• 대한공업교육학회지
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• 제34권2호
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• pp.346-362
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• 2009

The purpose of this study was to develop the handy non-contact measurement device of the surface roughness by using the optical fiber sensor. The advantages of fiber optic sensors are high-speed responsibility, non-effect of the magnetic, convenience of the product and high precision. The measurement theory for surface roughness of optical fiber sensor is one to one correspondence between the reflected light intensity based on the surface roughness of the object and the measurement value of previously known for surface roughness. The reflected light intensity was determined using the distance to the surface from the sensor probe and the limit reflection angle based on the surface roughness. Therefore, in this study, the sensor probe was produced for determining the value of surface roughness only using the limit reflection angle based on the surface roughness with the fixed distance from the surface. A prototype measurement system was composed of a transmitting part, a receiving part and a signal processing circuit. The materials of standard measurement which was used in this experiment were SM45C, STS303 and Al60. According to the results of this study, approximation surface roughness formulas which was deduced from the correlation of between the standard surface roughness and the sensing output were verified that they were effect against the surface roughness measurement value of the option sample. And handy optical fiber surface roughness measurement device which was produced by an order was verified that it was effect for measuring of the precision surface roughness.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• 제17권6호
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• pp.160-168
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• 2003

In Korea, a large portion of aerial power-transmission cables is installed in the mountains. In the case of a fire in the mountains, steel wires coated with zinc and aluminum wires of those power cables exposed to the fire or near around will be deteriorated by the blaze and the high temperature. Deterioration proceeds by interactions of a variety of factors like quality, manufacturing process, the condition of installation and exposure environment of a wire, and so on. Generally, the characteristic of a conductor affect by a forest fire can not be analyzed without the effect through simulating a forest fire. However, there are little research accomplishments of that kind of simulation about it, and there's been no analysis of a sample exposed to an actual forest fire. This thesis shows the experimental results that apply to a new wire by an artificial flame-maker because it's difficult to directly analyze the characteristic of deterioration by a forest fire. Those results include the intensity of extension and wrench for a conductor. In addition, there's been an experiment and analysis about the mechanical characteristics of the wire of ACSR 480[$\textrm{mm}^2$] which was removed from Pohang area by a forest fire. Then, the database will be made to predict the state of deteriorated wires by a forest fire using those two data, and data necessary to diagnose the life state of an ACSR wire affected by a forest fire will be given.

• Journal of Music and Human Behavior
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• 제14권1호
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• pp.41-62
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• 2017

The purpose of this study was to examine the effect that preferred music listening had on police officers' occupational stress and fatigue. The musical intervention took place over a total of six sessions from October 11 to October 19, 2016. At each session, the experimental group (n = 19) received 20 minutes of music listening with individually customized playlists that were compiled based on their preferred music list. The control group (n = 21) simply took a break from work for 20 minutes. Every participant checked his or her occupational stress and fatigue level before and after the experiment using the Occupational Stress Inventory and Subjective Symptoms of Fatigue Test. The data were then analyzed by the SPSS 22.0 statistics program. To examine the homogeneity and pretest-posttest results between groups, an independent t test was conducted, and a paired t test was used to examine the pretest-posttest results within groups. The results confirmed all hypotheses. Findings support that the use of preferred music listening is an effective way to help police officers to control their occupational stress and fatigue. This study used a convenience sample and has limited generalizability. Future research should explore interactive approaches in music therapy as well as receptive music listening for alleviating police officers' occupational stress and fatigue.

• Journal of Korean Society of Environmental Engineers
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• 제30권5호
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• pp.560-566
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• 2008

In this paper, the solidification behaviour and compressive strength of fly ash, cement, and waste stone powder were studied each separately and with addition of each in different proportions. And also, we assessed stabilizing ability of waste stone powder in cement which was added in fly ash. The particle size of waste stone powder was found smaller than the fly ash and cement particle sizes. Moreover, when mixing all(fly ash, cement, and waste stone powder) showed distinctive crystal structure, and improved stiffness. In case of mixing fly ash, cement and waste stone powder in different proportions, the compressive strength was exceeded to the predicted compressive strength of 10 kgf/cm$^2$. The XRD analysis showed high contents of CaO in fly ash and SiO$_2$ in case of waste stone powder sample. Heavy metal emission experiment showed the 3mg/L of Pb after 14 days of mixing 150 kg/m$^3$ of cement with the 80$\sim$100 kg/m$^3$ of waste stone powder, which is fulfilling the National Waste Management Policy.

• Korean Journal of Environmental Agriculture
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• 제13권2호
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• pp.199-208
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• 1994

Analytical methods for the determination of the derivatives of the herbicide (${\pm}$)-2-(4-chloro-2-methylphenoxy)propionic acid (MCPP) by capillary column gas chromatography with mass spectrometer (GC-MS) and electron-capture detection (GC-ECD) were studied. A successful procedure was introduced for the ester preparation using $H_2SO_4$, as the catalyst and the alcohol 2,2,2-trichloroethanol (TCE) or 2,2,2-trifluoroethanol (TFE). The identificaiton and elucidation of MCPP by GC-MS spectrometry following the esterification with diazomethane, $BF_3$/methanol, $H_2SO_4$/methanol, TCE, TFE, or pentafluorobenzyl bromide (PFB) were carried out. A comparison of the response-sensitivities among those MCPP esters was made with GC-ECD. Although the methylation product of MCPP was confirmed by GC-MS, its low sensitivity to the ECD limited the detection of MCPP. TCE, TFE, and PFB derivatization methods resulted in a high rate of MCPP esterifications and very sensitive ECD molecular responses. Based on efficiency, convenience, worker safety, and least sample contamination, TFE esterificaiton was considered as the superior method for MCPP analysis to the other methods of derivatization. An accurate method is described for quantifying MCPP in soil leachates by GC-ECD at very low concentrations without the requirement of a complicated clean-up process. As a result, MCPP residues at concentrations of less than $0.1{\mu}g$ in 100ml soil leachate were detected.

• Women's Health Nursing
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• 제8권1호
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• pp.106-115
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• 2002

Little is known about sexual autonomy in the light of human sexual health or sexual behavior. The purpose of this study was to increase understanding of sexual autonomy by developing a scale to measure sexual autonomy in college students. The measure was based on the perspective of human beings as having autonomy. A methodological developmental design was used. The study was done in three steps and included concept development through content analysis of relevant literature individual interviews using open-ended questions with 19 college students, item analysis of data from self report questionnaires for item to total correlation, content validity index by professionals and college students, and factor analysis with principal component analysis. Three groups participated in testing the measurement scale; Group A in 1998, a nationwide convenience sample of college students (n=1,163), Group B, college students in 1999 (n=233), and Group C, college students in 2000 who responded to the measurement scale before and after a sex education program (n=216). A series of exploratory and confirmatory factor analyses were conducted to test validity. For analysis of the questionnaires, statistical methods including reliability (test-retest), item to total analysis, content validity, factor analysis for construct validity and t-test for mean difference according to gender, sexual coitus, previous sex education, and pre-post experiment sex education were used with SPSS 10.0. Results: 1. Two stable factors were extracted and these contributed 48.05% of the variance in the total score. All 13 items loaded above .40 on each factor. 2. Factor I with 10 items was named 'control' and factor II with 3 items and was named 'coping'. 3. Differences in sexual autonomy scores for college students according to their experience showed that there were significantly higher scores for sexual autonomy in the post sex education group(t=-10.841, p=.000), but there were no differences according to whether or not they had previous sex education. Female college students had higher sexual autonomy scores than male college students in A or B group (t=-5.933, p=.000/ t=-1.992, p=.048). 4. Cronbach's $\alpha$ was .8603 for the total 13 items with 1,632 college students, .8739 with 232 students, .8333$\sim$.7647 with pre-post sex education with 216 students. This measurement was found to have a high validity and reliability for measuring sexual autonomy in college students. Therefore, the author recommends that it be used to measure the effects of sex education. It is suggested that further study is needed to analyze the relationship between sexual autonomy and sexual behavior.

• Journal of the Korean Society for Marine Environment & Energy
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• 제14권3호
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• pp.205-211
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• 2011

On board comparison of pH and total alkalinity measurement in seawater was carried out during the JES expedition on R/V Roger Revelle in the East Sea using 550 real seawater samples from the surface to the bottom. Spectrophotometry and potentiometry without liquid junction were compared for pH measurement. The pH values of two methods are generally in a good agreement. Spectrophotometry with a pipette provides higher value compare with the potentiometry in the deep layer, where pH values are lower. However, spectrophotometry without a pipette shows same values with potentiometry within their precision range. The pipetting procedure may remove of $CO_2$ in the sample, which causes increase of pH. Potentiometric titration methods using a closed-cell and an open-cell were compared for the total alkalinity measurement. Values from open cell method are smaller by about 5~10 ${\mu}mol\;kg^{-1}$ than those from closed cell method. This may be caused by the bubble formed in the closed cell during the experiment. Although any analytical method compared in this study for the pH or TA measurement can be applied, special attentions should be paid for satisfactory results.

• Asian-Australasian Journal of Animal Sciences
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• 제18권10호
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• pp.1435-1439
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• 2005

Bacterio-mineral water (BMW) produced from manure has been known to exert a number of positive effects on animal production and odor control. An experiment was conducted to examine the effects of BMW produced from bio-reacted swine manure on in vitro gas production, cellulose degradation, microbial growth and fibrolytic enzyme activities of mixed rumen microorganisms. The five levels of 0, 0.001, 0.005, 0.01 and 1.0% BMW were supplemented into serum vials containing mixed rumen microorganisms. Incubations were carried out anaerobically at $39^{\circ}C$ without shaking for 0, 12, 24, 48, 72 and 96 h. There were no significant (p>0.05) differences among the treatments for the initial rate of gas production. At 72 h incubation, the gas production tended (p<0.1) to be increased by the 0.01 and 1.0% BMW treatments compared with control and the 0.001% BMW treatment. At the end of incubation (96 h), the sample supplemented with 0.01% BMW was higher (p<0.05) than control (0% BMW) in the gas production. The microbial growth rate was increased by all the BMW treatments, while 0.01% BMW was most effective in stimulating the growth rate. Although the addition of BMW on the filter paper DM degradation was not significantly influenced throughout the incubation period except the 48 h incubation, DM degradation tended to be increased by all BMW treatments compared with control. The addition of both 0.005 and 0.01% BMW highly increased (p<0.05) CMCase activity compared with control after 24 h and 48 h incubation, while at the 72 h incubation the 0.01% BMW addition only significantly increased (p<0.05). After 72 h incubation, the xylanase activity was significantly (p<0.05) increased with the addition of 1.0% BMW compared with the addition of 0.001 and 0.005% BMW, while at the other incubation times, the xylanase activity was not different among the treatments. In conclusion, the 0.01% BMW of supplementation level would be the suitable addition level to stimulate rumen fermentation increasing microbial growth and cellulose degradation.

• The Korean Journal of Pesticide Science
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• 제13권4호
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• pp.241-248
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• 2009

Pre-Harvest Residue Limit (PHRL) of bifenthrin during cultivation of grape was established by utilizing the dissipation curve and biological half-life of bifenthrin calculated from the analysis of 0, 1, 2, 3, 5, 7, 10, 15 days after treatment of bifenthrin. Grape sample was extracted and partitioned with acetonitrile and dichloromethane, respectively, and bifenthrin was determined with GC/ECD. Limit of quantitation (LOQ) of bifenthrin was 0.01 ng. Recoveries at two fortification levels of 0.1 and $0.5\;mg\;kg^{-1}$ were $104.08\;{\pm}\;1.24$ and $92.25\;{\pm}\;3.13%$, respectively. The biological half-lives of bifenthrin were about 21 days at standard application rate, while, 23 days at double application rate. Dissipation of bifenthrin on grape was not influenced by growth dilution effect. The PHRLs of bifenthrin were recommended as 0.60 and $0.55\;mg\;kg^{-1}$ for 10 and 5 days before harvest, respectively.

• Journal of Nutrition and Health
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• 제6권4호
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• pp.15-22
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• 1973

Sodium chloride plays an important role as the main condiment at daily meal. It is well known that humans require sodium chloride as an essential nutrient to keep the homeostasis of electrolytes. The amounts of salt intake may be a reflection of geography, culture and food habit rather than necessity. Lee has reported (1962) that Koreans ingest high amounts of sodium chloride in their meals, with an intake of excess carbohydrate (80-90% of total Calories) and low protein in their diet. This includes large amounts of rice, Kimchi and other fermented soybean products common in the Korean diet. This investigation was designed to study the dietary relations of sodium chloride to other nutrients in the Korean diet. Twenty four albino male rats, weighing from 290-300g, were divided into four dietary groups according to the amounts of carbohydrate, protein and fat in the basal diet. Each diet contained a rice powder as a carbohydrate source. Diet I was a control diet, Diet II, low protein, Diet III, low protein and low fat diet and Diet IV, low fat diet. All rats were provided with 3% sodium chloride solution. Diet and salt solution were given ad libitum. The experiment was carried out for 9 weeks during which time the body weight, the food intake, and 3% sodium chloride solution consumption were determined. At the 9th week, the urine was collected the blood sample from the artery of each rat for the analysis of sodium and potassium and other chemical studies. The rats were sacrificed and the kidney, adrenal, liver and spleen were measured, and observed changes of the pathological tissue in the kidney and adrenal. The results were summarized as follows: 1) The growth rate was higher in Diet I than in the other experimental diets (II, III and IV) after 4 weeks. There was no significant difference found between the experimental Diets II, III and IV. 2) The daily food intake was greater in the experimental diets II, III and IV than in the control diet. However, there was no difference among the high carbohydrate diets Diet II, III and IV. 3) The daily water (3% sodium chloride solution) intake was also greater in the Diets II, III and IV, than in the control diet. However, there was no difference between Diets II, III and IV. 4) The concentration of sodium and potassium in the blood were within the normal range in all diets. 5) The amount of sodium chloride in the urine was significantly greater in Diets II, III and IV than in the control diet. Diets II, III, IV had a larger amount of sodium solution consumption. 6) Observation of pathological tissue in the experimental diets found a cell proliferation in the glomerlulus of the kidney, while such change was not found in the control diet.