• 한국안전학회지
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• 제28권1호
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• pp.63-73
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• 2013

Dynamic strain history curve measured in the field is influenced by various factors such as vehicle type, speed, noise, temperature and running location etc.. Because such curve is used for vehicle weight estimation methodology suggested by Moses, exact strain history curve is the most important thing for exact estimation of vehicle weight. In this paper, effect of such factors mentioned above is investigated on the measured strain history curves, and results of weight estimation of vehicles are discussed quantitatively. From this study, it was known that temperature effect contained in the strain history curve measured for long time in-site gives the biggest effect on result of weight estimation and it can be removed by using the mode value. Furthermore, gross vehicle weight can be estimated within 5% error corresponding to A class of the European classification if effects of temperature and noise are removed and vehicle properties such as speed, axle arrangement and running location are considered properly.

• 펄프종이기술
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• 제42권5호
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• pp.31-36
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• 2010

When corrugated board is folded at the severely low humidity condition, crack can occur along the scored (or creased) lines of linerboard. This phenomenon is called as score (or crease) crack. It is mainly resulted from the excessive concentration of stress on the outer layer of linerboard. To overcome score crack, many approaches including the installation of constant temperature and humidity system, displacement of low grade raw material by long and strong fibers, or application of water have been tried. We examined the effect of the weight fraction of top layer in two-ply sheet, freeness of top layer stock and wet pressing on strain and elastic modulus of sheet to prevent score crack. Lower freeness and higher press load increased the density and elastic modulus of sheet. Pressing load over the $50kgf/cm^2$, however, decreased the strain of sheet. The weight fraction of top layer had positive effect on strain as well as elastic modulus without increasing the density of sheet.

• 한국버섯학회지
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• 제4권2호
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• pp.48-52
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• 2006

느타리는 4극성 자웅이주성으로 단포자분리주는 단핵으로 자실체를 형성하지 못하는 것으로 알려져 있다. 그러나 단포자분리주는 2종류로 구분되었는데 하나는 자실체를 완전히 형성하지 못하는 AHF형 (abortive homokaryotic fruiting, AHF) 이며, 나머지 하나는 원기형성 후 완전한 자실체로 발달하는 PHF형 (Pseudo- homokaryotic fruiting, PHF)이었다. 느타리 8개 계통으로부터 단포자분리주 155개를 얻어 단핵체 자실체를 유도하여 이중에서 102개임성체를 얻었으며, 이는 65.8%에 해당되었다. 단핵 자실체는 이핵체 모균주에 비해 대부분 자실체가 빈약하였으나 일부 모균주와 유사한 크기의 자실체도 발생하였다. 이들 단핵 임성균주를 이용하여 계통간 교잡조합 11개에서 535 교잡체와 비임성균주간 교잡체 79개를 얻어 톱밥병재배를 하여 자실체 생산력을 모균주와 조사 비교하였다. 자실체 생육일수는 임성주가 비임성주간 교잡 집단에 비해 빨랐다. 병당 유효경수는 임성체간 교잡주가 모균주나 비임성교잡체보다 많았으며, 대길이도 두 집단에 비해 길었다. 그러나 대굵기와 자실체 개체중은 3개 집단간 거의 차이가 없었다. 단핵 임성체간 교잡주 집단의 병당 자실체 수량이 비임성간과 모균주 집단보다 높은 경향이었다. 모균주 집단의 자실체 수량지수를 100으로 하였을 때 임성체간 교잡체 집단은 105, 비임성간 교잡체 집단은 86으로 나타났다. 특히 $2194{\times}2344$ 조합은 59.95%, $2194{\times}2730$ 조합은 27.39%, $1982{\times}2504$ 조합은 22.43% 양친균주보다 자실체 수량이 증수되는 것으로 나타났다. 따라서 단핵 임성체를 이용한 우수 균주개발 가능성은 높다고 할 것이다.

• 한국버섯학회지
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• 제4권2호
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• pp.53-56
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• 2006

느타리버섯의 포자는 버섯재배 농업인의 호흡기계통질환인 알레르기를 유발한다. 느타리버섯의 무포자형성 균주는 재배농업인의 건강에 도움을 줄뿐 아니라 다른 재배사에 바이러스병 감염의 위험을 감소시킬 수 있다. 소포자 형성 느타리버섯을 육성하기 위해 무포자형성 균주의 선발 및 특성검정 결과 ASI 2069 균주가 무포자이면서 수량성이 높으나 형태적으로 상품적 가치가 없어 원형질체 재생에 의한 단핵화를 시도하여 neohaplont를 분리하였다. 원형 1호(ASI 2180) 및 무포자 느타리간의 단핵교배 (Mon-Mon)를 시도한 결과 128교잡체를 얻어 이 중 30균주를 특성 검정한 다음 자실체형성 및 담자 포자비산량 조사에 의해 소포자형성 유망 13균주를 선발하였다. 그 중에서 G192 교잡체가 소포자이면서 수량성이 좋은 가장 우량 균주로 선발되었다.

• 한국지반신소재학회논문집
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• 제13권4호
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• pp.33-43
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• 2014

최근 들어 연약지반상에 구조물을 건설하는 경우가 증가하고 있으며, 사회기반 시설의 유지관리 및 건설 비용의 절감을 위해 사전압밀공법 및 연직배수공법과 같은 기존의 방법을 이용하여 지반 개량이 행해지고 있다. 이와 같이 연약점성토 지반상에 다양한 개량공법이 적용 될 때, 점성토의 낮은 투수계수로 인한 장기간에 걸친 압밀침하가 중요하게 된다. 압밀침하와 관련된 기존 연구결과에 따르면, 기존의 표준압밀시험의 재하기간은 압밀정수 산정에 최소한 10일 이상의 시간을 요하게 된다. 따라서 이 연구에서는 서남해안의 대표적인 연약지반으로 구성된 광양만 재성형 해성점토를 이용하여 표준압밀시험과, 일정변형률 압밀시험의 변형률 속도를 변화시킨 실험을 수행하였다. 실내시험결과를 통해 등변형률 속도에 따른 압축특성, 변형률-유효응력관계, 재하속도에 따른 간극수압 변화특성, 압밀정수와 등변형률 속도의 관계를 비교/분석하였다.

• 한국안전학회지
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• 제30권1호
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• pp.72-78
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• 2015

According to the report of the WHO, workers have been exposed to much job strain such as job load, responsibility, role, interpersonal conflict etc. In Korea, studies on job strain started to become active from 1990s and now hundreds of studies are actively under going or publishing so that the studies are contributing to development and improvement of job strain. Representative measurement models of job strain are Job Strain Model of Karasek, Job Stress Model of NOISH, Korea Occupational Stress Scale, JSQ(Job Stress Questionnaire), K-OSI(Korea Version of Occupational Stress Inventory) etc. (Lee Kwan-Suk, 2012 ; KOSHA, 2003). Among them, Job Strain Model of Karasek had been loved by many researchers of job strain before Korea Occupational Stress Scale was developed. Job Strain Model of Karasek had been fitted to Korean style and then, used to analyze job strain of Korean people so that this Scale highly contributed to seeking relationship with cardiovascular disease, musculoskeletal disease caused by job, smoking, drug, alcohol poisoning, and pulse(Lee Kwan-Suk, 2012). But as this Model was studied and developed based on foreign culture and life pattern, a model fit to Korea was developed to measure job strain for Korean people, which is Korea Occupational Stress Scale now most frequently used in measuring job strain. Accordingly, after this study made questionnaire survey about same population using the two methods used most frequently in measuring job strain, the study investigated what features appeared, what correlations appear between two models, and comparatively analyzed characteristics each independent and dependent variable. Based on this, the study aimed to exactly express job strain of Korean people. The subjects of the study were a population of 233, and Karasek's Questionnaire and KOSS's Questionnaire were surveyed at the same time. The results were analyzed by statistical program to obtain significant difference between two models. Four particular groups were divided with Job Strain Model of Karasek and the four particular groups were measured with Korea Occupational Stress Scale. And job strain come from combination of two models was measured, with which new comparative analysis method was suggested.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 가을 학술발표회 논문집
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• pp.585-592
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• 2002

Discharge capacity of PBD is the most important factor of specification items to control any product of PBD. There is no standard specification for the PBD. Because the degree of discharge capacity is related to well resistance, install depth, maximum strain etc in the field. Discharge capacity test of PBD, permeability test of filter are conducted using PBD materials used in Korea. This paper proposes the critical discharge capacity for deep PBD under condition of non well resistance based upon their test and theoretical calculation. It was found that discharge capacity more than about 10 ㎤/sec is enough to undergo designing of deep PBD without well resistance.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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• pp.183-190
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• 2000

Effective range of Hydraulic Hammer Compaction was studied by numerical analysis instead of empirical method. Numerical analyses were carried out with commercial FEM code, ABAQUS, and verified by comparing the numerical results with field tests of Hydraulic Hammer Compaction. Most of material properties were evaluated by data from laboratory and in-situ tests. Vertical effective range was estimated by distribution curve of plastic strain energy dissipated through soil layers under dynamic load and these results were in good agreement with field tests. Based on verification, the effects of governing properties of Hydraulic Hammer Compaction such as number of hit can be determined by numerical analyses. In addition, vertical effective range can also be determined by Menard's empirical equation using the external work at converging time of plastic strain energy in numerical analysis. This implies that the minimum energy of Hydraulic Hammer Compaction for improvement can be determined by Menard's equation.

• 한국기계가공학회지
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• 제5권2호
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• pp.3-9
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• 2006

HSM(High-speed Machining) is widely used in rapid manufacturing of precision products and molds of various materials. Improvement in cutting efficiency is one of the important subjects in the HSM process. To analyse the dynamic behavior during a very short cutting time, the computational analysis code, LS-DYNA3D, was employed for the simulation of the mechanism of HSM for aluminium 7075. This cutting mechanism includes some difficult points in simulation, for example, material and geometrical non-linearity, high-speed dynamic impact, contact with friction, etc. In this paper, a finite element model considering the strain rate effect is proposed to predict the cutting phenomena such as chip deformation, strain and stress distributions, which will help us to design the HSM process.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.247-250
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• 1995

The development and empirical validation of a mathematical model for predicting the depth of deformed layer in a machined surface are presented. The main assumption for develioping this model is that there is a linear relationship between plastic strain and the depth to which it extends. The model relates the work required to shear the workpice material to the work needed to compress the workpiece material ahead of the cutting tool. The results show that the percent difference between the calculated and the measured depth of deformed layer ranges form 4 percent to 19 percent. An improvement of the model is suggested through application of actual distribution data of plastic strain.