• Journal of the Korean Society for Precision Engineering
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• v.16 no.3 s.96
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• pp.47-52
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• 1999

Theoretical and experimental studies on burr formation and deburring in many manufacturing processes have been actively pursued. Though micro-drilling has become more important in the production of precision parts such as PCB, air bearing, camera and nozzle, most studies on drilling burr formation have focused on the conventional drilling process. This paper describes burr formation process and the effect of cutting conditions such as spindle speed, feedrate and drilling depth per one step on burr formation in drilling A6061 with drills of diameter 1.0mm and 0.6mm. Experimental results showed that burr with cap were formed at relatively low feedrates, while petal burrs with several large burr fragments were formed at high feedrates. Burr height appeared to increase at the hight feedrates and lower spindle speeds. The effect of final cutting depth on burr height was negligible.

• Preventive Nutrition and Food Science
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• v.1 no.1
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• pp.87-92
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• 1996

This study describes a stable and simple method for the measurement of cholesteryl ester transfer protein(CETP) activities using reconstituted HDL and LDL as substrates. Apolipoproteins (apo) A-I and -B were purified from hog plasma by a new strategy without ultracentrifugation and delipidation. a simple two-step column chromatography was administered. In the first step of phenyl-sepharose CL-4B column chro-matography, hydrophobic plasma proteins were isolated. The most hydrophobic proteins bound to the column appeared to be A-I and apo-B. Contaminat proteins were efficiently eliminated from the sample by washing the column with 0.3M NaCI containing buffer after loading the plasma on the column. Two pure proteins showing each single band on SDS-PSGE of apo A-I and apo-B were individually obtained by a subsequent gel filtration column chromatography(Sephadex G-200). This two-step purification was simple and inexpensive compared to the ultracentrifugation and/or delipidation method that are most commonly used. Reconstituted hight-density lipoproteins(HDL) and low-density lipoproteins(LDL) were prepared using the purified apo A-I and-B, respectively. When these artificially prepared HDL and LDL were used in the assays for CETP as the cholesteryl ester(CE) donor and acceptor respectively, the specific transfer of CE increased up to two fold compared to that used the native HSL and LDL.

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.1
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• pp.18-26
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• 2016

The semiconductor industry is one of the key industries of Korea, which has continued growing at a steady annual growth rate. Important technology for the semiconductor industry is high integration of devices. This is to increase the memory capacity for unit area, of which key is photolithography. The photolithography refers to a technique for printing the shadow of light lit on the mask surface on to wafer, which is the most important process in a semiconductor manufacturing process. In this study, the width and step-height of wafers patterned through this process were measured to ensure uniformity. The widths and inter-plate heights of the specimens patterned using photolithography were measured using transmissive digital holography. A transmissive digital holographic interferometer was configured, and nine arbitrary points were set on the specimens as measured points. The measurement of each point was compared with the measurements performed using a commercial device called scanning electron microscope (SEM) and Alpha Step. Transmission digital holography requires a short measurement time, which is an advantage compared to other techniques. Furthermore, it uses magnification lenses, allowing the flexibility of changing between high and low magnifications. The test results confirmed that transmissive digital holography is a useful technique for measuring patterns printed using photolithography.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.435-437
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• 2002

Polishing of copper, a process called copper chemical mechanical polishing, is a critical, intermediate step in the planarization of silicon wafers. During polishing, the electrodeposited copper films are removed by slurries: and the differential polishing rates between copper and the surrounding silicon dioxide leads to a greater removal of the copper. The differential polishing develops dimples and furrows; and the process is called dishing and erosion. In this work, we present the results of experiments on dishing and erosion of copper-CMP, using patterned silicon wafers. Results are analyzed for the pattern factors and properties of the copper layers. Three types of pads - plain, perforated, and grooved - were used for polishing. The effect of slurry chemistries and pad soaking is also reported.

• Journal of Life Science
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• v.20 no.2
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• pp.304-313
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• 2010

Out of the tenth graders of K girl's high school in J city, 24 students whose %fat was over 30% were divided into 3 groups through Purposing Sampling. Groups A and B were exercise groups and C was the control group. Using Borg's RPE (rating of perceived exertion), RPE 15-17 (hard-very hard) $\times$ 3 sets were set up for group A, RPE 11-13 (fairly light-somewhat hard) $\times$ 3 sets were set up for group B, and both groups performed step aerobics (step box: 68cm in length, 28cm in width, 15cm in hight, 450g in weight) for 50-60 minutes a day, 3 days a week for 8 weeks in total. This research was conducted to find out the effects of various RPE in step aerobics on the immunologic function (neutrophil, lymphocyte, monocyte, eosinophil, basophil, IgG, IgA, and IgM levels) of overweight female high school students. By using SPSS Ver. 14.0, a repeated two-way ANOVA was conducted to find out the effects of interaction between the groups and time period, paired t-test to evaluate data within each group, and pre- and post experiment difference rates (%diff) to perform one-way ANOVA for group comparisons. The following results were found. As for WBC, within group A, neutrophil, monocyte, basophil, and eosinophil levels increased, while lymphocyte levels remained the same. Within group B, eosinophil levels decreased while neutrophil, lymphocyte, monocyte, and basophil levels showed no differences. Within the control group, neutrophil, basophil, and eosinophil levels decreased while lymphocyte and monocyte levels showed no differences. As for the group comparisons, neutrophil levels increased more in group A than group B and the control group. There were no differences in lymphocyte levels among the three groups. Monocyte levels increased more in group A and B than the control group. Basophil and Eosinophil increased more in group A than group B and the control group. As for immunoglobin, within group A, the IgG level increased but the levels of IgA and IgM did not change. Within group B, the IgA level increased but the level of IgG decreased, and the level of IgM did not change. Within the control group, the IgG level decreased but the levels of IgA and IgM did not change. As for the group comparisons, the level of IgA increased more in group A than the control group, and the level of IgG increased more in group A than group B and the control group, but levels of IgM among the three groups did not show any difference. In summary, WBC and Ig levels showed that the three groups remained at the reference interval even after the exercise program. However, group A, which performed RPE 15-17 in step aerobics, showed increase in more measured items than the other groups, and this implies that the immunologic function has improved in the range of the reference intervals. Therefore, it will be effective to conduct step aerobics with the RPE 15-17 (hard-very hard) in order to increase the immunologic function.

• Journal of muscle and joint health
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• v.1 no.1
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• pp.97-115
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• 1994

The purpose of this study was to examine the reliability and validity of the observed behaviors of subjects who suffered from low back pain with spinal diseases, Thirty two low back pain patients admitted on the neurosurgical unit in an army hospital were compared with 30 normal controls belonged to an army unit, by means of matching the age, hight and weight. Observed pain behaviors were developed by the researcher on the bases of literature and patient observation. This tool consists of 18 behaviors seperated into two major groups : mutually exclusive and concomittent behaviors. The mutually exclusive behaviors included coding cathegories for 6. body motions assumed by the subjects during the observation session. These 6 standardized motions consisted of sitting from standing first, and serially tying down, reclining, sitting again, and then standing, 6 steps walking. Concomittent behaviors consisted of 12 observable patterns that can be observed systematically from the face, grimacing, bracing, rubbing, walking with arms fixed, support with hands on sitting or standing, guarded movement, limping, unbalaced weightbearing, stopped movement from tying position to sitting, sighing and graoning. Subjects were videotrecorded as they performed a 6-standardized sequence of motions, simultanously researcher measured the time spent performing each motion and step length. Patients were asked torate their subjective pain score on the 10 mm graphic rating scale ranging from 'no pain' to 'sever pain'. For scoring of the pain behaviors, two trained nursing officiers independently and simutanously viewwd each videorecording and checked subject 'pain behaviors at the observational item checklist. The result of the study are summarized as follows : 1. Reability of the observational tool was a=.845. 2. Spearman's rho and percentage agreement were p=.97 and 81.7 persent respectively, that indicate adequate interrater reability of this tool. 3. The sensitivity rate of the tool was .875 while specificity rate .866 for differentiating patient from the normal. 4. When difference in the objective pain indices between patient group and control were compared, there was significant difference of all indices, such as pain behavior(t=7.71, p=.0001). spent time performing motion(t=14.2, p=.0001), step length (t=-10.72, p=.0001). 5. There were differences in the objective indices the subjective pain subgroups (low, medium, high). Differences in the mean score of objective pain behavior (F=6.376. p=.005) and spent time for moyion(F=4.631, p=.018). But there were no significant differences in the step length among the subgroups(F=.667, p=.521). 6. Highly correlated pain behavior items wiyh subjective pain score were 'stopped movement from lying position to sitting', 'limping', 'support with hands on sitting or standing', 'bracing', 'guarding' and 'walking with arms fixed'. In summary, although some of rho behavior items such as sighing and groaning in this study could not be observed because of videotaped datd, the reliability and validity of the over all observation method were satifactory. Thus, the results of the present study demonstrate rye potetional utility of the tool in assessing objective pain complementing self-reported pain in low back pain patients.

• Fire Science and Engineering
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• v.34 no.2
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• pp.97-102
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• 2020

The purpose of this study was to investigate the effectiveness of a Tabata exercise program as an alternative for firefighters whose working environment makes it difficult to manage physical fitness. The Tabata exercise program, in which 16 people participated, led to increased muscle mass and reduced weight and body fat, which not only improved the health of the firefighters but also improved their cardiopulmonary endurance, muscle endurance, and muscle strength, which are essential elements during firefighting emergency relief activities. On the basis of these results, it is believed that developing and providing guidelines for scientific and systematic exercise programs to firefighters will lead to better work capability during fire and disaster situations.

• The Journal of Industrial Distribution & Business
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• v.8 no.7
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• pp.63-70
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• 2017

Purpose - Due to the lack of physical activities and the increase of sedentary behaviors such as screen time, the health condition for contemporaries has been deteriorating. This study is designed to investigate how the use of worktable or tools unfit for body and sedentary behaviors can exercise influence on muscular skeletal disease and how it has an impact on lowering work efficiency and the quality of life with the medium of the muscular skeletal disease. Research design, data, and methodology - The research has developed a questionnaire with 5 hypothesis. The questionnaires were also made by interview and E-mail. 350 copies of questionnaires were distributed and 315 questionnaire were used for the analysis as valid data responses. SPSS ver.22.0 were used and made Cronbach's and reliability test, correlation, Baron & α Kenny 3 step mediated regression analysis. Results - The research has found that living environment factors have positive effect on the occurrence of musculosketal disease. Particularly, repeated use of unfit worktable or tools has a positive effect on the muscular skeletal disorder. And sedentary lifestyle also has a positive effect on the disease. The musculoskeletal disease caused by living environment has a positive impact on lowering the work efficiency. This study has also showed that the muscular skeletal disease has mediated the relationship between the living environment factors and the decrease of work efficiency due to musculoskeletal disease. The musculoskeletal disorders can effect the decrease of the quality of life as well, for the decrease of work efficiency has a positive effect on lowering the quality of life. Conclusions - Sedentary lifestyles, the use of worktable unfit for body, and the repeated use of a tool have caused the increase of muscular-skeletal diseases, and reduction of productivity as well as the hight cost of medical treatment for our contemporaries. Understanding the cause of disease morbidity, finding ways to prevent the disease, and educating people about them would contribute not only to improvement of individual health but also to the advancement of welfare for all.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.4
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• pp.76-85
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• 2018

This study aims to analyze citizen's preference of rail station lifts(stairs & Escalation) and estimate the user benefit of Escalation, Also it includes how high is the height of the entrance ramp when citizens want to set up an escalator. 89 percent of subway users prefer escalators and said escalators are needed for stairs higher than the double-deck stairs. Especially It is higher for the age older than 30 and woman. Therefore, personnel characteristics and facility characteristics should be considered in relation to escalator installation. Based on the multiple logistic model, WTP(Willing to pay) was estimated at 34.37 won in a survey conducted to estimate practical user benefit(physical side) of escalator.

• Journal of the Korean Vacuum Society
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• v.6 no.2
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• pp.103-108
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• 1997

Silicon field emitter arrays (FEAs) have been fabricated by a novel method employing a two-step tip etch and a spin-on-glass (SOG) etch-back process using double layered thermal/tetraethylortho-silicate (TEOS) oxides as a gate dielectric. A partial etching was performed by coating a low viscous photo resist and $O_2$ plasma ashing on order to form the double layered gate dielectric. A small gate aperture with low gate leakage current was obtained by the novel process. The hight and the end radius of the fabricated emitter was about 1.1 $\mu\textrm{m}$ and less than 100$\AA$, respectively. The anode emission current from a 256 tips array was turned-on at a gate voltage of 40 V. Also, the gate current was less than 0.1% of the anode current.