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A Study of the Additional Toxicity of Mixed Food Additives to Rat (혼합(混合)된 식품첨가물(食品添加物)이 흰쥐의 생리(生理)에 미치는 상승적(相乘的) 독성(毒性) 효과(效果)에 관(關)한 연구(硏究))

  • Chung, Ho-Kwon
    • Applied Biological Chemistry
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    • v.18 no.2
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    • pp.71-97
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    • 1975
  • To improve the food qualities in Korea, two hundred and fourtynine kinds of food additives have been allowed in food processing, of which one hundred and nineteen kinds could be used under the limitted conditions. Hence, in practical uses in food processing, many kinds of them are mixed at random within the permitted amounts for their special purposes. For last several years, many kinds of the food additives were prohibited because they have been proved to be toxic even with the single dose. Until recently a few studies on the toxicity in the mixture of food additives were reported, however, they were shown to be no severe additional effect on the animal. This study was performed to see if any elevation of chronic or subacute toxicity of food additives occur especially when they are mixed with each other, using three kinds of food additives (DHA, AF-2, BHT) most widely used as food preservatives, antiseptics and antioxidants. One hundred and fifty young male rats were taken and divided into ten feeding groups, one first control group (food additives blank), three second control groups (DHA 0.1%, AF-2 0.1%, BHT 0.5%), three mixture groups of low level (mixture of each 60% of two second control level) and three mixture groups of high level (mixture of each 90% of two second control level). As the methods of biological and clinical tests, the change of body weight (growth rate), daily intake of diets, organ to body weight ratio, histopathological findings of organs, hematological observation, liver and kidney function tests were checked three times during the periods of 24 weeks. The following results were obtained. 1. The low level group of DHA, AF-2 mixture and DHA, BHT mixture revealed a little retardation in growth rate than the first control group, however, they were similar to the second controls, while all the mixture groups of high level showed a more remarkable retardation than the first and second controls. 2. Average daily intake of the diets was the same in each group, showing a similar decreasing tendency (70-100g/kg of body weight) in accordance with the growth rate. It was observed that there are no differences in the taste and appetite in each group of rats. 3. Abnormal enlargements of kidney and lung were not seen in all the mixture groups compared with the controls, while a slight hepatomegaly was observed in all mixture groups of low level as in the second controls. Significant differences (almost 1% level) were observed between the high level groups and the first control group. 4. Histopathological effects of the food additives on lung, kidney and liver tissues were found in all mixture group of high level. The less frequencies of the same effects were also seen in the low level groups. 5. The esterified cholesterol to total cholesterol ratio in the mixture groups of high level showed a little lower values, and the activities of serum glutamate oxaloacetate transaminase and alkaline phosphatase decreased almost with significance of 5% level compared with the first control group. The serum A/G ratio in the mixture groups also decreased. The results demonstrated that the liver function was decreased in the mixture groups compared with the controls. 6. In all groups throughout the test period, kidney functions (concentration of protein and creatinine excreated per hour in urine and renal filtration rate) were shown almost as normal as the first control. 7. Average values of hematocrit, erythrocytes and leucocytes in the mixture groups were in the normal ranges as in the controls, which denotes that the production of blood cells in bone marrow were also normal in all groups. With the above results, it is concluded that when the food additives (DHA, AF-2, BHT) were given together to the rats in several combinations even in less amount, they showed more toxic signs than the single doses.

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Lessons from Cross-Scale Studies of Water and Carbon Cycles in the Gwangneung Forest Catchment in a Complex Landscape of Monsoon Korea (몬순기후와 복잡지형의 특성을 갖는 광릉 산림유역의 물과 탄소순환에 대한 교차규모 연구로부터의 교훈)

  • Lee, Dong-Ho;Kim, Joon;Kim, Su-Jin;Moon, Sang-Ki;Lee, Jae-Seok;Lim, Jong-Hwan;Son, Yow-Han;Kang, Sin-Kyu;Kim, Sang-Hyun;Kim, Kyong-Ha;Woo, Nam-Chil;Lee, Bu-Yong;Kim, Sung
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.9 no.2
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    • pp.149-160
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    • 2007
  • KoFlux Gwangneung Supersite comprises complex topography and diverse vegetation types (and structures), which necessitate complementary multi-disciplinary measurements to understand energy and matter exchange. Here, we report the results of this ongoing research with special focuses on carbon/water budgets in Gwangneung forest, implications of inter-dependency between water and carbon cycles, and the importance of hydrology in carbon cycling under monsoon climate. Comprehensive biometric and chamber measurements indicated the mean annual net ecosystem productivity (NEP) of this forest to be ${\sim}2.6\;t\;C\;ha^{-1}y^{-1}$. In conjunction with the tower flux measurement, the preliminary carbon budget suggests the Gwangneung forest to be an important sink for atmospheric $CO_2$. The catchment scale water budget indicated that $30\sim40%$ of annual precipitation was apportioned to evapotranspiration (ET). The growing season average of the water use efficiency (WUE), determined from leaf carbon isotope ratios of representative tree species, was about $12{\mu}mol\;CO_2/mmol\;H_2O$ with noticeable seasonal variations. Such information on ET and WUE can be used to constrain the catchment scale carbon uptake. Inter-annual variations in tree ring growth and soil respiration rates correlated with the magnitude and the pattern of precipitation during the growing season, which requires further investigation of the effect of a monsoon climate on the catchment carbon cycle. Additionally, we examine whether structural and functional units exist in this catchment by characterizing the spatial heterogeneity of the study site, which will provide the linkage between different spatial and temporal scale measurements.

Antimicrobial and Antioxidant Activity of Grapefruit and Seed Extract on Fishery Products (수산물에 대한 Grapefruit 종자추출물의 항균 및 항산화효과)

  • CHO Sung-Hwan;SEO Il-Won;CHOI Jong-Duck;JOO In-Saeng
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.23 no.4
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    • pp.289-296
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    • 1990
  • The antimicrobial and antioxidant activities of grapefruit seed extract(GFSE), which was extracted with glycerine in the special schematic extraction apparatus, were investigated for handling and processing of fishery products. The effectivity of GFSE has been tried on sardine, mackerel and shrimp divided into six lots for each fishery product: control(no treatment) and five GFSE-treated samples. Samples were inoculated with Salmenella typhi, incubated for 24hrs at $30^{\circ}C$ in dextrose-tryptone broth medium and prepared for microbiological 8f chemical analysis and organoleptic assessment. The bacteriological analytical results with GFSE(250ppm) showed the reduction of $1.8\times10^6\to2.0\times10^4,\;1.9\times10^6\to1.8\times10^4$ and $1.6\times10^6\to2.7\times10^3$ in total bacterial count for sardine, mackerel and shrimp, respectively. The test results with GFSE(500ppm) showed a $100\%$ reduction of bacterial mackerel treated with GFSE(500ppm) was reduced to $1.1\times10^4$ and $9.0\times10^3$ respectively. Antioxidant effect of treatment with GFSE at 500ppm level for three products was significant. LSD test results on organoleptic parameter for the samples treated with various showed a significant influence on the appearance, odor and texture in which at concentration 500ppm level give the excellent scours compared to each control.

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Effects of Namhae Specialized Crops Water Extract on Lipid Metabolism in Rats Fed a Cholesterol Diet (남해군 특용작물 열수 추출분말이 콜테스테롤 급이 흰쥐의 혈청 및 장기 중 지질성분에 미치는 영향)

  • Shin, Jung-Hye;Kang, Min-Jung;Yang, Seung-Mi;Lee, Soo-Jung;Sung, Nak-Ju
    • Korean journal of food and cookery science
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    • v.27 no.5
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    • pp.599-610
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    • 2011
  • This study was performed to investigate the effect of water extracts from Namhae special crops (NSC) on improved serum lipid composition using rats fed a 1% cholesterol diet for 4 weeks. Male Wister rats (200-210 g) were divided into six groups: Normal cholesterol diet group (Normal), 1% cholesterol diet group (Control), 1% cholesterol and NSC water extract powder supplemented groups, including, turmeric (Tu-EP), cactus (Ba-EP), aloe vera (Al-EP) and asparagus (As-EP). No significant differences were observed for food intake or body weight gain between the control and experimental groups. However, food efficiency ratio (FER) was the lowest in the As-EP group. The serum levels of total cholesterol and triglycerides in the NSC water powder extract supplement groups were lower than those in the control group. The serum high density lipoprotein (HDL)-cholesterol content in the Tu-EP group was higher than that in the other experimental groups. Very low density lipoprotein (VLDL)-cholesterol content in the As-EP group was similar to that in normal group. Furthermore, the VLDL content in the Al-EP group was lower than that in the normal group. Serum antioxidant activity by TBARS level and DPPH radical scavenging were significantly higher in the Ba-EP group than that in the control group. Hepatic total cholesterol and lipid content in the Al-EP group decreased significantly compared to that in the control group. These results suggest that the NSC water extract may reduce serum cholesterol and prevent oxidative stress by stimulating antioxidative systems in rats fed a 1% cholesterol diet.

Behavior of Steel Fiber-Reinforced Concrete Exterior Connections under Cyclic Loads (반복하중을 받는 강섬유 보강 철근콘크리트 외부 접합부의 거동 특성)

  • Kwon, Woo-Hyun;Kim, Woo-Suk;Kang, Thomas H.K.;Hong, Sung-Gul;Kwak, Yoon-Keun
    • Journal of the Korea Concrete Institute
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    • v.23 no.6
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    • pp.711-722
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    • 2011
  • Beam-column gravity or Intermediate Moment frames subjected to unexpected large displacements are vulnerable when no seismic details are provided, which is typical. Conversely, economic efficiency of those frames is decreased if unnecessary special detailing is applied as the beam and column size becomes quite large and steel congestion is caused by joint transverse reinforcement in beam-column connections. Moderate seismic design is used in Korea for beam-column connections of buildings with structural walls, which are to be destroyed when the unexpected large earthquake occurs. Nonetheless, performance of such beamcolumn connections may be substantially improved by the addition of steel fibers. This study was conducted to investigate the effect of steel fibers in reinforced concrete exterior beam-column connections and possibility for the replacement of some joint transverse reinforcement. Ten half-scale beam-column connections with non-seismic details were tested under cyclic loads with two cycles at each drift up to 19 cycles. Main test parameters used were the volume ratio of steel fibers (0%, 1%, 1.5%) and joint transverse reinforcement amount. The test results show that maximum capacity, energy dissipation capacity, shear strength and bond condition are improved with the application of steel fibers to substitute transverse reinforcement of beam-column connections. Furthermore, several shear strength equations for exterior connections were examined, including the proposed equation for steel fiber-reinforced concrete exterior connections with non-seismic details.

Biological Activities and Artificial Cultivation of Cordyceps pruinosa Petch (붉은자루동충하초의 자실체 증식 특성)

  • Hong, In-Pyo;Nam, Sung-Hee;Jung, I-Yeon;Sung, Gyoo-Byung;Kim, Hyun-Bok;Jung, In-Mo;Cho, Soo-Muk;Lee, Min-Woong
    • Journal of Mushroom
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    • v.3 no.4
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    • pp.133-139
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    • 2005
  • Fruiting bodies of Cordyceps have been regarded as popular folk and effective medicines to treat human diseases such as asthma, bronchial and lung inflammation, and kidney disease. Cordyceps pruinosa (Clavicipitaceae; Hypocreales; Ascomycotina) has received special attention for medicinal purpose due to its various physiological activites. The nucleoside derivative N6-(2-hydroxyethyl) adenosine (HEA) isolated from it showed a $Ca^{2+}$ antagonistic effect and negative inotropic response. The artificial production of fruiting body of C. pruinosa has not been tried successfully yet by using living silkworm substrate. To develop techniques for the production of C. pruinosa stromata on a large scale, the infection of Bombyx mori with C. pruinosa and the growth characteristics of stroma of C. pruinosa were investigated. Also, studied about biological activities of fruiting body formed on silkworm. Infection rate of the silkworm pupae with C. pruinosa was the highest in injection inoculation. The formation of the fruiting body of C. pruinosa was quite good in the room controlled at $21{\sim}25^{\circ}C$, over 91% of relative humidity and over 1500 lx. Glucose concentration was high in the fruiting bodies of the silkworm pupae infected with C. pruinosa on a dry weight basis. The most abundant amino acid in the fruiting bodies was arginine and phenylalanine. The fruiting bodies of silkworm pupae infected with C. pruinosa was rich in oleic acid. The high amount of citric acid was found in the fruiting bodies of silkworm pupae infected with C. pruinosa.

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Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2013 (설비공학 분야의 최근 연구 동향 : 2013년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.26 no.12
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    • pp.605-619
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    • 2014
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.

A Review on the Air Carrier's Liability for the Cargo under the Montreal Convention and the Commercial Law through the Recent Supreme Court's Case (최근 판례를 통해 본 몬트리올 협약과 상법상 항공운송인의 책임 - 대법원 2016. 3. 24. 선고 2013다81514판결 -)

  • Kim, Kwang-Rok
    • The Korean Journal of Air & Space Law and Policy
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    • v.32 no.2
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    • pp.33-66
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    • 2017
  • The Korean government enacted the Chapter 6 as of Air Transportation to the Korean Commercial Act, which was enforced in 2011, in order to treat some arguments occurred from air transportation Contracts since air transportations has rapidly increased in Korea. Air transportations has been used more in the field of international market than in the field of domestic market under it's own characteristic. Therefore, many international agreements and protocols related to the air transportations has been appeared from old times and the 1999 Convention for the Unification of Certain Rules for International Carriage by Air ("Montreal Convention") is one of them. The Montreal Convention was adopted in May 28, 1999 at International Conference of Air Law hosted by the International Civil Aviation Organization ("ICAO") in Montreal, Canada where the Headquarter of ICAO is located. The Montreal Convention has been effected from September 5, 2003 and the Korean government ratified the convention in 2007. Therefore, the Montreal Convention came in to force in Korea since 2007. This year, 2017, is the 10th anniversary year since the Montreal Convention has taken effect in Korea. However, there are rare cases that argued the Montreal Convention's scope of application and this Article examines the Korean Supreme Court's case that argued the Convention's scope of application. Thus the Article basically analyzes the case from the perspective of the Montreal Convention's scope of application and examines the Montreal Convention's articles related to the air carrier's liability and extent of compensation for damage that occurred from the international carriage by air. Also this Article analyzes the Korean Commercial Act Chapter 6, which regulated the air carrier's liability and the Article tries to make a comparison between the Montreal Convention and the Korean Commercial Act in order to draw some scheme for the betterment of Korean Commercial Act. It is the hope that the Article contribute to the improvement of Korean Commercial Act through the comparison with the chance of the 10th Anniversary of the Montreal Convention in Korea.

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Screw Joint Stability under Cyclic Loading of Zirconia Implant Abutments (지르코늄 임플란트 지대주의 나사결합부 안정성에 관한 연구)

  • Lee, Mi-Soon;Suh, Kyu-Won;Ryu, Jae-Jun
    • The Journal of Korean Academy of Prosthodontics
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    • v.47 no.2
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    • pp.164-173
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    • 2009
  • Purpose: The purpose of this study was to evaluate the effect of abutment material on screw-loosening before and after cyclic loading. Among the different materials of abutments, zirconia and metal abutment were used. Material and methods: Two types of implant systems: external butt joint(US II, Osstem Implant, Korea) and internal conical joint(GS II, Osstem Implant, Korea) were used. In each type, specimens were divided into two different kinds of abutments: zirconia and metal(n=5). The implant was rigidly held in a special holding to device ensure fixation. Abutment was connected to 30 Ncm with digital torque gauge, and was retightened in 30 Ncm after 10 minutes. The initial removal torque values were measured. The same specimens were tightened in 30 Ncm again and held in the cycling loading simulator(Instron, USA) according to ISO/FPIS 1480. Cycling loading tests were performed at loads 10 to 250 N, for 1 million cycles, at 14 Hz,(by subjecting sinusoidal wave from 10 to 250 N at a frequency of 14 Hz for 1 million cycles,) and then postload removal torque values were evaluated. Results: 1. In all samples, the removal values of abutment screw were lower than tightening torque values(30 Ncm), but the phenomenon of the screw loosening was not observed. 2. In both of the implant systems, initial and postload removal torque of zirconia abutment were significantly higher than those of metal abutment(P<.05). 3. In both of the implant systems, the difference in removal torque ratio between zirconia abutment and metal abutment was not significant(P>.05). 4. In metal abutments, the removal torque ratio of GS II system(internal conical joint system) was lower than that of US II system(external butt joint system)(P<.05). 5. In zirconia abutments, the difference in removal torque ratio between the two implant systems was not significant(P>.05). Conclusion: Zirconia abutment had a good screw joint stability in the condition of one million cycling loading.

A Theoretical Review of Basin Storage Coefficient and Concentration Time Using the Nash Model (Nash 모형을 이용한 유역 저류상수 및 집중시간의 이론적 검토)

  • Yoo, Chul-Sang
    • Journal of Korea Water Resources Association
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    • v.42 no.3
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    • pp.235-246
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    • 2009
  • This study theoretically reviews the basin storage coefficient and concentration time using the Nash model, a simple unit hydrograph theory. First, the storage coefficient and concentration time of Nash instantaneous unit hydrograph (IUH) are derived based on their definitions, whose characteristics as well as their relationship are also reviewed. Additionally, several empirical equations of storage coefficient and concentration time commonly used in Korea are evaluated by comparing them with those for the Nash IUH. Major results of this study are summarized as follows. (1) The concentration time of Nash IUH is approximately linearly proportional to the number of linear reservoirs, but the storage coefficient non-linearly to the square root. That is, if increasing the number of linear reservoirs by four times, the concentration time becomes also increased by about four times, but the storage coefficient only about two times. This result has a special meaning to understand the effect of basin subdivision on the concentration time and storage coefficient. (2) The storage coefficient and concentration time of Nash IUH are not independent each other, so their independent estimation does not make any physical sense. As the concentration time among the two is more sensitive to the number of linear reservoirs, which should be estimated first, then the storage coefficient considering the concentration time estimated. (3) Empirical equations of concentration time can be divided into two groups, one following the linear channel theory and the other not, whose equation forms are also found to be very similar. This result indicates that the characteristic factors dominating the concentration time are very similar, indicating the possibility of its regionalization over a basin with consistent equation forms. (4) Those for storage coefficient like the Russell formulae are found to consider the physical characteristics of a basin, so their unreasonable applications could sufficiently be excluded.