• 한국추진공학회지
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• 제6권4호
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• pp.37-45
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• 2002

The development process of KSR-III propulsion feeding system is subscripted. The purpose of propulsion feeding system is to feed a certain amount of propellant from propellant tank to engine by the end of combustion. Pressure-fed liquid rocket, KSR-III has the unique characteristics of both pressure regulator and cavitation venturi as a passive flow control device. Main parameters of feeding system are confirmed by both water test and CFD(전산유체) technique. Flow control effect with venturi is confirmed by water test. Initial stabilization characteristic of pressure regulator is confirmed by real propellant test. And, to avoid the effect of resonance between rocket and feeding system, this article deal with POGO(포고) analysis to the feeding system.

• 한국정밀공학회지
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• 제14권5호
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• pp.157-163
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• 1997

In the case of direct connecting the nut of ballscrew to guide table, machining error and misalignment of ballscrew largely affect to the motional accuracy of guideway. For decreasing these influences, two type of floating couplings: leaf spring type and hybrid type which releases the table from nut of ballscrew except feed and rotational direction is proposed in this study. In order to verify practical availability of the proposed floating couplings, motional accuracy, dynamic characteristics and micro step response of hydrostatic guideway, mounted with each type of couplings are tested. The conventional fixed type coupling is also tested as the reference in characteristics. From the results of experiments, it is proved that the hybrid type coupling is superior to other couplings and is available to high precision feeding system with ballscrew.

• Fisheries and Aquatic Sciences
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• 제17권2호
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• pp.229-247
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• 2014

Seven feeding trials were conducted to determine the effects of feeding rate and frequency in the Korean rockfish Sebastes schlegeli at seven different water temperatures. Two feeding-rate experiments for 5-g Korean rockfish at $17^{\circ}C$ and $20^{\circ}C$; three feeding rate experiments for 16-g Korean rockfish at $16^{\circ}C$ and $24^{\circ}C$; and finally, two feeding frequency experiments for 93- and 100-g at $15^{\circ}C$ and $20^{\circ}C$ were conducted. Twenty fish averaging $5.5{\pm}0.2$ g ($mean{\pm}SD$) were randomly distributed into 18 indoor tanks containing 40-L seawater from a semi-recirculation system. Fish were fed a commercial diet for 4 weeks at water temperatures of $17^{\circ}C$ and $20^{\circ}C$. Two feeding trials were conducted to determine the optimum feeding frequency in growing Korean rockfish reared at temperatures of $15^{\circ}C$ and $19^{\circ}C$. Broken line regression analysis of weight gain (WG) indicated that the optimum feeding rates of 5-g growing Korean rockfish were 4.48% (BW/day; BW, body weight) at $17^{\circ}C$ and 4.83% (BW/day) at $20^{\circ}C$. Broken line regression analysis of WG showed optimum feeding rates of 16-g juvenile Korean rockfish of 3.41% (BW/day) at $16^{\circ}C$, 3.75% (BW/day) at $20^{\circ}C$, and 3.34% (BW/day) at $24^{\circ}C$. The biological performance, results, along with morphological indices and serological characteristics, suggest that a feeding frequency of 1 meal/day was optimal to improve WG in growing Korean rockfish grown from 93 to 133 g at a water temperature of $15^{\circ}C$, and 100 to 132 g at $19^{\circ}C$.

• Asian-Australasian Journal of Animal Sciences
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• 제1권4호
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• pp.223-232
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• 1988

Fifty-two wether lambs weighing 30 kg were randomly assigned to 5 treatment groups; 1) initial slaughter. 2) control-maintenance (CON-MT), 3) control-ad libitum (CON-AL), 4) cimaterol-maintenance (CIM-MT) and 5) cimaterol-ad libitum (CIM-AL). Ad libitum-fed animals had free access of a high-concentrate diet, whereas maintenance animals were restricted in feed intake to maintain the initial weight of 30 kg for 90 days. Cimaterol was administered in the feed at 10 mg/kg. Regardless of feeding level, the administration of CIM improved carcass weight (p < .05), dressing % (p < .01), longissimus muscle area (p < .01), leg conformation and muscling (p < .01), USDA yield and quality grades (p < .01) and protein concentration (p < .01) in carcass as well as in muscle. Cimaterol feeding decreased organ wt (p < .01), baekfat depth (p < .01), intramuscular fat and overall fatness. Cimaterol was effective for muscle accretion even under restricted feeding condition. The greater accretion of muscle was the result of the hypertrophy of both type I and type II muscle fibers but the hypertrophy of type II fiber (110%) was much greater than that of type I fiber (37%). Cimaterol feeding decreased muscle DNA concentrations but the number of nuclei per muscle fiber was not changed, indicating that the lower DNA concentration was due to the dilution effect caused by the hypertrophy of muscle fiber. As evidenced by lower flank streaking, lower marbling and darker muscle, CIM feeding adversely affected meat quality. Meat tenderness was also adversely affected, resulting in significantly (p H .01) tougher meat in CIM-fed animals.

• 한국응용곤충학회지
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• 제43권1호
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• pp.21-26
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• 2004

아메리카잎굴파리의 내부기생봉인 Neochrysocharis formosa의 산란과 기주체액섭취 선호성을 조사하였다. N. formosa는 기주유충의 몸 뒤쪽에 대부분 산란하였다. 온도 조건에 따른 일산란수와 일기주체액섭취수를 조사한 결과 온도가 높을수록 증가하는 경향이었으며 15, 20, 25, 3$0^{\circ}C$에서의 산란수와 체액섭취수의 비율은 각각 0.5, 0.9, 1.0, 1.0이었다. $25^{\circ}C$ 항온조건하에서 N. formosa의 총산란수와 기주체액섭취수는 각각 176개 188.7개이었으며 산란수와 기주체액섭취수 비율은 0.9이었고 암컷 수명은 11.8일이었다. 산란과 기주체액섭취는 주로 아메리카잎굴파리 3령유층을 선호하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제34회 춘계학술대회논문집
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• pp.89-94
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• 2010

액체로켓 기체공급계는 추진제를 요구되는 유량, 온도, 압력으로 엔진에 공급하여야 한다. 이를 위한 정상상태의 공급특성은 기존의 열역학 및 열전달, 유체역학 이론을 적용하여 해석하며 방법론이 잘 정립되어 있다. 발사체의 비행 중에 발생하는 탱크와 공급배관에서의 추진제의 진동은 정상상태의 공급특성을 변하게 하며 추진제공급 요구조건을 만족시키지 못하게 한다. 이러한 진동을 발생시키는 것으로서 발사체의 가속도로 인한 슬로싱 및 엔진의 추력섭동에 의해 배관 내 추진제가 진동하는 포고 불안정이 있다. 포고와 슬로싱에 의한 발사체 제어와 구조측면에서 미치는 영향에 대해서는 기존에 많은 연구가 있으나 추진제 공급특성에 미치는 영향에 대해서는 잘 알려져 있지 않다. 본 연구에서는 추진제의 진동이 엔진으로의 추진제 공급에 미치는 영향을 기존 자료를 이용하여 살펴보고 진동을 제어하기 위한 기구를 살펴본다.

• Child Health Nursing Research
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• 제1권1호
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• pp.16-25
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• 1995

The purpose of this study was to estimate primiparas' perceptions of their newborns and compare the changes of their perceptions related to feeding methods between the time I (post-partum 2nd-3rd day) and the time ll (post-partum 1st month). At the time Ⅰ, bottle-feeding method was 100% because mothers were separated from their babies. At the time Ⅱ, the methods of feeding were breast-feeding(29.7%), bottle-feeding(30.7%), mixed feeding(39.6%) .The subjects of this study were 101 primiparas. Data were collected between May to October 1994, using the Neonatal Perception Inventory devised by Broussard(1963) and added by Lee Ja Hyurg(1986) .The results of this study are as follows : 1. There was no significant difference of primiparas' perceptions of their newborns according to general characteristics. 1) The younger tended to estimate that newborns were less capable, and perceived that it would be more difficult for them to take care of babies. 2) There was no difference of mothers' perceptions of their babies according to having a job or not. 3) The lower educated tended to estimate that newborns were less capable, and perceived that it would be more difficult for them to take care of babies. 2. There were some changes of primiparas' perceptions of their babies related to feeding methods between the time I (post-partum 2nd-3rd day) and the time Ⅱ (post-partum 1st month).1) At the time Ⅰ, Breast-feeding mothers estimated that newborns were less capable, and perceived that it would be more difficult for them to take care of babies. But they showed positive perceptions at the time Ⅱ (P<0.05, p<0.1) 2) At the time Ⅰ, Bottle-feeding mothers tended to estimate that newborns were more capable, and perceived that it would be more easy for them to take care of babies. But they showed negative perceptions at the time Ⅱ 3) For breast-feeding mothers, positive-positive group was 53%, positive-negative group was 20%, negative-positive group was 10%, negative-negative group was 17%. For bottle-feeding mothers, positive-positive group was 55%, positive-negative group was 32%, negative-positive group was 10%, negative-negative group was 3%.

• Asian-Australasian Journal of Animal Sciences
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• 제16권10호
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• pp.1482-1486
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• 2003

In order to compare effects of feeding systems on rumen fermentation characteristics and nutrient digestion, steers were fed either total mixed ration (TMR) or separate concentrate-roughage ration (CR). Total tract digestibility of nutrients was higher in steers receiving TMR. Especially, DM, ADF and NDF in TMR were digested to a greater extent than those in CR. Rumen pH was not influenced by the feeding systems. Holstein steers on TMR had higher ruminal $NH_3$-N than those on CR. Feeding system did not alter VFA production but TMR feeding resulted in lower A/P ratio. TMR feeding tended to increase the number of bacteria and protozoa in the rumen fluid. Also steers fed TMR generally had higher fiber degrading enzyme activities, which might be the result of increased number of cellulolytic microbes in the rumen of animals on TMR. Our results indicate that TMR may provide more favorable condition for nutrient digestion both in the rumen and in the total tract of steers.

• 한국생산제조학회지
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• 제19권5호
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• pp.596-602
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• 2010

In this study, a fmite element model was developed for analysis of feeding a structure in open loop control The finite element analysis (FEA) can simulate dynamic behavior of the structure of a machine tool rapidly traveling with a screw feeding driving system. The feeding mechanism was implemented with screw element of the FEA tool used in this study. The procedure was developed for the dynamic transient FEA. First, motion parameters such as jerk and velocity were introduced for the structure to be fed in open loop control When its traveling distance was determined, set-points for the distance were generated based on the motion parameters. The set-points were applied to the FE model constructed for the traveling structure. The FEA was executed and evaluated. In this study, the FEA procedure was applied to the column of a machine tool and the dynamic behavior of the column was evaluated. The FEA helps in evaluation of the motion characteristics of a structure. The convergence time of the structure vibration posterior to feeding termination can be estimated and the stiffness of the flexible structure is also evaluated against jerk, and acceleration. It provides the feeding force which is helpful in selection of the feeding motor.

• 한국식생활문화학회지
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• 제35권1호
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• pp.97-106
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• 2020

This study aimed to evaluate dietary behaviors and food allergy status of preschool children in Gwangsan-gu, Gwangju Metropolitan city. The survey included 592 preschool children aged 1-5 years old in 31 childcare facilities. General characteristics, feeding type, complementary feeding, food allergy, dietary behaviors based on the NQ-P questionnaire, and dietary habits of their family were considered. Exclusively breast-fed children was 32.2% of the subjects and the breast feeding duration was 6.5 months. Subjects who had complementary feeding within 6 months was 77.2% and starting time of complementary feeding was 6.1 months. Fifteen percent of the subjects had food allergies and foods that induced allergy were instant foods, eggs, milk and dairy products, nuts, seafood. Food allergy was not related to breast feeding nor complementary feeding. The NQ-P score and its 3 factors including 'balance', 'moderation', and 'environment' were 59.9, 61.1, 56.0, 62.6, respectively. There were positive relations between children's dietary behaviors and family dietary habits such as breakfast eating frequency and meal regularity. As age of children increased, instant food intake increased and breakfast eating frequency decreased. Proper nutrition education is needed to children, their parents, and their care givers at childcare facilities to improve children's dietary behavior and health.