Experimental Study on Shear Strength of Prestressed PC-CIP Composite Beams

학위논문 (석사)-- 서울대학교 대학원 : 건축학과, 2015. 2. 박홍근.Recently, demands of precast (PC) composite method combined prestressed PC concrete and cast-in place(CIP) concrete increase in modular architectures. Because there is not obvious design code for shear strength of composite beam, in spite of increasing demands, engineers lead to being in difficulty to estimate shear strength of composite beams. Current design code (KCI 2012, ACI 318-11) suggests that properties of the individual elements or the most critical values shall be used in design if the specified strength, unit weight, or other properties of the various elements are different. Based on current code, 34 of prestressed composite specimens were tested and investigated consideration for shear design of composite beam. Test variables were section type, prestressing force (fse/fpu), shear span-to-depth ratio (a/d), and shear reinforcement ratio (ρvfy). In the result of tests, there were three failure modes: shear compression failure, horizontal shear failure, and web shear failure. Shear strength occurred shear compression failure was 2.4 times higher than that occurred horizontal shear failure and web shear failure. Also, shear strength increased as prestressed area and prestressing force increased and shear span-to-depth ratio decreased. Especially, in the case of specimens having a/d=3.0 and 62 percent~65 percent of effective prestressing force, shear strength did not increase though shear reinforcement ratio increased. Comparison between experimental values in this study and predicted values with current design code (KCI 2012, ACI 318-11), Eurocode2, empirical equation of Sozen et al., and theoretical equation of Bažant et al. was investigated. Consequently, shear strength with simplified method and detailed method of ACI 318 were in safety side and detailed method was rather conservative than simplified method. Thus it is reasonable to estimate shear strength of composite beams using current design code (ACI 318-11) which reflects properties of the individual elements. In addition, shear database (UTPCSDB) analysis which the number of specimens is 159 was performed included data in this study. As a results according to experimental variables, there was 2.3 percent of non-safety side in the case of upper 40 percent effective prestressing force in the case of simplified method (ACI 318-11) but all specimens were in safety side in case of detailed method.Contents Abstract i Contents iii List of Tables vi List of Figures viii List of Symbols xi Chapter 1. Introduction 1 1.1 General 1 1.2 Scope and Objectives 4 1.3 Outline of Masters Thesis 5 Chapter 2. Review 6 2.1 Design Codes 6 2.1.1 ACI 318-11 6 2.1.2 Other Design Codes for Prestressed Member 9 2.2 Preceding Research 11 2.2.1 Revesz (1953) 11 2.2.2 Saemann and Washa (1964) 12 2.2.3 Bryson, Skoda, and Watstein (1965) 14 2.2.4 Loov and Patnaik (1994) 16 Chapter 3. Shear Strength of Prestressed PC-CIP Composite Beams without Web Reinforcement 19 3.1 Test Program 19 3.1.1 Test Parameters 19 3.1.2 Test Specimens and Set-up 23 3.1.3 Materials 26 3.2 Result 28 3.2.1 Specimens 1-A ~ 1-D (a/d=3.0, fpj=0.55fpu) 28 3.2.2 Specimens 2-A ~ 2-D (a/d=3.0, fpj=0.70fpu) 30 3.2.3 Specimens 3-A ~ 3-D (a/d=4.0, fpj=0.70fpu) 32 3.2.4 Specimens 4-A ~ 4-D (a/d=4.0, fpj=0.70fpu, s=450 mm) 34 3.3 Analysis 36 3.3.1 Effect of Test Parameters 36 3.3.2 Contribution of prestress force 39 3.3.3 Comparison with Criteria of Vertical Shear Strength 42 3.3.4 Comparison with Criteria of Horizontal Shear Strength 44 3.4 Discussion 47 Chapter 4. Shear Strength of Prestressed PC-CIP Composite Beams with Web Reinforcement 49 4.1 Test Program 49 4.1.1 Test Parameters 49 4.1.2 Test Specimens and Setup 54 4.1.3 Materials 58 4.2 Result 60 4.2.1 Specimens 1-AS ~ 1-DS (a/d=3.0, fpj=0.55fpu, s=200 mm) 60 4.2.2 Specimens 2-AS ~ 2-DS (a/d=3.0, fpj=0.55fpu, s=450 mm) 62 4.2.3 Specimens 3-BS ~ 3-DS (a/d=3.0, fpj=0.70fpu, s=200 mm) 64 4.2.4 Specimens 4-AS ~ 4-DS (a/d=3.0, fpj=0.70fpu, s=300 mm) 66 4.2.5 Specimens 5-BS ~ 5-DS (a/d=3.0, fpj=0.70fpu, s=450 mm) 68 4.2.6 Specimens 6-AS ~ 6-DS (a/d=4.0, fpj=0.70fpu, s=450 mm) 70 4.3 Analysis 72 4.3.1 Effect of Test Parameters 72 4.3.2 Contribution of Shear Reinforcement 76 4.3.3 Relationship between tensile strain of shear reinforcement and shear crack occurrence 80 4.3.4 Comparison with Criteria of Vertical Shear Strength 84 4.3.5 Comparison with Criteria of Horizontal Shear Strength 86 4.4 Discussion 91 Chapter 5. Shear Database for Prestressed Concrete Members 93 5.1 Introduction 93 5.2 Prediction of Experimental Values 94 5.3 Shear Database Analysis 102 Chapter 6. Conclusion 109 References 111 Appendix A: List of Collected References 113 Appendix B: Evaluation Database 115 초 록 122Maste

포름산염 및 질산염을 활용한 석회 활성화 플라이애시 결합재 개발

학위논문 (박사)-- 서울대학교 대학원 : 공과대학 건축학과, 2019. 2. 박홍근.알칼리 활성화된 물질 (Alkali-activated materials, AAM)은 시멘트 생산에서 발생하는 이산화탄소 (CO2) 배출을 제한하고, 산업 현장의 폐기물을 유용한 제품으로 제조하여 일반 포틀랜드 시멘트 (OPC)의 잠재적 대안으로 인정받고 있다. 그러나, 기존의 알칼리 활성화 과정은 고농축의 알칼리성 용액을 제조하고 이를 결합재에 첨가하는 두 단계 (two-part)로 구성되며, 용액의 높은 pH와 비경제성으로 인해 안전 및 비용 문제가 발생한다. 따라서 시멘트처럼 결합재에 물만 첨가하면 경화될 수 있는 one-part AAM의 개발은 기존 two-part AAM보다 현장타설 및 프리캐스트 콘크리트 분야에서 더 큰 잠재력을 가질 수 있다. One-part AAM은 플라이애시와 같은 알루미노실리케이트계 물질, 고체 알칼리 활성화제 및 첨가제로 구성되며, 결합재의 반응성을 촉진하기 위해 고온에서 제조 될 수 있다. 이 논문은 플라이애시를 바탕으로 한 one-part AAM에 대해 기계적 및 물리적 특성, 강도 발현 메커니즘, 반응 생성물의 관점에서 논의하였다. 고로슬래그 활성화에 주로 사용되는 생석회 (CaO) 및 소석회 (Ca(OH)2)와 같은 석회 활성제는 기존 알칼리 활성제보다 덜 위험하고 경제적이므로 이를 플라이애시 활성화에 사용할 수 있다. 석회 활성화된 플라이애시는 주요 반응생성물로 칼슘실리케이트계 수화물 (C-S-H)을 생성하며, 이는 OPC의 주요 반응생성물과 유사하다. 그러나 석회 활성제가 다른 첨가제 없이 단독으로 사용될 경우, 압축강도는 플라이애시의 낮은 반응성으로 인해 OPC의 압축 강도보다 상당히 낮다. 따라서, 플라이애시의 반응성를 촉진시키고 석회 활성화된 플라이애시 결합재의 강도를 확보하기 위해 적절한 첨가제를 논의할 필요가 있다. 기존에는 석회 활성화제에 황산나트륨 (Na2SO4), 염화칼슘 (CaCl2), 염화나트륨 (NaCl) 등과 같은 추가적인 화합물을 첨가하여 기계적 특성을 개선하였으나, 이러한 물질들은 염화 이온 또는 황산 이온을 포함하여 염해 및 황산염 침투로 인한 철근 부식과 같은 내구성 문제를 일으킬 수 있으므로 사용을 지양해야 한다. 따라서 OPC에 필적하는 우수한 성능을 발휘할 수 있고 동시에 염화 및 황산 이온을 포함하지 않는 보다 효과적인 첨가제의 제안이 필요하다. 실제로, 포름산염 및 질산염은 경화 촉진제, 부식 방지제 또는 제빙제와 같은 역할로써 OPC의 혼화제로 주로 사용되고 있다. 포름산염과 질산염 사용이 OPC에 미치는 영향에 대한 수많은 연구에도 불구하고, 이 화합물들이 석회 활성화된 플라이애시 결합재의 강도와 반응생성물에 어떤 영향을 미치는지에 대한 연구는 수행된 사례가 없다. 따라서 석회 활성화된 플라이애시 결합재의 첨가제로서 포름산염 및 질산염의 역할을 조사할 필요가 있다. 제안된 화합물을 사용하여 개발된 석회 활성화된 플라이애시 결합재의 기계적 특성을 파악하고 미세구조 분석을 통해 강도발현 메커니즘을 규명하였다. 압축 강도, 비중, 흡수율 등의 기계적 특성을 알아보고, X 선 형광 분광법 (XRF), 유도결합플라즈마 분광분석기 (ICP-OES), pH 측정, X-선 회절 (XRD), 열중량 분석 (TGA), 수은 압입법 (MIP), 27Al 및 29Si 핵 자기 공명 분광법 (MAS-NMR), 에너지 분산분광분석 (EDS)을 이용한 주사전자현미경 (SEM) 등을 이용하여 미세구조 분석을 수행하였다. 본 연구에서는 포름산 칼슘 (Ca(HCOO)2), 포름산 마그네슘 (Mg(HCOO)2), 포름산 나트륨 (NaHCOO), 포름산 칼륨 (KHCOO), 총 네 가지 포름산염이 각각 CaO-활성화된 플라이애시의 강도에 미치는 영향에 대해 분석하였다. 실험 결과, Ca(HCOO)2 및 Mg(HCOO)2의 첨가는 C-S-H 형성을 증가시키고 공극 크기를 현저히 감소시켜 결합재 강도를 증가시켰으며, 특히 반응 초기에 활성화제인 CaO의 용해를 촉진시켜 강도 향상에 영향을 주었다. 더불어, 초기 카토이트 (katoite) 생성 역시 결합재 내 매트릭스를 더욱 조밀하게 하여 강도 향상에 기여하였다. 반면, NaHCOO 또는 KHCOO의 첨가는 플라이애시의 용해에는 도움이 되지만 주요 활성화제인 CaO의 추가 용해를 억제하여 강도 증진에 효과적이지 않았다. 질산 칼슘 (Ca(NO3)2), 질산 마그네슘 (Mg(NO3)2), 질산 나트륨 (NaNO3)의 질산염을 첨가하여 CaO-활성화된 플라이애시 결합재의 강도 증진 및 미세구조 특성을 조사하였다. Ca(NO3)2 및 Mg(NO3)2의 첨가는 초기반응에서 플라이애시의 용해도 증가, C-S-H 형성 촉진 및 공극 크기의 현저한 감소로 인해 결합재의 강도 향상에 크게 기여하였다. 그러나, NaNO3의 첨가는 플라이애시의 용해를 촉진하였으나 강도 향상에 크게 기여하지 않았다. 실제 산업 적용을 고려하여, 경량 골재인 팽창 진주암 및 팽창 질석을 CaO-Mg(NO3)2-활성화된 플라이애시 결합재에 혼입하여 경량 모르타르 경화체를 개발하였다. 팽창 진주암 및 팽창 질석이 결합재 매트릭스와 화학적으로 반응하여 추가적인 반응생성물과 천이영역 (interfacial transition zone, ITZ)을 형성하지는 않았으나, 우수한 강도 및 낮은 비중을 나타내어 상업용 경량블록 기준을 만족하였다. 개발된 One-part 석회 활성화된 플라이애시 결합재는 시멘트 및 건설 산업에서 CO2 배출 감소에 크게 기여할 수 있다. 이러한 환경적 이익과 함께, 현재 재이용되는 상당량의 산업 부산물을 재사용함으로써 경제적 이익도 얻을 수 있다. 마지막으로, 이 연구의 결과로부터 기본 원리가 다른 부산물에 적용하여 새로운 결합재를 개발할 수 있으므로 관련 연구 분야의 확장에 기여할 학문적 가치가 있다. 그러나 본 연구에서 사용된 산업부산물, 즉 플라이애시는 화학 조성, 결정상의 종류, 입자 크기 등에 따라 화학 반응이 변화하기 때문에 재현성이 매우 낮다. 또한, 높은 강도를 보인 플라이애시 결합재일지라도 주 재료인 플라이애시가 다른 재료로 변경되면 동일한 실험 조건 하에서 경화되지 않을 수 있다. 플라이애시는 석탄 연소 방식, 석탄 특성, 배출시기, 저장 조건 등에 따라 특성이 매우 다르고 이질적이기 때문에 정확한 정량적 특성 평가를 바탕으로 혼합비를 계산할 필요가 있다. 이것은 실제 기술의 상용화에서 가장 중요한 요소이며 향후 추가적인 연구가 필요하다.Alkali-activated materials (AAM) are recognized as potential alternatives to ordinary Portland cement (OPC) to limit CO2 emissions, and beneficiate several wastes into useful products. However, the alkali activation is difficult to handle because it contains a concentrated alkaline solution that is corrosive and dangerous. Consequently, the development of so-called one-part AAM may have greater potential than the conventional two-part AAM, especially in cast-in-situ and precast concrete (PC) applications. One-part AAM involves a dry binder mixture that consists of a solid aluminosilicate precursor, a solid alkali source, and possible admixtures to which water is added, similar to the preparation of OPC. The dry mixture can be prepared at elevated temperatures to facilitate the reactivity of certain raw materials. This paper discusses the development of one-part AAM by using fly ash (FA) as precursor, lime-type activator, and various chemical additives, and validates their mechanical properties and microstructural characteristics. Lime-type activators such as CaO and Ca(OH)2, which are commonly used for granulated blast-furnace slag (GGBFS) activation, are much less expensive and dangerous than alkaline activators (pH = ~12.5 in a saturated solution), so they can function as suitable alkaline activator substitutes for fly ash (FA) activation. Similar to OPC, lime-activated FAs produced calcium silicate hydrates (C-S-H) as their main reaction producthowever, when the limes were used alone without any other additives in the activations, their compressive strengths were considerably lower than that of OPC, mainly due to low reaction degree of FA. Thus, it is necessary to find suitable additives to promote the reaction degree and significantly strengthen lime-activated FA binders. Previously, additional chemicals such as Na2SO4, CaCl2, NaCl were used to improve the mechanical properties. However, these additives, which contain chloride or sulfate ions, should be avoided in concrete because they might cause durability problems, such as steel corrosion or sulfate attacks. Still, it is necessary to identify more effective additives without having chloride and sulfate ions to achieve a good mechanical performance comparable to OPC. In practice, formate and nitrate compounds are mainly used as organic chemical admixtures for OPC, such as set accelerators, corrosion inhibitors, or deicers. Despite numerous studies on how formate and nitrates affect an OPC system, no study has been conducted on how those chemicals impact a lime-activated FA binders. Thus, the role of the formate and nitrate compounds as additives in lime-activated FA needs to be investigated because those chemicals may be very effective at improving mechanical properties of lime-activated FA binders. Mechanical performance and microstructures characterisctics of one-part alkali-activated FA binders with new chemical compounds were developed as a possible alternative to OPC using compressive strength test, specific gravity, water absorption, X-ray fluorescence spectroscopy (XRF), laser diffraction, inductively coupled plasma atomic emission spectroscopy (ICP-OES), pH measurement, X-ray diffraction (XRD), thermogravimetric analysis (TGA), mercury intrusion porosimetry (MIP), solid-state 27Al and 29Si magic-angle spinning nuclear magnetic resonance spectroscopy (MAS-NMR), and scanning electron microscopy (SEM) with energy dispersive spectroscopy analysis (EDS). This study investigated whether four formate compounds (i.e., Ca(HCOO)2, Mg(HCOO)2, NaHCOO, and KHCOO) could improve the strength of a CaO-activated FA. The addition of Ca(HCOO)2 and Mg(HCOO)2 significantly strengthened the FA binder system by substantially increasing C-S-H formation and measurably reducing overall pore size. Initially, in particular, dissolution of the activator, CaO, was promoted, which affected the strength enhancement. Furthermore, the initial formation of katoite could make the hardened matrix denser, resulting in enhanced strength. However, adding NaHCOO or KHCOO was much less advantageous to strength improvement because although helpful in dissolving FA, the high pH environment caused by their reaction with CaO inhibited further dissolution of CaO, which was the main activator used in this study. Three potential additives of nitrate compounds (i.e., Ca(NO3)2, Mg(NO3)2 and NaNO3) to improve the strength of a CaO-activated FA were investigated by using various microstructurual approaches. The use of Ca(NO3)2 and Mg(NO3)2 was greatly beneficial in the strength improvement of the binder system primarily due to the significant increase in the dissolution degree of fly ash, C-S-H formation, and pore size refinement from early dayshowever, NaNO3 was much less advantageous in strength improvement, although it also aided in dissolving fly ash. Considering for practical application, expanded perlite (EP) and expanded vermiculate (EV), as a lightweight aggregate, mixed CaO-Mg(NO3)2-activated FA binder mortars were successfully produced. From SEM, although EP and EV did not chemically contribute to formation of reaction products because they do not form an interfacial transition zone (ITZ) between the binder matrix and aggregates, or react with the binder matrix, mortar samples showed excellent lightness and strength, consistent with standard for commercial autoclaved aerated concrete (AAC). The developed one-part alkali-activated binders made from industrial by-products can contribute significantly to CO2 emissions reduction in the cement and construction industries. Along with these environmental benefits, economic benefits by reusing a significant amount of industrial byproducts currently being reclaimed could be achieved. Finally, the results of this study are of academic value that will contribute to the expansion of related research fields, since the basic principles of the new binder system can be applied to different by-products.Chapter 1. Introduction 1 1.1 CO2 emission and global warming 1 1.2 Alkali-activated materials 4 1.2.1 Geopolymer as two-part alkali-activated material 4 1.2.2 One-part alkali-activated materials 6 1.2.3 Lime-activated fly ash 9 1.3 Scope and objectives 11 1.4 Organization 13 Chapter 2. Materials and Experimental Programs 16 2.1 Fly ash 16 2.1.1 Chemical composition and classification of fly ash 17 2.1.2 Reaction chemistry of fly ash 20 2.2 Activators 26 2.2.1 Lime type 26 2.2.2 Lime/fly ash ratio 27 2.3 Experimental programs for microsturcture 30 2.3.1 X-ray diffraction analysis 30 2.3.2 Thermogravimetric analysis 32 2.3.3 Solid-state 27Al and 29Si magic-angle spinning nuclear magnetic resonance spectroscopy 35 2.3.4 Mercury intrusion porosimetry 39 2.3.5 Scanning electron microscopy 41 2.3.6 Inductively coupled plasma-optical emission spectrometer 44 2.3.7 Hydration stop using solvent exchange method 46 2.3.8 Test procedure 48 Chapter 3. Cation-Dependent Effects of Formates on CaO-Activated Fly Ash Binders 51 3.1 Introduction 51 3.2 Materials and test methods 53 3.3 Results and discussion 59 3.3.1 Compressive strength 59 3.3.2 X-ray diffraction analysis 60 3.3.3 Thermogravimetric analysis 65 3.3.4 27Al MAS-NMR spectroscopy 69 3.3.5 Mercury intrusion porosimetry 70 3.4 Concluding remarks 75 Chapter 4. Influence of Magnesium Formate on CaO-Activated Fly Ash binders 77 4.1 Introduction 77 4.2 Materials and test methods 79 4.3 Results and discussion 85 4.3.1 Compressive strength 85 4.3.2 Pore solution analysis 86 4.3.3 X-ray diffraction analysis 91 4.3.4 Thermogravimetric analysis 96 4.3.5 29Si and 27Al MAS-NMR spectroscopy 100 4.3.6 Mercury intrusion porosimetry 105 4.4 Concluding remarks 108 Chapter 5. Cation-Dependent Effects of Nitrates on CaO-Activated Fly Ash Binders 110 5.1 Introduction 110 5.2 Materials and test methods 112 5.3 Results and discussion 118 5.3.1 Compressive strength 118 5.3.2 Pore solution analysis 119 5.3.3 X-ray diffraction analysis 122 5.3.4 Thermogravimetric analysis 127 5.3.5 27Al MAS-NMR spectroscopy 130 5.3.6 Mercury intrusion porosimetry 132 5.3.7 Scanning electron microscopy 134 5.4 Concluding remarks 138 Chapter 6. Influence of Magnesium Nitrate on CaO-Activated Fly Ash Binder 140 6.1 Introduction 140 6.2 Materials and Test methods 143 6.3 Results and discussion 151 6.3.1 Compressive strength 151 6.3.2 Pore solution analysis 152 6.3.3 X-ray diffraction analysis 154 6.3.4 Thermogravimetric analysis 157 6.3.5 29Si and 27Al MAS-NMR spectroscopy 160 6.3.6 Mercury intrusion porosimetry 165 6.3.7 Scanning electron microscopy 169 6.3.8 Its application 172 6.4 Concluding remarks 182 Chapter 7. Conclusion 185 References 190 Appendix A. BSE/EDS results 218 A.1 Cation-Dependent Effects of Nitrates on CaO-Activated Fly Ash Binders 218 A.1.1 CF 218 A.1.2 CFCN 219 A.1.2 CFSN 220 A.2 Influence of Magnesium Formate on CaO-Activated Fly Ash Binders 221 A.2.1 CF 221 A.2.2 6CFMN 223 A.2.3 6CFMN20EP 224 A.2.4 6CFMN80EP 226 A.2.5 6CFMN20EV 227 A.2.6 6CFMN80EV 229 초 록 230Docto

제도적 환경 변화가 기업전략의 적합성에 미치는 영향에 대한 연구 : 1980년대 후반 이전과 이후의 우리 나라 기업집단의 다각화전략에 대한 비교연구

학위논문(석사)--서울대학교 대학원 :경영학과 경영학전공,2000.Maste

Louis I. Kahn`s urban projects in 1960-74 : representation and communication of American city

학위논문(박사)--서울대학교 대학원 :건축학과,2006.Docto

루이스 칸의 건축에서 빛이 `룸 형성`에 기여하는 역할에 관한 연구

학위논문(석사)--서울대학교 대학원 :건축학과,1998.Maste

비치성 통증으로 안면통증 클리닉에 내원한 환자의 특성

Dept. of Dentistry/박사Etiology as well as diagnosis and treatment methods for non-odontogenic (NO) pain have not yet been clearly established. Patients with NO pain generally have complex histories of dental treatment without improvement of symptoms. Patients often suffer from persistent pain because of failure to establish the NO etiology, resulting in incorrect diagnosis and inappropriate dental treatment unnecessary to resolving NO pain. Despite this issue, NO pain has not been systemically evaluated in Korea. This study therefore investigated the various clinical profiles of patients with NO pain as well as diagnosis and treatment methods of NO pain. Subjects included 210 patients with orofacial pain complaints who were admitted to the Department of Orofacial Pain and Oral Medicine of Yonsei University Dental Hospital between May 2003 and April 2013. Chart reviews were conducted on all 210 patients. The profiles were evaluated using patient charts (gender, age, smoking, alcohol consumption, systemic disease, pain duration, pain location, and areas affected by pain) and surveys (pain intensity, spontaneity of pain, referred pain, and dental history associated with the NO pain). Based on the obtained results, we report the following findings: 1. NO pain was diagnosed mainly as neuropathic pain (53.8%) and myofascial pain (MFP) (23.3%). 2. There were 65.7% without medical history, 20.5% cardiovascular diseases, 6.7% with GI troubles and 4.3% with psychogenic diseases. And only few of them have smoking (male 6.7%, female 1.0%) and drinking habits (male 8.6%, female 5.7%). 3. The common site of NO pain is left maxilla (30.0%), and right maxilla (27.6%). Distribution of affected area were generally in accordance with previous reports but was not predominant in maxillary posterior region. Single area was affected in 90 patients (42.9%) with similar occurrence with multiple lesions (41.0%). 4. 17 patients (8.1%) had referred pain. 63.8% of patients have spontaneous pain. And the number of patients who have severe pain and who have moderate pain were 24.3%, 51.9% each. The average period of treatment was 6.7 months. 5. NO pain occurs more often to the female (74.8%) than to the male (25.2%). The average age is 49.0 years and the average pain duration is 31 months. 6. Considering the departments referring to the Department of Orofacial Pain and Oral Medicine, treatments related to NO pain, previous dental treatment history, and visiting dental departments, NO pain is very closely related to the RCT. 48.6% of patients have treated more than 3 dentists. 7. The used drugs were mainly antidepressants (42.9%) and anticonvulsants (38.9%). And the effectiveness of anticonvulsants (79.2%) is better than that of antidepressants (75.3%). 8. Mainly the treatment drugs of neuropathic pain used amitriptyline (18.9%) and gabapentin (14.1%). And topical capsaicin has a limited effect. 9. Mainly the treatment drugs of MFP used eperisone HCl (24.3%) and cyclobenzaprine HCl (13.6%).ope

Functional Studies on Two Positive Osmotic Stress Regulators, AtBG2 and AtANAC096

DoctorAbstractThe phytohormone abscisic acid (ABA) plays critical roles in plant growth and development as well as biotic and abiotic stress responses in plants. As abiotic stress is one of most serious challenges for plants, it is of great importance to understand genetic traits that are specifically responsible to abiotic conditions as well as for further conduct of genetic engineering. In this study, by using forward genetic screening, that are, firefly luciferase reporter (LUC) activity suppression screening, in which LUC reporter is driven by the osmotic stress-responsive RD29A promoter, in the presence of NaCl stress conditions and cotyledon stay green screening in the presence of ABA, we isolated two mutants, AtBG2 as well as AtANAC096, respectively, and further conduct the functional studies.In Arabidopsis thaliana, ABA levels are increased both through de novo biosynthesis and via AtBG1-mediated hydrolysis of glucose-conjugated ABA (ABA-GE). However, it is not known how many different -glucosidase proteins produce ABA from ABA-GE and how the multiple ABA production pathways are coordinated to increase ABA levels. Here, we report that a previously undiscovered -glucosidase homolog, AtBG2, produced ABA by hydrolyzing ABA-GE and plays a role in osmotic stress response. AtBG2 localized to the vacuole as a high molecular weight complex and accumulated to high levels under dehydration stress. AtBG2 hydrolyzed ABA-GE to ABA in vitro. In addition, AtBG2 increased ABA levels in protoplasts upon application of exogenous ABA-GE. Overexpression of AtBG2 rescued the atbg1 mutant phenotype, as observed for the overexpression of NCED3 in bg1 mutants. Multiple Arabidopsis atbg2 alleles with a T-DNA insertion in AtBG2 were more sensitive to dehydration and NaCl stress, whereas AtBG2 overexpression resulted in enhanced resistance to dehydration and NaCl stress. Based on these observations, we propose that, in addition to the de novo biosynthesis, ABA is produced in multiple organelles by organelle-specific -glucosidases in response to abiotic stresses.Diverse signaling pathways are used to respond to ever-changing environmental conditions. In these signaling circuits, various types of transcription factors are a core component by activating expression of a large number of genes involved in the response reactions. Accordingly, the action mechanism of transcription factors has been one of the main focuses in research on abiotic stress responses. However, it is still far from full understanding on the physiological roles and action mechanism of theses transcription factors involved in abiotic stress responses. In this study, we provide evidence that AtANAC096, a member of the NAC transcription factor family, plays a positive role in the abiotic stress responses in Arabidopsis. An Arabidopsis mutant that has a T-DNA insertion at AtANAC096 exhibited hyposensitivity to exogenous ABA in germination and growth, delayed stomatal closure and increased water loss, whereas transgenic plants overexpressing AtANAC096 exhibited hypersensitivity to exogenous ABA and decrease in water loss. At the molecular level, AtANAC096 activated transcription of a subset of ABA and dehydration stress-inducible genes including RD29A and NCED3. Moreover, AtANAC096 interacted with ABF2 and ABF4 and exhibited a synergistic relationship with ABFs in transcription of common target genes. Expression of AtANAC096 itself is induced by ABA and dehydration stress. Based on these results, we propose that AtANAC096 is involved in transcription of genes regulated by ABA-dependent signaling pathways by acting alone or together with ABFs in a synergistic manner in response to dehydration stress

An Experimental Study on the Effects of Concentration Gradient and Mean Velocity on the Liftoff Characteristics of the Triple Flame

A triple flame in a mixing layer was studied experimentally with concentration gradient and mean velocity by using a multi-slot burner, which can stabilize the lift-off flame. Flame stabilization condition, lift-off heights, and some other characteristics were examined for methane and propane flame within a range of very low concentration gradient. Pitot-tube and LDV(Laser Doppler Velocimetry) were used for velocity. Mass spectroscopy and Rayleigh scattering signal were used for concentration gradients. Thermo-couples and SiC TFP(Thin Filament Pyrometer) were used for temperature. It was found that minimum values of the lift-off heights exist at a certain concentration gradient for constant mean velocity and this means that the propagation velocity has a maximum value. The scales of flame to the burner nozzle and intensity variation of the diffusion flame were suspected as the cause.연소기술연구센터(CERC

The Concept and Embodiment of ‘Atmosphere’ in SANAA’s Architecture

SANAA(Sejima and Nishizawa and Associates), a leading Japanese architectural firm, has developed the architectural ‘atmosphere’ as its general principle and aim of their design practice. Ultimately defining it as “a landscape (the contemporary scenery) for people,” the firm has been pursuing a ‘new freedom’ and has incorporated multiple values into it: contemporaneity,integrity of programs and phenomena, and potentiality. SANAA tries to embody the concept of ‘atmosphere’ through the various representational strategies: hierarchical reconstitution of space, transparent and abstract simplification, and non-deceptive trick. In the resulting architectural representation, a heterotopia can be found.