• 농업과학연구
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• 제33권2호
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• pp.167-177
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• 2006

This study was performed to evaluate void ratio, compressive and flexural strength, and pH properties according to the admixture ratio of rice husk ash, aggregate size, and neutral treatment time of porous concrete with an admixture of rice husk ash produced as an agricultural by-product. The SEM results for cement mortar with a 5% rice husk ash admixture for the weight of cement formed more C-S-H hydrates due to the $SiO_2$ present in the applied rice husk ash. According to the results of the SEM test, the $SiO_2$ that was a major chemical element of rice husk ash generated a large amount of calcium hydroxide in the early stage of the hydration process of cement leading to the formation of ettringite. The void ratio of porous concrete with an admixture of rice husk ash decreased with increasing admixture ratio of rice husk ash. In addition, the void ratio of porous concrete with an admixture of rice husk ash decreased compared to porous concrete with no admixture of rice husk ash. The compressive and flexural strength of porous concrete with a 5% and 10% admixture ratio of rice husk ash slightly increased compared to concrete with no admixture of rice husk ash. The pH value of porous concrete rapidly decreased immediately after neutral treatment. Then, it gradually increased and decreased again after 14 days. Also, for neutral treatment, the pH value of porous concrete showed appropriate pH levels(less than 9.5) in all mixtures for planting at 28 curing days.

• Journal of Preventive Medicine and Public Health
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• 제26권4호
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• pp.628-649
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• 1993

국민학생들의 학습부진에 관련된 요인을 조사하여 의학적 예방 및 치료 대책을 고안해 보기 위해, 대구 시내에서 고소득층 밀집지역과 저소득층 밀집지역의 국민학교 1개씩을 선정하고, 각 학교의 2, 4, 6학년 학생 중 학업 성적이 하위 10%에 속하는 학생(학습부진군) 175명과 이에 대한 대조군으로 성적이 상위 5%에 속하는 학생(우수군) 97명을 대상으로 하여 이들에게 시력검사, 청력검사, 신체검사(체중, 신장, 두위)를 한 후, 고대 Stanford-Binet test를 이용한 지능검사와 TAI-K로 시험불안반응검사를 하고 발달소아학 전문의사가 신경학적 검진을 하였다. 아동의 어머니에게는 가정 환경, 어머니의 출산력, 아동의 출생 전후 및 과거력에서 의학적 특이사항, 그리고 행동양상에 관해 설문조사하고, 담임 선생에게 설문지를 통해 학교에서의 행동양상을 조사하였다. 아동의 두발을 적당량 채취하여 두발중 납, 카드뮴, 아연의 함량을 원자흡광분광광도계로 분석하였다. 학습부진과 각 요인과의 단순상관 관계분석에서 통계적으로 유의한 요인들을 이용한 다중지수형 회귀분석 (multiple logistic regression analysis)을 하여 학습부진의 관련요인을 찾았다. 단순분석에서 학습부진과 유의한 관련성이 있는 것은 남아인 경우, 출산순위가 높은 경우, 결손가정인 경우, 부모의 학력이 낮거나 직업이 노동직인 경우, 아동의 체중, 신장 및 두위가 작은 경우, 시력장애가 있는 경우, 지능지수가 낮은 경우, 시험불안반응점수가 높은 경우, 과잉활동성 아동인 경우로 나타났다. 다중지수형 회귀분석결과 학습부진과 관련되는 요인은 아동의 높은 출산순위 (odds ratio=2.06), 남아인 경우(odds ratio=5.91), 결손가정(odds ratio=9.29), 신장이 표준치-1 표준편차보다 작은 경우(odds ratio=11.12), 높은 시험불안점수(odds ratio=1.07), 과잉활동성 장애아동(odds ratio=9.67), 그리고 지능지수(odds ratio=0.85)였다. 두발중 중금속 함량의 분석결과 모두 학습부진과 뚜렷한 관련성이 없었으며, 납과 카드뮴의 함량은 학습부진군과 우수군 모두 남아가 여아에 비해 높았으며, 남은 학년과 역상관 관계(p<0.05)를, 아연은 정상관 관계(p<0.05)를 나타내었다. 학습부진과 유의한 관련성이 있는 요인들 중 조정가능한 것은 출산순위, 신장, 과잉활동성 장애 등으로, 가족계획을 통해 알맞은 수의 자녀를 갖도록 하고, 영유아기에서부터 사춘기에 이르기까지 적절한 영양공급을 하며, 과잉활동성 아동을 조기에 발견하여 의사의 진단을 받아 치료를 받도록 하는 것이 학습부진을 예방 및 해결하는데 도움이 될 것이다. 또한 부모와 담임 선생이 학습부진아에게 본인의 지적능력 이상의 기대나 학습의 강요로 불안을 조장하지 않도록 해야 할 것이다.

• 대한물리의학회지
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• 제5권3호
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• pp.363-373
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• 2010

Purpose : The purpose of this study was to compare differences in thoracolumbar ranges of motions by comparing ratios among 4 type diagnosis for patient with chronic low back pain. Methods : The subjects were 58 chronic low back pain patients. A motion analysis program (Global Postural System) was used after photography for posture measurement. To analyze differences in mobility percentages and ratios of thoracolumbar ranges of motion, one-way ANOVA was used. Results : Regional difference spinal posture and movement were found to diagnosis patients with chronic low back pain. Comparison of thoracolumbar ranges of motion revealed significant differences in the thoracic region during forward-bending of the trunk (p<.05). In the upper thoracic region, the herniated intervertebral lumbar disc (HILD) group was significantly larger than the spinal stenosis/herniated intervertebral lumbar disc (SS/HILD) group (p<.05). In the lower thoracic region, chronic sprains (CS) were significantly greater than in the spinal stenosis (SS) group and in the (SS/HJLD) group (p<.05). Comparative analysis of thoracic/lumbar mobility ratio showed the CS group's ratio during forward bending was largest: 1.66, while the HILD group's ratio was smallest: 84 a significant difference between the two groups (p<.01). Diagnosis was not associated with difference in thoracolumbar backward-bending range of motion (p>.05). Conclusion : Theses results indicate the clinical efficacy of diagnosing for chronic low back pain by evaluating spinal mobility.

• 한국건설관리학회논문집
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• 제5권5호
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• pp.143-150
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• 2004

본 연구는 다기준의사결정문제인 건설 프로젝트의 공법선정문제에 있어서 퍼지계층분석법 및 그 결과 생성되는 각 공법별 퍼지 점수의 상대평가를 위해 퍼지 선호도 함수를 적용하여 상대평가를 하고자 하였다. 지금까지의 건설 공법 선정에 대한 퍼지계층분석법에 대한 연구는 대부분 최종적인 공법선정을 위해서 각 공법별로 도출된 퍼지 점수의 순위결정기법으로 절대평가를 수행하였다. 그러나 이러한 기법은 비교 대상공법에 대한 일관적인 순위결과를 산출해 내지 못하므로 결과적으로 공법선정과정의 전반적인 타당성을 저해하는 문제점을 지니고 있었다. 따라서 본 연구에서는 건설 분야의 MCDM(Multiple Criteria Decision Making)에 관한 기존의 연구들을 바탕으로 순위 결정기법에 R.P.R(Relative Preference Ratio)기법을 도입하여 각 공법에 대한 퍼지 점수를 상대 평가함으로써 체계적이고 효율적인 건설 공법선정기법을 제시하였고, 이를 창호공법의 선정문제에 적용하여 그 타당성을 살펴보았다.

• 보험의학회지
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• 제2권1호
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• pp.195-217
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• 1985

A statistical analysis on the ratio of weight-for-height in insurance medicine was carried out in a total of 12,690 insured persons who were medically examined at the Honam medical department, Dong Bang life insurance company, ltd. from June, 1979 to February, 1984. The results were as follows: 1. The mean value of the ratio of weight-for-height(W/H ratio) was $102.3{\pm}11.3%$ in all males, and $105.2{\pm}103.6%$ in all females. The difference of the values between males and females showed statistical significance(P<0.001). The mean value of W/H ratio in all the insureds was $103.8{\pm}12.9%$. In each age group, the mean value of female was higher than that of male without exception(P<0.001). The mean value of both sexes in each age group showed gradual increase with age except for the age group over 50(P<0.001). 2. The incidences of the average weighted, overweighted and underweighted lives were respectively 91.6% in all males, 84.2% in all females(P<0.001); 7.9% in all males, 15.4% in all females(P<0.001); 0.5% in all males, 0.4% in all females(P>0.05). The incidences of average weighted, overweighted and underweighted lives in all the insureds were respectively 87.6%, 12.0% and 0.5%. The incidence of the average weighted lives in male in each age group was always higher than that in female with the exception of the age group below 19(P<0.001), whereas the incidence of the overweighted lives in male in each age group was always lower than that in female(P<0.05 in the age group below 19, P<0.001 in the other age groups). The incidence of average weighted lives of both sexes in each age group showed gradual decrease with age from the second to fifth decade(P<0.001), whereas the incidence of the overweighted lives of both sexes in each age group showed gradual increase with age from the second to fifth decade(P<0.001). 3. The relative frequency distribution polygons of W/H ratio of both sexes drawn in a pair on one coordinate plane revealed lying in juxtaposition each other horizontally and showed the shifting of female's polygon to male's one toward the direction of greater value of W/H ratio at a short distance which increased gradually with age. 4. Correlations between both sexes and among age groups relating to W/H ratios of the insureds seem to be a physiological phenomenon of body build and should be considered on the rating of the build. Author prepared a rating table of build based on the correlations above menthioned. Some gradients by sex and age in the rating table of build are organized; in female group, the ratings of 0, 30-50, 50-100 and 100-D are to calculate by the build with W/H ratio of 80-125%, $126{\sim}145%,\;146{\sim}165%$ and over 166% respectively in the age group of 29 or under, by the build with W/H ratio of $80{\sim}130%,\;131{\sim}150%,\;151{\sim}170%$ and over 171% respectively in the age group of $30{\sim}59$, and by the build with W/H ratio of $80{\sim}135%,\;136{\sim}155%,\;156{\sim}175%$ and over 176% respectively in the age group of 60 or over. In male group, the ratings of 0, $30{\sim}50$, 50-100, and 100-D are to calculate by the build with W/H ratio of $80{\sim}120%,\;121{\sim}140%,\;141{\sim}160%$ and over 161% respectively in all ages. Of under weighted lives, in both sexes, the ratings of 30-50 and 50-D are to calculate by the build with W/H ratio of $76{\sim}79%$ and under 75% respectively. The results of the ratings according to a rating table by author were as follows: The incidence of the ratings of 0, 30-50, 50-100 and 100-D showed no difference between male and female. The incidence of the ratings of 0(indicating the average weighted lives) showed gradual decrease with age and the incidence of the ratings of 30-50 and 50-100(indicating the overweighted lives) showed gradual increase with age. These results are thought to be considerably reasonable because the incidence of the builds in each age group is supposed to have no difference by sex and the incidence of the overweighted lives would increase with age.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.291.1-291.1
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• 2016

Graphene by one of the two-dimensional (2D) materials has been focused on electronic applications due to its ultrahigh carrier mobility, outstanding thermal conductivity and superior optical properties. Although graphene has many remarkable properties, graphene devices have low on/off current ratio due to its zero bandgap. Despite considerable efforts to open its bandgap, it's hard to obtain appropriate improvements. To solve this problem, heterojunction barristor was proposed based on graphene. Mostly, this heterojunction barristor is made by transition metal dichalcogenides (TMDs), such as molybdenum disulfide ($MoS_2$) and tungsten diselenide ($WSe_2$), which have extremely thickness scalability of TMDs. The heterojunction barristor has the advantage of controlling graphene's Fermi level by applying gate bias, resulting in barrier height modulation between graphene interface and semiconductor. However, charged impurities between graphene and $SiO_2$ cause unexpected p-type doping of graphene. The graphene's Fermi level modulation is expected to be reduced due to this p-doping effect. Charged impurities make carrier mobility in graphene reduced and modulation of graphene's Fermi level limited. In this paper, we investigated theoretically and experimentally a relevance between graphene's Fermi level and p-type doping. Theoretically, when Fermi level is placed at the Dirac point, larger graphene's Fermi level modulation was calculated between -20 V and +20 V of $V_{GS}$. On the contrary, graphene's Fermi level modulation was 0.11 eV when Fermi level is far away from the Dirac point in the same range. Then, we produced two types heterojunction barristors which made by p-type doped graphene and graphene treated 2.4% APTES, respectively. On/off current ratio (32-fold) of graphene treated 2.4% APTES was improved in comparison with p-type doped graphene.

• 생물정신의학
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• 제21권4호
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• pp.168-174
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• 2014

Objectives Sensory gating dysfunctions in patients with schizophrenia and bipolar disorder have been investigated through two similar methods ; P50 suppression and prepulse inhibition paradigms. However, recent studies have demonstrated that the two measures are not correlated but rather constitute as distinct neural processes. Recent studies adopting spectral frequency analysis suggest that P50 suppression reflects the interaction between gamma and other frequency bands. The aim of the present study is to investigate which frequency component shows more significant interaction with gamma band. Methods A total of 108 mood disorder patients and 36 normal subjects were included in the study. The P50 responses to conditioning and test stimuli with an intra-pair interval of 500 msec were measured in the study population. According to P50 ratio (amplitude to the test stimulus/amplitude to the conditioning stimulus), the subjects with P50 ratio less than 0.2 were defined as suppressed group (SG) ; non-suppressed group (NSG) consisted of P50 ratio more than 0.8. Thirty-five and 25 subjects were included in SG and NSG, respectively. Point-to-point correlation coefficients (PPCCs) of both groups were calculated between two time-windows : the first window (S1) was defined as the time-window of one hundred millisecond after the conditioning auditory stimulus and the second window (S2) was defined as the time-window of 100 msec after the test auditory stimulus. Spectral frequency analysis was performed to investigate which frequency band results in the difference of PPCC between SG and NSG. Results Significant reduction of PPCC between S1 and S2 was observed in the SG (Pearson's r = 0.24), compared to PPCC of the NSG (r = 0.58, p < 0.05). In spectral frequency analysis, gamma band showed "phase-reset" and similar responses after the two auditory stimuli in suppressed and non-suppressed group. However in the case of alpha band, comparison showed significantly low PPCC in SG (r = -0.14) compared to NSG (r = 0.36, p < 0.05). This may be reflecting "phase-out" of alpha band against gamma band at approximately 50 msecs after the test stimulus in the SG. Conclusions Our study suggests that normal P50 suppression is caused by phase-out of alpha band against gamma band after the second auditory stimulus. Thus it is demonstrated that normal sensory gating process is constituted with attenuated alpha power, superimposed on consistent gamma response. Implications of preserved gamma and decreased alpha band in sensory gating function are discussed.

• 생물환경조절학회지
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• 제10권2호
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• pp.95-100
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• 2001

본 연구에서는 팽연화왕겨를 이용한 토마토 양액재배시 높은 근권 pH를 적정 수준으로 유지학 위해 공급배양액의 pH를 낮추는 방안과 배지 내에 pH 3.0∼4.0 수준의 sphagnum peatmoss를 혼합하는 두 가지 방법을 시도하였다. 급액 pH를 낮추는 방법은 근권 pH의 경시적 변화가 매우 커서 뿌리에 장해가 있는 것으로 판단되며, 유의성은 없으나 수량이 약간 감소하는 경향을 보였다. Spagnunm peatmoss를 혼합하는 방법은 10%(v/v) 혼합처리에서 안정적인 pH 수준이 생육 전기간에 걸쳐 유지되었으며 수분 특성 개선 등의 부수적인 효과가 있어 유의성 있는 증수 효과를 보여 팽연화왕결르 이용한 양액재배시 높은 근권 pH의 문제는 sphagnum peatmoss를 10%(v/v) 혼합하는 처리로 해결할 수 있을 것으로 판단되었다.

• Journal of Animal Science and Technology
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• 제47권4호
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• pp.625-636
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• 2005

본 연구는 비섬유탄수화물(NFC)과 반추위분 해단백질(RDP)을 젖소사료에 다양하게 배합하여 NFC : RDP의 비율을 3.5, 3.0 및 2.5로 다양하게 조정하였을 때, in vitro 발효성상 및 젖소의 산유성적에 미치는 영향을 조사하여 적정 NFC : RDP비율을 결정하고자 실시하였다. In vitro 발효시험은 반추위 cannulae가 장착된 Holstein 젖소로부터 반추위액을 얻어 3, 6, 9, 12시간 동 안 배양하였다. 반추위내 pH는 NFC비율이 증가함에 따라 유의한 영향을 받지 않았고, 암모 니아질소농도는 배양 6시간까지 처리군간에 유의한 차이가 나타나지 않았으나, 9시간과 12 시간에서는 NFC : RDP비율이 증가함에 따라 유의하게 감소하였다(P < 0.05). 휘발성지방산생산 량은 acetate 및 propionate농도가 발효 3시간에 NFC함량이 증가함에 따라 유의하게 증가하였 으나(P < 0.05), 나머지 시간대에서는 유의차가 나타나지 않았다. Valerate 및 A : P비율은 NFC : RDP비율에 의하여 영향을 받지 않았고, iso- acids 및 총 휘발성지방산은 전반적으로 NFC함 량이 증가함에 따라 유의하게 증가하였으며(P < 0.05), 3.0비율구가 가장 높은 값을 나타내었다(P < 0.01). 한편, 사양시험은 18 두의 착유우를 공시하여 처리구당 6 두씩 배치하여 총 24주간 실시하였 다. 건물 및 에너지섭취량은 NFC : RDP비율이 증가함에 따라 유의하게 증가하였고(P < 0.01), 섬 유소섭취량은 NFC : RDP비율이 감소함에 따라 직선적으로 증가하였다(P < 0.01). 산유량은 3.5(32.7 kg)비율구가 다른 처리구보다 유의하게 높았다(P < 0.05). 유지방율은 3.0(3.79 %) 및 2.5(3.79 %)비율구가 3.5(3.48 %)비율구보다 유의하 게 높았고(P < 0.05), 유지방생산량은 처리구간 에 차이가 나타나지 않았다. 유단백질과 무지 고형분은 NFC : RDP비율이 증가함에 따라 직선 적으로 증가하였다(P < 0.01). 그러나 우유중 요소태질소농도는 NFC함량이 증가함에 따라 유 의하게 감소하였다(P < 0.05). 이상의 결과로부터 사료내 증가하는 수준의 NFC는 반추위발효, 질소이용효율 및 산유량을 향상시켰고, 사료중 NFC : RDP비율이 3.0이상일 때 반추위발효뿐만 아니라 산유성적이 최대화되는 것으로 나타났다.

• 한국세라믹학회지
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• 제35권8호
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• pp.813-818
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• 1998

A simple method to measure the elastic modulus E and Poisson's ratio v of diamod-like carbon (DLC) films deposited on Si wafer was suggested. Using the anisotropic etching technique of Si we could make the edge of DLC overhang free from constraint of Si substrate. DLC film is chemically so inert that we could not on-serve any surface damage after the etching process. The edge of DLC overhang free from constraint of Si substrate exhibited periodic sinusoidal shape. By measuring the amplitude and the wavelength of the sinu-soidal edge we could determine the stain of the film required to adhere to the substrate. Since the residual stress of film can be determine independently by measurement of the curvature of film-substrate com-posite we could calculated the biaxial elastic modulus E/(1-v) using stress-strain relation of thin films. By comparing the biaxial elastic modulus with the plane-strain modulus E/(1-{{{{ { v}^{2 } }}) measured by nano-in-dentation we could further determine the elastic modulus and Poisson's ratio independently. This method was employed to measure the mechanical properties of DLC films deposited by {{{{ { {C }_{6 }H }_{6 } }} rf glow discharge. The was elastic modulus E increased from 94 to 169 GPa as the {{{{ { V}_{ b} / SQRT { P} }} increased from 127 to 221 V/{{{{ {mTorr }^{1/2 } }} Poisson's ratio was estimated to be abou 0.16∼0.22 in this {{{{ { V}_{ b} / SQRT { P} }} range. For the {{{{ { V}_{ b} / SQRT { P} }} less than 127V/{{{{ {mTorr }^{1/2 } }} where the plastic deformation can occur by the substrate etching process however the present method could not be applied.