• 임산에너지
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• 제21권2호
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• pp.1-9
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• 2002

소용량 실험실용 탄화로 및 3종류의 대형 탄화로 (간이 탄화로 (400 - 500℃), 개량 탄화로(600 - 700℃) 및 전용탄화로 (800 - 1,000℃))를 이용하여 소나무 수피의 탄화를 실시하였다 그리고 제조된 수피탄의 물성과 세공구조를 분석하였다. 소나무 수피를 실험실용 소용량 탄화로를 이용하여 질소 존재하에서 500℃에서 900℃까지의 다양한 온도 조건에서 탄화시키면, 탄화수율은 탄화 온도의 증가와 함께 급속하게 낮아졌으며, 700 - 900℃에서 일정하게 유지되었다. 수피의 탄화수율은 동일 탄화온도에서 소나무 목부의 탄화수율보다 16 - 18％더 높았다. 제조된 수피탄의 BET 비표면적은 탄화수율 약 35 - 40％에서 약400 - 500㎡／g 을 나타내었다. 600℃ 30분의 탄화조건에서 제조된 소나무 목부탄은 미세공이 많이 발달해 있었으나, 동일조건에서 제조된 수피탄이 경우 미세공은 물론 중세공도 많이 존재하였다. 대형 탄화로에서 제조된 수피탄의 탄화 수율 및 요오드가 및 BET 비표면적은 소용량 탄화로의 결과와 매우 유사하였다. 이러한 결과는 소나무 수피가 높은 비표면적과 수율을 가지는 양질의 숯을 생산 할 수 있는 원료로 사용될 수 있음을 나타낸다.

• 대한토목학회논문집
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• 제33권6호
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• pp.2277-2284
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• 2013

본 연구에서 개발하고자 하는 지하수위 변동 해석모델은 지하수의 흐름과 관련된 반응계수 및 함양형태와 관련된 비산출율을 매개변수로 하여 부정류상태에서의 지하수위 변동특성을 해석한다. 모델의 시험적용을 위해 제주도 한천지역의 JD 용담1과 JW 공항지점의 5년(2006-2010)간의 지하수위 관측자료를 이용하였다. 매개변수 산정결과, JD 용담1지점에서는 비산출율 0.023, 반응계수 0.039로 추정되었고, JW 공항지점에서는 각각 0.009와 0.028로 추정되었다. 본 연구에서 개발한 모델을 이용하면, 지하수위에 의한 함양량 및 포화대에서의 매개변수를 추정할 수 있어 수문모형의 매개변수 및 비포화대에서의 침루특성을 확인하는 수단으로 활용되기를 기대한다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2005년도 춘계학술대회 논문집
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• pp.354-359
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• 2005

The objective of this research work is to investigate into static characteristics of ISB panels with the pyramidal structure as a internally structured material. In order to investigate the behavior of material deformation and fracture characteristics, several tensile tests have been carried out for the ISB panel and skin sheet. Through the results of the experiments, the mechanical properties of ISB panel and skin sheet and fracture characteristics have been obtained. In addition, the mechanical properties of the ISB panel have been compared with that of the skin sheet by the view point of a specific modulus, a specific yield strength and a specific strength. From the results of the comparision, it has been shown that the ISB panel has an excellent static characteristics.

• 산업기술연구
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• 제20권B호
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• pp.131-138
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• 2000

In this paper, we would like to develop the bending collapse specific equation of aluminum members which are usually used in light-weight vehicle or electromobiles. The result of the developed equation are compared with that of test and finite element methods as the moment-rotational angle curves. Three types of aluminum members are tested with the pure bending collapse test rig. PAM-CRASH and ABAQUS program are used for finite element analysis. As the result the developed bending collapse governing equation is accurate in estimating the yield moment and the maximum moment. Especially, in the case of the local buckling and the delayed buckling, the developed equation is better effective than F.E.M.

• 지질공학
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• 제9권2호
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• pp.101-118
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• 1999

본 연구는 덕산온천내에 수행된 28개 양수시험자료를 종합하여 덕산온천의 수리적 특성 및 매개변수를 파악하였다. 프락탈 모델, 누수성 프락탈 모델 그리고 정상류의 이중공극 프락탈 모델을 이용한 양수시험분석 결과, 대체로 온천의 중심부에서는 1.9 또는 2.0의 유동차원을 보이며, 주변부에서는 1.5∼l.7의 유동차원을 보인다. 2.0차원의 경우에, 투수량계수와 대수층 손실에 의한 산출계수의 상관성이 총 수위강하를 이용한 비양수량의 상관성보다 훨씬 높게 나타난다. 그러나, 1.9차원의 경우에는 일반화 투수량계수와 산출계수간의 상관성이 일반화 투수량계수와 비양수량간의 상관성과 비슷하게 나타나며 상관계수도 높게 나타난다.

• 한국작물학회지
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• 제53권4호
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• pp.434-439
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• 2008

The amount of salt to make seed sorting solution of the specific gravity of 1.13 was reconsidered and determined as 3.8 kg salt in 18 L water, which is lower amount than currently used. Five rice cultivars were examined. Percent germination and seedling emergence were not similar. Seedling emergence rate of Japonica varieties, Nampyungbyeo and Daerypbyeo-1 were 87% and 95% under specific gravity of 1.13, respectively. Seedling emergence rate of Tongil type variety, Dasanbyeo was as high as 67% in specific gravity of 1.06. Seedling emergence rate of waxy rice, Hwasunchalbyeo and Aranghangchalbyeo were examined. Seedling emergence rate was 94% in both cultivars in specific gravity of 1.04. Seedling emergence rate was same in specific gravity of 1.08 which is generally used for selecting seed currently. Early growth (plant height, leaf number, and dry weight) were not significantly different by specific gravity within species. In all cultivars except waxy rice, highest seedling emergence rate was observed in specific gravity of 1.13 which is currently used for selection and decreased as specific gravity is lowed. However, considering total amount of seeds in each group of specific gravity, amount of seed in lower specific gravity group is relatively small and total seedling emergence rate within variety dose not show big difference. However, if seeds with low speicific gravity are produced due to the bad grain filling condition and consequently total seed content of low specific gravity increases, results will be differnt. Reduction in total growth and yield could occur. It will be important to comply with the seed sorting criterion of 1.13 for Japonica, 1.06 for Tongil, and 1.04 for waxy rice variety to ensure the maximum rice growth and yield.

• 소성∙가공
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• 제20권8호
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• pp.527-533
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• 2011

In order to take into account the strong anisotropy and the tension-compression asymmetry of AZ31 sheet alloy, the Cazacu-Plunkett-Barlat yield criterion(Cazacu, 2006), CPB06, was adopted in the present material modeling. The variation of anisotropic coefficients which describe the yield surface evolution of AZ31 is optimized using an interpolation function based on specific calibration results. It generates continuous yield surfaces, which makes it possible to describe the different hardening rates in tension and compression as well as tension-compression asymmetry of magnesium alloys. The ability of the CPB06 yield criterion to predict experimental results was demonstrated and compared with that of the Hill(1948) yield criterion.

• Nuclear Engineering and Technology
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• 제3권1호
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• pp.15-19
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• 1971

높은 비방사능의 $^{51}$ Cr은 주로 $K_2$CrO$_4$를 표적으로 하여 Szilard-Chalmers process에 의해 제조되고 있다. 종래에는 그 화학적 분리과정에서 recoil된 Cr* (III) 를 담체 Fe(III)와 같이 공침시키는 방법을 쓰고 있다. 담체 없이 0. 1 N NaOH와 $C_2$H$^{5}$ OH를 사용하여 침전시키는 방법을 씀으로써 그 화학적 조작을 간편하게 하고 소요시간을 단축할 뿐만 아니라 보다 높은 비방사능의 제품을 높은 수율로 얻을 수 있었다. 실제 이 방법을 재래방법 및 프랑스방법과 비교해 보았을 때 다음의 결과를 얻을 수 있었다. 즉 재래방법보다는 훨씬 단시간내에 두 배 이상의 비방사능의 제품을 보다 높은 수율로 얻을 수 있었고, 프랑스방법과의 비교에서는 제품의 비방사능이나 소요시간은 비슷하나 수율은 새 방법 쪽이 2배에 가까왔다.

• 한국환경과학회지
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• 제9권1호
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• pp.75-80
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• 2000

Kinetic data for the acid phase anaerobic digestion were presented in this study and the constants were determined with acid production rate and gas production rate. Process models based on continuous culture theory were used to describe the characteristics of the acid forming microorganisms and to enable further development toward utilization of the process in a more rational manner. Acid phase digestion can be separated with appropriate manipulation of hydraulic retention time in anaerobic digestion. Kinetic analysis of data from the various hydraulic retention times using a phase specific model obtained form the acid phase indicated maximum specific growth rate of 0.40/h, saturation constant of 2,000mgCOD.$\ell$, yield coefficient of 0.35 mgVSS/msCOD utilized and decay constant of 0.04/h for the acid production rate. Similar analysis of data for the gas production rate indicated maximum specific growth rate of 0.003/h, saturation constant of 2,200mgCOD/$\ell$, yield coefficient of 0.035 mgVSS/mgCOD utilized and decay constant of 0.06/h.

• The Plant Pathology Journal
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• 제24권1호
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• pp.58-62
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• 2008

Utilization of carbon sources by Bacillus cereus D324, a biological control agent, and Pythium species, which causes rice seedling disease, was studied with the objective of increasing the efficacy of biological control by providing the biological control agent with specific beneficial carbon sources. D-galactose, D-sorbitol, and D-mannitol were poor carbon sources for Pythium spp. growth but were good for B. cereus D324 growth. Growth in a growth chamber of rice seeds coated with B. cereus D324 amended with specific carbon sources, such as D-galactose and D-sorbitol, showed significantly enhanced seedling emergence compared to seeds coated only with B. cereus D324. Field trials showed that both seedling emergence and yield increased, when the above specific carbon sources were added to B. cereus D324 in seed coating formulations. This result indicated that amending seed coating formulations with specific carbon sources could significantly increase seedling emergence and yield in the field.