• 한국자기학회지
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• 제17권2호
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• pp.71-75
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• 2007

계면활성제를 첨가한 음향화학적 침전법으로 두 가지 크기의 아연페라이트 나노입자를 합성하였다. 열분석장치(TGA/DSC)를 이용하여 열적 특성 및 결정화 온도를 조사하였고, 결정구조 확인을 위하여 X선 회절실험을 실시하였다. 제조된 입자는 $240^{\circ}C$ 부근에서 결정생성이 시작되었으며, 결정구조는 전형적인 스피넬 구조를 나타내었다. Scherrer식에 의해 측정된 입자의 크기는 11.2nm와 13.4nm이었다. SQUID를 통하여 자기적 성질을 분석한 결과, 작은 크기의 입자에 대한 방해온도 $T_B$(Blocking temperature)가 큰 입자의 경우보다 더 높게 나타났다.

• 대한영양사협회학술지
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• 제13권1호
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• pp.15-29
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• 2007

This study was designed to : (a) investigate the present situations of a college union foodservice and suggest authority on establishing new college foodservice, (b) estimate the service quality attributes as perceived by students, (c) identify the effecting factor to customer satisfaction, and (d) formulate the plans and marketing strategies for the increasing usage rate of the foodservice in the future. The questionnaire that developed by interviewing student were conducted with 305 male and female students, who were registered for daytime classes. A total of 284 were usable and data was analyzed by the SPSS(ver. 11.0) for the descriptive analysis, factor analysis, reliability test, multiple regression analysis, t-test, and $x^2$. The decrease in the usage rate of college foodservice by the respondents were influenced most by the 'taste of meal' and next by the 'distance'. The service quality attributes of foodservice currently under operation were evaluated above the average only for the 'price' while evaluated generally to be in the lower level of the average or under for others. As the overall level of satisfaction with the college union foodservice, most of the respondents showed the 36% for the ‘dissatisfaction’ and dissatisfied at 54.4%. Two service quality dimensions,"food . sanitation . service" and "price and comfortable environment" were derived from factor analysis and the reasons for decreasing usage rate of the college foodservice both the nearly located group from college union foodservice(NG) and the far away located group from college union foodservie(FG) indicated the ‘poor taste’ and the 'far distance', and the 'evaluation of students' dining room showed a low rating for the factor of "food . sanitation . service". "food . sanitation . service" was analyzed to have more influence to the overall customer satisfaction.

• 대한한방내과학회지
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• 제34권4호
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• pp.362-374
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• 2013

Objectives : This study was carried out to investigate the inhibitory effect of Banhasasim-tang on early reflux esophagitis by control of gastric peristalsis and the lower esophageal sphincter in mice. Methods : Experimental mice were classified into three groups. The normal group were mice with no inflammation. The control group were mice with gastroesophageal reflux elicited by alcohol. The sample group were mice administered Banhasasim-tang after gastroesophageal reflux elicitation. We observed morphological change and production of ghrelin, substance P, and inducible nitric oxide synthase (iNOS) in gastroesophageal junction mucosa. In addition, we examined change of epithelial junction in esophageal mucosa and change of lower esophageal sphincter distribution. Results : The migration of inflammation-related cells in lamina propria of gastroesophageal junction decreased more in the sample group than in the control group. The positive reaction of ghrelin, substance P, and iNOS significantly decreased more in the sample group than in the control group (p<0.05). Injury of the epithelial junction in the esophageal mucosa and outer oblique layer in the lower esophageal sphincter were significantly mitigated by Banhasasim-tang administration in the sample group (p<0.05). Conclusions : According to the above results, it is supposed that Banhasasim-tang inhibits early reflux esophagitis by controlling not only gastric peristalsis and acid secretion through ghrelin, and substance P but also the lower esophageal sphincter through iNOS.

• Smart Structures and Systems
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• 제20권2호
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• pp.139-150
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• 2017

The structural strain plays a significant role in structural condition assessment of in-service bridges in terms of structural bearing capacity, structural reliability level and entire safety redundancy. Therefore, it has been one of the most important parameters concerned by researchers and engineers engaged in structural health monitoring (SHM) practices. In this paper, an SHM system instrumented on the Jiubao Bridge located in Hangzhou, China is firstly introduced. This system involves nine subsystems and has been continuously operated for five years since 2012. As part of the SHM system, a total of 166 fiber Bragg grating (FBG) strain sensors are installed on the bridge to measure the dynamic strain responses of key structural components. Based on the strain monitoring data acquired in recent two years, the strain-based structural condition assessment of the Jiubao Bridge is carried out. The wavelet multi-resolution algorithm is applied to separate the temperature effect from the raw strain data. The obtained strain data under the normal traffic and wind condition and under the typhoon condition are examined for structural safety evaluation. The structural condition rating of the bridge in accordance with the AASHTO specification for condition evaluation and load and resistance factor rating of highway bridges is performed by use of the processed strain data in combination with finite element analysis. The analysis framework presented in this study can be used as a reference for facilitating the assessment, inspection and maintenance activities of in-service bridges instrumented with long-term SHM system.

• Asian-Australasian Journal of Animal Sciences
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• 제13권2호
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• pp.167-175
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• 2000

This paper describes the magnetic orientation of bull sperm separated into the head and the flagellum treated by DTT or heparin in a 5,400G static field. Semen samples collected from four bulls (Japanese Black) were mixed to the same sperm density. One percentage triton X-100 was used to extract the plasma membrane. The intact and demembranated sperm suspensions were treated with 20, 200, 2,000 mM DTT, 100, 1,000 or 10,000 units heparin solutions at $4^{\circ}C$ for 6 days. The decondensation of the sperm nuclei treated by DTT or heparin was examined by measuring the head area at 1, 3 and 6 days. After measuring the area, each sample was exposed to a 5,400G static magnetic field generated by Nd-Fe-B permanent magnets for 24 hours at room temperature. Results showed that the sperms were separated into the head and the flagellum through the DTT treatment. Almost of the separated heads showed that their long axis oriented perpendicularly to the magnetic lines of force, and most of the long axis perpendicularly oriented heads showed that their flat plane oriented perpendicularly in a 5,400G magnetic field. Also, the demembranation of the head tended to increase those perpendicular orientations, while those perpendicular orientations of the head declined with the decondensation of the sperm nuclei. These findings suggest that strong magnetic anisotropy for the perpendicular orientation of the long axis and the flat plane of the head occurs in the sperm nuclei in a 5,400G magnetic field. The separated flagellum showed lower parallel orientation, and the separated and demembranated flagellum showed parallel orientation to the magnetic lines of force in this magnetic field. These findings suggest that weak magnetic anisotropy of the parallel orientation of the flagellum occurs in the inside components in a 5,400G field.

• 대한임베디드공학회논문지
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• 제15권5호
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• pp.215-225
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• 2020

Light detection and ranging (LiDAR) sensors detect the distance of the surrounding environment and objects. Conventional LiDAR sensors require a certain amount of a power because they detect objects by transmitting lasers at a regular interval depending on a constant resolution. The constant power consumption from operating multiple LiDAR sensors is detrimental to autonomous and electric vehicles using battery power. In this paper, we propose two algorithms that improve the inefficient power consumption during the constant operation of LiDAR sensors. LiDAR sensors with algorithms efficiently reduce the power consumption in two ways: (a) controlling the resolution to vary the laser transmission period (T_P) of a laser diode (LD) depending on the vehicle's speed and (b) reducing the static power consumption using a sleep mode depending on the surrounding environment. A proposed LiDAR sensor with a resolution control algorithm reduces the power consumption of the LD by 6.92% to 32.43% depending on the vehicle's speed, compared to the maximum number of laser transmissions (N_x·max). The sleep mode with a surrounding environment-sensing algorithm reduces the power consumption by 61.09%. The proposed LiDAR sensor has a risk factor for 4-cycles that does not detect objects in the sleep mode, but we consider it to be negligible because it immediately switches to an active mode when a change in surrounding conditions occurs. The proposed LiDAR sensor was tested on a commercial processor chip with the algorithm controlling the resolution according to the vehicle's speed and the surrounding environment.

• Asian-Australasian Journal of Animal Sciences
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• 제12권6호
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• pp.939-943
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• 1999

Three 28 day-old $Duroc{\times}Large$ $White{\times}Landrace$ litter mate gilts weighing an average of 6.5 kg were used to study the intestinal absorption of amino acids when provided in dipeptide form or in the form of a free amino acid mixture. The pigs were given one of three treatments. The control involved a duodenal infusion containing no amino-acids (phosphate buffer plus 5% sorbitol) while the remaining two treatments involved either a duodenal infusion containing a glycine-lysine dipeptide (1 g) or a mixture of the free amino acids glycine and lysine at the same concentration as in the dipeptide. Blood was drawn from a cannula inserted in the portal vein, at 5 to 20 minute intervals, for two hours following infusion. The concentration of intact dipeptide as well as free glycine and lysine in the portal blood was determined by high performance liquid chromatography. The intact dipeptide was never detected in the portal blood at any time after infusion. Lysine appeared in the portal blood more rapidly after infusion of dipeptide than after infusion of free lysine and the concentration of lysine in portal blood was higher in the pig infused with the dipeptide than after infusion of free lysine at almost all time points measured. The cumulative absorption of lysine and glycine from the intestine during the two hour period after infusion was greater in the pig infused with dipeptide than in the pig infused with free amino acids. The results suggest that although intact dipeptide did not reach he portal circulation, a special transport mechanism for absorption of dipeptide by intestinal cells appears to be present in pigs similar to that observed in other species.

• Asian Pacific Journal of Cancer Prevention
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• 제13권3호
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• pp.1031-1038
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• 2012

Background: Turmeric ($Curcuma$ $longa$) has been shown to possess anti-inflammatory, antioxidant and antitumor properties. However, despite the progress in research with $C.$ $longa$, there is still a big lacuna in the information on the active principles and their molecular targets. More particularly very little is known about the role of cell cycle genes $p57^{kip2}$ and Rad9 during chemoprevention by turmeric and its derivatives especially in prostate cancer cell lines. Methods: Accordingly, in this study, we have examined the antitumor effect of several extracts of $C.$ $longa$ rhizomes by successive fractionation in clonogenic assays using highly metastatic PC-3M prostate cancer cell line. Results: A mixture of isopropyl alcohol: acetone: water: chloroform: and methanol extract of $C.$ $longa$ showed significant bioactivity. Further partition of this extract showed that bioactivity resides in the dichloromethane soluble fraction. Column chromatography of this fraction showed presence of biological activity only in ethyl acetate eluted fraction. HPLC, UV-Vis and Mass spectra studies showed presence three curcuminoids in this fraction besides few unidentified components. Conclusions: From these observations it was concluded that the ethyl acetate fraction showed not only inhibition of colony forming ability of PC-3M cells but also up-regulated cell cycle genes $p57^{kip2}$ and Rad9 and further reduced the migration and invasive ability of prostate cancer cells.

• 한국연소학회지
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• 제22권3호
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• pp.17-22
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• 2017

An experimental study has been conducted to elucidate the effect of AC electric field on behaviors of laminar lifted flame in nitrogen-diluted methane coflow-jets. Our concerns are focued on the regime to show a decrease in liftoff height, $H_L$ with increasing nozzle exit velocity, $U_O$ (hereafter, $decreasing-H_L$). The $H_L$ with $U_O$ near flame extinction were measured by varying the applied AC voltage, $V_{AC}$ and frequency, $f_{AC}$ in a single electrode configuration. The behavior of $H_L$ with a functional dependency of $V_{AC}$ and $f_{AC}$ was categorized into two regime : (I) $H_L$ decreased for nozzle diameter, D = 1.0 mm, and (II) $H_L$ increased in the increase of $f_{AC}$ for a fixed $V_{AC}$ in a D = 4.0, 8.4 mm. The lifted flames in $decreasing-H_L$ region was unstable in high voltage regimes while the $H_L$ showed a decreasing tendency with $U_O$ except them. Such behaviors in $H_L$ were also characterized by functional dependencies of related physical parameters such as $V_{AC}$, $f_{AC}$, $U_O$, fuel mole fraction ($X_{F.O}$) and D.

• Tribology and Lubricants
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• 제33권6호
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• pp.263-268
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• 2017

The significance of maintaining the soil environment is gradually increasing owing to soil and underground water contamination by petroleum leak accidents. However, the purification of soil is an expensive and more time-consuming process than the purification of contaminated water and air. Moreover, determining the source and people responsible for soil pollution gets often embroiled in legal conflicts, further delaying the cleanup process of the contaminate site. Generally, TPH (total petroleum hydrocarbon) pattern analysis is used to determine the petroleum species and polluter responsible for soil contamination. However, this process has limited application for petroleum products with a similar TPH pattern. In this study, we analyze the TPH pattern and specific sectional ratio (${\sim}C_{10}$, $C_{10}-C_{12}$, $C_{12}-C_{36}$, and $C_{36}{\sim}$) of various domestic petroleum products to identify the petroleum product responsible for soil contamination. Also, we perform BTEX (benzene, toluene, ethyl benzene, xylene) quantitative analysis and determine B:T:E:X ratio using GC-MS. The results show that gasoline grade 1 and 2 have a similar TPH pattern but different BTEX values and ratios. This means that BTEX analysis can be used as a new method to purify soil pollution. This complementary TPH and BTEX method proposed in this study can be used to identify the petroleum species and polluters present in the contaminated soil.