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A STUDY OF ADDITIONAL VIBRATION EFFECT ON DENTIN BOND STRENGTH (진동이 상아질 결합력에 미치는 영향에 관한 연구)

  • Lee, Jin;Kim, Jung-Wook;Lee, Sang-Hoon;Kim, Chong-Chul
    • Journal of the korean academy of Pediatric Dentistry
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    • v.29 no.4
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    • pp.632-640
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    • 2002
  • The objective of the study was to apply the vibration technique to reduce the viscosity of bonding adhesives and thereby compare the bond strength and resin penetration into dentinal tubules achieved with those gained using the conventional technique. Eighty-eight noncarious extracted human permanent molar teeth were sectioned to remove the coronal enamel and were embedded in 1-inch PVC pipe with acrylic resin. The occlusal surfaces were placed so that the tooth and the embedding medium were at the same level to form one flat surface, and the samples were subsequently polished with silicon carbide abrasive papers. The samples were randomly assigned to 4 groups(n=22). On Group 1 and 2, Single Bond(3M-ESPE, St. Paul, USA) was used, and on Group 3 and 4, One-Step(Bisco Inc., Schaumburg, USA) was used, and each was applied according to its manufacturer's instructions. For Group 2 and Group 4, vibration was applied with ultrasonic scaler for 10 seconds, and the adhesive was light-cured for 10 seconds. Resin composite was condensed on to the prepared surface in two increments using a mold kit(Ultradent Products Inc., USA) and each was light-cured for 40 seconds. After 24 hours in tap water at room temperature the specimens were thermocycled, and shear bond strengths were measured with a universal testing machine(Instron 4465, Canton, USA). To investigate infiltration patterns of the adhesive materials, the surface of specimen was examined with scanning electron microscope. The results were as follows. 1. The shear bond strengths of vibration groups(Group 2, Group 4) were significantly greater than those of the non-vibration groups(Group 1, Group 3)(p<0.05). 2. The shear bond strengths of Single Bond and One-Step were not significantly different (p>0.05). 3. The vibration groups showed greater number of resin tags in tubules and lateral branches under SEM.

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A Study of the Accidents of the Residents in a Rural Area (일개 보건진료소 사업 지역의 사고조사)

  • Kang, Pock-Soo;Lee, Kyeong-Soo;Kim, Seok-Beom;Kim, Chang-Yoon;Lee, Ok-Keum
    • Journal of Yeungnam Medical Science
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    • v.8 no.2
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    • pp.174-184
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    • 1991
  • To determine the incidence rate of accidents and its associated factors, a prospective survey was carried out in a rural area of a total of 1,360 residents for 1 year from January 1 to December 31, 1988 in Shin-am Ri, Jungdong Myun, Sangju Kun, Kyungpook Province. Data for accidents were collected by the community health practitioner who is working at Primary Health Post in Shin-am Ri. A total number of accident cases was 85 among 1,360 persons during one year study period, and annual incidence rate was 62.5 per 1,000 persons. The highest incidence rate of accident was observed in the age group of 30-39 was 179.8. The incidence rate of accident in male was 86.5 which was about 2 times that in female. In male, the highest incidence rate was seen in 30-39 age group and in female, 60-69 age group. The highest incidence rate of accident was observed in spring(29.4%) and summer(29.4%), and the lowest in fall(17.7%). The highest incidence rate of accident was observed in Friday(24.5%) by day of week, and between 9 a.m. to 12 a.m. by time zone. The most frequent use of medical facilities was Primary Health Post(51.8%) and the next was clinic(38.8%). Mean duration of treatment was 9.8 days. The accident occured in the room and kitchen(23.5%), in the yard and barn(23.5%), on the road(22.4%). and in the rice field and dry field(20.0%). The causes of accident were motor vehicle accident(20.0%), piercing or cutting(20.0%), collision or fighting(12.9%), and poisoning(11.8%) in order of frequency. The most common type of injury was open wound which was 43.5%. The most common tool of accident was farm machine which was 23.5%. The most common injuried part of body was extremity(55.3%).

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The Case Study of the Entrepreneurship Intensive Programs and the Successful Diffusing Strategies of the Entrepreneurship Education. (벤처창업전문과정(EIP) 사업추진 성공사례와 확산전략)

  • Ha, Kyu-Soo;Rhee, Taik-Ho;Lee, Seung-Weon;Kim, Ki-Hak
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.1 no.1
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    • pp.127-156
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    • 2006
  • This paper introduced successful case studies of the EIP (Entrepreneurship Intensive Programs) programs that are planed by 5MBA (Small and Medium Business Administration) and executed by Hoseo University and Jinju National University in 2004. Therefore, the illustrations and examples used in this paper are based on the EIP programs of those schools. Currently there are five graduate schools for Entrepreneurship educations that are originated from the EIP program models and those graduateschools are actively and successfully working. The purpose of this paper is to find out the diffusing strategies of the Entrepreneurship spirits and Entrepreneurship Education programs after careful analysis and review of the EIP programs. The main factors of the Success of the EIP are as follows. First, there were excellent modules of the education process. Second, there were firm and clear goals of the education. Three, there were differentiated contents of the entrepreneurship education programs. Four. each and every education performance was monitored. Five, during the programs, real start-up cases were actually handled and students had many opportunities to present their cases. However, there were some shortcomings to improve and change of the entrepreneurship education. First of all, it was very difficult to make proper education formation that is fit in the purpose of the program. Second, motivating students to find out their own business opportunities so as to turn them into real business was not satisfactory or easy. Third, there were some limitations in distributing and executing the EIP budgets. Therefore, to improve the efficiency of the Entrepreneurship education, following expanding strategies should be complemented. First, continuous redesigning of the entrepreneurship education programs is very important. Second, the specialization of the contents of the entrepreneurship education programs is essential. Third, there should be some discretionary room for the management of the entrepreneurship programs. Fourth, it is also important activating the entrepreneurship networks among schools of the entrepreneurship education. Finally, it is necessary to give some incentives and motivations based on the proper performance evaluation system.

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Immunoelectron Microscopic Study on the Paneth Cell of Rabbit after the Common Bile Duct Ligation (총담관결찰후 집토끼 Paneth세포의 변화에 대한 면역전자현미경적 연구)

  • Park, Kyung-Ho;Cho, Hwee-Dong;Yang, Nam-Gil;Ahn, E-Tay;Ko, Jeong-Sik;Kim, Jin-Gook
    • Applied Microscopy
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    • v.24 no.2
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    • pp.78-92
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    • 1994
  • Lysozyme has been reported to be present in the secretory granules of the Paneth cell, and lysozyme immunoreactivity has been detected by immunogold method in Paneth cells of the intestine of human, mouse and rat. The present study was aimed at clarifying the intracellular distribution and changes of the lysozyme immunoreactivity in rabbit Paneth cell after common bile duct ligation of rabbit, using the electron microscope immunogold technique. Healthy adult rabbits weighing about 2kg body weight were divided into normal and bile duct ligated groups. Common bile duct ligation was performed aseptically under ether anesthesia. Experimental animals were sacrificed on the 1st, the 3rd, the 5th, the 7th and the 14th day after the operation. Mucosal specimens from the intestinal gland of ileum were fixed in 2.5% glutaraldehyde-1.5% paraformaldehyde, followed by 1% osmium tetroxide, embedded in araldite mixture, cut with LKB-V ultratome. Ultrathin sections were placed on parlodion coated nickel grids (200mesh). The section-bearing grids were floated upside down on the added substance in a moist chamber at room temperature except for the primary antibody step, which was at $4^{\circ}C$. Sections were etched with a saturated solution of sodium m-periodate for 60min. After etching, sections were pretreated with 0.02M tris buffered saline (TBS), pH 8.4, with 1% bovine serum albumin (BSA, Sigma) for 60min, then treated polyclonal rabbit anti-human lysozyme (Dakipatts) diluted 1 : 50 in TBS with 0.1% BSA for 20hr. Subsequently, grids were incubated 60min in biotinylated goat anti rabbit IgG (Amersham) diluted 1 : 100 in TBS with 0.1% BSA. After this, sections were incubated 60min on streptavidin gold G10 (Amersham) diluted 1 : 50 in TBS with 0.1% BSA. After each step, the grids were briefly rinsed with TBS with 0.1% BSA. After the strepavidin gold step, the sections were jet washed with distilled water. Counterstain of the sections performed by uranyl acetate and lead citrate, and observed with JEM 100 CX II electron microscope. Observed results were as follow; 1. Secretory granules of mouse Paneth cells have a lysozyme immunoreactivity and also eosinophil leucocyte of rabbit applied for the positive-control stain, are well labeld with gold particles. 2. Normal rabbit Paneth cells have a lysozyme immunoreactivity restricted on the secretory granules. 3. Amount lysosomes containing myelin figures in the Paneth cells were significantly increased from 5th day after the common bile duct ligation. 4. Immunoreactivity of Paneth cell secretory granules were more activated on the 3rd day after the common bile duct ligation as compared with those of the normal animal. But the lysozyme immunoreactivity were decreased from the 5th day after the common bile duct ligation. 5. Considering the above finding, lysozyme contained Paneth cell are affected following of common bile duct ligation, whereas lysosomes containing myelin-figure do not exhibit any immunoreactive relationship with those of secretory granules.

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Effects of Bacillus Calmette-Guerin (BCG) on the DNA Synthesis of Mouse Duodenal Mucosal Epithelial Cells Inoculated with Ehrlich Carcinoma Cells (Bacillus Calmette-Guerin (BCG) 투여가 Ehrlich 종양세포를 이식한 생쥐 샘창자 상피세포의 DNA합성에 미치는 영향)

  • Ko, Jeong-Sik;Kim, Heung-No;Park, Kyung-Ho;Park, Dae-Kyoon;Kim, Duk-Soo
    • Applied Microscopy
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    • v.40 no.4
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    • pp.193-200
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    • 2010
  • This experiment was performed to evaluate the morphological responses of the duodenal epithelial cells of the mouse, inoculated with Ehrlich carcinoma cells in the inguinal area, following administration of Bacillus Calmette-Guerin (BCG). In the experimental groups, each mouse was inoculated with $1{\times}10^7$ Ehrlich carcinoma cells subcutaneously in the inguinal area. From next day after inoculations, 0.2 mL of saline or BCG (0.5 mL/25 g B.W.: $0.03{\times}10^8\sim0.32{\times}10^8$ CFU) were injected subcutaneously to the animals every other day, respectively. The day following the 7th injection of saline or BCG, each mouse was injected with a single dose of $0.7{\mu}Ci$/g of methyl-$^3H$-thymidine (25 Ci/mmol, Amersham Lab, England) through tail vein. Seventy minutes after the thymidine injection, animals were sacrificed, and duodenal tissues were taken and fixed in 10% neutral formalin. Deparaffinized sections were coated with autoradiographic emulsion EM-1 (Amersham Lab, England) in a dark room and dried and were placed in a light-tight box. The number of labeled epithelial cells in the duodenal mucosae (mean number of labeled epithelial cells per 3.5 mm length of mucosa) were observed and calculated. On the light microscopic study, duodenal mucosae had no severe morphological changes following the injection of BCG. In the tumor control and BCG treated groups, a number of small lymphocytes and eosinophile leucocytes are slightly increased as compared with those of the normal control ones. On the autoradiographic study, number of the labeled cells of normal control, tumor control and BCG-treated mice were 632.3 (${\pm}14.47$), 761.7 (${\pm}27.65$) and 505.0 (${\pm}17.09$) respectively. From the above results, BCG may suppress the DNA synthesis of the duodenal epithelial cells, but does not results severe structural defect on the duodenal mucosae. And it is suggested that BCG may greatly improve the anticancer therapy on certain kind of cancer.

Clinical Usefulness of Arterial Spin Labeling Perfusion MR Imaging in Acute Ischemic Stroke (급성 허혈성 뇌경색 환자에서 동맥스핀표지 관류자기공명영상의 유용성)

  • Oh, Keun-Taek;Jung, Hong-Ryang;Lim, Cheong-Hwan;Cho, Young-Ki;Ha, Bon-Chul;Hong, Doung-Hee
    • Journal of radiological science and technology
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    • v.34 no.4
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    • pp.323-331
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    • 2011
  • We evaluated clinical usefulness of Arterial spin labeling perfusion MR imaging on the acute ischemic cerebral infarction patients through this study. We compared 22 patients who were done with DSC imaging and ASL imaging in admitted emergency room with acute ischemic cerebral infarction, with 36 normal comparison persons (DSC image on 21persons, ASL images on 15persons). Siemens Magnetom Verio 3.0T with 12 channel head coil was used for this study. DSC image obtained 4 maps(rCBV, rCBF, rMTT, TTP) through post-processing. For qualitative analysis we compared the area of lesion macro-diagonal with the size of diffusion weighted MR image for rMTT, TTP, rCBF, rCBV, ASL maps. For Quantitative analysis we analyzed significant correlations between less than 3 cm infarction group and normal comparison group using mean relative value of flowing image with Mann-Whitney U test. TTP(95.5%) and rCBF(95.5%) maps showed high recognition rate in qualitative analysis for >3cm infarction group. The rCBF and rCBV map tests were highly related with final stage stroke areas. Mean relative value of infarction group showed a significant correlations in quantitative analysis(p<0.05). As a conclusion, arterial spin labeling image showed high lesion recognition rate in the >3cm infarction group. Mean relative values in quantitative evaluation were used for reference data. If we do more sustainable researches, ASL image will be useful for an early diagnosis of cerebral infarction, determination of the range of ischemic pneumbra and effective treatments.

Professionalism raising of the escort which leads an instance analysis (사례분석을 통한 경호 전문성 제고)

  • Yu, Hyung-Chang
    • Korean Security Journal
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    • no.18
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    • pp.73-99
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    • 2009
  • There are three assassination and treatening cases in this thesis introduced as analysis data. They are shooting accidents of the U.S.A's President Reagun (1981,3.30), and the President Park Jeong Hee of South Korea(1974.8.15), assassination of the Prime Minister Lavin of Israel (1995.11.4) In March 30, 1981, there was an accident where criminal, Hinckley, fired ball cartridges right before the President Reagan got into the car to move to White House after completing the announcement of Hilton Hotel of Washington. As a result, the chest of president was shot and public information secretary and safeguard were wounded. In August, 15, pm 10:23, where the 29th 8.15 independent anniversay event was being celebrated by the people at the National theater in Jangchungdong, Seoul, the criminal Moon Sekwang fired ball cartridges, he failed to assassinate the President Park Jeong Hee of Korea, but shot the First lady Yuk Young Soo. She was wounded right part of head and died. In November 4, Saturday, pm 22:00 the Prime Minster Lavin had finished the supporting event of Middle Asia's Peace project and was taking on the car when he was killed by the criminal Amir's shooting, The accidents left very important lesson from the aspect of security analysis and it has been frequently used as a material for the education and training of safeguard organization. In Korea, as well as Presidential Security Service, national security departments have selected it as an important model for the subjects such as 'Security Analysis, 'Security Practice' and 'Security Methodology'. In the performance of security duty, security skill is the most important matter. Moreover, it has a close relationship with politics, society and culture. The purpose of this study is to analyze and reevaluate the case, which has been treated as a usual model from the aspect of security analysis, beyond its introduction. Attempted assassination of President Reagan was evaluated as a positive success example because of its rapid response of adjacent guards to evacuate Reagan, who is a guard target, within 10 seconds after the shot. When comparing it to President Kennedy Assassination of 1963, it was evaluated that guards were significantly specialized. In the study, however, it was possible to found many problems such as carelessness of guard, who is in charge of external area of event place, idle attitude for frequently used event place, confusion of wireless communication, risk of wireless security disclose, insufficient provision of compulsory record file, insufficient profiling of dangerous person and unsecured hospital and first-aid room.

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Analysis of the growth environment and fruiting body quality of Pleurotus eryngii cultivated by Smart Farming (큰느타리(새송이)버섯 스마트팜 재배를 통한 생육환경 분석 및 자실체 품질 특성)

  • Kim, Kil-Ja;Kim, Da-Mi;An, Ho-Sub;Choi, Jin-Kyung;Kim, Seon-Gon
    • Journal of Mushroom
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    • v.17 no.4
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    • pp.211-217
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    • 2019
  • Currently, cultivation of mushrooms using the Information and Communication Technology (ICT)-based smart farming technique is increasing rapidly. The main environmental factors for growth of mushrooms are temperature, humidity, carbon dioxide (CO2), and light. Among all the mentioned factors, currently, only temperature has been maintained under automatic control. However, humidity and ventilation are controlled using a timer, based on technical experience.Therefore, in this study, a Pleurotus eryngii first-generation smart farm model was set up that can automatically control temperature, humidity, and ventilation. After installing the environmental control system and the monitoring device, the environmental condition of the mushroom cultivation room and the growth of the fruiting bodies were studied. The data thus obtained was compared to that obtained using the conventional cultivation method.In farm A, the temperature during the primordia formation stage was about 17℃, and was maintained at approximately 16℃ during the fruiting stage. The humidity was initially maintained at 95%, and the farm was not humidified after the primordia formation stage. There was no sensor for CO2 management, and the system was ventilated as required by observing the shape of the pileus and the stipe. It was observed that, the concentration of CO2 was between 700 and 2,500 ppm during the growth period. The average weight of the mushrooms produced in farm A was 125 g, and the quality was between that of the premium and the first grade.In farm B. The CO2 sensor was in use for measurement purposes only; the system was ventilated as required by observing the shape of the pileus and the stipe. During the growth period, the CO2 concentration was observed to be between 640 and 4,500 ppm. The average weight of the mushrooms produced in farm B was 102 g.These results indicate that the quality of the king oyster mushroom is determined by the environmental conditions, especially by the concentration of CO2. Thus, the data obtained in this study can be used as an optimal smart farm model, where, by improving the environmental control method of farm A, better quality mushrooms were obtained.

A Survey on Preliminary Dental Hygienists' Senses of Employment (예비치과위생사의 취업에 관한 의식 조사)

  • Han, Su-Jin;Lee, Sun-Mi;Lim, Mi-Hee
    • Journal of Korean society of Dental Hygiene
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    • v.7 no.4
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    • pp.583-594
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    • 2007
  • The purpose of this study was to conduct a survey on the senses that preliminary dental hygienists have on employment, who applied for the National Dental Hygienist Examination, so that it could provide a basic reference required for fostering good human resources specializing in oral health with a sense of mission and responsibility as professional. To meet these goals, a self-administered questionnaire survey was conducted for participants in a refresher education meeting for preliminary dental hygienists across three major regions(Seoul, Daejeon and Busan), which was held by the Korean Dental Hygienists Association(KDHA) on Jan. 15, 2006. Total 289 sheets of questionnaire were collected, and 262 sheets except invalid or incomplete ones were used for examination and analysis. As a result, this study came to the following conclusions: First, it was found that 40.4% respondents wanted to be employed in dental clinic or hospital. Most respondents(90.1%) answered that faithfulness is most valued as prerequisite qualification for employment in hospital, and highest percentage of respondents(39.3%) wanted to earn 16 to 17 million Korean won annually. For internship opportunities, 61.9% respondents replied that they could willingly accept the internship, provided that basic pay and switchover to regular employee are all assured. Second, as the results of survey on employment circumstances around respondents, it was found that most respondents(58.3%) were employed in dental clinic or hospital, and highest percentage of respondents(35.0%) earned 15 to 16 million Korean won. Third, it was found that interpersonal relationships among employees had most significant effects(4.81) on selection of employment, which was followed by in-house welfare benefits 1(monthly/annual vacation, resting room, etc; 4.56). For possible influential factors on the selection of employment depending on whether employed or not, it was found that there were Significant differences in pay, welfare benefit 2(seminar, orientation, refresher training opportunities, etc), post-wedding continued employment and merit system between employees and non-employees(pE0.05). Fourth, the survey on respondents' occupational senses of dental hygienist showed that major tasks of dental hygienists were represented by oral disease prevention(92.6%), case management(71.5%), oral health education(66.3%), hospital/clinic management and dental management support(10.4%) and public oral health activities(6.7%) respectively. For job satisfaction, it was found that almost half respondents(48.9%) showed satisfaction at their job and 32.6% felt satisfied at and proud of their job. That is, majority of respondents(81.5%) felt satisfied at their job as dental hygienist. For follow-up requirements to qualify for dental hygienists, it was found that 73.3% felt it necessary to give more investments to self-development, 62.2% respondents considered protection of membership's rights as one of future assignments that KDHA should be more committed to. For future social awareness about dental hygienists as occupation, 69.2% respondents expected that they would be better developed and treated as professional. And desired training courses as a part of qualification for professional dental hygienists were represented by case management(services, manners, etc; 33.3%), implant(28.9%), esthetics(correction, prosthesis, whitening; 18.9%) and so on. For an item on working years, it was noted that 75.9% respondents would keep working as dental hygienists as long as they could.

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Efficiency Test for Surface Protecting Agents for the Chemical Resistance of Concrete Structures Using Sulfur Polymers (Sulfur Polymer를 사용한 콘크리트 구조물용 내화학성 표면보호재의 성능 평가)

  • Lee, Byung-Jae;Lee, Eue-Sung;Chung, Woo-Jung;Kim, Yun-Yong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.18 no.5
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    • pp.1-8
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    • 2014
  • Structures requiring chemical resistance are usually coated with surface protecting agents, but the cost for maintenance and re-construction is incurred due to the low durability. Therefore, in this study, sulfur was polymerized and the performance was examined so that it could be used as the concrete surface protecting agents for structures requiring chemical resistance. The evaluation results indicated that for the spray of the sulfur polymer surface coating agents, the application of the gravity type was appropriate; and for the number of coating times, about 3 cycle spray gave the best results. For the surface condition of the concrete to be coated with the surface protecting agents, outstanding quality was obtained above room temperature ($20{\sim}30^{\circ}C$), and the bond strength increased as the temperature increased. The evaluation results of the strength characteristics depending on the filler content of the surface protecting agents indicated that about 20~40% filler mixing contributed to the strength improvement as it reduced the shrinkage of the sulfur polymer. Also, the mixing of silica showed larger increase in the bond strength than the mixing of fly ash, and the most outstanding bond strength characteristics could be obtained by the mixing of both silica and fly ash. In the case of the chemical resistance, the strength reduction was minimized and outstanding chemical resistance was obtained when the fly ash and silica were substituted by 20%, respectively. The performance evaluation of the chloride ion penetration indicated that for the specimens coated with the sulfur polymer surface protecting agents, the chloride ion penetration resistance increased by 29~48% compared to the specimen without the coating of the surface protecting agent. The examination of the coating condition of the surface protecting agents, compressive strength, bond strength, chemical resistance, and salt damage resistance indicated that in the range of this study, the optimal level was when the silica and fly ash were substituted by 20%, respectively, as the filler for the sulfur polymer.