• Journal of agriculture & life science
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• v.44 no.6
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• pp.83-89
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• 2010

The objective of this study was to investigate the effect of the environmental and genetic factors on the carcass traits of Korean cattle. We have used the data of 22,954 Korean cattle slaughtered from 2005 to 2009 in Gyeongnam region and estimated the genetic parameters of 36,868 cattle including the pedigree individuals by means of EM-REML analytical method. In summary, the heritability of the carcass weight, eye muscle area, backfat thickness and marbling score was 0.39, 0.30, 0.33 and 0.62, respectively. The carcass weight and the eye muscle area showed high correlation between them with the genetic correlation of 0.86 and the phenotypic correlation of 0.72. The high heritability of marbling score is assumed to be the result of focusing the breed improvement on the quality of the meat. Through this study, it is considered that the Korean cattle in Gyeongnam region are improving, which will thus contribute to the increase of the farmer's income. Additional study on the economic trait must be carried out to obtain clearer results that will lead to further improvement of Korean cattle.

• Food Science of Animal Resources
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• v.27 no.4
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• pp.450-456
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• 2007

This study was carried out investigate the effects of the period of dietary supplementation and the level of fermented mineral feed on daily body weight gain and carcass characteristics of Hanwoo steer. The dietary treatments were compared during two supplementation periods (T1:Feeding Hanwoo steers from 18 months to 25 months, T2: feeding Hanwoo steers from 7 months to 25 months), and the diets tested were of four types (0%: normal concentrate as a basal diet, 1%: 1% addition of fermented mineral feed, 2%: 2% addition of fermented mineral feed, and 3%: 3% addition of fermented mineral feed). A Total of 35 Hanwoo steers were allocated into 7 feeding groups. The daily gain of the 0% fermented mineral feed group was lower (0.64 kg) than that of the other groups (1%: 1.08 kg, 2%: 0.90 kg, 3% treatment: 0.75 kg) for the T1 period, and for the T2 period the order was 1% (0.98 kg) > 0% (0.75 kg) > 1% (0.89 kg). The amount of back fat in decreasing order was as follows: 0% (12.0) > 1% (10.8) > 2% (10.2) > 3% fermented mineral feed (7.8 mm) for the T1 period, and for the T2 period the order was C (16 mm) > T1 (13.8 mm) > T3 treatment (12.6 mm). Eye muscle area increased with increased fermented mineral feed levels. The marbling score of the T1 groups was highest with 3% fermented mineral feed (4.2), and of the T2 groups, the highest score was seen with 1% fermented mineral feed (5.6). Meat color and meat maturity were not different among all groups. The grade of meat quantity and meat quality of both the T1 and T2 groups were highest with the addition of 3% fermented mineral feed. The daily income ranged from 2,062 won to 5,265 won in the T1 groups, which were ordered as follows: 1% > 2% > 3% > 0% fermented mineral feed, and of the T2 groups, the 1% group was highest at 6,098 Won, while the 3% group was lowest at 4,590 Won.

• Korean Journal of Heritage: History & Science
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• v.47 no.2
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• pp.4-19
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• 2014

In Joseon dynasty, Gongsin-Gyoseo(Royal Edicts rewarding meritorious vassals) was issued for the reward of the contribution to the specific event of the nation. The family decided as vassals succeeded this Gongsin-Gyoseo as the family treasure to later generations. When one happened to lose this caused by an unavoidable situation such as war in this process, there were a few cases of reissuing of Gongsin-gyoseo by the nation. The confirmative reissued Gongsin-gyoseo among Gongsin-gyoseo that descended down by now are three pieces which is Park dongnyang Hoseong Gongsin-Gyoseo, Gu goeng Jeongsa Gongsin-Gyoseo, and Park jung Jeongsa Gongsin-Gyoseo. This research considered the form and mounting about these three pieces. It was indicated that the reissued Gongsin-Gyoseo was produced following the same form with the original Gongsin-Gyoseo, that is pyeongchul(moving to next lines) and daedu (writing one or two letters ahead compared to the first letter) and so on. But, it was indicated that the change of the position of the vassals in the reissued time was reflected compared to position of the original Gongsin-Gyoseo. In case of Jeonsa Gongsin-Gyoseo, it was indicated that it was 'Wonjongdaewang-whi' since the original Gongsin-Gyoseo was 'Jeongwongun-bu' and the reissued time he became the father of King Injo. Also, it was confirmed that the case of deprivation because of conspiracy such as 'Kim jajeom, Kim ryeon, Sim kiwon, Sim kisung' was produced as the original document and deleted with black ink stick. It was newly confirmed while the original Gongsin-Gyoseo was produced by a designated writer from the nation, the reissuance was written by a writer from the family of the vassals. Since the mounting of Gongsin-Gyoseo could be changed according to the favor and technique of the craftsman participated in the practical production such as Baezeopjang and economical situation of the country supplying the material, the mounting of these three Gongsin-Gyoseo should be different from the original mounting, especially because of the loss of the original by the Manchu war of 1636. The comparison result of Gongsin-Gyoseo produced in the same period with the original issued one in the record of the related Uigwe (a collection of documents from the Joseon Dynasty), the reissued one seems to be larger in the form or ratio of the mounting compared to the first issued one. First of all, the width of Byunah was expanded as twice bigger, center and both side Hoejang also was bigger as over 2cm, and the below Hoejang was expanded as 10cm, and the ratio of the upper Hoejang and the below Hoejang was wider as 1.5 times and the reissuance was 1:1 ratio. The bisect of upper shaft in Park dongnyang Hoseong Gongsin-Gyoseo is assumed as the form of an equilateral triangle, not a half-moon shape of the present, and Gu goeng and Park jung Jeongsa Gongsin-Gyoseo will be the form whose bisection form is same but the size is smaller. Chuksu is confirmed that the size is not changed significantly. Osaekdahoe can be assumed that the width was smaller compared to the first issued one. The 3 pieces of the reissued versions provide the clue of the verification for the form of the mounting of Bosa Gongsin-Gyoseo in the same production period. In the situation that the mounting of the production time was not confirmed among the currently descended Bosa Gongsin-Gyoseo, they can be very important materials.

• Journal of Korean Society of Steel Construction
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• v.20 no.5
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• pp.633-644
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• 2008

The structural framework design uses high-strength bolts and welding in column splices. However, for the column under high compression, the number of the required high-strength bolts can be excessive and the increase of welding results in difficulty of quality inspection, the transformation of the structural steels, and the increase of erection time. According to the AISC criteria, when columns have bearing plates, or they are finished to bear at splices, there shall be sufficient connections to hold all parts securely in place. The Korean standard sets the maximum 25% of the load as criteria. Using direct contact makes it possible to transfer all compressive force through it. The objective of this study is to examine the generally applied stress path mechanism of welded or bolted columns and to verify the bending moment and compression transfer mechanism of the column splice according to metal touch precision. For this study,22 specimens of various geometric shapes were constructed according to the change in the variables for each column splice type, which includes the splice method, gap width, gap axis, presence or absence of splice material, and connector type. The results show that the application of each splice can be improved through the examination of the stress path mechanism upon metal contact. Moreover, the revision of the relative local code on direct contact needs to be reviewed properly for the economics and efficiency of the splices.

• Journal of the Korean Institute of Telematics and Electronics
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• v.13 no.5
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• pp.17-23
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• 1976

The buildup of fission product, i.e. Xe-135 poisoning, is a prime factor in restarting a nuclear reactor from the shutdown, which was under normal operation in the high flux thermal reactor, It is caused by the high absorption crosssection of Xe-135 to thermal neutrons and its long half life, from which the thermal power is affected. It is then possible to restart a nuclear reactor after the sufficient excess reactivity to override this poisoning must be inserted, or its concentration is decreased sufficiently when its temporary shutdown is required. As ratter of fact, these have an important influence not only on reactor safety but also on economic aspect in operation. Considering these points in this study, the shutdown process was cptimized using the Pontryagin's maximum principle so that the shutdown mirth[d was improved as to restart the reactor to its fulpower at any time, but the xenon concentration did not excess the constrained allowable value during and after shutdown, at the same time all the control actions were completed within minimum time from beginning of the shutdown.

• Journal of Radiation Protection and Research
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• v.22 no.2
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• pp.119-125
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• 1997

PHWR achieves high neutron economy by adopting heavy water as its moderator and coolant. On the other hand it permits much tritium generation, compared to LWR, due to the neutron capture reaction of deuterium in heavy water. Meanwhile in the reactor core, $^3He formed as the result of-decay of tritium, captures a thermal neutron and transforms to tritium again. The existing calculation models on tritium generation in PHWR neglect the contribution of $^3He$ in both moderator and coolant due to its relatively low solubility. However the neutron capture cross-section of $^3He$ is almost $1.6{\times}10^7$ times as large as that of deuterium. That means that the dissolved amount of 0.03 ppm of $^3He$ in heavy water is enough to generate the same amount of tritium as that generated by the deuterium of total heavy water in the system. This study dealt with the contribution of $^3He$ to tritium generation. As a sample case, the contribution of $^3He$ to the tritium generation in Wolsong #1 was evaluated and compared to the measured values. According to the result of this study, it is concluded that $^3He$ in coolant contributes very much to the tritium generation but that in moderator shows negligible effects due to the low solubility and $^4He$ cover gas. At the beginning of the plant operation, the contribution of $^3He$ is slightly greater than the measured value but agrees well with the measured as the operating time increases.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.4
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• pp.605-615
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• 2016

It is difficult to form a rational strut-tie model that represents a true load transfer mechanism of structural concrete with disturbed stressed region(s). To overcome the difficulty and handle numerous load cases with just one strut-tie model, a two-dimensional grid strut-tie model method was proposed previously. However, the validity of the method was not fully examined, although the incorporated basic concepts and new methods regarding the effective strength of concrete strut, load carrying capacity of struts and ties, and geometrical compatibility of grid strut-tie model were explained in detail. In this study, for accurate strength analysis and reliable design of reinforced concrete deep beams, the appropriateness of the two-dimensional grid strut-tie model method is verified. For this, the failure strength of 237 reinforced concrete deep beams, tested to shear failure, is predicted by the two-dimensional grid strut-tie model method, and the results are compared with those obtained by the sectional shear design methods and conventional strut-tie model methods of current design codes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.24-30
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• 2018

As the demand for underground space increases, many researchers have been studying the load reduction method using high compressible materials to solve for the stability problem of the overhead load and for the increase of the earth pressure which decreases the function of the underground structure. This paper determines the optimum soft zone and the effect of the using EPS Geofoam as a load reduction material to arch structures. A finite element analysis program, ABAQUS, is used to analyze the soil-structure interaction and the behavior of buried arch structures considering different four EPS Geofoam forms to confirm the most conservative shape. The optimum cross-sectional shape was determined by comparing the results of earth pressure reduction rate in accordance with the change of span-rise ratio and span length of the arch structure. It was confirmed that the earth pressure generated in the arch structure using the optimal soft zone selected by the numerical analysis was reduced by an average of 78%. In this study, the effect of EPS Geofoam on soil pressure reduction and its applicability to underground arch structures will provide an economical and conservative way to design underground structures and will help to increase the usability of deep underground space.

• Journal of the Korea Concrete Institute
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• v.18 no.5 s.95
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• pp.579-588
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• 2006

In recent years, the availability of high-strength reinforcing and prestressing steels leads us to build economically and efficiently designed concrete structural members. One of critical problems faced to the structural engineers dealing with these types of structural member is controls of crack width that is used as a criterion for the serviceability in the limit state design. Especially, flexural cracking must be controlled to secure the structural safety and to improve the durability as well as serviceability of the load carving members. The proposed method utilizes the results of pure tension test in which tensile loads are applied both side of specimen, done by Ikki. The bond characteristics of deformed reinforcing bar under pure tension is considered by the area of concrete and rib area. The results of proposed method are compared with the test data and the results show that the proposed method can take into account the dimensions, variation of sectional properties, and direction of reinforcing and gives more accurate maximum bond stress and corresponding relative slip than the existing methods. the characteristics of bonding is considered by using dimensionless slip magnitude and effective reinforcement ratio. The validity of the proposed equation is verified by test experimental data.

• Journal of the Korea Concrete Institute
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• v.29 no.3
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• pp.249-257
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• 2017

The purpose of this study was to contribute to the field application cost effectively and reasonably by developing the functional piles that make up for the defects of PHC piles. CFP (Concrete Filled Pretensioned Spun High Strength Concrete Pile with Ring type Composite shear connectors) piles developed in this study increases the compressive stress through enlarged cross section by rearranging composite shear connectors and filling the hollow part of PHC pile with concrete. And it improved shear and bending performance placing the rebar (H13-8ea) within the PHC pile and the hollow part of PHC pile of rebar (H19-8ea). In addition, the composite shear connectors were placed for the composite behavior between PHC pile and filled concrete. Placing Rebars (H13-8ea) of PHC pile into composite shear connector holes are sleeve-type mechanical coupling method that filling the concrete to the gap of the two members. Nonlinear finite element analyzes were performed to verify the performance of shear and bending moments and it deduced the spacing of the composite shear connectors. Through a various interpretation of CFP piles, it's proved that the CFP pile can increase the shear and bending stiffness of the PHC pile effectively. Therefore, this can be utilized usefully on the construction sites.