중공슬래브 연속교의 거동시험 및 격자구조해석

곽계환,장기웅,곽경헌 圓光大學校大學院 1995 論文集 Vol.14 No.-

본 연구의 목적은 중공슬래브 연속교의 실제거동에 근접하는 합리적인 격자해석모델(grillage analysis model)을 제시하고 이방성(orthotropic)고 등방성(isotropic)에 대한 거동 특성을 비교 분석하는데 있다. 중공슬래브 연속교의 구조거동을 잘 표현함과 동시에 해석하는데 시간과 노력이 비교적 적게 드는 격자망을 구성하기 위해 교축방향과 교축직각방향의 부재수가 각기 다른 세가지의 격자모델에 대해 해석을 실시하고, 각각의 모델에 대해 이방성과 등방성의 단면상수를 적용하여 그 결과를 비교 분석한다. 그리고 실제교량에 대해 현장에서의 정적 및 동적 재하시험을 실시한 후 그 시험결과와 해석결과를 비교함으로써 격자모델의 타당성을 입증하고 합리적인 격자망을 제시한다. The aim of this paper is to present a resonable grillage model for approxmately analyzing actual behavior of a voided slab bridge and to compare two geometrical properties of isotropic and orthotropic in the bridge deck. In this study, three models were prepared and analyzed to form the grillage mesh relevant to the voided slab continuous bridge. The grillage mesh was consisted of the longitudinal beams and the transverse beams equivalent to the prototype slab stiffness . By applying the different section properites fo isotropic and orthotropic slab to each model, the difference of the resultant force was compared and studied. The loading tests in field were carried out to evaluate the static and dynamic behavior of a existing voided slab bridge. The results from the tests have been compared with it analyzed with the grillage model. Finally, it is concluded that the total number of logitudinal members should be les B(slab width)/1.5, spacing of transverse members should be about L(span length)/2.5.

정신분열병의 경과 중 발생하는 우울증

곽경환,박두병,최태영,민경준,이영식,기백석,나철 大韓神經精神醫學會 2002 신경정신의학 Vol.41 No.3

연구목적 : 정신분열병을 음성증상군과 양성증상군으로 나누어 두 군 사이에 우울증이 차이가 있는지를 조사하고 정신분열별의 증상과 우울증과의 연관과 정신분열병의 경과 중 보이는 우울증사의 특징에 대해서 알아보고자 하였다. 방 법 : 중앙대학병원에 입원한 총 31명(남자 13명, 여자 18명)의 정신분열병 환자를 대상으로 PANSS, BDI, HDRS와 Simpson Angus Scale을 시행하였다. 결 과 : 1) BDI 21점 이상을 기준으로 했을 때, 정신분열병의 경과 중 우울증이 발생한 환자는 총 18%였으며, 양성증상군과 음성증상군 간에 차이는 없었다. 2) 양성증상군과 음성증상군 간에 BDI, HDRS 그리고 PANSS-D 등의 점수의 차이는 없었다. 3) 주관척도인 BDI와 객관척도인 HDRS와 PANSS-D 사이의 연관은 없었다. 결 론 : 정신분열병의 우울증은 양성증상이나 음성증상의 한 부분으로 생각하기보다는 또 다른 영역으로 받아들여야 할 것으로 보인다. 임상적으로 정신분열병에서 우울증은 발생되는 비율의 정도를 고려할 대 다른 증상과 더불어 집중적인 관심이 필요하며 이와 함께 우울증으로 인한 결과와 예후의 심각성을 고려할 때 우울증에 대한 인식 및 진단과 치료에 더 많은 진전이 있어야 한다. Objective : The heterogeneity of symptomatology within the group of schizophrenias is still a major obstacle for defining clinically useful subgroups of these disorders. One of these symptoms is depression. Recently there is a growing evidence suggesting that depressive symptoms and related mood disturbances are important in treating schizophrenia. This so because of the improvement of such side effects as extraphramidal symptoms with increasing use of atypical antipsychotics. Althought depression is known to be a serious problems of many schizophrenic patients, the nature and course of depression in schizophrenia remain unknown. Methods : The author examined the depressive features in 31 patients with schizophrenia. Rating on the PANSS, BDI and HDRS were obtained. Eighteen percent of the total patients had BDI score above 21, considered depressed. Results : There were no difference in BDI, hDRS and PANSS-D between positive symptoms group and negative synptom group. There was also no correlation between subject scale(BDI) and objective scales(HDRS, PANSS-D). Conclusions : Depression in schizophrenia needs intensive studies. It is also considered as another hereogeneous domain beside negative or positive symptom domain. Out of respect for the high prevalence and serious outcome of depression in schizophrenia, a more differentiated assessment, analysis, and treatment of depressive symptom is recommended.

서울의 PPNG 발생 빈도(1991-1992)

김재홍,윤기범,박평원,김영진,전경민,김영태,김중환,곽호,구상완,송민석,유옥,지혜구,김동원,문상은,박영립,정승호,성범진,성순제,엄주용,황정열,이기홍,이주협,전태진 대한화학요법학회 1994 대한화학요법학회지 Vol.12 No.1

The prevalence of PPNG among pretreated gonorrhea cases isolated at the STD clinic of Choong-Ku Public Health Center in Seoul has been studied and reported annually since 1981. In 1991, 123 strains of N.gonorrhoeae were isolated, among which 58(47.1%) were PPNG. In 1992, 98 starains of N.gonorrhoeae were isolated, among which 51(52.0%) were PPNG. In all, 109(49.3%) strains were found to be PPNG among 221 strains isolated between 1991-1992. The prevalence of PPNG in Seoul showed increased tendency till 1989, thereafter, it has been stationary or slightly decreasing.

Effects of β-Lapachone on Gastric Secretion

Yun-Bae Kim, Dongsun Park, In Geun Cho, Yun-Hui Yang, Jangbeen Kyung, Dajeong Kim, Ehn-Kyoung Choi, Tae Hwan Kwak3, Sang Ku Yoo 충북대학교 동물의학연구소 2011 Journal of Biomedical and Translational Research Vol.12 No.3

The effects of β-lapachone on gastric secretion were investigated. The pylorus of male Sprague-Dawley rats was ligated and intraduodenally injected with β-lapachone, and the volume, pH, free HCl, and total acidity of gastric fluid were measured 6 hours after the operation. Treatment with β-lapachone resulted in dose-dependent inhibition of gastric secretion Gastric fluid was reduced to 42.9% of control level by 100 mg/kg of β-lapachone, leading to an increase of pH to 6.70 from 1.85 in the control group. In parallel with the increase of pH, at this dosage, free HCl and total acidity decreased to 16.7% and 12.0%, respectively, of control levels. β-Lapachone exhibited ED50 values of 72, 46, and 47 mg/kg for inhibition of gastric volume, free HCl, and total acidity, respectively, implying a superior efficacy on gastric acid to volume. In comparison, pantoprazole (30 mg/kg) reduced the volume, free HCl and total acidity of gastric fluid to 53.0%, 26.0%, and 25.0%, respectively, of control levels, resulting in an increase in pH to 6.36. In the current study, it was confirmed that β-lapachone at an appropriate dose (100 mg/kg) exerted a higher inhibitory effect on gastric secretion than pantoprazole (30 mg/kg), a well-known proton-pump inhibitor. Therefore, it is suggested that β-lapachone could be a candidate compound for prevention or treatment of gastric ulcers induced by diverse psychological and physical stimuli.

Synthesis and Cytotoxic Activities of 2-Alkyl-2,3-dihydro-1H-2,6,9-triazacyclopenta[b]anthracene-5,10-diones[Author's correction]

Kwak, Jae-Hwan,NamGoong, Kwon,Jung, Jae-Kyung,Cho, Jung-Sook,Kim, Hwan-Mook,Park, Sung-Gyu,Yoo, Yeong-Ah,Kwon, Joo-Hee,Lee, Hee-Soon 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.9

Urban air quality simulation in a high-rise building area using a CFD model coupled with mesoscale meteorological and chemistry-transport models

Kwak, Kyung-Hwan,Baik, Jong-Jin,Ryu, Young-Hee,Lee, Sang-Hyun Elsevier 2015 Atmospheric environment Vol.100 No.-

<P><B>Abstract</B></P> <P>An integrated urban air quality modeling system is established by coupling a computational fluid dynamics (CFD) model with mesoscale meteorological and chemistry-transport models. The mesoscale models used are the weather research and forecasting (WRF) model and the community multiscale air quality (CMAQ) model, which provide the initial and time-dependent boundary conditions for the CFD model. For the consistency of chemical processes in the CFD and CMAQ models, the same chemical mechanism used in the CMAQ model is implemented in the CFD model. Urban air quality simulations are performed from 0900 to 1800 LT on 3 June 2010 in a high-rise building area of Seoul, Republic of Korea, where mobile emission sources are concentrated. The NO<SUB>2</SUB> and O<SUB>3</SUB> concentrations in the CFD simulation are evaluated with data measured at a roadside air quality monitoring station, showing better agreements than those in the CMAQ simulation. The NO<SUB>2</SUB> and O<SUB>3</SUB> concentration fields exhibit high spatial variabilities in the high-rise building area. The spatial variabilities near the surfaces are strongly associated with the heterogeneity of mobile emission on roads, whereas the spatial variabilities near the top of high-rise buildings are strongly associated with the heterogeneity of building geometry. The average NO<SUB>2</SUB> and O<SUB>3</SUB> concentrations (46 and 30 ppb, respectively, at <I>z</I> = 30 m) near the surfaces are considerably different from the NO<SUB>2</SUB> and O<SUB>3</SUB> concentrations in the CMAQ simulation (17 and 44 ppb, respectively, at <I>z</I> = 30 m), implying the insufficient urban surface representation in the CMAQ simulation. The heterogeneity of building geometry is found to enhance the vertical pollutant transport, whereas the heterogeneity of mobile emission is found to confine emitted pollutants near the surfaces. When the vertical mixing is efficient, the O<SUB>3</SUB> concentration decreases in substantial vertical ranges with the same amount of NO<SUB> <I>x</I> </SUB> emission. The integrated urban air quality modeling system realistically simulates the spatial variabilities associated with the local influences of building geometry and mobile emission. This is a promising modeling approach that accounts for multiscale influences on urban air quality.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An integrated urban air quality modeling system is developed based on a CFD model. </LI> <LI> The WRF and CMAQ models provide time-dependent boundary conditions of the CFD model. </LI> <LI> Simulation results show good agreements with the measurement at an on-road site. </LI> <LI> NO<SUB>2</SUB> and O<SUB>3</SUB> dispersion in a high-rise building area is realistically simulated. </LI> <LI> Spatial variability of air quality is associated with buildings and mobile emission. </LI> </UL> </P>

Synthesis and In Vitro Cytotoxic Activities of 2-Alkyl-2,3-dihydro-1H-2,6-diazacyclopenta[b]anthracene-5,10-diones

Kwak, Jae-Hwan,NamGoong, Kwon,Jung, Jae-Kyung,Han, Sang-Bae,Cho, Jung-Sook,Kim, Hwan-Mook,Park, Song-Gyu,Lee, Ki-Ho,Kang, Jong-Soon,Lee, Hee-Soon 대한약학회 2010 Archives of Pharmacal Research Vol.33 No.5

A series of 2-alkyl-2,3-dihydro-1H-2,6-diazacyclopenta[b]anthracene-5,10-diones (4a-f) was synthesized and their in vitro cytotoxic activities were evaluated against six human cancer cell lines (HCT15, SK-OV-3, SNB19, A549, MCF7 and MCF7/ADR). They all appeared to be less potent than doxorubicin against all doxorubicin sensitive human cancer cell lines tested. However, these compounds retained considerable cytotoxic activity against the doxorubicinresistant cell line MCF7/ADR, implying their therapeutic potential to treat doxorubicin-resistant tumors. The most active compound 4c was equipotent with doxorubicin against HCT15 cell line.

Modeling the Diurnal Variation of Urban Street Canyon Flow

Kyung-Hwan Kwak,Jong-Jin Baik,Sang-Hyun Lee 한국기상학회 2008 한국기상학회 학술대회 논문집 Vol.2008 No.-

Hierarchical Ru- and RuO2-foams as high performance electrocatalysts for rechargeable lithium-oxygen batteries

Kwak, Kyung-Hwan,Kim, Dong Wook,Kang, Yongku,Suk, Jungdon The Royal Society of Chemistry 2016 Journal of Materials Chemistry A Vol.4 No.42

<P>The structural design and synthesis of cathode materials with superior catalytic activity is still a major challenge for rechargeable lithium-oxygen batteries. Here we prepared hierarchical Ru- and RuO2-foams as binder- and carbon-free electrocatalysts<I>via</I>an electrodeposition process using a hydrogen bubble template. The as-prepared Ru- and RuO2-foams were grown vertically on stainless steel mesh, with a dendritic bracken-like structure and highly divided thin branches. These freestanding Ru- and RuO2-foams provide high catalytic activity, large space to accommodate the discharge products, short ion diffusion lengths and channels for rapid transport of oxygen and electrolytes. The hierarchically dendritic cathodes without carbon and binders present low charge/discharge overpotential, remarkable cyclability, good oxygen efficiency and reduced irreversible formation/decomposition. The excellent performance of these foams, as characterized by systematic analysis and the facile fabrication approach provide an alternative method to develop advanced cathodes for Li-O2batteries.</P>

도로 협곡 내부와 외부 간 반응성 오염물질 교환의 일변화

Kyung-Hwan Kwak,Jong-Jin Baik 한국기상학회 2013 한국기상학회 학술대회 논문집 Vol.2013 No.4