20 research outputs found
ν볡μ λν λ³Έμ§μ£Όμμ λ―Ώμμ΄ μ°λΉμ λ―ΈμΉλ μν₯
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Όλ¬Έ (μμ¬)-- μμΈλνκ΅ λνμ : μ¬λ¦¬νκ³Ό, 2015. 2. μ΅μΈμ² .Lay theories about happiness are pervasive in lay peoples everyday life. However, to date, despite lay peoples fascination with happiness, we know little about lay theories about happiness and its implications for well-being. The current research investigated lay theories about happiness within a framework of psychological essentialism. In Study 1 and 2, I developed and validated a new scale to assess the essentialist beliefs about happiness with three components: (1) the immutability, (2) the biological basis, and (3) the effort constructivism. In Study 3, I found that the essentialist beliefs about happiness were negatively correlated with well-being measures and with intention of happiness-seeking behaviors. To clarify the causal effect, in Study 4, I experimentally manipulated essentialist beliefs about happiness and revealed that viewing happiness in a perspective of essentialists significantly reduced intentions to engage in happiness exercises. In Study 5, a one-week intervention study was conducted to examine whether there exist moderating effects of the essentialist belief about happiness on the effectiveness of happiness-boosting interventions. The results showed that positive interventions yielded equal effectiveness. Implications for well-being are discussed.Abstract Ρ
Introduction 1
Study 1 10
Method 10
Results & Discussion 11
Study 2 15
Method 15
Results & Discussion 18
Study 3 23
Method 23
Results & Discussion 25
Study 4 29
Method 29
Results & Discussion 31
Study 5 37
Method 38
Results & Discussion 41
General Discussion 46Maste
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Όλ¬Έ (λ°μ¬)-- μμΈλνκ΅ λνμ : 곡과λν ννμ물곡νλΆ, 2018. 2. κΉλν¬.With increasing concerns about the depletion of fossil fuels and global warming, various researches on sustainable and renewable energy have attracted much attention. Hydrogen has been considered as one of the most advantageous energy carriers because of its high energy density, eco-friendliness, and abundance. Steam reforming of natural gas is the predominant means of producing hydrogen due to its high hydrogen conversion efficiency and excellent economical advantage. Nickel-based catalysts are known to show high activity in the steam reforming of natural gas. However, nickel-based catalysts retain weak resistance toward catalyst deactivation caused by nickel sintering and carbon deposition. Therefore, it is important to develop a new preparation method for nickel-based catalyst to achieve high catalytic activity and enhanced stability in the steam reforming of natural gas.
In this work, in order to achieve efficient catalyst system for steam reforming of natural gas, mesoporous nickel/alumina catalysts were designed by various catalyst compositions such as the addition of alkaline earth metal and vanadium, and preparation methods such as a supercritical CO2 drying method and the use of butyric acid.
First, A series of mesoporous alkaline earth metal-promoted nickel-alumina xerogel (M/NA, M = Mg, Ca, Sr, and Ba) catalysts were prepared by a single-step epoxide-driven sol-gel method and a subsequent incipient wetness impregnation method. For reference, a nickel-alumina xerogel catalyst without promoter (NA) was prepared by a single-step epoxide-driven sol-gel method. Hydrogen chemisorption analyses showed that nickel surface area of reduced catalysts decreased in the order of Mg/NA > Sr/NA > Ca/NA > NA > Ba/NA. In the hydrogen production by steam reforming of natural gas, the catalytic performance of NA and M/NA catalysts was well correlated with the nickel surface area of the catalystsnatural gas conversion and hydrogen yield increased with increasing nickel surface area. Among the catalysts tested, Mg/NA catalyst with the highest nickel surface area showed the best catalytic performance. The amount of carbon deposition on the used M/NA catalysts was less than that on the used NA catalyst.
In order to improve the best catalyst Mg/NA above, magnesium-doped mesoporous nickel-alumina aerogel catalyst (Mg/NAA) was prepared by a single-step epoxide-driven sol-gel method and a subsequent supercritical CO2 drying followed by an incipient wetness impregnation method. For comparison, magnesium-doped mesoporous nickel-alumina xerogel catalyst (Mg/NAX) was prepared by the similar method of Mg/NA above. Surface area, pore volume, and average pore dimeter of Mg/NAA catalysts were larger than those of Mg/NAX catalyst due to suppressed collapse of nickel-alumina gel network during the drying step. Nickel surface area and nickel dispersion of reduced catalysts were better in Mg/NAA catalyst than in Mg/NAX catalyst. In the CH4-TPD analyses, CH4 affinity of Mg/NAA catalyst was higher than that of Mg/NAX catalyst. In the hydrogen production by steam reforming of natural gas, Mg/NAA catalyst with the higher nickel dispersion and high CH4 affinity showed the better catalytic performance than Mg/NAX catalyst in terms of natural gas conversion and hydrogen yield.
Vanadium-nickel-alumina catalysts with different vanadium loading (xVNA, x = 0, 0.5, 1.0, 1.5, and 2.0) were prepared by a single-step sol-gel method. TPR analyses revealed that the addition of vanadium increased reducibility of xVNA catalysts. From XRD analyses of reduced xVNA catalysts, it was found that an appropriate amount of vanadium reduced nickel crystallite size. In the hydrogen production by steam reforming of natural gas, natural gas conversion and hydrogen yield showed volcano-shaped trends with respect to vanadium loading. Among the catalysts, vanadium-nickel-alumina catalyst with 1.0 wt% vanadium, which retained the smallest crystallite size of metallic nickel, showed the best catalytic performance.
A series of butyric acid (BA)-assisted nickel/alumina catalysts (denoted as xBAN/A) with different butyric acid/Ni molar ratio (x) were prepared by an impregnation method. xBAN/A catalysts with an appropriate amount of butyric acid showed the enhanced nickel dispersion because of steric hindrance of butyric acid shell surrounding nickel particle. Addition of butyric acid also increased methane adsorption capacity of the catalysts, which was directly related to the catalytic performance. In the steam reforming of natural gas, both natural gas conversion and hydrogen yield showed volcano-shaped trends with respect to butyric acid/Ni molar ratio (x). Natural gas conversion and hydrogen yield increased with increasing nickel dispersion. Among the catalysts tested, 0.25BAN/A catalyst with the highest nickel dispersion exhibited the best catalytic performance in the steam reforming of natural gas.
In summary, various nickel/alumina catalysts were designed to produce hydrogen by steam reforming of natural gas. In order to investigate the effect of physicochemical properties of the catalysts on catalytic performance in the steam reforming of natural gas, several characterizations such as N2 adsorption-desorption, XRD, TPR, TEM, SEM, H2-TPD, CH4-TPD, and FT-IR analyses were conducted. It was concluded that nickel dispersion played a crucial role in determining the catalytic performance in the hydrogen production by steam reforming of natural gas.νμ μ°λ£μ κ³ κ°κ³Ό μ§κ΅¬ μ¨λνμ λν μ°λ €κ° 컀μ§μ λ°λΌ μ§μ κ°λ₯ν μ μ¬μ μλμ§μ λν μ°κ΅¬κ° νλ°ν μ§νλκ³ μλ€. μ¬λ¬ μ μ¬μ μλμ§ μ€μμλ μμλ μλμ§ λ°λκ° ν¬κ³ νκ²½ μΉνμ μ΄λ©° 맀μ₯λμ΄ νλΆνκΈ° λλ¬Έμ κ°μ₯ μ°μν μλμ§ μ λ¬ λ§€μ²΄ μ€μ νλλ‘ κ°κ΄μ λ°κ³ μλ€. μμλ₯Ό μμ°νλ λ°©λ²μΌλ‘λ μλμ§ μ νμ¨μ΄ λκ³ κ²½μ μ±μ΄ ν° μ²μ°κ°μ€μ μμ¦κΈ° κ°μ§ λ°μμ΄ μ΄μ©λκ³ μλ€. μ²μ°κ°μ€μ μμ¦κΈ° κ°μ§ λ°μμλ λμΌκ³ μ΄λ§€κ° λμ λ°μ νμ±μ λνλΈλ€κ³ μλ €μ Έ μλ€. κ·Έλ¬λ λμΌκ³ μ΄λ§€λ λμΌ μκ²° λ° νμ μΉ¨μ μ μν λΉνμ±νμ μ·¨μ½νλ€λ λ¨μ μ΄ μλ€. λ°λΌμ λμ λ°μ νμ±κ³Ό μ°μν μμ μ±μ κ°λ μ κ· μ΄λ§€λ₯Ό κ°λ°νλ κ²μ΄ λ§€μ° μ€μνλ€κ³ ν μ μλ€.
λ³Έ μ°κ΅¬μμλ μ²μ°κ°μ€μ μμ¦κΈ° κ°μ§ λ°μμμ λμΌ/μ루미λ μ΄λ§€μ ν¨μ¨ ν₯μμ μν΄ μ칼리 ν κΈμ 첨κ°, μ΄μκ³ μ΄μ°ννμ 건쑰λ², λ°λλ 첨κ°, λΆν°λ₯΄ μ°μ μ΄μ©ν ν¨μΉ¨λ² λ±μ μ΄μ©νμλ€.
μ°μ , λ¨μΌκ³΅μ μνμ¬μ΄λ μ λ μ‘Έ-κ²λ² λ° μ΄κΈ°μ΅μ€ν¨μΉ¨λ²μΌλ‘ μ칼리 ν κΈμμ΄ μ²¨κ°λ μ€νκΈ°κ³΅μ± λμΌ-μ루미λ μ λ‘μ € (M/NA, M = Mg, Ca, Sr λ° Ba) μ΄λ§€λ₯Ό μ μ‘°νμλ€. λΉκ΅λ₯Ό μν΄ μ칼리 ν κΈμμ΄ μ²¨κ°λμ§ μμ μ€νκΈ°κ³΅μ± λμΌ-μ루미λ μ λ‘μ € (NA) μ΄λ§€λ₯Ό λ¨μΌκ³΅μ μνμ¬μ΄λ μ λ μ‘Έ-κ²λ²μΌλ‘ μ μ‘°νμλ€. μμ ν‘μ°© λΆμ κ²°κ³Ό λμΌ νλ©΄μ μ Mg/NA > Sr/NA > Ca/NA > NA > Ba/NAμ μμλ‘ κ°μνλ κ²μ νμΈν μ μμλ€. NA μ΄λ§€μ M/NA μ΄λ§€λ₯Ό μ²μ°κ°μ€μ μμ¦κΈ° κ°μ§ λ°μμ μ μ©μν¨ κ²°κ³Ό, μ΄λ§€ νμ±κ³Ό λμΌ νλ©΄μ μ΄ μμ μκ΄κ΄κ³λ₯Ό λνλ΄λ κ²μ νμΈν μ μμλ€. μ μ‘°λ μ΄λ§€ μ€μμ λμΌ νλ©΄μ μ΄ κ°μ₯ λμ Mg/NAκ° κ°μ₯ λμ λ°μ νμ±μ λνλ΄μλ€. λ°μ ν μ΄λ§€μ νμλ λΆμ κ²°κ³Ό M/NA μ΄λ§€κ° NA μ΄λ§€μ λΉν΄ νμ μΉ¨μ μ΄ μ κ² μΌμ΄λ κ²μ νμΈνμλ€.
μκΈ° μ΄λ§€ μ€ κ°μ₯ μ°μν μ±λ₯μ λνλΈ Mg/NA μ΄λ§€λ₯Ό λ κ°μ νκΈ° μν΄ λ¨μΌκ³΅μ μνμ¬μ΄λ μ λ μ‘Έ-κ²λ² λ° μ΄μκ³ μ΄μ°ννμ 건쑰λ²κ³Ό μ΄κΈ°μ΅μ€ν¨μΉ¨λ²μ μ΄μ©νμ¬ λ§κ·Έλ€μμ΄ μ²¨κ°λ μ€νκΈ°κ³΅μ± λμΌ-μ루미λ μμ΄λ‘μ € (Mg/NAA) μ΄λ§€λ₯Ό μ μ‘°νμλ€. λΉκ΅λ₯Ό μν΄ μκΈ° Mg/NA μ΄λ§€μ μ μ¬ν λ°©λ²μΌλ‘ λ§κ·Έλ€μμ΄ μ²¨κ°λ μ€νκΈ°κ³΅μ± λμΌ-μ루미λ μ λ‘μ € (Mg/NAX) μ΄λ§€λ₯Ό μ μ‘°νμλ€. μ΄μκ³ μ΄μ°ννμ 건쑰λ²μ μ΄μ©νμ¬ μ μ‘°λ Mg/NAA μ΄λ§€κ° Mg/NAX μ΄λ§€μ λΉν΄ λμ λΉνλ©΄μ , ν° κΈ°κ³΅ λΆνΌ λ° κΈ°κ³΅ ν¬κΈ°λ₯Ό λνλ΄μλ€. μ΄λ μμ΄λ‘μ €μ 건쑰 κ³Όμ μμ λμΌ-μ루미λ κ²μ λ€νΈμν¬ κ΅¬μ‘°κ° λΆκ΄΄λλ νμμ΄ μ΅μ λμκΈ° λλ¬Έμ΄λΌκ³ νλ¨λλ€. λΉνλ©΄μ μ΄ λμ Mg/NAA μ΄λ§€λ Mg/NAX μ΄λ§€μ λΉν΄ λμ λμΌ νλ©΄μ λ° λμ λμΌ λΆμ°λλ₯Ό λνλ΄μλ€. λ©ν μΉμ¨ νμ°© λΆμ κ²°κ³Ό Mg/NAA μ΄λ§€κ° Mg/NAX μ΄λ§€μ λΉν΄ μ°μν λ©ν μΉνλλ₯Ό 보μ΄λ κ²μ νμΈνμλ€. Mg/NAA μ΄λ§€μ Mg/NAX μ΄λ§€λ₯Ό μ²μ°κ°μ€μ μμ¦κΈ° κ°μ§ λ°μμ μ μ©μν¨ κ²°κ³Ό λμ λμΌ λΆμ°λ λ° λ©ν μΉνλλ₯Ό κ°λ Mg/NAA μ΄λ§€κ° λ λμ μ²μ°κ°μ€ μ νμ¨κ³Ό μμ μμ¨μ λνλ΄λ κ²μ νμΈν μ μμλ€.
λ€μν λ°λλ λ΄μ§λμ κ°λ μ€νκΈ°κ³΅μ± λ°λλ-λμΌ-μ루미λ μ μ‘°μ € (xVNA, x = 0, 0.5, 1.0, 1.5 λ° 2.0) μ΄λ§€λ₯Ό λ¨μΌκ³΅μ μνμ¬μ΄λ μ λ μ‘Έ-κ²λ²μ μ΄μ©νμ¬ μ μ‘°νμλ€. TPR λΆμ κ²°κ³Ό λ°λλμ΄ μ²¨κ°λ μ΄λ§€μμ λμΌ νμμ±μ΄ ν₯μλ κ²μ νμΈνμλ€. νμλ μ΄λ§€μ XRD λΆμμ ν΅ν΄ μ μ ν μμ λ°λλμ΄ μ²¨κ°λμμ κ²½μ° λμΌ κ²°μ ν¬κΈ°κ° μμμ§λ κ²μ νμΈν μ μμλ€. xVNA μ΄λ§€λ₯Ό μ²μ°κ°μ€μ μμ¦κΈ° κ°μ§ λ°μμ μ μ©μν¨ κ²°κ³Ό μ²μ°κ°μ€ μ νμ¨κ³Ό μμ μμ¨μ΄ λ°λλ λ΄μ§λμ λ°λΌ νμ°νμ κ°νμ λνλ΄μλ€. μ μ‘°λ μ΄λ§€ μ€μμ 1.0 wt%μ λ°λλμ΄ λ΄μ§λ μ΄λ§€κ° κ°μ₯ μμ λμΌ κ²°μ ν¬κΈ° λ° κ°μ₯ μ°μν λ°μνμ±μ λνλ΄μλ€.
ν¨μΉ¨ κ³Όμ μμ λ€μν λΆν°λ₯΄ μ°/λμΌ λͺ° λΉ(x)λ₯Ό μ μ©ν μ€νκΈ°κ³΅μ± λμΌ/μ루미λ μ λ‘μ € (xBAN/A) μ΄λ§€λ₯Ό μ μ‘°νμλ€. ν¨μΉ¨ κ³Όμ μμ μ μ ν μμ λΆν°λ₯΄ μ°μ΄ 첨κ°λμμ κ²½μ° λμΌ μ
μλ₯Ό λλ¬μΌ λΆν°λ₯΄ μ°μ μ
체μ₯μ λ‘ μΈν΄ λμΌ λΆμ°λκ° ν₯μλλ κ²μ νμΈν μ μμλ€. μ μ ν μμ λΆν°λ₯΄ μ°μ΄ 첨κ°λ κ²½μ° μ΄λ§€ λ°μ νμ±κ³Ό μ§μ μ μΈ κ΄λ ¨μ±μ΄ μλ λ©ν ν‘μ°© λ₯λ ₯ λν ν₯μλλ κ²μ νμΈνμλ€. μ μ‘°λ μ΄λ§€λ₯Ό μ²μ°κ°μ€μ μμ¦κΈ° κ°μ§ λ°μμ μ μ©μν¨ κ²°κ³Ό λ°μ νμ±μ΄ λΆν°λ₯΄ μ°/λμΌ λͺ° λΉμ λ°λΌ νμ°νμ κ°νμ λνλ΄μλ€. μ μ‘°λ μ΄λ§€ μ€μμ 0.25BAN/A μ΄λ§€κ° κ°μ₯ λμ λμΌ λΆμ°λ λ° λ°μνμ±μ λνλ΄μλ€.
μμ½νλ©΄, λ³Έ μ°κ΅¬μμλ λ€μν λμΌ/μ루미λ μ΄λ§€λ₯Ό μ μ‘°νμ¬ μ²μ°κ°μ€μ μμ¦κΈ° κ°μ§ λ°μμ μ μ©μμΌ°λ€. μ΄λ§€μ 물리ννμ νΉμ±μ΄ μ²μ°κ°μ€μ μμ¦κΈ° κ°μ§ λ°μ νμ±μ λ―ΈμΉλ μν₯μ μ€λͺ
νκΈ° μν΄ μ§μ ν‘νμ°©, XRD, TPR, TEM, SEM, H2-TPD, CH4-TPD λ° FT-IR λ±μ λ€μν λΆμμ μννμλ€. κ²°κ³Όμ μΌλ‘, λμΌμ λΆμ°λκ° μ²μ°κ°μ€μ μμ¦κΈ° κ°μ§ λ°μμ ν΅ν μμ μμ°μμ μ΄λ§€ νμ±μ κ²°μ μ§λ μ€μν μΈμμμ νμΈνμλ€.Chapter 1. Introduction 1
1.1. Hydrogen energy 1
1.2. Steam reforming of natural gas 5
1.3. Objective 9
Chapter 2. Experimental 12
2.1. Preparation of catalysts 12
2.1.1. Preparation of mesoporous alkaline earth metal-doped nickel-alumina xerogel catalyst 12
2.1.2. Preparation of mesoporous nickel-alumina aerogel catalyst by a supercritical CO2 drying method 15
2.1.3. Preparation of mesoporous vanadium-nickel-alumina xerogel catalyst 18
2.1.4. Preparation of mesoporous nickel/alumina catalyst by a butyric acid-assisted impregnation method 20
2.2. Characterization 22
2.2.1. Physicochemical properties 22
2.2.2. Crystalline structure 22
2.2.3. Reducibility 22
2.2.4. Morphological feature 23
2.2.5. H2 and CH4 adsorption studies on reduced catalysts 23
2.2.6. Carbon deposition on used catalysts 25
2.2.7. Chemical states of elements 25
2.3. Hydrogen production by steam reforming of natural gas 26
Chapter 3. Results and Discussion 29
3.1. Mesoporous alkaline earth metal-doped nickel-alumina xerogel catalyst 29
3.1.1. Textural properties of calcined catalysts 29
3.1.2. Crystalline structures of calcined catalysts 32
3.1.3. Reducibility and metal-support interaction 34
3.1.4. Characterization of reduced catalysts 36
3.1.5. Catalytic performance in the steam reforming of natural gas 41
3.1.6. Characterization of used catalysts 45
3.2. Mesoporous nickel-alumina aerogel catalyst by a supercritical CO2 drying method 47
3.2.1. Textural properties of calcined catalysts 47
3.2.2. Crystalline structure of calcined catalysts 51
3.2.3. Reducibility and metal-support interaction 53
3.2.4. Characterization of reduced catalysts 55
3.2.5. Catalytic performance in the steam reforming of natural gas 63
3.3. Mesoporous vanadium-nickel-alumina xerogel catalyst 65
3.3.1. Textural properties of calcined catalysts 65
3.3.2. Crystalline structure of calcined catalysts 68
3.3.3. Reducibility and metal-support interaction 70
3.3.4. Characterization of reduced catalysts 73
3.3.5. Catalytic performance in the steam reforming of natural gas 76
3.4. Mesoporous nickel/alumina catalyst by a butyric acid-assisted impregnation method 81
3.4.1. Surface chemical state of as-prepared catalysts 81
3.4.2. Textural properties of calcined catalysts 84
3.4.3. Crystalline structure of calcined and reduced catalysts 87
3.4.4. Morphology of calcined and reduced catalysts 89
3.4.5. Reducibility and metal-support interaction 92
3.4.6. Characterization of reduced catalysts 94
3.4.7. Catalytic performance in the steam reforming of natural gas 101
Chapter 4. Conclusions 106
Bibliography 109
μ΄ λ‘ 114Docto
Variable Breast Conditions: Comparison of Conventional and Real-time Compound Ultrasonography
OBJECTIVES:
To illustrate and compare the appearances of variable breast conditions by conventional and real-time spatial compound images.
METHODS:
Cases illustrative of a broad range of breast conditions were collected. Each image pair consisted of conventional and real-time compound images with a stationary probe to maintain an identical projection.
RESULTS:
The various breast conditions, including normal anatomic structures and abnormal lesions, were evaluated and compared by conventional and real-time compound images. The real-time compound images revealed more realistic and clear images with reduced artifacts.
CONCLUSIONS:
Real-time compound images are superior to conventional images of normal and abnormal breast conditions. Real-time compound imaging is a good technique for evaluating the breast state.ope
Focal Fibrosis of the Breast Diagnosed by a Sonographically Guided Core Biopsy of Nonpalpable Lesions Imaging Findings and Clinical Relevance
OBJECTIVE: The purpose of this study was to evaluate the frequency of focal fibrosis of the breast diagnosed by a sonographically guided core biopsy of nonpalpable lesions, to characterize imaging features, and to evaluate their clinical relevance.
METHODS: In a retrospective review of 724 lesions that underwent sonographically guided core biopsy of nonpalpable breast lesions, 62 cases had a diagnosis of focal fibrosis. Two radiologists analyzed the sonographic and mammographic findings according to the Breast Imaging Reporting and Data System. The results were compared with histologic findings at surgery or imaging findings during surveillance.
RESULTS: The incidence of focal fibrosis was 8.6% (62/724). Sonographic films were available in 56 cases, so 56 cases were reviewed for their sonographic findings. Among the mammograms reviewed, 64.7% (33/51) had negative findings. Among the sonograms reviewed, the most common features were oval shape (32/56, 57.1%), parallel orientation (36/56, 64.3%), microlobulated margin (24/56, 42.9%), abrupt interface (50/56, 89.3%), isoechoic pattern (42/56, 75.0%), and a lack of posterior acoustic features (45/56, 80.4%). The Breast Imaging Reporting and Data System final assessment was category 3 in 27 (48.2%) and category 4 in 29 (51.8%). Most of the category 4 lesions were category 4A (26/29, 89.7%). Surgical excision (n = 7) and follow-up for at least 1 year (n = 49) showed no malignancy.
CONCLUSIONS: Focal fibrosis was found in 8.6% by a sonographically guided core biopsy of nonpalpable breast lesions. Most of the lesions were categorized as probably benign (category 3) or having a low suggestion of malignancy (category 4A). Focal fibrosis diagnosed at core biopsy can be managed with a 6-month follow-up protocol.ope
μ΄μνμμ μ μ±μ΄ μμ¬λμλ κ³ ν νΉμ μ¬ λΆμ
Purpose: The objective of our study was to reconsider the usefulness of many characteristics on US for differentiating
benign and malignant masses.
Materials and Methods: From February 2000 through April 2001, we retrospectively evaluated 309 solid
breast nodules (282 patients) on US, which were categorized suspicious malignancy or suggestive malignancy,
prospectively and confirmed by core-needle biopsy or operation. We analyzed the solid nodules,
according to eight known malignant characteristics, which have been described in Stavros et alβs study.
The sensitivity, specificity, positive predictive value, negative predictive value and odds ratio were calculated.
Results: Among 309 lesions diagnosed as suspicious or suggestive malignancy prospectively, 140 lesions (45.31
%) were confirmed as malignant nodules. The mean number of these findings per one nodule was 2.5
(benign nodule: 2.2, malignant nodule: 2.7). Spiculated margin, marked hypoechogenecity, shadowing,
and punctate microcalcifications were statistically significant. Odds ratio of punctate calcifications is the
highest (19.5), followed by marked hypoechogenecity (3.1), spiculated margin (1.9), spiculated, microlobulated
or angular margin (1.7), taller than wide (1.2), additional findings (1), and shadowing (0.6).
Conclusion: Ultrasonographic findings are useful to differentiate malignant from benign solid nodules by that
of Stavros et alβs.ope
Hydrogen production by steam reforming of liquefied natural gas (LNG) over mesoporous nickel-alumina catalysts: Effect of alkaline earth metal addition
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νμλ€. NA μ΄λ§€μ μ΄κΈ°μ΅μ€ν¨μΉ¨λ²μ ν΅ν΄ μ‘°μ΄λ§€λ‘ μ칼리 ν κΈμ(Mg, Ca, Sr λ° Ba)μ λ΄μ§νμ¬ M/NA (M = Mg, Ca, Sr λ° Ba)λ‘ λͺ
λͺ
νμλ€. μκΈ° μ΄λ§€λ₯Ό μ²μ°κ°μ€μ μμ¦κΈ° κ°μ§ λ°μμ ν΅ν μμ μμ°μ μ μ©μμΌ μ칼리 ν κΈμ μ‘°μ΄λ§€κ° μ΄λ§€μ λ°μ νμ±μ λ―ΈμΉλ μν₯μ μ‘°μ¬νμλ€. μ μ‘°λ μ΄λ§€μ νλ©΄μ λ° κΈ°κ³΅ λΆνΌλ₯Ό μΈ‘μ νκΈ° μν΄ μ§μ ν‘νμ°© λΆμμ μννμκ³ , μ‘°μ΄λ§€κ° λ΄μ§λμμ κ²½μ° κΈ°κ³΅μ΄ λ§νλ©΄μ νλ©΄μ λ° κΈ°κ³΅ λΆνΌκ° κ°μνλ κ²μ νμΈνμλ€. μ΄λ§€μ κ²°μ μμ XRD λΆμμ ν΅ν΄ νμΈνμκ³ , NAμ M/NA μ΄λ§€ λͺ¨λ λμΌ μ루미λ€μ΄νΈμ ν΄λΉνλ νμ ν¨ν΄μ λνλ΄μλ€. μ΄λ§€μ νμ± κΈμ-λ΄μ²΄ κ° μνΈμμ©μ νμΈνκΈ° μν΄ TPR λΆμμ μννμκ³ , μ‘°μ΄λ§€μ λ΄μ§ μ¬λΆμ μκ΄μμ΄ λͺ¨λ μ΄λ§€μμ νλ©΄ λμΌ μ루미λ€μ΄νΈ μμ΄ λνλ¬λ€. μμννν‘μ°© λΆμμ ν΅ν΄ νμλ μ΄λ§€μ λμΌ νλ©΄μ μ μΈ‘μ νμμΌλ©°, Mg/NA > Sr/NA > Ca/NA > NA > Ba/NA μμλ‘ λμΌ νλ©΄μ μ΄ κ°μνλ κ²μ νμΈνμλ€. μ΄λ§€ νμ±μ LNG μ νμ¨κ³Ό μμ μμ¨λ‘ νκ°νμκ³ , μ΄λ§€μ λμΌ νλ©΄μ μ΄ μ¦κ°ν μλ‘ LNG μ νμ¨ λ° μμ μμ¨μ΄ μ¦κ°νλ κ²½ν₯μ 보μμΌλ©° μ μ‘°λ μ΄λ§€ μ€ Mg/NA μ΄λ§€μ νμ±μ΄ κ°μ₯ λκ² λνλ¬λ€. μ¬μ©λ μ΄λ§€μ νμ μΉ¨μ λμ CHNS λΆμμ ν΅ν΄ μΈ‘μ λμμΌλ©°, μ칼리 ν κΈμμ΄ μ²¨κ°λμ§ μμ μ΄λ§€μ λΉν΄ μ칼리 ν κΈμμ΄ μ²¨κ°λ μ΄λ§€μ νμ μΉ¨μ λμ΄ λ μ κ² λνλ¬λ€. λ°λΌμ μκΈ° μ€ν κ²°κ³Όλ‘λΆν°, μ칼리 ν κΈμμ΄ μ€νκΈ°κ³΅μ± λμΌ-μ루미λ μ λ‘μ € μ΄λ§€μ μ‘°μ΄λ§€λ‘ μ΄μ©λμμ κ²½μ° μ²μ°κ°μ€μ μμ¦κΈ° κ°μ§λ°μμμ λ°μ νμ± λ° μ΄λ§€ λΉνμ±νμ λ―ΈμΉλ μν₯μ νμΈν μ μμλ€.
μκΈ° μ΄λ§€ μ€ νμ±μ΄ κ°μ₯ μ’μλ Mg/NA μ΄λ§€λ₯Ό κ°μ νκΈ° μν΄ λ¨μΌκ³΅μ μνμ¬μ΄λ μ λ μ‘Έ-κ²λ²κ³Ό μ΄μκ³ μ΄μ°ννμ 건쑰λ²μ λ° μ΄κΈ°μ΅μ€ν¨μΉ¨λ²μ μ΄μ©νμ¬ λ§κ·Έλ€μμ΄ λ΄μ§λ λμΌ-μ루미λ μμ΄λ‘μ € μ΄λ§€(Mg/NAA)λ₯Ό μ μ‘°νμλ€. Mg/NAA μ΄λ§€μμ λΉκ΅λ₯Ό μν΄ λμΌ-μ루미λ μ λ‘μ €μ λ΄μ²΄λ‘ μ΄μ©ν Mg/NAX μ΄λ§€λ₯Ό μκΈ° Mg/NA μ΄λ§€μ μ μ¬νκ² μ μ‘°νμλ€. μκΈ° μ΄λ§€λ₯Ό μ²μ°κ°μ€μ μμ¦κΈ° κ°μ§ λ°μμ ν΅ν μμ μμ°μ μ μ©μμΌ μ΄λ§€μ 기곡 νΉμ±μ΄ μ΄λ§€μ λ°μ νμ±μ λ―ΈμΉλ μν₯μ μ‘°μ¬νμλ€. μ μ‘°λ μ΄λ§€μ νλ©΄μ λ° κΈ°κ³΅ λΆνΌλ₯Ό μΈ‘μ νκΈ° μν΄ μ§μ ν‘νμ°© λΆμμ μννμκ³ , Mg/NAA μ΄λ§€κ° Mg/NAX μ΄λ§€μ λΉν΄ νλ©΄μ , 기곡 λΆνΌ λ° νκ· κΈ°κ³΅ μ§κ²½μ΄ λ ν¬κ² λνλ¨μ νμΈνμλ€. μ΄λ§€μ κ²°μ μμ XRD λΆμμ ν΅ν΄ νμΈνμκ³ , NAμ M/NA μ΄λ§€ λͺ¨λ λμΌ μ루미λ€μ΄νΈμ ν΄λΉνλ νμ ν¨ν΄μ λνλ΄μλ€. μ΄λ§€μ νμ± κΈμ-λ΄μ²΄ κ° μνΈμμ©μ νμΈνκΈ° μν΄ TPR λΆμμ μννμκ³ , Mg/NAA μ΄λ§€κ° Mg/NAX μ΄λ§€μ λΉν΄ λ κ°ν κΈμ-μ§μ§μ²΄ μνΈμμ©μ λνλ΄λ κ²μ νμΈνλ€. μμννν‘μ°© λΆμμ ν΅ν΄ νμλ μ΄λ§€μ λμΌ νλ©΄μ μ μΈ‘μ νμμΌλ©°, Mg/NAA μ΄λ§€κ° Mg/NAX μ΄λ§€μ λΉν΄ λμΌ λΆμ°λκ° λ ν¬κ² λνλ κ²μ νμΈν μ μμλ€. CH4-TPD λΆμ κ²°κ³Ό Mg/NAA μ΄λ§€κ° Mg/NAX μ΄λ§€μ λΉν΄ λ©νκ³Όμ μΉνλκ° λ λμ κ²μ νμΈν μ μμλ€. μ²μ°κ°μ€μ μμ¦κΈ° κ°μ§ λ°μμ μνν κ²°κ³Ό λμΌ λΆμ°λκ° λκ³ λ©νκ³Όμ μΉνλ ₯μ΄ κ°ν Mg/NAA μ΄λ§€μ LNG μ νμ¨κ³Ό μμ μμ¨μ΄ Mg/NAX μ΄λ§€λ³΄λ€ ν₯μλ κ²μ νμΈνμλ€. λ³Έ μ°κ΅¬ κ²°κ³Όλ₯Ό ν΅νμ¬, κ³ νμ± μ₯μλͺ
μ μ²μ°κ°μ€μ μμ¦κΈ° κ°μ§ λ°μμ© μ΄λ§€λ₯Ό κ°λ°νκ³ , μ΄λ§€μ λ°μ νμ±κ³Ό λμΌ λΆμ°λμμ μκ΄ κ΄κ³λ₯Ό κ·λͺ
ν μ μμλ€.1. μ λ‘ 1
2. μ΄λ‘ λ° λ°°κ²½ 4
3. μ€ ν 8
3.1. μ΄λ§€ μ μ‘° 8
3.1.1. μμ½ 8
3.1.2. μ€νκΈ°κ³΅μ± λμΌ-μ루미λ μ λ‘μ € μ΄λ§€(NA)μ μ μ‘° 8
3.1.3. μ칼리 ν κΈμμ΄ μ‘°μ΄λ§€λ‘ μ΄μ©λ μ€νκΈ°κ³΅μ± λμΌ-μ루미λ μ λ‘μ € μ΄λ§€(M/NA, M = Mg, Ca, Sr λ° Ba) μ μ‘° 9
3.1.4. λ§κ·Έλ€μμ΄ μ‘°μ΄λ§€λ‘ μ΄μ©λ λμΌ-μ루미λ μμ΄λ‘μ € μ΄λ§€(Mg/NAA)μ μ μ‘° 10
3.2. μ΄λ§€ νΉμ± λΆμ 12
3.2.1. N2 adsorption-desorption mesurement 12
3.2.2. ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectroscopy) 12
3.2.3. XRD (X-Ray Diffraction) 12
3.2.4. H2-TPR (Temperature Programmed Reduction) 12
3.2.5. Hydrogen-chemisorption measurement 13
3.2.6. TEM (Transmission Electron Microscopy) 13
3.2.7. CHNS (Carbon, hydrogen, nitrogen and sulfur) elemental analyses 13
3.2.8. CH4-TPD (Temperature Programmed Reduction) 14
3.3. μ²μ°κ°μ€μ μμ¦κΈ° κ°μ§ λ°μμ ν΅ν μμ μμ° 15
3.3.1. μ²μ°κ°μ€μ μμ¦κΈ° κ°μ§ λ°μ μμ€ν
15
3.3.2. μ΄λ§€λ₯Ό ν΅ν μ²μ°κ°μ€μ μμ¦κΈ° κ°μ§ λ°μμ κ΅¬μ± 15
4. μ€ν κ²°κ³Ό λ° κ³ μ°° 20
4.1. M/NA (M = Mg, Ca, Sr λ° Ba) μ΄λ§€λ₯Ό μ΄μ©ν μ²μ°κ°μ€μ μμ¦κΈ° κ°μ§ λ°μ 20
4.1.1. μ΄λ§€μ 물리ννμ νΉμ± νμΈ 20
4.1.2. μμ±λ μ΄λ§€μ κ²°μ ꡬ쑰 νμΈ 21
4.1.3. μμ±λ μ΄λ§€μ κΈμ-μ§μ§μ²΄ μνΈμμ© νμΈ 22
4.1.4. νμλ μ΄λ§€μ νΉμ± λΆμ 23
4.1.5. μ²μ°κ°μ€μ μμ¦κΈ° κ°μ§ λ°μ νμ± 25
4.2. Mg/NAA μ΄λ§€λ₯Ό μ΄μ©ν μ²μ°κ°μ€μ μμ¦κΈ° κ°μ§ λ°μ 39
4.2.1. μ΄λ§€μ 물리ννμ νΉμ± νμΈ 39
4.2.2. μμ±λ μ΄λ§€μ κ²°μ ꡬ쑰 νμΈ 40
4.2.3. μμ±λ μ΄λ§€μ κΈμ-μ§μ§μ²΄ μνΈμμ© νμΈ 40
4.2.4. νμλ μ΄λ§€μ νΉμ± λΆμ 41
4.2.5. μ²μ°κ°μ€μ μμ¦κΈ° κ°μ§ λ°μ νμ± 43
5. κ²° λ‘ 55
μ°Έκ³ λ¬Έν 57
Abstract 63Maste
Gravity separation of Cu-speiss and slag using Knelson concentrator and vibrating ball bed method
Even though the hydrometallurgical residue of non-ferrous metals contains small amounts of gold and silver, the residue has been landfilled due to low economic feasibility. Nowadays pyrometallurgical processes were developed to recover valuable metals from the residue, and, in these processes, gold and silver could be concentrated to an amount comparable to the content of gold or silver concentrates. In the pyrometallurgical process, impurities such as Fe, SiO2, and Ca are separated into slag, while Cu, Pb, Au, Ag are reduced to a metal phase and then recovered by specific gravity separation in the molten state at a high temperature. When separation efficiency is low, slag is mixed into the speiss, which causes many problems in the process.
n this study, the slag mixed with the speiss obtained from the process was separated by conducting the specific gravity separation methods. In the case of the simulated sample experiment using the conventional Knelson concentrator, the separation efficiency decreased as the centrifugal force increased from 20% to 30%, and the possibility of specific gravity separation was confirmed. In the case of speiss mixed with slag, the separation efficiency was low at about 17%, indicating that it was difficult to separate specific gravity the materials. A newly designed Vibrating ball bed method using zirconia balls was investigated to separate the speiss and slag. As the number of particles increased, a particle interfere with the sinking of other particles. The separation efficiency increased to 100% at 22Hz (shaking power) with 3 limestones and 3 speiss, respectively.1. μ λ‘ 1
1.1 μ°κ΅¬ λ°°κ²½ 1
1.1.1 μμ°μ λ ¨μμ¬ μ²λ¦¬ λ°©λ² 2
1.1.2 μμ°μ λ ¨μμ¬ μ€ μ κ°κΈμμ κ°μΉ 3
1.1.3 μ€νμ΄μ€ μ€ μ κ°κΈμμ μ μ 4
1.2 μ°κ΅¬ λ΄μ© 5
2. μ΄λ‘ μ κ³ μ°° 6
2.1 μ΅μλΉμ€μ λ³ 6
2.1.1 λ¬μ¨ μ λ³κΈ°λ₯Ό μ΄μ©ν λΉμ€μ λ³ 7
2.2 건μλΉμ€μ λ³ 8
2.2.1 μ§λ₯΄μ½λμλ³Όμ μ΄μ©ν λΉμ€μ λ³ 8
3. λ¬μ¨ μ λ³κΈ°λ₯Ό μ΄μ©ν μ λ³ μ°κ΅¬ 10
3.1 μλ£μ 물리μ νΉμ± 10
3.1.1 λΉμ€ 10
3.1.2 μ
λ λΆν¬ 11
3.2 μλ£μ ννμ νΉμ± 14
3.2.1 ICP λΆμ 14
3.2.2 SEM-EDS λΆμ 16
3.2.3 XRF λΆμ 18
3.3 μ€ν λ°©λ² λ° μ‘°κ±΄ 19
3.3.1 λ¬μ¨ μ λ³κΈ°λ₯Ό μ΄μ©ν λΉμ€μ λ³ 19
3.4 λ¬μ¨ μ λ³κΈ° λΉμ€ λΆλ¦¬ κ²°κ³Ό 21
3.4.1 λͺ¨μ¬ μλ£λ₯Ό μ΄μ©ν λΉμ€ λΆλ¦¬ 21
3.4.2 μ μ μ€νμ΄μ€μ μ¬λκ·Έκ° νΌμ
λ μ€νμ΄μ€μ λΉμ€ λΆλ¦¬ 25
4. μ§λλ³ΌμΈ΅λ²μ μ΄μ©ν μ λ³ μ°κ΅¬ 27
4.1 μ§λ₯΄μ½λμλ³Όμ μ΄μ©ν λΆλ¦¬ 27
4.2 μ§λλ³ΌμΈ΅λ² μ΄μ©ν λΉμ€ λΆλ¦¬ κ²°κ³Ό 28
4.2.1 μ§λ μΈκΈ°μ λ°λ₯Έ μν μ£ΌκΈ° 28
4.2.2 μ
μ κ°μ λ° μ§λμΈκΈ°μ λ°λ₯Έ λΆλ¦¬ ν¨μ¨ 29
5. κ²°λ‘ 38
μ°Έκ³ λ¬Έν 40Maste
Intestinal Behçet's disease: breath-hold MR imaging
BACKGROUND: To determine the feasibility of magnetic resonance (MR) imaging in the evaluation of intestinal Behçet's disease.
METHODS: Eight patients diagnosed to have intestinal Behçet's disease prospectively underwent MR imaging. Five patients had previously undergone abdominal surgery for intestinal Behçet's disease 27-81 months previously. Breath-hold T2-weighted single-shot fast spin echo, T1-weighted multiplanar spoiled gradient recalled echo, and postgadolinium-enhanced fat-suppressed T1-weighted opposed-phase multiplanar spoiled gradient recalled echo images were obtained. MR findings were analyzed by three independent radiologists in terms of the presence and location of bowel wall thickening and ulcer, maximal bowel wall thickness, grade of bowel wall enhancement, and presence and nature of extraluminal manifestations. K statistics were used to evaluate interobserver variability.
RESULTS: Seven cases (88%), including the five cases with previous operations, demonstrated bowel thickening of more than 9 mm and increased enhancement. Ulcer was depicted in four cases (50%) in the terminal ileum or an anastomosis site. Three cases (38%) showed extraluminal manifestation, such as mesenteric infiltration around the involved bowel (two cases) and a sinus tract to subhepatic abscess from perforation (one case).
CONCLUSION: Breath-hold MR imaging is useful for the evaluation of bowel wall thickening, enhancement, mesentery infiltration, and abscess formation. Characteristic ulcerative lesions may be also depicted on T1- and T2-weighted breath-hold images. MR imaging is a useful method for postoperative follow-up study for the evaluation of recurrence.ope
Clinical evaluation of JPEG2000 compression for digital mammography
Medical images, such as computed radiography (CR), and digital mammographic images will require large storage facilities and long transmission times for picture archiving and communications system (PACS) implementation. American College of Radiology and National Equipment Manufacturers Association (ACR/NEMA) group is planning to adopt a JPEG2000 compression algorithm in digital imaging and communications in medicine (DICOM) standard to better utilize medical images. The purpose of the study was to evaluate the compression ratios of JPEG2000 for digital mammographic images using peak signal-to-noise ratio (PSNR), receiver operating characteristic (ROC) analysis, and the t-test. The traditional statistical quality measures such as PSNR, which is a commonly used measure for the evaluation of reconstructed images, measures how the reconstructed image differs from the original by making pixel-by-pixel comparisons. The ability to accurately discriminate diseased cases from normal cases is evaluated using ROC curve analysis. ROC curves can be used to compare the diagnostic performance of two or more reconstructed images. The t test can be also used to evaluate the subjective image quality of reconstructed images. The results of the t test suggested that the possible compression ratios using JPEG2000 for digital mammographic images may be as much as 15:1 without visual loss or with preserving significant medical information at a confidence level of 99%, although both PSNR and ROC analyses suggest as much as 80:1 compression ratio can be achieved without affecting clinical diagnostic performance.restrictio
Metastasis of primitive neuroectodermal tumor to the breast
We performed mammography and sonography on a 49-year-old woman who had a mass in her left axilla that had been present for 1 month and who had undergone excision of a primitive neuroectodermal tumor (PNET) on her back 1 year before. Mammography revealed 2 adjacent, dense nodules in the left breast and enlarged lymph nodes, without a fatty hilum or internal microcalcifications, in the left axilla. Sonography showed 2 round to oval, markedly hypoechoic nodules in the left breast and enlarged, markedly hypoechoic lymph nodes, without microcalcifications, in the left axilla. We then performed sonographically guided core biopsy. Histopathologic analysis of the specimens confirmed the presence of PNET in the left breast and axillary lymph nodes. The patient was then treated with chemotherapy. To our knowledge, this report is the first to describe radiologic findings of metastasis of PNET to the breast. Β© 2002 Wiley Periodicals, Inc. J Clin Ultrasound 30:374β377, 2002; Published online in Wiley InterScience (www.interscience.wiley.com).ope