energy due to the influences of each energy source's correction coefficient according to the mandatory 11% of new renewable energy in anticipated energy consumption. The greater installation capacity percentage photovoltaic energy had, the more excellent tendency was observed. $TCO_2$ recorded in the descending order of geothermal, photovoltaic and solar energy with the decreasing installation capacity of photovoltaic energy. The greater installation capacity percentage a geothermal energy system had, the more excellent tendency it demonstrated. (4) Optimal systems include the geothermal energy(100%) system in the category of single systems, the photovoltaic energy(62%)+geothermal energy(38%) system in the category of 2-combined systems, and the photovoltaic energy(50%)+solar energy(12%)+geothermal energy(38%) system and the photovoltaic energy(12%)+solar energy(12%)+geothermal energy(76%) system in the category of 3-combined systems.

Clinical diagnostic study on Physiological Signal data measured on 31 cases of lumbago with EAV(Electro-puncture According to Voll) (요통환자(腰痛患者) 31례(例)에 대(對)한 EAV측정치(測定値)의 진단적(診斷的) 고찰(考察))

  • Han, Sang-Gyun;Ha, Chi-Hong;Kim, Jae-Hong;Cho, Myung-Rae;Bae, Eun-Jeong;Shin, Young-Il;Yang, Ki-Yong;Hwang, Kyu-Jung;Lee, Byung-Ryul
    • Journal of Acupuncture Research
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    • v.19 no.1
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    • pp.101-110
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    • 2002
  • Background and Purpose : Most diagnostic method for lumbago were invasive and complex. So we need to simplify and objectify diagnostic method for lumbago. Some study with EAV which is one of Physiological Signal Measuring Instruments, report significantly result as objective diagnostic method for other clinical symptom. By using EAV, we have obtained some physiological signal data from meridian-acupoints of 31 lumbago cases. Objective and Methods : This study researched into the clinical statistics for 31 case who ware in lumbago, and they ware treated with oriental medical care at the Dong-shin university oriental hospital during 6 month from June 1 2001 to November 10 2001. The data were analyzed and interpreted to compare with traditional differentiation of symptom-complexes, then further evaluated as the Five Evolutive Phases to make them differentiated. The EAV valus of Five Evolutive Phases were identified with the sequence of wood(木), fire(火), earth(土)steel(金), water(水). Results and Conclusion : These values of physiological signal were identical with standard differentiation of symptom-complexes of lumbago which is the main cause of deficiency of Qi and blood of the kidney and bladder. Among Five Evolutive Phases, Earth and wood values were increased, steel, fire and water were decreased significantly. This data imply the possibility of somewhat generalization from measuring instruments.

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Synthesis and Application of cPSMA-PSMA Microcapsule Absorbent for Cement Mortars (시멘트 모르타르용 cPSMA-PSMA 마이크로캡슐 흡수제 제조 및 적용)

  • Hwang, Ki-Seob;Jang, Seok-Soo;Jung, Yong-Wook;Lee, Seung-Han;Ha, Ki-Ryong
    • Polymer(Korea)
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    • v.36 no.2
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    • pp.216-222
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    • 2012
  • We synthesized microcapsule absorbent with crosslinked poly(styrene-$alt$-maleic anhydride) (PSMA) as a core and PSMA as a shell by a precipitation polymerization method for the delayed absorption of excess water in cement mortar. cPSMA-PSMAs with core-shell structure were synthesized with ratios of 1/1, 1/2 and 1/3 as core monomer mass to shell monomer mass to control shell thickness. We observed the hydrolysis of PSMA in cement-saturated aqueous solution by a FTIR spectrometer. We observed good core-shell structure microcapsules for 1/2(cPSMA #3), but observed incomplete core-shell structure for 1/1(cPSMA #2) and 1/3(cPSMA #4) of core/shell monomer ratios. The swelling ratio of cPSMA #3 in cement-saturated aqueous solution was increased until 20 min. After that it was decreased until 2 hrs swelling time, and they started to increase again. The viscosities of cement paste with cPSMA #3 microcapsules were very slowly increased until 1 hr and increased fast after 1.5 hrs. Cement mortar with 0.5 wt% cPSMA #1 having only core part showed about 5% increase in compressive strength compared to that of plain cement mortar. cPSMA #3 added cement mortar showed the highest compressive strength with 7% increase.

Studies on the Strength of Cement Mortars with Surface Crosslinked cPSA Absorbent (표면이 가교된 Crosslinked Poly(sodium acrylate) 흡수제가 첨가된 시멘트 모르타르의 강도 특성 연구)

  • Hwang, Ki-Seob;Jang, Seok-Soo;Jung, Yong-Wook;Lee, Seung-Han;Ha, Ki-Ryong
    • Polymer(Korea)
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    • v.36 no.2
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    • pp.208-215
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    • 2012
  • To study the effect of surface crosslinked layer on the crosslinked poly(sodium acrylate) (cPSA) absorbent, we synthesized several surface crosslinked cPSAs with 5, 10 and 20 g of ethylene glycol dimethacrylate (EGDMA) by an inverse emulsion polymerization method to delay the absorption of excess water in concrete. We measured the compressive and flexural strength of mortars having 0.5, 1.0 and 1.5 wt% cPSA-EGDMA. We observed the increase of compressive and flexural strength of the cPSA-EGDMA added cement mortars except for the 0.5 wt% cPSA-EGDMA (20 g) added cement mortar. 1.0 wt% cPSA-EGDMA (5 g) added cement mortar showed about 16% and 10% increased compressive and flexural strength than those of plain cement mortar. To study the effect of porosity on compressive and flexural strength, we used FE-SEM and porosimeter. FE-SEM analysis showed swollen cPSMAEGDMA (5 g) filled between calcium silicate hydrate (C-S-H) crystals. We observed the decreased porosity of the cPSA-EGDMA added cement mortars than that of plain cement mortar. 1.0 wt% cPSA-EGDMA (5 g) cement mortar showed the lowest porosity of 16.5%.

CAVITY FORMATION IN INTERFACE BETWEEN POWER LAW CREEP PARTICLE AND ELASTIC MATRIX SUBJECTED TO A UNIAXIAL STRESS

  • Lee, Yong-Sun;Ha, Young-Min;Hwang, Su-Chul
    • Journal of Theoretical and Applied Mechanics
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    • v.1 no.1
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    • pp.69-88
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    • 1995
  • The paper attempts to estimate the incubation time of a cavity in the interface between a power law creep particle and an elastic matrix subjected to a uniaxial stress. Since the power law creep particle is time dependent, the stresses in the interface relax. Through previous stress analysis related to the present physical model, the relaxation time is defined by ${\alpha}$2 which satisfies the equation $\Gamma$0 |1+${\alpha}$2k|m=1-${\alpha}$2 [19]. $\Gamma$0=2(1/√3)1+m($\sigma$$\infty$/2${\mu}$)m($\sigma$0/$\sigma$$\infty$tm) where $\sigma$$\infty$ is an applied stress, ${\mu}$ is a shear modulus of a matrix, $\sigma$$\infty$ is a material constant of a power law particle, $\sigma$=$\sigma$0 $\varepsilon$ and t elapsed time. the volume free energy associated with Helmholtz free energy includes strain energies associated with Helmholtz free energy includes strain energies caused by applied stress anddislocations piled up in interface (DPI). The energy due to DPI is found by modifying the results of Dundurs and Mura[20]. The volume free energies caused by both applied stress and DPI are a function of the cavity size(${\gamma}$) and elapsed time(t) and arise from stress relaxation in the interface. Critical radius ${\gamma}$ and incubation time t to maximize Helmholtz free energy is found in present analysis. Also, kinetics of cavity fourmation are investigated using the results obtained by Riede[16]. The incubation time is defied in the analysis as the time required to satisfy both the thermodynamic and kinetic conditions. Through the analysis it is found that [1] strain energy caused by the applied stress does not contribute significantly to the thermodynamic and kinetic conditions of a cavity formation, 2) in order to satisfy both thermodynamic and kinetic conditions, critical radius ${\gamma}$ decreases or holds constant with increase of time until the kinetic condition(eq.40) is satisfied. Therefore the cavity may not grow right after it is formed, as postulated by Harris[11], and Ishida and Mclean[12], 3) the effects of strain rate exponent (m), material constant $\sigma$0, volume fraction of the particle to matrix(f) and particle size on the incubation time are estimated using material constants of the copper as matrix.

Toxicities and Control Effect of Three Insecticides to Greenhouse Whitefly, Trialeurodes vaporariorum and Sweetpotato Whitefly Bemisia tabaci (Homoptera: Aleyrodidae) (몇 가지 살충제의 온실가루이와 담배가루이의 생육 단계별 살충효과 및 방제효과)

  • Ha, Tae-Ki;Hwang, In-Cheon;Kim, Jong-Kwan;Song, Yoo-Han;Kim, Gil-Hah;Yu, Yong-Man
    • The Korean Journal of Pesticide Science
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    • v.7 no.3
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    • pp.207-215
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    • 2003
  • This study was carried out to evaluate toxicities of 3 registered insecticides to greenhouse whitefly(GWF), Trialeurodes vaporariorum and sweetpotato whitefly(SWF), Bemisia tabaci, B-biotype. Insecticide activities were evaluated by testing systemic action, residual effect in the laboratory, and control efficacy in the greenhouse. All experiments were tested at the recommended concentration(RC), half and a quarter concentrations of RC of each insecticides. Acetamiprid showed 45%, 42% ovicidal effect to greenhouse whitefly and sweetpotato whitefly at 40 ppm, respectively. Acetamiprid showed more than 97% larvicidal activities on the 3rd instars larvae of GWF and SWF at the recommended and its half concentrations. On the adults of the two whitefly species, acetamiprid and acetamiprid+ethofenprox showed more than 92% mortality even at half of recommended concentrations. Acetamiprid and acetamiprid+ethofenprox showed both residual effect and systemic activity. In the control efficacy test on GWF and SWF, 90% control values were obtained at the 3th day after treatments of acetamiprid and acetamiprid + ethofenprox by application with recommended concentration. These results indicate that acetamiprid and acetamiprid+ethofenprox can be used in the control of the two whitefly species in field.

Synthesis of Surface Crosslinked Poly(sodium acrylate) for Delayed Absorption in Cement Solution (시멘트 수용액에서 흡수 지연을 위한 Crosslinked Poly(sodium acrylate)의 표면 가교)

  • Hwang, Ki-Seob;Jang, Seok-Soo;Jung, Yong-Wook;Lee, Seung-Han;Ha, Ki-Ryong
    • Polymer(Korea)
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    • v.35 no.4
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    • pp.363-369
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    • 2011
  • To study the effect of incorporation of a surface crosslinking layer on a crosslinked poly (sodium acrylate) (cPSA) absorbent with ethylene glycol dimethacrylate CEGDMA), we synthesized several surface crosslinked cPSAs with EGDMA by an inverse emulsion polymerization method to delay the absorption of excess water in concrete, Liquid paraffin was used as a continuous phase. cPSA was synthesized with acrylic acid (AA) neutralized with aqueous 8 M sodium hydroxide solution as a monomer, N,N-methylene bisacrylamide (MBA) as crosslinking agent and ammonium persulfate (APS) and sodium metabisulfite (SMBS) as a redox initiator system by inverse emulsion polymerization. FTIR spectroscopy was used to characterize $Ca^{2+}$ ion interaction with cPSA and cPSA-EGDMAs. The swelling ratios of synthesized absorbents were evaluated from the absorption in deionized water, cement saturated aqueous solution and aqueous solution of calcium hydroxide (pH 12). Equilibrium swelling times for cPSA and surface crosslinked cPSA with EGDMA were 2 and 3 hrs, respectively. We also observed an increase in setting time of the cement and an increase in the compressive strength of mortar by addition of the synthesized cPSA-EGDMA.

Surgical Treatment Guideline of Meningococal Induced Purpura Fulminans (수막알균에 의한 전격자색반의 외과적 치료지침)

  • Kim, Eui Sik;Kim, Jeong Min;Yoo, Sung In;Noh, Bok Kyun;Hwang, Jae Ha;Kim, Kwang Seog;Lee, Sam Yong
    • Archives of Plastic Surgery
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    • v.34 no.1
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    • pp.77-80
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    • 2007
  • Purpose: Purpura fulminans is a rare but rapidly progressive, serious, often life-threatening disorder in childhood, which is complicated with septic shock or disseminated intravascular coagulopathy during acute infection. It occurs first as acute-onset petechial rash, and spreads rapidly into full thickness skin and soft tissue necrosis. In the past, it had high mortality rate, up to 80%, but recently, survival rate has increased due to early diagnosis, and rapid advancement of critical care and antibiotics. From our experiences of PF management, we would like to review the pathophysiology and suggest the surgical treatment guideline about meningococcal induced purpura fulminans. Methods: Two cases of purpura fulminans over the last 3 years were reviewed retrospectively about reconstructive management. After they were treated resuscitative management initially by the critical intensive care, reconstructive surgery was performed by plastic surgeon as soon as the patients were vitally and mentally stable. Results: There were 6 procedures in case 1, and 3 procedures in case 2. The mean delayed period from admission with sepsis to the first surgical debridement was 24 days and 42 days, respectively. Total hospitalization period was 103 days and 69 days, respectively. All of them were treated with debridement and split thickness skin graft, but delayed debridement was superior to early one in the point of preserving much more tissues. Conclusion: From our experience, we suggest that conservative therapy to the wounds appears to be the best tool in the initial vitally unstable period in order to preserve as much tissues and functions as possible if no active inflammation and compartment syndrome are detective.

Mastopexy with Mammary Parenchymal Z-plasty Pattern (유방 실질 조직 Z-성형술을 이용한 유방 하수 교정술)

  • Kim, Kyung-Pil;Kim, Ji-Hoon;Hwang, Jae-Ha;Kim, Kwang-Seog;Lee, Sam-Yong
    • Archives of Plastic Surgery
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    • v.38 no.4
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    • pp.408-414
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    • 2011
  • Purpose: To correct breast ptosis, reduction mammoplasty and mastopexy have been developed in a way that minimizes complications. Recently, as the mean age of breast cancer occurrence is decreasing, the need for breast reconstruction in patients with breast cancer is rising. If mastopexy is performed with breast reconstruction at the same time, the size of the normal breast and the new one is not quite different. We decided to apply Z-plasty, which is a widely-used technique in plastic surgery to lengthen or change the direction of tension of the tissue. Methods: From March 2008 to December 2009, we performed breast reconstruction in 6 patients with breast cancer and scar contracture. After breast reconstruction, mastopexy with Z-plasty was applied to correct the asymmetry. The new nipple-areolar complex is placed on the line connecting the midclavicle and the current nipple. The inferior border of the new areola corresponds with the inferior border of the original areola, and the superior border about 2 cm upward the original superior border. We drew two oblique lines connecting the medial end of the incision line lower to the nipple-areola complex and the lateral end of the inframammary fold for Z-plasty. The excess tissue between these two lines was removed and the new triangular flaps were put together. Results: The average age of patients was 42.6 years, aged from 36.1 to 48.1 The weight of removed tissue was between 54g and 95 g, with the mean of 74 g. The average distance from the midclavicle to the nipple was 24 cm before surgery, and 21 cm after the surgery. The average operation time per patient (1 mastopexy) was 45 minutes, and the patients were satisfied with the size and shape. Conclusion: Applying Z-plasty for the mastopexy on the normal breast ptosis is a relatively simple way to achieve symmetry in patients who need breast reconstruction.

Reconstruction of Ischial Soft Tissue Defects using Adductor Magnus Perforator Island Flap (대내전근 천공지 도상 피판을 이용한 좌골부 연부조직결손의 재건)

  • Kim, Eui Sik;Park, Jang Wan;Hwang, Jae Ha;Kim, Kwang Seog;Lee, Sam Yong
    • Archives of Plastic Surgery
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    • v.36 no.5
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    • pp.559-564
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    • 2009
  • Purpose: Surgical reconstruction of an ischial soft tissue defect presents a challenging problem owing to a high rate of recurrence, especially paraplegic patients. Although various muscle, musculocutaneous and fasciocuta - neous flaps have been used in the reconstruction of ischial soft tissue defect, it is still debated which type of flaps are the best. We had performed a relatively durable adductor magnus perforator island flap based on the perforators originated from the first medial branch of the profunda femoris artery for coverage of ischial soft tissue defect where was not a region universally reconstructed by perforator flap. Methods: From August 2005 until January 2008, the adductor magnus perforator island flap had been used for resurfacing of the ischial soft tissue defects in a series of 6 patients (4 male and 2 female). Ages ranged from 26 to 67 years (mean, 47.5 years), and follow - up period from 13 to 26 months (mean, 16.7 months). Causes were 4 pressure ulcers, 1 cellulitis and 1 suppurative keratinous cyst. Results: The sizes of these flaps ranged from 12 to 18 cm in length and 7 to 9 cm in width. The flaps survived in all patients. Marginal loss over the distal area of the flap by infection was noted in one patient, which was treated successfully with a subsequent split - thickness skin graft. Average thickness of the flap was 0.94 cm, which was more thicker than other perforator flaps. Long term follow - up showed a good flap durability. Conclusion: In planning a reconstructive option of ischial soft tissue defect, the adductor magnus perforator island flap is a relatively large cutaneous flap with a durable thickness. With proper patient selection, careful vascular dissection and postoperative management, we recommend this flap is a good and suitable option for coverage of the ischial soft tissue defect.