미국선녀벌레의 분포 및 분산 이동 시기 모델링

학위논문 (박사) -- 서울대학교 대학원 : 농업생명과학대학 농생명공학부, 2020. 8. 이준호.The citrus flatid planthopper, Metcalfa pruinosa (Say) has showed rapid establishment and spread through Korea since its first detection in 2009, causing serious economic damage to various crops and wild plants. Thus, the necessity for management of M. pruinosa has been increasing in Korea. This study was conducted to provide the ecological information that could help efficient management for M. pruinosa. The objectives of this study were (1) to determine the factors responsible for the fast expansion of M. pruinosa in Korea and identify its spreading process, (2) to predict the current potential distribution and future habitat suitability of M. pruinosa in Korea, (3) to predict phenology of young nymphs of M. pruinosa (4) to understand population dynamics of M. pruinosa nymphs within crop fields. In order to verify cause of fast spreading of M. pruinosa, and predict its current potential distribution, several statistical modelling methods and MaxEnt software were used with spatio-temporal occurrence information in Korea. Results showed that range expansion of M. pruinosa in Korea were significantly different from a pattern of continuous spreading mechanism. In early spread phase in 2013, traffic volume, one of human mediated factors, was the most important in explaining M. pruinosa distribution. Traffic volume of the relative pre-occupied habitat in 2013 was also significantly higher than the one lately occupied in 2017. According to these results, traffic volume was strongly proposed as a main reason of rapid spreading of M. pruinosa in Korea, causing long-distance dispersal in stratified spread mechanism. However, the mean temperature in the warmest quarter became the most important environmental factor in current phase in 2017, and rather the distribution could be better explained without traffic factor. The current distribution model was finally developed using three bioclimatic variables, except for traffic variable. This final model was used to predict future habitat suitability under climate change scenario (RCP 8.5.) In 2030s and 2050s, most parts of Korea except for mountainous area and southern parts were estimated to be suitable for M. pruinosa to be established. The distribution models of egg hatching time and first instar falling time of M. pruinosa from host trees were developed based on degree-days with a lower development threshold of 10.1 °C. January 1, commonly used in degree-day models, and March 18, an empirical date estimated in this study were examined as starting points for degree-day accumulation. As a result, the egg hatching and first instar falling models both used January 1 because the starting point performed better. From simulation result projected by these two models, the optimal time range for chemical sprays targeting the tree hosts of M. pruinosa were deduced as 423 DD to 474 DD. The control time for nymphs around the trees was suggested by the first instar falling model, along with observations of population density on the ground plants. The model of nymphal immigration time into crop fields was developed based on degree-days with a lower development threshold of 10.1 °C. In addition, survival rate of the nymphs until adult emergence was observed in field cages, and proportions of stage transition from the nymphs to the adults were modelled based on degree-days. Finally, a population simulation model for M. pruinosa nymphs in crop fields was constructed by integrating following factors: (1) beginning time of plants growing, (2) amount of immigrant nymphs, (3) survival rate in the crop fields, and (4) proportion of stage transition to the adults. There was a good agreement between the population model output and the nymphal abundance in various crop cultivation conditions. After 205.5 DD, the beginning time of plants growing was important in determining nymphal density in crop fields. However, even with the delayed beginning of crop cultivation, the times of peak density did not change as much as delayed time. After 800 DD, the population of M. pruinosa within crop fields was predicted to gradually decrease due to emigration of the adults.외래 매미충류인 미국선녀벌레 (노린재목: 선녀벌레과)는 2009년 국내에서 최초로 보고된 이후 다양한 식물에 피해를 주며 국내 전 지역으로 빠르게 정착 및 확산하였다. 따라서 국내에서 미국선녀벌레를 해충으로 관리 해야 할 필요성이 증대되고 있다. 이 연구는 미국선녀벌레의 효율적 관리에 도움을 줄 수 있는 생태적 정보를 제공하고자 수행되었다. 연구의 목표는 (1) 국내에서 미국선녀벌레의 빠른 확산 원인을 규명하고, (2) 미국선녀벌레의 현재 잠재적 분포 및 미래 서식지 적합성을 예측하고, (3) 어린 미국선녀벌레 약충들의 계절 발생 및 이동 시기를 예측하고, (4) 마지막으로 작물 경작지로 유입되는 미국선녀벌레 약충들의 개체군 동태를 이해하는 것이다. 국내에서 미국선녀벌레의 빠른 확산과 관련하여, 인위적 요소 중 하나인 차량에 의한 확산 가능성과 이들의 잠재적 분포를 연구하였다. 확산 패턴 분석을 위해, 국내에서 미국선녀벌레의 시공간적 발생 정보들을 활용하여 이들의 확산 속도와 정착한 지역들 간의 군집 거리를 추정하였다. 또한 교통량 요소를 포함한 몇 가지 환경변수들을 이용하여 최대 엔트로피 방법(MaxEnt)으로 미국선녀벌레의 분포 모델들을 작성하고 비교하였다. 그 결과 국내에서 미국선녀벌레의 분포 확대는 초기 침입 집단의 점진적 확산이 아닌 정착한 개체군들의 장거리 운반에 의해 촉진되어왔음을 확인하였다. 2013년의 초기 확산 단계에서는 교통량 변수를 사용하였을 때 MaxEnt 모델이 미국선녀벌레의 분포를 더 잘 설명하였고, 가장 중요한 변수인 것으로 나타났다. 이 결과로부터 교통량 요소는 침입종의 징검다리 확산 메커니즘에서 이들의 장거리 확산을 가능케 하는 중요한 요소로 추정되었고, 미국선녀벌레의 확산을 촉진해왔을 것으로 예측되었다. 하지만 현재 침입 상태로 가정한 2017년 미국선녀벌레 분포 모델에서는 교통 요소의 기여도는 크게 감소하였고, 오히려 모델에서 제외하였을 때 분포를 더 잘 설명하였다. 따라서 미국선녀벌레의 현재 분포 모델은 교통량 변수를 제외한 가장 따듯한 분기의 평균 온도, 가장 추운 분기의 평균 온도, 연간 강수량을 이용하여 작성되었다. 작성된 현재 분포 모델을 통해 미래 기후 시나리오(RCP 8.5)에 따른 서식지 적합성이 예측되었다. 그 결과 가까운 미래 (2030년대 및 2050년대)에는 산악지역과 남부지방을 제외한 국내 전역이 미국선녀벌레가 정착하기에 적합할 것으로 추정되었다. 유효적산온도에 따른 미국선녀벌레의 월동 알 부화 시기와 부화한 1령 약충이 월동 기주(나무)로부터 낙하하는 시간에 대한 분포 모델을 작성하였다. 모델 개발을 위해, 1월 1일과 관찰된 데이터를 통해 추정된 경험적 날짜인 3월 18일이 유효적산온도의 누적 시작일로 검토되었으며, 10.1 °C의 발육영점온도가 사용되었다. 월동 알 부화 모델과 1령 낙하 모델 모두 1월 1일의 적산온도 누적 시작일이 사용되었을 때 예측 성능이 더 우수하였다. 이 두 모델을 이용한 시뮬레이션을 통해, 나무 기주에서의 미국선녀벌레 약충을 대상으로 한 최적의 방제 시간은 423DD에서 474DD까지로 추정되었다. 또한 1령 낙하 모델과 나무 주변의 약충 밀도 자료를 통해, 월동처 주변 초본 식물에서의 미국선녀벌레 방제 및 예찰 시기가 제안되었다. 미국선녀벌레 약충이 작물 경작지로 유입되는 시간의 분포가 유효적산온도를 기반으로 예측되었다. 유효적산온도 계산에는 10.1 °C의 발육영점온도가 사용되었다. 또한 준 야외조건에서 미국선녀벌레 약충의 성충 우화까지 생존율이 조사되었으며, 야외에서 약충 및 성충의 트랩 포획 비율을 바탕으로 발육 단계 전이 모델을 개발하였다. 최종적으로 농경지 내에서 미국선녀벌레 약충의 개체군 시뮬레이션 모델은 (1) 작물을 재배하기 시작하는 시간, (2) 약충의 유입량, (3) 성충 우화까지 약충의 생존율, (4) 약충이 성충으로 우화한 비율을 이용하여 구축되었다. 구축한 시뮬레이션 모델과 실제 작물 재배지에서 밀도 변화는 다양한 작물 재배조건에서 비교적 잘 일치하였다. 205.5 DD 이후에는 작물이 재배되는 시작 시간이 경작지 내 약충 밀도를 결정하는 중요한 요소인 것으로 판단되었다. 하지만 유입 시작 시점이 지연된다 하더라도, 작물 재배지 내에서의 약충의 최대 밀도 시기는 유입 시작 시점의 차이만큼 지연되지 않았다. 800 DD 이후에는 경작지 내에서 우화한 성충들의 이탈로 인해 미국선녀벌레 밀도가 점점 감소할 것으로 예측되었다.Chapter Ⅰ. General introduction 1 1-1. Distribution and invasion history 3 1-2. Life cycle and seasonal occurrence 8 1-3. Symptoms of damage and economic impact 13 1-4. Invasion stage and management in Korea 15 1-5. Objectives of this study 20 Chapter Ⅱ. Current and future distribution of Metcalfa pruinosa in Korea: Reasoning of fast spreading 23 2-1. Abstract 25 2-2. Introduction 27 2-3. Materials and methods 30 2-3-1. Species occurrence data 30 2-3-2. Spreading rate and pattern 31 2-3-3. Preparation of environmental variables 33 2-3-4. Modelling procedure 35 2-3-5. Model selection and projection 38 2-3-6. Comparison of traffic factor for M. pruinosa occurrence in 2013 and 2017 39 2-4. Results 42 2-4-1. Spreading rate and pattern 42 2-4-2. Distribution model in 2013 (early spreading phase) 45 2-4-3. Distribution model in 2017 (current phase) 45 2-4-4. Future habitat suitability 52 2-4-5. Comparison of traffic factor for M. pruinosa occurrence in 2013 and 2017 54 2-5. Discussion 55 Chapter Ⅲ. Phenology modelling of egg hatching and first instar falling of Metcalfa pruinosa 65 3-1. Abstract 67 3-2. Introduction 69 3-3. Materials and methods 73 3-3-1. Data collection for model development 73 3-3-2. Starting point of degree-day models 78 3-3-3. Estimation of model parameters 81 3-3-4. Validation and accuracy of models 82 3-3-5. Change of nymphal density 84 3-4. Results 86 3-4-1. Starting date of degree-day models 86 3-4-2. Egg hatching and first instar falling models 88 3-4-3. Change in nymphal density 94 3-5. Discussion 97 Chapter Ⅳ. Immigration risk and population simulation models for Metcalfa pruinosa within crop fields 103 4-1. Abstract 105 4-2. Introduction 107 4-3. Materials and methods 110 4-3-1. Nymphal immigration model 110 4-3-2. Immigration risk of nymphs in crop fields 115 4-3-3. Survival rate and development time of the nymphs 119 4-3-4. Stage transition model from the nymph to adult 122 4-3-5. Population simulation model for the nymphs within the crop fields 124 4-4. Results 127 4-4-1. Nymphal immigration model 127 4-4-2. Immigration risk of nymphs in crop fields 129 4-4-3. Survival rate and development time of the nymphs 132 4-4-4. Stage transition model from the nymph to adult 133 4-4-5. Population simulation model for the nymphs within the crop fields 136 4-5. Discussion 140 Chapter Ⅴ. General conclusion 147 5-1. National management plan 149 5-2. Optimal control timing in various landscape 151 5-3. Management in crop fields 152 Literatures Cited 153 Abstract in Korean 171Docto

일반화된 디리클레 형식의 비폭발성과 재귀성에 대한 기준

학위논문 (박사)-- 서울대학교 대학원 : 수리과학부, 2016. 8. Gerald Trutnau.In the thesis, we develop analytic criteria for recurrence, transience and conservativeness of non-sectorial perturbations of possibly non-symmetric Dirichlet forms on a metric measure space. These form an important subclass of generalized Dirichlet forms which were introduced in [St1]. In case there exists an associated strong Feller process, the analytic conditions imply recurrence, transience and conservativeness, i.e. non-explosion of the associated process, in the classical probabilistic sense. As an application of our general results, we consider a generalized Dirichlet form given on a closed or open subset of R^d which is given as a divergence free first order perturbation of a symmetric energy form or a non-symmetric sectorial energy form. Then using volume growth conditions of the carr'e du champ and the non-sectorial first order part, we derive an explicit criterion for recurrence and conservativeness. We present concrete examples with applications to Muckenhoupt weights and counterexamples for recurrence. The counterexamples show that the non-sectorial case differs qualitatively from the symmetric or non-symmetric sectorial case. Namely, we make the observation that one of the main criteria for recurrence in these cases fails to be true for generalized Dirichlet forms. Moreover, we present several concrete examples for conservativeness which relate our results to previous ones obtained by different authors. In particular, we show that conservativeness can hold for a cubic variance if the drift is strong enough to compensate it.Chapter 1 Introduction 1 Chapter 2 Framework 9 Chapter 3 Analytic and probabilistic characterization of recurrence and transience 13 3.1 A general criterion for recurrence and transience of a generalized Dirichlet form 13 3.2 Connection to recurrence and transience in the classical sense 23 Chapter 4 Applications on Euclidean space 31 4.1 Explicit conditions for recurrence 42 4.2 Examples and counterexamples 46 4.2.1 A counterexample using results from [36] 47 4.2.2 A generic counter example 48 4.2.3 Muckenhoupt weights 54 4.3 Explicit recurrence criteria for symmetric Dirichlet forms on R satisfying a Hamza type condition 57 4.3.1 Non-reflected case 57 4.3.2 Reflected case 66 Chapter 5 Proofs of Lemmas 4.1, 4.2 and 4.3 69 Chapter 6 A general criterion for conservativeness of a generalized Dirichlet form 78 Chapter 7 Applications to symmetric and non-symmetric Dirichlet forms 94 7.1 Symmetric Dirichlet forms 94 7.2 Sectorial perturbations of symmetric Dirichlet forms on Euclidean space 98 7.2.1 Example 100 7.3 Sectorial perturbations of sectorial Dirichlet forms 101 7.3.1 Example 105 Chapter 8 Non-sectorial applications on Euclidean space 107 8.1 The construction scheme 107 8.2 Conservativeness 111 8.2.1 Example one 113 8.2.2 Example two 115 Reference 119 국문초록 125Docto

The interactive effect between ozone, sulfate aerosol, East Asia summer monsoon under present and future climate

학위논문 (박사)-- 서울대학교 대학원 : 지구환경과학부, 2016. 2. 박록진.Abstract Changing climate and air quality are strongly connected each other. For example, ozone and aerosol concentrations are strongly influenced by wind and temperature changes. Those air pollutants also play an important role in climate as a short-lived climate forcer. However, the understanding of the interaction between the two is still very low. This dissertation is to address the uncertainties of the interactive effects between climate change and air pollutants focusing on three objectives: (1) The effect of aerosol on the East Asian summer monsoon, (2) Future ozone and oxidants change under the RCP scenarios, and (3) Relationship changes between the East Asian summer monsoon and ozone in surface air in the present and future climate. I first examine the effect of anthropogenic aerosol forcing on the East Asian summer monsoon (EASM) using a general circulation model. One control and two sensitivity model experiments were conducted in order to diagnose the separate roles played by sea surface temperature (SST) variations and anthropogenic sulfate aerosol forcing changes in East Asia. I find that the SST variation has been a major driver for the observed weakening of the EASM, whereas the effect of the anthropogenic aerosol forcing has been opposite and has slightly intensified the EASM over the recent decades. The reinforcement of the EASM results from radiative cooling by the sulfate aerosol forcing, which decelerates the jet stream around the jets exit region. Subsequently, the secondary circulation induced by such a change in the jet stream leads to the increase in precipitation around 18-23°N. This result indicates that the increase in anthropogenic emissions over East Asia may play a role in compensating for the weakening of the EASM caused by the SST forcing. I investigate the ozone air quality changes in 2050 caused by global changes in climate and anthropogenic emissions of ozone precursors using a global chemical transport model driven by meteorological fields from a general circulation model. My model results show that annual mean concentrations of surface ozone will be lower in 2050 relative to 2000 by -3.3, -3.7, and -4.2 ppbv under RCP6.0, RCP4.5, and RCP2.6, respectively. In contrast, the RCP8.5 projection results in a slight increase of 2.1 ppbv caused by a methane increase. The ozone reductions are driven primarily by decreases in NOx emission, which dominate the climate penalty on ozone driven by temperature increases. I also estimate the effect of 21st century climate change on ozone air quality, assuming no changes in anthropogenic emissions of ozone precursors in the future. Temperature increase is found to result in ozone increases of up to 2.2 ppbv over land. Ozone over the oceans, however, is largely reduced with specific humidity increase, particularly in Northern Hemisphere, where the ozone concentration decreases by 0.8 ppbv. I also examine the effect of the EASM change on surface ozone concentrations over East Asia using the GEOS-Chem, which is driven by meteorological fields from the Community Earth System Model (CESM). I conduct model simulations using the RCP8.5 scenario to estimate the effects of the EASM on ozone 2000 and 2050. My model results show that ozone concentrations are positively correlated with the EASM in Central China. On the other hand, an opposite relationship is found in downwind regions including Eastern China, Korea, and Japan owing to a cyclonic circulation associated with the EASM. However, the relationship between the ozone change and the EASM becomes opposite in 2050 compared to that of 2000. The 2000-2050 change in the relationship between the ozone and the EASM is mainly due to a EASM domain shift under the warming climate in 2050, indicating the conventional EASM index based on the present climate condition cannot be applied to the future climate. Therefore, a modified EASM index is applied to examine the relationship between the two. I find, however, a weaker correlation between ozone and the EASM change in the downwind region in 2050, which is associated with the weakening of cyclonic circulation associated with the EASM over East Asia in 2050. These results indicate that the ozone change owing to the inter-annual variation of the EASM may change under the global warming climate.CHAPTER Ⅰ Introduction 1 1.1. Background and motivation 1 1.2. East Asian summer monsoon change due to sulfate aerosol 3 1.3. Future ozone and oxidants change under warming climate 5 1.4. Relationship changes between the East Asian summer monsoon and ozone in surface air in the present and future climate 7 1.5. Objective of the thesis 8 CHAPTER Ⅱ Effect of sulfate aerosol forcings on the East Asian summer monsoon 10 2.1. Objective 10 2.2. Data and Methodology 12 2.3. Result 16 2.4. Summary 34 CHAPTER Ⅲ Future ozone and oxidants change under the RCP scenarios 36 3.1. Objective 36 3.2. Methods 38 3.3. Model evaluation 48 3.4. Future ozone under the RCP scenarios 57 3.5. Attribution of ozone change to meteorological variables 62 3.6. Effects of climate change on oxidants 70 3.7. Summary 75 CHAPTER Ⅳ Relationship changes between the East Asian summer monsoon and ozone in surface air in the present and future climate 77 4.1. Objective 77 4.2. Methodology 80 4.3. Model evaluation 83 4.4. Relationship changes between the EASM and ozone in the present and future climate 87 4.5. Summary 94 CHAPTER Ⅴ Conclusion 96 REFERENCES 101 국문 초록 126Docto

새로운 판 유한요소를 이용한 미소한 비대칭이 있는 원판의 동적해석

Thesis (master`s)--서울대학교 대학원 :기계설계학과,2000.Maste

TiO₂觸媒를 利用한 NO의 光分解

학위논문(석사)--서울大學校 環境大學院 :環境計劃學科,1995.Maste

백토 두개골 결손부에서 탈회골기질 전달체를 이용한 중국 햄스터 난소 세포 유례 rhBMP-2의 골재생 효과

Dept. of Dental Science/박사Recombinant human bone morphogenetic protein-2 (rhBMP-2) has long been believed to have the potential to accelerate the healing process and augment tissue formation in challenging regenerative procedures. The objective of this study was to evaluate the bone regenerative effects of DBM coated by newly-developed Chinese hamster ovary (CHO) cell-expressed rhBMP-2 in rabbit cranial defect.Two symmetric, 11-mm ø, critical-size osteotomy defects were created in 7 New Zealand white rabbit craniums received DBM and rhBMP-2 coated DBM, respectively. Implant sites were evaluated by microcomputed tomography and histologic and histometric parameters following an 8-week healing interval. Surgical implantation of rhBMP-2 coated DBM resulted in enhanced local bone formation at 8 weeks. In defect closure, the rhBMP-2 coated DBM group was statistically significant greater than the DBM group (P<0.05). Total augmented area was not significantly different between the DBM group and the rhBMP-2 coated DBM group. However, New bone area of the rhBMP-2 coated DBM group was a significantly greater than those of the DBM group (P<0.05).In conclusion, DBM coated by newly-developed CHO-rhBMP-2 produced significant new bone and tissue formation in rabbit cranial defect. It is suggested that DBM may be an available carrier for rhBMP-2.ope

3차원 전산화단층촬영을 이용한 한국인에서의 상악동 중격 분석 : 빈도, 위치, 형태, 임상적 의의

Dept. of Dental Science/석사[한글] 선천적 결손이나 상실된 치아를 수복하기 위해 골유착성 치과 임프란트가 폭넓게 사용되고 있다. 위축된 상악 구치부에 임프란트를 식립할 경우에는, 초기 고정을 위한 적절한 골량을 형성하기 위해 골이식이 필요하다. 그러나, 상악동 중격과 같은 상악동 내의 해부학적 변이가 있는 경우에 상악동 거상술시에 상악동막의 천공, 출혈, 비구강개통, 상악동염 등의 합병증이 일어날 수 있다. 본 연구에서는 3차원 전산화단층촬영을 이용해서 한국인 성인에서 위축된 상악골 (위축이 일어난 무치악/무분무치악 상악골) 과 위축되지 않은 상악골 (위축이 일어나지 않은 유치악/부분유치악 상악골) 의 상악동 중격을 분석하고, 빈도, 크기, 위치, 형태학적 특징을 조사하였다. 100명의 환자 (남성: 59명, 여성: 41명, 연령: 19-87세, 평균연령: 50세) 의 재구성화된 전산화 단층사진에서 얻은 200개의 상악동 자료를 ImagePro software로 분석하였다. 200개의 상악동에서 총 59개의 상악동 중격이 발견되었다. 하나 이상의 상악동 중격을 포함하는 상악동의 빈도는 26.5% (53/200) 로 나타났으며, 100명의 환자중 38명 (38%) 에서 상악동 중격이 발견되었다. 위축된 상악골에서는 31.76%, 위축되지 않은 상악골에서는 22.61%의 하나 이상의 상악동 중격을 포함하는 상악동의 빈도가 나타났다. 상악동 내에서의 중격의 위치에 대한 분석 결과, 59개의 상악동 중격 중 15개 (25.4%) 는 전방 부위에 위치하였고, 30개 (50.8%) 는 중간 부위, 14개 (23.7%) 는 후방 부위에 위치하였다. 상악동 중격의 높이는 측정 위치에 따라 다양하게 나타났다. 외측 부위는 0에서 15.42 mm (평균 1.63 ± 2.44 mm), 중앙 부위는 0 에서 17.09 mm (평균 3.55 ± 2.58 mm), 내측 부위는 0 에서 20.18 mm (평균 5.46 ± 3.09 mm) 의 길이 분포를 보였다. 이상의 결과에서 볼 때, 상악동 중격은 상악골의 위축 정도에 관계없이 빈도, 크기, 위치, 형태에서의 많은 해부학적 변이를 보인다. 따라서, 상악동 거상술시에 합병증을 예방하기 위해서는 상악동내의 해부학적 구조물들에 대한 철저하고 해박한 이해가 필수적이다. [영문]The placement of osseointegrated dental implants constitutes a widely used method of replacing lost or missing teeth. However, in order to provide adequate bone for implant fixation, resorption of the alveolar ridge of the edentulous posterior maxilla may necessitate augmentation prior to osseointegration. The technique of sinus lift may be difficult to perform when an aberrant sinus anatomy is encountered during surgical exposure, such as in those cases where a septum is present on the sinus floor. The objective of this study was to determine the prevalence, size, location, and morphology of maxillary sinus septa in the atrophic/edentulous maxillary segments and non-atrophic/dentate maxillary segments. Reformatted computerized tomograms from 200 sinuses were analyzed utilizing ImagePro software. The sample population consisted of 100 patients (41 women and 59 men, with ages ranging between 19 and 87 years and a mean age of 50 years), for whom treatment was being planned in order for them to receive implant-supported restorations. The prevalence of one or more septa per sinus was found to be 26.5% (53/200), 31.76% (27 of 85), and 22.61% (26 of 115) in the overall study population, the atrophic edentulous maxillary segments, the non-atrophic/dentate maxillary segments, respectively. In the analysis of the anatomic location of the septa within the sinus, it was revealed that 15 (25.4%) septa were located in the anterior region, 30 (50.8%) in the middle region, and 14 (23.7%) in the posterior region. The measured height of the septa varied among the different areas. The mean height of the speta was 1.63 ± 2.44 mm, 3.55 ± 2.58 mm, 5.46 ± 3.09 mm in the lateral area, the middle area, and the medial area, respectively. In conclusion, it can be inferred that there is a wide anatomical variation in the prevalence, size, location, and morphology of maxillary sinus septa, irrespective of the degree of atrophy. Therefore, in order to prevent the likelihood of complications arising during sinus augmentation procedures, a thorough and extensive understanding of the anatomic structures inherent to the maxillary sinus is indispensable.ope

Alloy design of ternary Al alloys and their production method for fast hydrogen generation from hydrolysis reaction

본 발명은 알칼리 용액에서 알루미늄에 의한 가수분해 반응으로부터 수소를 고속으로 생산하기 위하여 알루미늄에 전기화학적 귀한(noble) 원소와 알루미늄의 부동태 피막을 약화시키기 위한 원소를 동시에 첨가한 새로운 알루미늄 합금 설계 및 이의 제조방법에 관한 것이다. 보다 상세하게는 알루미늄에 전기화학적으로 귀한 원소를 첨가하여 전기화학적으로 귀한(noble) 상이 입계 또는 입내에 석출하고, 부동태피막을 약화시키는 원소를 합금의 전체에 고르게 분포하도록 합금설계 및 제조함으로써 알칼리 물에 침지하면 부동태피막이 약화된 상태로 알루미늄과 입계 또는 입내에 석출한 귀한 원소 혹은 귀한 상간의 갈바닉 부식이 동시에 일어나 수소 발생 속도를 획기적으로 높이는 알루미늄 합금의 설계 및 제조에 관한 것이다. 또한 알루미늄에 첨가하는 전기화학적으로 귀한 원소는 철, 구리, 니켈, 코발트 등이 있으며, 부통태 피막을 약화시키는 원소로는 주석, 갈륨, 수은, 아연, 마그네슘 등이 있으며 이들을 이용하여 알루미늄 합금을 용해, 주조, 압연, 열처리하는 단계로 구성되는 것을 특징으로 하는 알루미늄 합금의 제조 방법에 관한 것이다.본 발명의 연료전지 동력원에서 on-board로 직접 수소를 빠른 시간에 생산 가능하여 경제성이 우수하고, 사용이 간편하다. 그래서 자동차 동력원, 휴대용 전자기기용의 동력원 및 가정용 전기의 동력원으로 사용이 가능하다