1,721,732 research outputs found
Magneto-optical trapping of rubidium atoms and measurement of atomic density
No full text학위논문(석사) - 한국과학기술원 : 물리학과, 2001.2, [ 50 p. ]한국과학기술원 : 물리학과
Preparation and characterization of sustained release film and tablet using physicochemically modified rice starch
No full text학위논문(석사)--아주대학교 일반대학원 :약학,2016. 21. Introduction 1
2. Materials and methods 9
2.1. Materials 9
2.2. Preparation of rice starch 9
2.2.1. Preparation of thermally modified glutinous rice starch (TMR) 9
2.2.2. Preparation of spray-dried thermally modified glutinous rice starch (SDTMR) 9
2.3. Preparation of drug-loaded starch film and tablet 10
2.3.1. Preparation of drug-loaded starch film 10
2.3.2. Preparation of drug-loaded starch tablet 11
2.3.3. Tablet compression 11
2. 4. Characterization 16
2.4.1. Characterization of modified rice starch 16
2.4.1.1. Particle size analysis 16
2.4.1.2. Scanning electron microscopy (SEM) 16
2.4.1.3. Powder x-ray diffraction (PXRD) 16
2.4.1.4. Loss-on-drying (LOD) 17
2.4.1.5. pH measurement 17
2.5.1. Characterization of starch film and tablet 17
2.5.1.1. Thickness evaluation 17
2.5.1.2. Tensile strength and Elongation of film 17
2.5.1.3. Viscosity measurement 18
2.5.1.4. Confocal laser scanning microscopy (CLSM) 18
2.5.1.5. Swelling and erosion studies of tablet 18
2.5.1.6. Drug content determination of film 20
2.5.1.7. In vitro dissolution study 20
2.5.1.8. High performance liquid chromatography (HPLC) analysis of Sarpogrelate HCl 20
3. Results and discussion 23
3.1. Characterization of modified rice starch 23
3.1.1. Particle size of modified rice starch 23
3.1.2. Surface image of modified rice starch 23
3.1.3. Crystal structure of modified rice starch 25
3.1.4. Water content of modified rice starch 27
3.1.5. pH measurement of modified rice starch 27
3.2. Characterization of film and tablet 29
3.2.1. pH measurement and viscosity of film 29
3.2.2. Photographs and roughness of film surface without drug 31
3.2.3. Photographs and roughness of film surface with drug 34
3.2.4. Mechanical properties of film 38
3.2.5. Crystal structure of drug-loaded film 40
3.2.6. Physical properties of tablet with drug 42
3.2.7. In vitro dissolution studies of film and tablet 44
3.2.8. Swelling and erosion studies of tablet 51
4. Conclusions 54
5. References 55
국문초록 59
감사의글 61MasterThe aim of this study was to investigate a novel, biodegradable, spray-dried, thermally modified rice starch (SDTMR) as a film-forming agent and retardant polymer for preparing the solid dosage form. Films were prepared by the solvent casting method, and tablets were prepared by direct compression of drug-loaded powder. Sarpogrelate HCl was chosen as the model drug. Calcium chloride (CaCl2) and magnesium chloride (MgCl2) were utilized as crosslinking agents to obtain the desired effect. The size, surface morphology and crystallinity of starch powders (glutinous rice starch (GR), thermally modified rice starch (TMR) and SDTMR) were characterized by a particle size analyzer, scanning electron microscopy (SEM) and powder x-ray diffraction (PXRD). The surface morphology and roughness of the starch films were characterized by confocal laser scanning microscopy (CLSM). The tensile strength and elongation of the film were determined by a texture analyzer. The physical properties of tablets, such as weight, thickness and hardness were also measured. Swellability and erosion of the tablets were then analyzed by gravimetric evaluation. In vitro dissolution testing was performed in gastric fluid (pH 1.2 buffer) and intestinal fluid (pH 6.8 buffer). The crystallinity of TMR and SDTMR was transformed from the crystalline to the amorphous state. The SDTMR film had a smoother surface than the TMR and GR films. In pH 6.8 buffer, SDTMR film crosslinked with CaCl2 showed a significantly higher sustained drug release compared to SDTMR crosslinked with MgCl2. In conclusion, physicochemically modified rice starch provides a promising approach to prepare pharmaceutical film and tablets with sustained release
Characteristics of two-dimensional photonic bandedge laser
No full text학위논문(박사) - 한국과학기술원 : 물리학과, 2005.8, [ [iii], 96 p. ]최근 활발한 광결정 연구 중에서 광결정 레이저는 파장 정도의 크기와 설계의 용이성으로 인해 매우 흥미로운 주제이다. 대부분 광결정 레이저 연구는 광밴드갭 레이저에 국한되었다. 이 논문에서 우리는 다른 형태의 광결정 레이저인 광밴드 가장자리 레이저를 보이고자 한다. 공간적으로 광결정의 결함에 국한되는 광밴드갭 레이저와는 달리 광밴드 가장자리 레이저는 퓨리에 공간에서 웨이브벡터를 국소화시키고 광결정 패턴내에 정상파를 만든다. 따라서 작은 군속도로 인해 광자가 광결정 내에 오래 머물게 되고 광자와 물질의 상호작용이 커져서 광밴드 가장자리 레이저는 발진하게 된다.
본논문에서 보이는 2차원 프리 스탠딩 슬랩 구조에서 제작된 광밴드 가장자리 레이저는 높은 굴절율 차이로 인해 강한 되먹임을 가지게 된다. 이 광밴드 가장자리 레이저는 빛의 방출방향에 따라 크게 두가지로 나눌 수 있다. 하나는 슬랩을 따라 빛을 방출하는 in-plane-emitting 레이저이다. 이를 보이기 위해 비교적 품위값이 큰 사각격자를 선택해서 1.5μm 의 빛을 내는 InGaAsP 양자우물에 500 nm의 격자주기를 가진 공기구멍을 뚫어서 제작했다. 측정된 레이저의 모드 X2, M2의 파장과 편광을 3차원 평면파 전개법과 유한미분 시간영역법으로 구한 이론적 결과와 비교하여 모드를 확인하였다. 측정된 편광과 퓨리에 공간에서의 모드의 분포는 X2, M2 밴드 가장자리 모드의 되먹임 기작을 설명하고 in-plane-emitting형태 레이저의 방출을 설명한다. 그리고 본 논문에서는 in-plane-emitting형태 레이저가 슬랩 위아래로 나가는 광손실이 매우 작고 광밴드갭 레이저는 슬랩에 평행한 방향으로 광손실이 작은 것을 결합하여 다른 크기의 공기구멍을 가진 두개의 광결정으로 이뤄진 새로운 형태의 이종구조 광결정 레이저를 제안한다. 적외선 카메라로 관찰한 사진을 통해 제작된 레이저가 광밴드갭에 의해 국소화되는 것을 관찰하였다. 이 모드는 광밴드 가장자리 모드와 광밴드개 모드의 결합을 통해 50000이라는 상당히 높은 품위값을 가지고 있다.
본 논문에서는 격자 상수 900 nm를 가지는 삼각형 격자에서 surface-emitting형태의 광밴드 가장자리 레이저도 관찰하였다. 여기서 감마 점 광밴드 가장자리 모드의 수직방향으로 빛을 가두는 기작을 그룹 이론과 간섭을 통해 설명하였다. surface-emitting레이저의 측정된 먼장 모양은 주된 방출 방향은 슬랩에 수직에 가깝지만 정확한 수직방향의 방출은 금지됨을 보였다. 그리고 수직으로 좁은 분산각을 가지는 방출을 얻기 위해서 이차원 결합된 공진기 구조를 제안하였다. 두축에 대해 모두 양의 대칭성을 가지는 모드는 수직방출기가 될 수 있다. 실제로 헥사폴 같은 모드는 수직방향으로 빛을 방출한다. 이때, 헥사폴로 동작하는 단일세포 공진기를 적절히 2차원으로 배열하면 그 방출각을 더욱 줄일 수 있다. 우리는 이 연구를 통해 방출모양, 발진기작, 퓨리에 공간에서 모드의 분포 등과 같은 광밴드 가장자리 레이저의 특성들을 밝혔다. 나는 이와 같이 밝혀진 성질들이 다양한 형태의 광결정 소자를 제작하는 데 이용될 수 있을 것이라 믿는다.한국과학기술원 : 물리학과
Electrochemical fabrication of multi microelectrodes
No full text학위논문(석사) - 한국과학기술원 : 기계공학전공, 2004.2, [ v, 78 p. ]한국과학기술원 : 기계공학전공
Dielectric behavior of mixed crystals
No full text학위논문(석사) - 한국과학기술원 : 물리학과, 1986.2, [ [ii], 40 p. ]한국과학기술원 : 물리학과
MR rotary brake development with a permanent magnet
No full text학위논문(석사) - 한국과학기술원 : 기계공학과, 1998.2, [ 68 p. ]한국과학기술원 : 기계공학과
The Association Between the Supply of Primary Care Physicians and Population Health Outcomes in Korea
No full textBackground and Objectives: Several studies reported that primary care improves health outcomes for populations. The objective of this study was to examine the relationship between the supply of primary care physicians and population health outcomes in Korea. Methods: Data were extracted from the 2007 report of the Health Insurance Review, the 2005 report from the Korean National Statistical Office, and the 2008 Korean Community Health Survey The dependent variables were age-adjusted all-cause and disease-specific mortality rates, and independent variables were the supply of primary care physicians, the ratio of primary care physicians to specialists, the number of beds, socioeconomic factors (unemployment rate, local tax, education), population (population size, proportion of the elderly over age 65), and health behaviors (smoking, exercise, using seat belts rates). We used multivariate linear regression as well as ANOVA and t tests. Results: A higher number of primary care physicians was associated with lower all-cause mortality, cancer mortality, and cardiovascular mortality. However, the ratio of primary care physicians to specialists was not related to all-cause mortality. In addition, the relationship between socioeconomic variables and mortality rates was similar in strength to the relationship between the supply of primary care physicians and mortality rates. Accident mortality, suicide mortality, injection mortality, and perinatal mortality were not related to the supply of primary care physicians. Conclusions: The supply of primary care physicians is associated with improved health outcomes, especially in chronic diseases and cancer. However, other variables such as the socioeconomic factors and population factors seem to have a more significant influence on these outcomes.N
Design of ISOIEEE 11073 and HL7 Framework for Driver's Health Monitoring in Vehicles
No full textRecently, thanks to the rapid development ofcomputer convergence technology, driver monitoring systemwith various bionic sensor devices has become one of the mostpopular forms of technology to decrease the traffic accidents. Inthis paper, we present the issue of exploiting the driver's bionic data monitoring system by using ISO/IEEE 11073 and HL7 standard interfaces. The proposed system is based on the client and sever model, where the client agent encodes the health related data and server manager decodes the received message from the client. In order to gather the driver's health data, the client agent activates various bionic sensors which include not
only personal social information but also height, weight, body temperature, SPO2, blood pressure and etc. Every sensor device
is connected by configuring the wireless sensor network which is applicable to ZigBee or Bluetooth. After the health data is gathered in the remotely located database server, it can bemonitored by doctors or therapists for further investigations1
An approach for simplification of large equipment and skid B-rep model with assembly structure
No full text- …
