전북지역에 있어서 한우 종모우에 따른 번식효율 비교조사 연구

권대진,손승우,오재돈,신동현,임석기,허재영,최유림 경상대학교 농업생명과학연구원 2021 농업생명과학연구 Vol.55 No.1

번식효율은 농가수입에 직접적으로 영향을 미치는 요인으로 암소뿐 만 아니라 씨수소의 번식효율은 중요한 경제형질로 여겨지고 있다. 본 연구에서 는 한우 씨수소에 대한 번식효율을 분석하기 위하여 2010~2017년에 전북지역 분만기록 62,284개와 이에 사용된 132두의 KPN에 따른 인공수정 수태율을 분석하였다. 종부차수(NAIPC)가 증가함에 따라 분만간격(CI), 공태기간(CCI)이 유의적으로 증가하였으며(P<0.05), 임신율은 낮아졌다. 첫 종부 임신율은 62.365%로 나타났으나, 3차 이후에는 48.147 이하로 급격히 낮아졌으며, 6차 이후에는 15.664% 이하로 낮아졌다. KPN과 인공수정사 모두 수태율에 크게 영향을 미치는 것으로 나타났다. KPN에 따른 수태율은 39.154~70.621%로 분석되었으며, 인공수정사에 따른 수태율 은 22.237~85.517%로 나타났다. 인공수정 실패 시 같은 KPN의 재사용율은 20% 내외로 특별한 경향은 보이지 않았다. 첫 종부 기록만을 이용하여 상대적 추정 수태율(ESCR)을 분석한 결과 KPN1041이 가장 높은 11.107%로 나타났으며, KPN1112는 가장 낮은 -20.591%로 나타나 31.698%의 차이를 보였다. 본 연구결과 인공수정사 뿐 만 아니라 전북지역에서 사용되고 있는 KPN에 따라 번식효율이 크게 영향 받을 수 있는 것으로 나타났다. Reproductive efficiency is a factor that directly affects the income of farmers, and the reproductive capacity of not only cow but also sire has been considered an important economic trait. In this study, in order to analyze the reproductive efficiency of sires, we analyzed the fertility rate according to the KPN used in Jeonbuk province using 62,284 calving data in 132 KPNs from 2010 to 2017. As the number of artificial insemination (AI) per conception (NAIPC) increased, the calving interval (CI) and calving to conception interval (CCI) was significantly increased (P<0.05), whereas the pregnancy rate was decreased. The first-service conception rate (FSCR) was 62.365%, but after the 3rd, it was sharply decreased to 48.147% or less, and after the 6th, it was fell to 15.664% or less. Both KPN and artificial insemination (AI) technicians were found to have a great influence on the conception rate. The conception rate according to KPN shown to be 39.154~70.621% and the conception rate according to AI was 22.237~85.517%. When AI fails, the rate of repeatedly using the same KPN number was around only 20% of overall trials with no particular trend. As a result of analyzing estimated relative conception rate (ESCR) using the FSCR record, KPN1041 was the highest as 11.107% and KPN1112 was the lowest as -20.591%, showing a difference of 31.698%. As a result of this study, it was found that not only artificial insemination but also KPN used in the Jeonbuk region can greatly affect the reproductive efficiency of Hanwoo.

천연가스의 계절별 변동유량을 고려한 이중터보팽창기 감압시스템을 이용한 전기에너지회수에 관한 연구

박철우,유한빛,김효 한국가스학회 2019 한국가스학회지 Vol.23 No.2

천연가스 운송기지에서 전기에너지를 회수하기위하여 팽창 터빈시스템을 사용하는 것은 잘 알려진 기술이다. 터보팽창기의 효율은 천연가스의 유량과 터보팽창기 설계유량의 비에 따라 달라진다. 그러나 감압기지에서 계절적 공급패턴, 즉 여름에는 낮은 유량으로 반면에 겨울에는 높은 유량으로 공급되기 때문에, 단일 터보팽창기로는낮은 유량의 천연가스로부터 감압에너지를 충분히 회수하기가 비효율적이다. 따라서 본 연구에서는 대용량과 소용량의 이중 터보팽창기의 새로운 개념을 제안하게 되었다. 본 연구에서는 저압 정압기지에서 팽창밸브의 평균 입구, 출구 압력조건인 18.5 bar에서 7.5 bar로 감압될 때 입구의 온도, 유량조건에 따라서 생산 가능한 전력을 이론적배경을 통해 계산하였다. 최저 설계 효율 0.72에서 회수 가능한 전력생산량은 단일 터보팽창기로 운전될 때에는12.4 MW이었으나, 여기서 제안한 이중터보팽창기에서는 16.1 MW로 약 30% 증가한 결과를 얻게 되었다. Expansion turbine system to recover the electricity energy from natural gas transmission stations is a well-known technique. The turbo-expander efficiency depends on the ratio of the natural gas flow rates to the design flow rate of the turbo-expander. However, if there is a big difference of the natural gas flow rate through the pressure letdown station because of seasonal supply pattern, that is, high flow rate in winter while low flow rate in summer, single turbo-expander system is not so efficient as to recover the pressurized energy from the low flow-rate natural gas. Therefore, we have proposed a new concept of double turbo-expander system: one is a big capacity and the other a small capacity. Here we have theoretically computed the electric powers at the pressure reduction from 18.5 bar to 7.5 bar depending on the inlet conditions of temperature and flow rate. The calculated electricity generation has been increased by 30% from 12.4 MW in a single turbo expander to 16.1 MW in the proposed double turbo-expander system when a minimal design efficiency of 0.72 is applied.

Investigation of Relation between the Ovulation Confirmation and Conception Rate in Dairy Cattle

Hyun-Joo Lim,Ho-Beak Yoon 한국수정란이식학회 2018 한국동물생명공학회지 Vol.33 No.2

Ensuring timely ovulation concerning the service is valuable. A satisfactory conception rate can be achieved by making sure that ovulation occurs within 7-18 hours after artificial insemination (AI). Delayed ovulation is one of the disturbances commonly encountered in repeat breeding animals. Although demanding research, many studies have not been conducted. Therefore, we aimed to examine the relation between ovulation confirmation and conception rate in dairy cattle. The research findings showed that the signs of true estrus were bred 12 hours after the onset of estrus by AI in cattle. Also, the performance of AI on ovulation was confirmed by the presence of fluctuant Graafian follicles through rectal palpation. From the results, we confirmed that cow encountered delayed ovulation were bred again. The Conception rate in cows with confirmed ovulation was 51.9%, while for those without confirmed ovulation were 33.3%. In conclusion, the results indicate that ovulation confirmation will likely increase conception rate.

Investigation of Relation between the Ovulation Confirmation and Conception Rate in Dairy Cattle

Lim, Hyun-Joo,Yoon, Ho-Beak The Korean Society of Embryo Transfer 2018 한국동물생명공학회지 Vol.33 No.2

Ensuring timely ovulation concerning the service is valuable. A satisfactory conception rate can be achieved by making sure that ovulation occurs within 7-18 hours after artificial insemination (AI). Delayed ovulation is one of the disturbances commonly encountered in repeat breeding animals. Although demanding research, many studies have not been conducted. Therefore, we aimed to examine the relation between ovulation confirmation and conception rate in dairy cattle. The research findings showed that the signs of true estrus were bred 12 hours after the onset of estrus by AI in cattle. Also, the performance of AI on ovulation was confirmed by the presence of fluctuant Graafian follicles through rectal palpation. From the results, we confirmed that cow encountered delayed ovulation were bred again. The Conception rate in cows with confirmed ovulation was 51.9%, while for those without confirmed ovulation were 33.3%. In conclusion, the results indicate that ovulation confirmation will likely increase conception rate.

Investigation of Relation between the Ovulation Confirmation and Conception Rate in Dairy Cattle

임현주,윤호백 사단법인 한국동물생명공학회 2018 한국동물생명공학회지 Vol.33 No.2

Ensuring timely ovulation concerning the service is valuable. A satisfactory conception rate can be achieved by making sure that ovulation occurs within 7-18 hours after artificial insemination (AI). Delayed ovulation is one of the disturbances commonly encountered in repeat breeding animals. Although demanding research, many studies have not been conducted. Therefore, we aimed to examine the relation between ovulation confirmation and conception rate in dairy cattle. The research findings showed that the signs of true estrus were bred 12 hours after the onset of estrus by AI in cattle. Also, the performance of AI on ovulation was confirmed by the presence of fluctuant Graafian follicles through rectal palpation. From the results, we confirmed that cow encountered delayed ovulation were bred again. The Conception rate in cows with confirmed ovulation was 51.9%, while for those without confirmed ovulation were 33.3%. In conclusion, the results indicate that ovulation confirmation will likely increase conception rate.

자연환경이 인공수정 수태율에 미치는 영향 분석

전상곤,최진용,김진욱,이준희 경상대학교 농업생명과학연구원 2014 농업생명과학연구 Vol.48 No.6

본 논문은 자연환경의 변화가 젖소의 인공수정 수태율에 미치는 영향을 분석하였다. 먼저 종속변수로는 32개 농가의 인공수정자료를 이용하여 60개월(2008년 1월~2012년 12월)의 월별수태율을 구해 패널 자료로 구성하여 이용하였다. 젖소의 인공수정 수태율에 미치는 주요한 설명변수로 자연환경 변수로는 기온, 강수량, 그리고 풍속을 이용하였고, 월별 효과를 제어하기 위해 월별더미변수도 사용하였다. 분석 결과를 보면, 자연환경 설명변수 중 기온 변수가 가장 유의성이 큰 것으로 나타났다. 평균 기온이 1℃ 상승하면 수태율은 약 –0.6% 하락하는 것으로 추정되었다. 더미변수를 활용한 추정에서는 1월, 4월, 6월, 7월, 8월의 더미변수가 유의성이 큰 것으로 나타났다. 추정치를 보면 평균 수태율은 1월의 경우 약 44%, 4월의 경우 약 33%, 6월은 약 32%, 7월은 약 31%, 8월은 약 27%인 것으로 나타났다. 수태율은 기온이 높아지는 여름이 될수록 낮아지며 겨울의 경우 수태율이 높은 것으로 분석되었다. This study analyzes the effect of changes in natural environments on the artificial insemination conception rate. For the analysis we set panel data that is comprised of 32 farms and 60 months. For the dependent variable, we calculate artificial insemination conception rate from the 32 farms. For the explanatory variables, we consider three major natural environmental variables: temperature, precipitation, and wind speed. Furthermore, we use monthly dummy variables to control the effects of monthly fixed effects. Results show that temperature variable is highly significant variable. It is estimated that one celsius degree increase leads to -0.6% decrease in artificial insemination conception rate. Among monthly variables, January, April, June, July, and August are highly significant. Average conception rates are 44%, 33%, 32%, and 27% for January, April, June, July, and August, respectively. Conception rate is analyzed to be decreased in Summer season and to be increased in Winter season.

Analysis of Concept`s Diversity and Proximity for Photosynthesis in Grade 7 Students

( Soo Min Lim ),( Jae Hoon Jeong ),( Young Shin Kim ) 한국과학교육학회 2012 한국과학교육학회지 Vol.32 No.6

Concepts of science have been developed by occupying ``ecological niche`` within conceptual ecology. The ecological niche is determined from the mutual effect between intellectual environmental of the learner and new concept, which few studies have been conducted. This study examined how the ecological niche of the concept of photosynthesis in 7th grade is changed by instruction. The ecological niche was analyzed using 2 methods: (1) the change in the diversity of concepts, and (2) the change in the proximity of concepts based on the frequency and the relativeness score of the concepts. The concept of photosynthesis was analyzed in the 4 domains in the place of photosynthesis, products of photosynthesis, reactants of photosynthesis, and environmental factors. The results of this study are as follows: (1) reduced diversity of concepts, (2) increased frequency and relativeness score of the scientific concepts, and (3) increased proximity of the scientific concepts by instruction. With these results, the mutual effects of the concepts within the conceptual ecology have become active by class to differentiate the relationships between the concepts, which accordingly displayed their changes in status.

Fertility of Holstein Cows in Chengdu, China

Zi, X.D.,Ma, L.,Zhou, G.Q.,Chen, C.L.,Wei, G.M. Asian Australasian Association of Animal Productio 2003 Animal Bioscience Vol.16 No.2

Data on the use of breeding records of dairy cattle farm of Fenghuang-shan in Chengdu areas during a period of six years is systematically analyzed. The results show that Holstein heifers have their 1st estrus at an average age of $513.6{\pm}46.7$ d which is not related to the calving season. Estrus mostly occurs in the months with mild ambient temperature (March, April, May, November and December). There is a very poor rate of estrus detection; only 30.0% successive estrus is observed within 24 d, 29.3% within 25-48 d, 40.6% over 48 d. The average number of insemination per conception is 1.50 for heifers and 1.74 for cows, but conception rate (CR) is lower in the relatively warm months (July, August and September) ranged from 48.1% to 51.9% compared with 58.1% to 68.5% in other months. High temperature is the most important factor affecting fertilization in warm months, but neither did CR decline immediately with the increased air temperature in June, nor did it increase immediately with the declined air temperature in September. Post partum anestrous period is $119.5{\pm}60.5$ d. The average interval from calving to conception is $159.4{\pm}85.6$ d with only 19.8% of the cows conceived within 85 d of calving. Cows with high milk yield have longer acyclic periods and lower conception rates. Improvement of efficient managements must be a precedent condition in Chengdu areas.

초등학생들의 경제개념 발달 양상에 관한 연구: ‘환율’ 개념을 중심으로

이준혁 한국교육과정평가원 2010 교육과정평가연구 Vol.13 No.3

Although many studies of children's understanding different aspects of the economic world have been carried out, they have focused on some microeconomic ideas. Futhermore, most research has concentrated its efforts on delineating developmental stages of economic understanding or economic reasoning. But the results of this research have given little useful information to teachers and curriculum leaders. Unlike previous research, this study tried to treat not microeconomic ideas but “exchange rate” concept among macroeconomic ideas for school learners to need to understand the economic world and to place focus on exploring intuitive notions children had about “exchange rate” concept to offer economic educators about pupils' misunderstanding about economic world. For these purposes, 150 children from grades 4~6 in B elementary school, seoul, were interviewed. Putting the findings of interview together, the followings were found: Most of interviewees had various intuitive notions to be inconsistent with the real economic world. In particular, many children had the intuitive notions that some agents such as banks, government, international organizations determine the price of dollar in consideration of economic situations, prices and so on. But these erroneous notions decreased in the upper grades. Moreover, not a few interviewees in the upper grades had the notions to be consistent with the real economic world. They perceived the price of dollar dependent on the demand and supply. These findings can be seen as nothing but fragmentary informations about the development of children's economic understanding. But these informations need to be collected steadily to understand children's economic socialization more perfectly. 본 연구에서는 아동들을 대상으로 한 종래의 경제개념 발달 연구들이 몇 가지 한정된 미시적 경제개념들만을 다루어 왔다는 문제의식 하에, 그간의 연구에서 다루어 오지 않았던 거시적 경제개념들 가운데 하나인 ‘환율’ 개념의 발달 양상을 조사해 보고자 하였다. 특히 그간의 연구들이 개념 발달 ‘단계’를 도출하는데 초점을 맞추어 옴으로써 아동들이 경제세계에 대해 어떤 그릇된 상념을 가지고 있는지에 관한 구체적인 정보를 제공해 오지 못해 왔다는 비판적 인식 하에 ‘환율’ 개념과 관련한 직관적 상념을 탐색하고, 이를 중심으로 개념발달 양상을 살펴보고자 하였다. 이를 위해, 서울 B초등학교 아동 150명(4〜6학년 아동 각 50명)에게 환율 개념을 표상하고 있는 달러 가격과에 관련된 구체적인 문제들을 제시하고, 자신의 생각을 자유롭게 이야기하도록 하였다. 조사 결과, 대부분의 아동들이 현실과 부합되지 않는 다양한 직관적 상념들을 가지고 있는 것으로 나타났다. 특히 많은 아동들이 국가, 은행, 국제기구 등과 같은 기관들이 경제 사정이나 물가 등을 고려하여 달러의 가격을 직접 결정한다는 직관적 상념을 가지고 있는 것으로 나타났다. 하지만 이러한 그릇된 상념은 학년이 올라감에 따라 줄어드는 경향이 있었으며, 적지 않은 수의 고학년 아동들이 보다 현실적인 ‘시장 중심적 사고’, 즉 달러의 가격이 어떤 기관에 의해서가 아니라 달러 수급 상황에 따라 결정된다고 인식하고 있는 것으로 나타났다. 이러한 조사 결과는 단편적인 정보에 지나지 않는다고 할 수 있지만 아동들의 경제개념 발달 과정에 대한 이해의 폭을 넓히기 위해서 이 같은 정보들을 꾸준히 축적시켜 나갈 필요가 있다고 하겠다.

Simulation of material failure behavior under different loading rates using molecular dynamics

Kim, Kunhwi,Lim, Jihoon,Kim, Juwhan,Lim, Yun Mook Techno-Press 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.30 No.2

Material failure behavior is generally dependent on loading rate. Especially in brittle and quasi-brittle materials, rate dependent material behavior can be significant. Empirical formulations are often used to predict the rate dependency, but such methods depend on extensive experimental works and are limited by practical constraints of physical testing. Numerical simulation can be an effective means for extracting knowledge about rate dependent behavior and for complementing the results obtained by testing. In this paper, the failure behavior of a brittle material under different loading rates is simulated by molecular dynamics analysis. A notched specimen is modeled by sub-million particles with a normalization scheme. Lennard-Jones potential is used to describe the interparticle force. Numerical simulations are performed with six different loading rates in a direct tensile test, where the loading velocity is normalized to the ratio of the pseudo-sonic speed. As a consequence, dynamic features are achieved from the numerical experiments. Remarkable failure characteristics, such as crack surface interaction/crack arrest, branching, and void nucleation, vary in case of the six loading cases. These characteristics are interpreted by the energy concept approach. This study provides insight into the change in dynamic failure mechanism under different loading rates.