• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.7 no.4
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• pp.589-599
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• 1995

The frictional pressure drop of a capillary tube flow is experimentally investigated for pure refrigerants such as R32, R125, and R134a and refrigerant mixtures such as R32/R134a(30/70 by mass percent), R32/R125(60/40), R125/R134a(30/70), and R32/R125/R134a(23/25/52). The binary interaction parameters for the calculation of viscosities of refrigerant mixtures are found based upon the data in the open literature. Several homogeneous flow models predicting the viscosity of two-phase region are compared to select the best model. Cicchitti's equation is known to be the most adequate for the prediction of the viscosity for refrigerant mixtures, which is used in the analysis of adiabatic capillary flows. A model for the prediction of the frictional pressure drop of single and two-phase flow is developed for refrigerant mixtures in this study. This model may be used to design and analyze the performance of a capillary tube in the refrigerating system.

• Bulletin of the Korean Chemical Society
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• v.28 no.11
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• pp.2009-2014
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• 2007

The aminolysis of diphenyl thiophosphinic chloride (2) with substituted anilines in acetonitrile at 55.0 oC is investigated kinetically. Kinetic results yield large Hammett ρX (ρnuc = ?3.97) and Bronsted βX (βnuc = 1.40) values. A concerted mechanism involving a partial frontside nucleophilic attack through a hydrogen-bonded, four-center type transition state is proposed on the basis of the primary normal kinetic isotope effects (kH/kD = 1.0-1.1) with deuterated aniline (XC6H4ND2) nucleophiles. The natural bond order charges on P and the degrees of distortion of 42 compounds: chlorophosphates [(R1O)(R2O)P(=O)Cl], chlorothiophosphates [(R1O)(R2O)P(=S)Cl], phosphonochloridates [(R1O)R2P(=O)Cl], phosphonochlorothioates [(R1O)R2P(=S)Cl], chlorophosphinates [R1R2P(=O)Cl], and chlorothiophosphinates [R1R2P(=S)Cl] are calculated at the B3LYP/ 6-311+G(d,p) level in the gas phase.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.4
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• pp.378-383
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• 1989

For selection of mutants two rice varieties, Sangpungbyeo and Seomjinbyeo, were irradiated with 20 kR and 25 kR of gamma rays. One panicle per each plant was harvested in Ml, and single needling per hill was planted for M2 and M3 generations. Mutations for short culm, earliness and the major traits were examined. 1. The mutation rates were varied with the rice varieties and the doses of radiation, higher in Sangpungbyeo and 25kR than in Seomjinbyeo and 20 kR, respectively. 2. The rates in Sangpungbyeo with the 20 kR and 25 kR were 1.10％ and 1.47％. respectively and those of Seomjinbyeo were 0.51％ and 1.25％, respectively. 3. The culm lengths of short-culm mutants derived from Sangpungbyeo and Seomjinbyeo were reduced about 10％ compared to their mother varieties, especially it was possible to select the dwarf mutants reducing 57％ and 40％ of culm length in Sangpungbyeo and Seomjinbyeo, respectively with the dose of 25 kR irradiation. 4. The range of heading date of the mutant ion in the M3 generation was comparatively wide. Many earliness mutants shortened about 7 days were selected as compared with their mother varieties, some mutants of the irradiated group had early matured by 20 days and 30 days, respectively in both Seomjinbyeo and Sangpungbyeo.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.6
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• pp.791-799
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• 2011

This study examined the effect of restricting feed intake and the subsequent compensatory growth in Guzera females. Eighteen animals with an initial age of 21 months and a mean weight of 268.17 kg were placed in three groups according to the alimentary regime: feed ad libitum; feed restricted to 20% dry matter; and feed restricted to 40% dry matter. In the restricted feed phase, the dry mater intake decreased as the restriction levels increased, influencing the reduction in intake of other nutrients. In the realimentation phase, the 40% restricted feed group ingested more dry matter (% BW) and crude protein ($weight^{0.75}$) than the group fed ad libitum (p<0.001). The serum nutrient concentrations were inversely proportional (p<0.001) to the restriction level, and there was no difference (p>0.001) in the realimentation phase. In the restricted feed phase, the final live weight decreased (p<0.05) as the restriction level increased. For the daily mean weight gain in the control group, there was no difference (p>0.05) compared to the animals with 20% feed restriction, but this was higher than in the group with 40% feed restriction. In the re-alimentation phase, the group with 40% feed restriction achieved higher weight gain rates, which was different from the control and 20% restriction groups. In both phases, the animals in the group with 40% feed restriction presented better feed conversion which was different (p<0.05) from the control group. In the feed restriction phase, it was observed that the intake of N, nitrogen excreted in feces and urine, nitrogen balance and nitrogen retention decreased (p<0.05) with the restriction level. None of the variables were influenced in the re-alimentation phase. These results show that feed restriction by 40% can be adopted as a nutritional management practice.

• Journal of the Korean Wood Science and Technology
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• v.45 no.5
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• pp.519-524
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• 2017

Physical, mechanical and deteriorating properties of Phellodendron amure were investigated. Air dried density located indoor was 0.41 but $0.43g/cm^3$ outdoor. In oven dry shrinkage, T/R ratio for located indoor was 1.40 but 1.32 outdoor. Hygroscopic property at $40^{\circ}C$ with 90% relative humidity was 16.30% for indoor and 15.80% for outdoor. Compressive strength for outdoor conditioned sample was 43.81 MPa but 40.33 MPa for indoor conditioned. Also bending strenght for outdoor conditioned was 84.63 MPa but 68.80 MPa for indoor conditioned. Impact strength was 3.43 and $4.00J/cm^2$ indoor and outdoor, respectively. Hardness at cross-section was 47.92 and 49.20 MPa indoor and outdoor, respectively. With one-year conditioning at indoor or outdoor, there was no significantly different in strength properties, which came from strong resistance for deterioration. Also Phellodendron amure wood showed dimensionally stable raw material based on low T/R ratio.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.37.1-37.1
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• 2010

세계적으로 신재생에너지에 대한 관심이 높아지면서 이에 대한 국가적인 지원이 2006년에 1000억을 넘어 불과 3년 만에 그 2배인 2000억을 돌파했다. 또한 내년부터 2015년까지 민 관 합동으로 총 40조원을 신재생에너지에 투입한다고 보고되어 주위를 술렁이게 하고 있다. 우리는 신재생에너지가 더 이상 일부 국한된 기관이나 기업만의 단순 관심분야가 아닌, 세계 시장에서의 우위를 점령하기 위한 국가차원의 광대한 경쟁분야임을 다시 한번 인식해야 한다. 이러한 시점에서 국내 신재생에너지 R&D산업의 과거 발자취를 통해 미래에 나아가야 할 방향을 예측해 보는 것은 상당히 의미가 있을 것으로 생각된다. 본 고에서는 신재생에너지 분야 중 현재 가장 큰 비중을 차지하고 있는 태양광 분야에 초점을 맞추어 보았다. 그간 진행되거나 현재 진행되고 있는 R&D관련 데이터들을 수집하여 다양한 방면으로 검토해본 결과 눈에 띄는 경향을 일부 확인할 수 있었는데, 이를 통해 향후 태양광 R&D산업이 나아가야 할 방향을 예측해 보고자한다.

• Journal of Microbiology
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• v.40 no.1
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• pp.43-50
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• 2002

A cluster of genes encoding the pyruvate dehydrogenase complex (PDC) of Streptomyces seoulensis, a Gram-positive bacterium, was cloned and sequenced. The genes of S. seoulensis consist of four open reading frames. The first gene, lpd, which encodes a lipoamide dehydrogenase, is followed by pdhB encoding a dihydrolipoamide acetyltransferase (E2p), pdhR, a regulatory gene, and pdhA encoding a pyruvate dehydrogenase component (Elp). Elp had an unusual homodimeric subunit, which has been known only in Gram-negative bacteria S. seoulensis E2p contains two lipoyl domains like those of humans and Streptomyces faecalis. The pdhR gene appears to be clustered with the structural genes of S. seoulensis PDC. The PdhR-overexpressed S. seoulensis howed growth retardation and the decrease of Elp, indicating that PdhR regulates the function of PDC by repressing the expression of Elp. A strain of Streptomyces licidans overexpressing S. seoulensis PdhR showed a significant decreasein the level of actinorhodin, implying a regulatory role for Streptomyces PDC in antibiotic biosynthesis.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.5 no.4
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• pp.306-317
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• 1993

In this study, a performance comparison of scroll compressor for various refrigerants(CFC-12, HCFC-22 and HFC-134a) has been numerically carried out. The thermodynamic properties have been calculated by using the recent experimental equations and the performance has been investigated qualitatively at the same geometric specifications and operating conditions of scroll compressor. The results are as follows; HFC-134a has the highest compression ratio of 5.40. The mass flow rate of HCFC-22, which affects the cooling capacity of refrigerant system, is higher than that of other refrigerants. HFC-134a has the highest adiabatic efficiency in comparison with CFC-12 and HCFC-22.

• International Journal of Air-Conditioning and Refrigeration
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• v.8 no.1
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• pp.40-49
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• 2000

The capillary tube performance for R-407C is experimentally investigated. The experimental setup is a real vapor-compression refrigerating system. Mass flow rate is measured for various diameter and length while inlet pressure and degree of subcooling are changed. These data are compared with the results of a numerical model. The mass flow rate of the numerical model is about 14% less than the measured mass flow rate. It is found that mass flow rate and length for R-407C are less than those for R-22 under the same condition. Based on this experimental study and the numerical model, a set of design charts for capillary tube of R-407C is proposed.

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.39.2-40
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• 2008