• 한국버섯학회지
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• 제19권3호
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• pp.246-250
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• 2021

갈색양송이 수집균주를 단포자교배하여 육성한 신품종 '진향'의 주요특성은 다음과 같다. '진향'의 균사배양, 초발이 소요일수, 자실체 발생소요기간은 대조품종인 '다향'과 차이없었다. '진향'의 갓두께는 '다향' 보다 두꺼웠으며, 갓색은 진했다, '진향'자실체 경도와 개체중은 '다향'보다 다소 높았고, 수량은 14.1 kg/m²로 '다향'의 13.1 kg/m²에 비해 8% 증수되어 양송이 재배농가에 보급이 가능할 것으로 예상된다.

• The Journal of Advanced Prosthodontics
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• 제13권3호
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• pp.172-179
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• 2021

Purpose. This intra-patient retrospective study of up to 10 years evaluated the clinical success and risk factors of 6- and 8-mm long implants and their respective prostheses. Materials and Methods. The sample consisted of patients treated at a Military Polyclinic dental service, who received both 6- and 8-mm long tissue level implants in the posterior region of the same arch. Data were collected from the dental charts, clinical and radiographic exams, self-report of sleep bruxism, measurement of maximum occlusal force, and clinical crown-to-implant (C/I) ratio. Data were analyzed by descriptive and inferential statistics with univariate and hierarchical multivariate models, at the 0.05 significance level. Results. The 30 patients (27 women) had 85 implants and 83 prostheses. Two implants were lost before prosthesis installation (implant survival: 97.6%). Ten events of prosthetic complication (screw tightening loss) occurred in five patients (success rate: 87.9%) in a single moment. Only the variable C/I ratio had a significant effect for repairable prosthesis complication (P<.05). Conclusion. The results suggest that 6- and 8-mm long implants have similar long-term clinical success for implants and prostheses.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제3권2호
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• pp.113-119
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• 1999

The quality of the effluent from an activated sludge aeration tank can deteriorate when the substrate removal rate decreases due to an abrupt reduction in the DO concentration, which is affected by such operating conditions as the loading rate, temperature, wastewater composition, and so on. In this research, a DO control system that includes a PI (proportional-integral) controller/Hiraoka controller was developed and applied to a pilot-scale activated sludge process, then its acceptability was estimated. The applicability of the respiration rate to DO control was also estimated. The respiration rate indicated a variety of input organic loading rates, which is the main disturbance to the DO concentration in an aeration tank. When the influent concentration incrementally decreased and increased between CODcr 1,000 mg/l and 100 mg/l, the control system with a PI controller exhibited a good llperformance-the average DO concentrations were 2.00$\pm$0.14 mg/l and 1.88$\pm$0.15 mg/l (set value was 2.0 mg/l), respectively, and the settling time was just 10 minites. When the control system was operated for 4 days, the DO concentration was 1.99$\pm$0.18 mg/l and 32.6% of the air flowrate was saved. However, the fluctuations in the respiration rates and air flowrates were severe, which could be harmful to the stability of the biomass and mechanical stability of the blower. A possible approach to solve this problem may be the simultaneous control of the loading rate and DO concentration.

• 한국물환경학회지
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• 제24권6호
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• pp.659-669
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• 2008

Two sets of four parallel activated sludge reactors (ASRs) maintaining an MLSS of 3000 mg/L were operated to investigate the effect of DO, HRTs and bio-contact media (BCM) packing ratios on the removal efficiency of organic matters and nitrogen. Packing ratios of BCM to BCM-ASR systems 1, 2, 3, and 4 were 0% (suspended growth only), 10%, 15% and 20%, respectively. All systems were operated at an HRT of 4 hr, 6 hr, and 8 hr, respectively; DO concentration was maintained 0.5~1.0 mg/L and 1.5~2.0 mg/L for each HRT condition. In terms of TSS, TCODcr and SCODcr removal efficiency, all systems had a similar level of the removal efficiency under varied HRTs, and DO. But organic removal efficiency of systems with BCM was approximately 3~5% higher than systems without BCM at the same HRT and the DO. About the nitrification efficiency, with high DO (1.5~2.0 mg/L), as HRT (4 hr, 6 hr, 8 hr) or BCM packing ratio increased, the slight increment of nitrification efficiency was observed. However, under the low DO (0.5~1.0 mg/L), increase of BCM packing ratio and HRT resulted in large increase of the nitrification efficiency. At the same HRT and BCM packing ratio, the nitrification efficiency increased greatly with up to 15% as DO increased. When the HRT increased from 4hr to 8hr, the denitrification efficiency slightly increased by 5~10% only, under all DO conditions. Systems with BCM had higher denitrification efficiency, ranged 62.7~91.1% than systems without BCM showed 32.1~65.6%. And the increase in BCM packing ratio from 10% to 20% resulted in about 14~16% denitrification efficiency increment. BCM packing ratio showed great effect on the denitrification. The increase of the DO (from 0.5~1.0 mg/L to 1.5~2.0 mg/L) at the same HRT and BCM packing ratio resulted in slight decrease of denitrification efficiency with up to 7% for systems with BCM. But for systems without BCM, the denitrification efficiency decreased with up to 28%. In all system, the denitrification efficiency had more influence on the TN removal efficiency than nitrification efficiency. So, BCM packing ratio (0%, 10%, 15%, 20%) has greater effect on the TN removal than HRT and DO. The TN removal efficiency increased as packing ratio of BCM increased with up to 45%. As a result, the highest TN removal efficiency was observed 73.7% at the condition showed the highest denitrification efficiency that DO of 0.5~1.0 mg/L, an HRT of 8 hr, and 20% of BCM packing ratio was maintained.

• 생태와환경
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• 제50권1호
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• pp.148-156
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• 2017

전라남도에 위치한 12개의 호소에서 식물플랑크톤 군집변화 양상 및 환경요인과 시공간적 특징의 상관관계를 알아보기 위하여 2014년 3월부터 11월까지 총 4차례에 걸쳐 조사를 시행하였다. 전체 조사기간 동안 출현한 식물플랑크톤은 총 297종으로, 규조류 98종, 녹조류 148종, 남조류 23종, 그 외 와편모조류를 포함한 기타조류 28종으로 확인되었고, 조사시기별 출현종은 3월 116종, 6월 163종, 8월 162종, 11월 169종으로 1차 조사를 제외한 대부분의 시기에 다소 높은 출현종수를 보였다. 조사기간 동안 확인된 식물플랑크톤의 개체수는 $124{\sim}59,148cells\;mL^{-1}$의 범위를 나타냈고, 조사시기별 평균 출현개체수는 3월 $3,443cells\;mL^{-1}$, 6월 $4,055cells\;mL^{-1}$, 8월 $11,763cells\;mL^{-1}$, 11월 $4,614cells\;mL^{-1}$로 봄철에서 여름철로 계절이 진행되면서 증가한 후 가을철로 접어들면서 다시 감소하는 경향을 보였는데 이는 남조류의 개체수 변화에 따른 결과로 확인되었다. 식물플랑크톤 군집과 이화학적 요인을 이용한 SOM 분석 결과 $9{\times}6$ 격자에서 최적화되었고, 5개의 그룹으로 분류되었다. SOM 분석을 통한 식물플랑크톤의 군집과 연관이 있는 이화학적 요인은 수온, SS, DO, BOD, TP, Chl-a로 확인되었고 pH, TN, $NH_3-N$, $NO_3-N$, $PO_4-P$, 전기전도도 등은 관련성이 낮은 것으로 나타났다. 식물플랑크톤 군집과 이화학적 요인 간의 Pearson's correlation coefficient를 산출한 결과 식물플랑크톤의 군집은 대체로 수온, DO, SS, TP, 전기전도도, Chl-a와 통계적 유의성을 보였고, pH, TN, $NH_3-N$, $NO_3-N$, $PO_4-P$ 등과는 유의성이 낮은 것으로 확인되었다. 결론적으로 전라남도 내 주요 호소에서의 식물플랑크톤 군집의 분포는 주로 수온, SS, DO, BOD, Chl-a와 관계가 있는 것으로 확인되었고 pH, TN, $NH_3-N$, $NO_3-N$, $PO_4-P$와의 관련성은 낮은 것으로 확인되었다.

• The Korean Journal of Ecology
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• 제7권3호
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• pp.132-157
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• 1983

This study was performed to investigated the flora and vegetation of Kokum-do island from July 1982 thru December 1983; and the findings hereof are summarized as follows: The flora investigated thereform comprises 737 species whih are classified into 128 families, 466 genera, 651 species, 79 varieties and 7 formae; and those which are worthy of close attention among the same include such endemic species of Korea as Celtis choseniana, Corylopsis coreana, Carpinus tschonoskii var. eximia and Tricyrtis dilatata, and a few plants, to be distributed in the north, such as Lilium distichum, Girardinia cuspidata and Orostachys sikokianus. Now that the said island belongs to the warm temperate zone, the distribution thereof consists of 120 species of evergreen plants including 74 species of evergreen broadleaf trees. The rich distribution of evergreen broadleaf trees in the island is thanks to the plantation thereof by the public organizations for scenic beauty. The destruction of flora in this island was caused by felling, fire nization and other human activities around 1940, and in particular, has been correlated with the population densiity of Yonhong-do, Sanghwa-do, and Hahwado islets; and that of top soil and ground vegetation in he quarry area of Ojon-ri town resulted from the collection of natural rocks an stones. It is evaluated as necessary that such evergreen broadleaf trees as Castanopsis cuspidata var. thunbergii, Machillus thunbergii and Ligustrum japonicum of Hyongje-do. Chun-do, Tok-do, Taech'wi-do, and Soch'wi-do islets, andPhyllostachys bambusoides, Caesalpinia japonica and Albizzia julibirssin of Kokum-do island, and Machillus thunbergii of Hongryon-ri town be under protection. The average DGN of the whole archipelago proves to be 5.84, which shows the tendency of the inverse proportion to the number of resident population per unit area. The pteridophyta distributed in this island comprises 39 species, and the coefficient of cryptogam as to the destruction of vegetation shows a high value of 1.4 which is regarded as indicating the diversified distribution of pteridophyta, forestbed shade plants under the forestbeds of some wellpreserved lots of this island. The naturalized plants, distributed in this island, were found out comprising a total of 23 species, and the Urbanization Index(UI) as to the destruction degree of natural vegetatioin shows a low value of 20.9.

• 건축역사연구
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• 제2권2호
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• pp.26-36
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• 1993

The ${\ulcorner}$Dae${\lrcorner}$ is a place where a man could commune with nature. Our ancestors, who had very interested in natural landscape, and were named to the typical rock in the nature, which they called 'Dae'. The results of a analyzed the old literature(1530 : early stage of Chosen Danasty) are as follows. 1. The distribution of Dae is differ from provinces. Gangwon-do, Kyongsang-do, Cholla-do had many of the Daes. 2. The characteristics of form were classified into five groups. 1) A type of huge flat rock, which able to sit 5-6 persons(30.2%) 2) A type of mountain peak, which unable to use but seems to use images (27%) 3) A type of cliff(25.4%) 4) A type of fantastic rock (9.5%) 5) A type of stratified rock (6.3%) 3. The behavioral characteristics of the Dae were summarized watching a scenery and strolling (유(遊)), enjoying acenery, and relaxation. 4. The site locations of Dae are various such as, hill top, on cliffs, on the mountain, around river, river side cliff or grand rocks, and so forths.

• 한국환경과학회지
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• 제8권1호
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• pp.107-113
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• 1999

A new biological nutrient removal system combining $A^2/O$ process with fixed film was developed in this work and the characteristics of denitrification were especially investigated in the combined fixed film reactor(CFFR). Media was added in the anaerobic, anoxic and aerobic reactors, respectively. Tests were made to establish the effluent level of $NO_x-N$, COD, DO and nitrite effects on $NO_x-N$ removal in the CFFR by decreasing hydraulic retention time (HRT) from 10.0 to 3.5 hours and by increasing internal recycle ratio form 0% to 200%. The influent was synthesized to levels similar to the average influent of municipal wastewater treatment plants in Korea. SARAN media with a porosity of 96.3% was packed 40% / 130% / 25% based on its reactor volume, respectively. It was found that COD rarely limited dentrification in the anoxic reactor because of high $C/NO_x/-N$ ratio in the anoxic reactor, while DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent inhibited denitrification in the anoxic reactor. It was proved that the critical points of DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent were 0.15mg/L and 10%, respectively. As the internal recycle ratio increased, DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent increased. Especially, at the condition of internal recycle ratio, 200%, DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent exceeded the critical points of 0.15mg/L and 10%, respectively. Then, denitrification efficiency considerably decreased. Consequently, it was represented that the control of DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent can assure effective denitrification.

• Restorative Dentistry and Endodontics
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• 제46권4호
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• pp.57.1-57.9
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• 2021

Objectives: This study aimed to compare and evaluate the porosity and pore size distribution of high-viscosity glass ionomer cements (HVGICs) and conventional glass ionomer cements (GICs) using micro-computed tomography (micro-CT). Materials and Methods: Forty cylindrical specimens (n = 10) were produced in standardized molds using HVGICs and conventional GICs (Ketac Molar Easymix, Vitro Molar, MaxxionR, and Riva Self-Cure). The specimens were prepared according to ISO 9917-1 standards, scanned in a high-energy micro-CT device, and reconstructed using specific parameters. After reconstruction, segmentation procedures, and image analysis, total porosity and pore size distribution were obtained for specimens in each group. After checking the normality of the data distribution, the Kruskal-Wallis test followed by the Student-Newman-Keuls test was used to detect differences in porosity among the experimental groups with a 5% significance level. Results: Ketac Molar Easymix showed statistically significantly lower total porosity (0.15%) than MaxxionR (0.62%), Riva (0.42%), and Vitro Molar (0.57%). The pore size in all experimental cements was within the small-size range (< 0.01 mm³), but Vitro Molar showed statistically significantly more pores/defects with a larger size (> 0.01 mm³). Conclusions: Major differences in porosity and pore size were identified among the evaluated GICs. Among these, the Ketac Molar Easymix HVGIC showed the lowest porosity and void size.

• 한국식품영양과학회지
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• 제38권2호
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• pp.146-153
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• 2009

손바닥선인장의 항당뇨 효과와 기작을 알아보기 위한 연구의 일환으로, 손바닥선인장의 열매 및 줄기의 급여가 STZ으로 당뇨가 유발된 8주령 수컷 흰쥐의 음수량, 식이섭취량, 체중, 공복혈당, 당내성에 미치는 효과와 당뇨의 합병증인 고지혈증(중성지방, 유리지방산, 총콜레스테롤, LDL-콜레스테롤, HDL-콜레스테롤)을 조사하였다. 손바닥선인장의 열매 및 줄기는 동결건조 후 분쇄하여 분말사료에 8%(열매) 및 5%와 10%(줄기) 수준으로 첨가하여 3주간 자유채식 시켰다. 실험군은 정상군(NC), 당뇨대조군(DC), 열매급여군 (DOF), 줄기5%급여군(DO-5), 줄기10%급여군(DO-10)으로 구분하였으며, 음수량은 1일, 식이섭취량은 2일 간격, 체중 및 혈당은 1주 간격으로 측정하였는데, 혈당은 12시간 절식 후 꼬리정맥에서 측정하였다. 당 내성은 공복 시 혈당을 측정한 후 포도당(50 mg/체중 1 kg)을 복강에 주사한 다음, 30, 60, 90, 120분 경과하였을 때 혈당과 동일한 방법으로 측정하였다. 수분함량은 열매가 94.5%, 줄기가 92.3%였고, 조회분, 조단백, 조지방, 조섬유 등의 농도는 줄기가 열매에 비해 높았고, NFE는 열매가 줄기에 비해 높았다. 체중변화는 DC에 비해 DOF에서 체중이 적게 감소했다. 음수량과 사료섭취량은 NC에 비해 DC가 각각 7.5배 및 1.5배 이상 증가하였고, 처리군들은 음수량 및 식이섭취량이 DC에 비해 낮았다. NC의 공복혈당은 평균 100 mg/dL이었고 DC는 379 mg/dL이었으며, DOF는 DC에 비해 28%의 혈당 감소를 보인 반면(P<0.05), DO-5는 5%와 DO-10은 9% 감소하여 유의적 차이를 보이지 않았다. 당 내성 실험에서 NC와 DO-5는 급여한지 30분 후에, 다른 처리군은 60분 후에 최고 혈당을 나타내었다. 혈장 인슐린 함량도 당뇨대조군과 비교해 DOF, DO-5와 DO-10에서 유의적(p<0.05)인 증가를 보였다. 이로써 손바닥선인장의 열매가 STZ으로 당뇨가 유발된 쥐에서 당뇨의 개선효과가 있는 것으로 판단된다. 또한 손바닥선인장의 열매 및 줄기 모두 당뇨의 합병증인 지질대사에서 혈장의 중성지방, 유리지방산, 총 콜레스테롤 그리고 LDL-콜레스테롤을 모두 DC와 비교해 DOF, DO-5와 DO-10에서 유의적인 감소를 보였다(p<0.05). 이상의 결과에서 볼 때, 손바닥선인장의 열매는 항당뇨효능이 있었고, 또 당뇨 합병증인 지질대사의 이상도 개선하는 것으로 관찰되었으며, 그 줄기는 통계적으로 유의한 혈당감소 효과를 보이지는 않았지만 당뇨의 합병증인 고지혈증을 개선시키는 것으로 나타나, 보다 구체적인 작용기작을 추가적 연구를 통해 확인할 필요가 있다고 사료된다.