• 한국치위생학회지
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• 제7권2호
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• pp.153-166
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• 2007

The job of dental hygienists is specialized, and they have to be capable of performing their primary duties including prevention of oral diseases, oral prophylaxis, and oral health education. To ensure their successful job performance, dentists should have an accurate understanding of their duties and need a change of mind-set about them. And there should be written legal and concrete regulations on the coverage of their work in order to let them boost their job performance with pride and a sense of responsibility. The purpose of this study was to examine the actual roles and job performance of dental hygienists in clinical field in an attempt to discuss the substantial job performance of dental hygienists and their job enlargement. It's basically meant to help enhance the efficiency and quality of medical services. The subjects in this study were 471 dental hygienists in dental clinics, dental hospitals, university hospitals and general hospitals across the nation, on whom a survey was conducted in person from March 2 to 25, 2005. The collected data were analyzed with SPSS Win 12.0 program, and the findings of the study were as follows: 1. The major jobs they currently performed included oral health education, hospital management, simple duties, extensive dental hygiene duties and joint treatment assistance. They hoped to continue to be responsible for oral health education, preventive treatment and extensive dental hygiene duties. 2. As for their current job by age, extensive dental hygiene duties, preventive treatment, joint treatment assistance, preserving treatment, prosthetic treatment and pediatric treatment were most conducted by the dental hygienists who were at the age of 26 to less than 31, and those who were at the age of 31 and up were most responsible for hospital management and simple duties. 3. As to job awareness by workplace, their workload was statistically significantly different according to their workplace. The hospital employees took care of more work than those in clinics. 4. Concerning job awareness by age, the younger dental hygienists suffered more role conflicts and were given a less free hand in work handling, the middle-aged group's job was uncertain. Legal regulations about the coverage of their work should be prepared in detail as a measure to stir up their responsible job performance and pride. In order to take advantage of experienced dental hygienists, their duties should be more differentiated and specialized, and their working conditions should be improved to boost their job satisfaction. That is, they should be given ample chances for promotion and serving as a middle manager and be given fair treatment according to their career. If their work is accurately darified and specialized based on career, it will boost the efficiency of dental treatment. Dental hygienists also should direct sustained efforts into self-development in order to become a skilled and professional oral health personnel.

• 한국물환경학회지
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• 제18권3호
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• pp.327-336
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• 2002

Disinfection process in water treatment plants (WTPs) is one of the most important step in order to inactivate waterborne disease. However, what is the necessary disinfection in WTPs was not properly established in Korea. This study was conducted to evaluate disinfection performance in nationwide water treatment plants (n=474). Disinfection requirement based on the SWTR (Surface Water Treatment Rule) of the U.S. (1-log Giardia removal) was chosen in estimating the compliance. The scope of unit process for evaluating disinfection performance includes postdisinfection process in clearwells, pipeline, and storage tank. The worst water quality condition in individual WTPs was applied for the disinfection performance evaluation. The major results are as follows. First, it was appeared that 184 WTPs (39 %) provided insufficient disinfection performance. Disinfection performance was significantly improved during past 2 years. The ratio of the number of WTPs providing insufficient disinfection performance in 1999 and 2001 was 78 % and 41 %, respectively. One of major factors for this improvement was due to the improvement of $T_{10}/T$ value in clearwell, as a result of modification of clearwell facility. Second, if disinfection criteria is 3-log Giardia inactivation at worst water quality condition, then 19 % of all WTPs can not meet this disinfection criteria. And if disinfection criteria is strengthened to 4-log Giardia inactivation, then 58 % of all WTPs can not meet this disinfection criteria. Since disinfection criteria is decided by contamination level of Giardia in source water, it also needs the investigation of Giardia occurrence in source water.

• 한국환경보건학회지
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• 제34권3호
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• pp.233-239
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• 2008

In order to improve reactor performance of existing sewage treatment plants, the feasibility of enhancing reactor performance by bioaugmentation using EM as bioaugmentation agent and the effects of anoxic: oxic time ratio on reactor performance were investigated. Continuous and intermittent aeration modes were compared under the 6 hr of HRT. Three different types of intermittent aeration modes, that is, 15 min, of anoxic:45 min of oxic, 30 min of anoxic: 30 min of oxic, and 45 min of anoxic: 15 min oxic respectively were chosen as test modes to study the effects of anoxic : oxic time ratios on reactor performance. The optimum anoxic: oxic time ratio was 30 min:30 min when considering simultaneous removal of organic, nitrogen and phosphorus. When applying EM into a continuously aerated reactor under the varying dosing rates of 50-200 ppm, reactor performance in terms of organic and nitrogen removal efficiencies was not improved at all. Nitrogen removal efficiency was increase when the EM dosing rate was increased. However the degree of improvement was slight when the EM was injected above 100 ppm. However optimum phosphorus removal was found at the EM dosing of 200 ppm. Thus it was found that optimum injection concentration of EM is 200 ppm. It is apparent that putting EM into a sewage treatment plant significantly affects the T-N removal efficiency of the reactor by enhancing denitrification efficiency especially in operational conditions of relatively long anoxic periods. To achieve reciprocal condition in a reactor with intermittent aeration it is necessary to enhance the reactor performance by EM injection. In the case of modifying existing continuously aerated reactors into intermittent aerated reactors, it is obvious that operating costs of aeration would be reduced by reducing aeration time when compared with existing conventional sewage treatment plants.

• 상하수도학회지
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• 제24권6호
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• pp.723-734
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• 2010

With a belief of high water quality production and less chemical usage, membrane technology including Microfiltration (MF), Ultrafiltration (UF), and Nanofiltration(NF) is being employed more and more in drinking water treatment process. However, due to higher energy consumption of UF and NF, MF is normally used for drinking water treatment especially in a plant of large scale. In this investigation, performance ofsand filtration and membrane filtration was compared regarding removal of various water quality parameters, such as TOC, DOC, KMnO4 consumption, THMFP, and HAAFP. Two lines of pilot plant have been operated, one of which line is a traditional advanced water treatment process which includes sedimentation, sand filtration, ozonation, and activated carbon, and the other line is an alternative treatment process which includes sedimentation with inclined plate, MF membrane, ozonation, and activated carbon. For the first about 4months of period, MF filtration showed similar or little bit higher performance than sand filtration. However, after about 4month later, sand filtration showed much higher performance in removing all parameters monitored in the investigation. It was found that sand filtration is a better option than MF filtration as far as microbial community is fully activated in sand filter bed.

• 반도체디스플레이기술학회지
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• 제16권4호
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• pp.59-62
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• 2017

In this paper, atmospheric pressure plasma treatment was proposed for high performance indium gallium zinc oxide thin film transistor (IGZO TFT). RF Ar plasma treatment is performed at room temperature under atmospheric pressure as a simple and cost effective channel surface treatment method. The experimental results show that field effect mobility can be enhanced by $2.51cm^2/V{\cdot}s$ from $1.69cm^2/V{\cdot}s$ to $4.20cm^2/V{\cdot}s$ compared with a conventional device without plasma treatment. From X-ray photoelectron spectroscopy (XPS) analysis, the increase of oxygen vacancies and decrease of metal-oxide bonding are observed, which suggests that the suggested atmospheric Ar plasma treatment is a cost-effective useful process method to control the IGZO TFT performance.

• 한국기계가공학회지
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• 제12권5호
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• pp.149-156
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• 2013

The performances of solar collectors with single and double evacuated tube were experimentally compared. The solar collector with single evacuated tube using surface treatment in this study consists of radiation fin, heat pipe, absorber plate, glass tube, cap and regulating valve, and so on. Surface treatment was conducted for heat pipe and absorber plate with black chrome plating and copper black coating. As the results, the performance of solar collector with single evacuated tube using surface treatment showed good results compared that of double evacuated tube. Absorber plate played a positive role in performance and showed increase of about 28%. Further performance depends on vacuum degree and vacuum degree has to be considered economical efficiency in solar collector.

• Asian-Australasian Journal of Animal Sciences
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• 제13권12호
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• pp.1750-1757
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• 2000

A total of 864 broiler chicks were used at Kansas State University and the University of Nebraska to determine the effects of heat treatment of two soybean genotypes on the growth performance. The soybeans were Williams 82 variety with (+K) and without (-K) gene expression for the Kunitz trypsin inhibitor. Heat treatment (autoclaving at $121^{\circ}C$ and $1.1kg/cm^2$) was applied for 0, 3, 6, 12, 18, and 24 min, resulting in a $2{\times}6$ factorial arrangement of treatments. Station and station treatment effects occurred, indicating that response in nutritional value of the soybean genotypes to heat treatment varied from year to year and location to location. However, the interactions were in magnitude of response rather than direction of response, with greater reductions in trypsin inhibitor concentrations for the soybeans heat processed at the Nebraska location. Pooled data indicated that -K supported greater (p<0.001) ADG, ADFI and gain/feed than the +K genotype. As the length of heat treatment increased, the ADG, ADFI, and the gain/feed ratio increased for chicks fed both soybean genotypes (p<0.0001). However, heating the -K soybeans resulted in a greater response in ADG, ADFI, and gain/feed than heating the +K soybeans (genotype heat treatment interaction, p<0.001). Pancreatic weights (mg pancreas/g of BW) of chicks fed -K soybeans were reduced compared to those from chicks fed +K (p<0.001). Increasing heat treatment decreased pancreas weights in chicks fed both soybean genotypes (p<0.001). Chicks fed heated soybeans in the Nebraska experiment had lower pancreatic weights than chicks fed heated soybeans in the Kansas experiment (station heat treatment interaction, p<0.0001). Chick growth performance was improved and pancreatic weights decreased by feeding raw -K soybeans versus raw +K soybeans, and by increasing heat treatment of both soybean genotypes. However, the response to heat treatment was not independent of genotype. Both +K and -K soybeans heated for 24 min supported similar ADG, ADFI, gain/feed, and pancreas weights, although chicks fed raw +K soybeans had lower growth performance than chicks fed -K soybeans. In conclusion, raw -K soybeans supported greater growth performance in broiler chicks than raw +K soybeans, although this advantage was lost when both soybean genotypes were heated for 24 min. Heat treatment of +K soybeans supported similar growth performance to heated -K soybeans, even though +K soybeans supported lower rates and efficiencies of gain than -K soybeans when fed raw.

• 상하수도학회지
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• 제27권3호
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• pp.339-349
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• 2013

Biological treatment of RO concentrate from wastewater reuse process is known to be very difficult due to its high concentration of non-degradable organics and salt ions such as chloride, nitrate and phosphate. In this research, the treatment performance of MBR was examined using RO concentrate mixed with raw wastewater as the influent of MBR. Addition of PAC (powdered activated carbon) to MBR was also evaluated in order to enhance the treatment performance and stability. The performance of MBR for treating only RO concentrate decreased gradually although external carbon source was added. The average removal performance of MBR with and without PAC decreased from 99.1 %(98.8 %) to 94.9 %(91.4 %) for COD, 81.3 %(80.3 %) to 42.0 %(41.9 %) for T-N and 57.3(55.0 %) to 30.0 %(21.0 %) for T-P with the increase of RO concentrate mixing rate of 0 % to 20 % in the feed water. Addition of PAC showed positive effect on the performance of MBR for the removal of COD and phosphorus in case that the ratio of RO concentrate to feed water increased.

• Korean Chemical Engineering Research
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• 제51권2호
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• pp.263-266
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• 2013

본 연구에서는 친수화 처리된 격리막을 이용한 니켈수소전지의 전기화학적 특성을 연구하였다. 수계 전해액을 사용하는 니켈수소전지로의 적용을 위해 폴리올레핀계 분리막을 친수화 처리하였다. 친수화 미처리품은 방전성능, 용량보존성, 내구성 등의 전기화학적 성능에서 KS 규격기준에 미달되었지만 친수화 처리품은 KS 규격기준을 모두 만족시켰다. 친수화 처리품을 적용한 모든 시료는 유사한 전지성능을 보여주었다. 그 중 술폰화 처리 시료의 경우 용량 보존율(>88%) 측면에서 가장 우수한 특성을 보였으며, 불소화 처리시료는 내구성 측면에서 가장 우수한 성능을 보였는데, 이는 KS 규격기준(500회)과 비교할 때 약 3배 정도(1480회)의 우수한 성능을 유지함을 확인하였다.

• 한국가금학회지
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• 제43권2호
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• pp.97-103
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• 2016

This study aimed of effects of replacing maize with rice or brown rice on laying performance, egg quality, and apparent fecal digestibility of nutrient in Hy-Line Brown laying hens. A total of 200, 25-week old Hy-Line Brown laying hens were randomly assigned to one of 5 treatments, each of which was replicated 4 times. Four experimental diets that were formulated two different grains (brown rice or rice) with two inclusion levels of (15 and 30%) as a replacement of maize. The experimental period was 8 weeks. During the experiment, hens were provided with feed and water ad libitum and were exposed to a 16:8=L:D lighting schedule. There were no differences in feed intake, egg weight, and egg mass during the 8 weeks of the feeding trial among groups. However, hen-day egg production was greater (P<0.05) for Brown rice treatment groups than that for basal and rice treatment groups. In addition, the supplementation of brown rice or rice did not have an effect on eggshell strength, eggshell thickness, and HU during of the feeding trial (Table 4). However, egg yolk color was less (P<0.05) for basal treatment groups than that for among treatment group. ATTD of dry matter (DM) and crude fat were greater (P<0.05) for brown rice 15 treatment than for rice 30 treatment. Crude protein (CP) was greater (P<0.05) for brown rice 15 treatment than for basal treatment. In conclusion, brown rice or rice grains is a good alternative energy feedstuff and can be used in laying hens, totally replacing maize, without any negative effect on the laying performance, egg quality, and nutrient digestibility.