New fitting formula for cosmic non-linear density distribution

We have measured the probability distribution function (PDF) of cosmic matter density field from a suite of N-body simulations. We propose the generalized normal distribution of version 2 (Nv2) as an alternative fitting formula to the well-known log-normal distribution. We find that Nv2 provides significantly better fit than the log-normal distribution for all smoothing radii (2, 5, 10, 25 [Mpc/h]) that we studied. The improvement is substantial in the underdense regions. The development of non- Gaissianities in the cosmic matter density field is captured by continuous evolution of the skewness and shifts parameters of the Nv2 distribution. We present the redshift evolution of these parameters for aforementioned smoothing radii and various background cosmology models. All the PDFs measured from large and high-resolution N-body simulations that we use in this study can be obtained from a Web site at https://astro.kias.re.kr/jhshin.Comment: Accepted for publication in Ap

Key Strains, Anger and Delinquency: The General Strain Theory Test on Sourth Korean Youths From Low-Income Households

General Strain Theory: Negative relations of strains create unpleasant emotions (e.g., anger and depression), which lead strained people to commit crimes as their coping methods. Strains are more likely to lead to crimes

Impacts of Gender Inequality and Poverty on Trafficking in Women

Women represent approximately 75% of human trafficking victims. This study reviews what is and is not known about human trafficking and what might be accomplished in future research

Functionalization of Stable Metal-Organic Frameworks and Their Applications

Metal–organic frameworks (MOFs) are newly emerging inorganic–organic hybrid porous materials with diverse crystalline structures, high surface areas, and tunable pores. This dissertation primarily focuses on design and synthesis of MOFs as well as the development of synthetic methodologies to target stable MOFs with desired functionalities. In the second section, a linker exchange strategy was developed as a route to functionalize a mesoporous MOF, PCN-333, through thermodynamic control. This strategy allowed a facile incorporation of a variety of functional groups into the mesoporous MOF without compromising integrity of the parent MOF. In the third section, a dual-exchange method was studied using a sequential linker exchange and metal metathesis on PCN-333(Fe) to achieve a chemically robust mesoporous Cr-MOF with desired functional group. Dual exchange showed the potential of this method to be a general approach to highly stable Cr-MOFs with desired functional groups upon selection of appropriate MOF template. In the fourth section, a new Zn-MOF, SO-PCN, was designed and synthesized as a host of two dye linkers. SO-PCN showed energy transfer between the 2D porphyrinic photosensitizer layer and the photochromic switch pillar in the framework. Using photochromic reaction of the linker in SO-PCN, a reversible control of singlet oxygen generation was demonstrated. The catalytic activity of SO-PCN was also studied for photooxidation of 1,5-dihydroxynaphthalene. In the fifth section, a new synthetic strategy to incorporate multiple functional molecules within the MOF nanoparticles was demonstrated for control of 1^O2 generation for PDT. This strategy was developed to improve several inherent limitations from SOPCN in the previous section. First, a Zr-MOF nanoplatform showed much improved stability in aqueous media, compatible under physiological conditions. This strategy allows for tuning of the ratios between the photosensitizer and the switch molecule within the Zr-MOF nanoparticles, thus enabling maximization of the 1^O2 generation controllability. As a result, MOF nanoparticle formulation showed an enhanced PDT efficacy with superior 1^O2 control compared to that of homogeneous molecular analogues. In the sixth section, size-controlled synthesis of Zr-based porphyrinic MOF nanoparticles was studied through a bottom-up approach. The study provided mechanistic insights about the size control of the porphyrinic Zr-MOF nanoparticles. Size-dependent cellular uptake and ensuing PDT efficacy were also investigated to optimize the size of the MOF nanoparticles for PDT. Additionally, folic acid modification on the Zr6 node in the MOF showed further enhanced PDT efficacy via active targeting, demonstrating multifunctional MOF nanoplatform. In summary, methodologies to allow functionalization of highly stable MOFs have been designed and studied. Conceptual utilizations of MOF nanoparticles for biomedical applications have also been demonstrated with stable MOF nanoparticles, showing the advantages of the MOF formulation. The findings in this dissertation provide design principle and possible options for preparing targeted MOFs as required in desired applications

천연 제올라이트가 혼합된 흡착성 성토재의 전단강도 특성 및 아연 흡착 특성 평가

학위논문 (석사)-- 서울대학교 대학원 : 건설환경공학부, 2017. 2. 박준범.In industrial complexes, gas stations and railbeds, soil and groundwater contamination have occurred frequently and at a high concentration. Especially, zinc, which is one of the most common contaminants in the industrial areas, is needed to be controlled properly. A concept of fill layer construction using adsorptive soil materials is introduced in this study to minimize spreading of contamination. The purpose of this study is to evaluate shear strength characteristics and adsorption capacity of candidate materials for adsorptive fill materials. The candidate materials consist of weathered granite soil as a base material and natural zeolite for adsorptive materials. The composition methods were amendment and partial substitution. Amendment was the composition method that zeolite similar to particle size distribution of weathered granite soils was amended to weathered granite soils. Partial substitution was the method that fine parts of weathered granite soils were substituted with fine particles of natural zeolite. Shear stength characteristics and adsorption capacities of zeolite-amended soils and partially substituted materials through compaction test, direct shear test and sorption isotherm equilibrium test. In case of amendment, test results showed that internal friction angle was decreased with increasing zeolite content while adsorption capacity was increased linearly. In case of partial substitution, shear strength parameters and adsorption capacities were higher than those of zeolite-amended soils. That is, partially substituted materials could be developed as adsorptive fill materials with maximizing adsorption capacity of materials and maintaining the shear strength of materials at weathered granite soils level.Chapter 1 Introduction 1 1.1 Background 1 1.2 Research Concept 4 1.3 Objective 5 Chapter 2 Literature Review 6 2.1 Previous Research 6 2.1.1 Zn Removal Efficiency of Zeolite 7 2.1.2 Zeolite-amended Materials 8 2.1.3 Researches on Development of Fill Materials 10 2.2 Data Analysis of Adsorption Isotherm Equilibrium Test 11 2.2.1 Langmuir Adsorption Isotherm Model 11 2.2.2 Freundlich Adsorption Isotherm Model 12 Chapter 3 Materials and Methods 14 3.1 Materials 14 3.2 Methods 15 3.2.1 Amendement 15 3.2.2 Adsorption Isotherm Equilibrium Tests in Different Particle Size of Zeolite Weathered Granite Soils 16 3.2.3 Partial Substitution 17 3.2.4 Tests of Evaluating Properties for Adsorptive Fill Materials 19 Chapter 4 Experimental Results and Discussion 20 4.1 Amendment 20 4.1.1 Compaction Test 20 4.1.2 Direct Shear Test 21 4.1.3 Adsorption Isotherm Equilibrium Test 23 4.1.4 Comparison with Different Zeolite Content 25 4.2 Adsorption Isotherm Equilibrium Tests in Different Particle Size of Zeolite Weathered Granite Soils 26 4.3 Partial Substitution 30 4.3.1 Compaction Test 30 4.3.2 Direct Shear Test 31 4.3.3 Adsorption Isotherm Equilibrium Test 33 Chapter 5 Conclusions 35 Bibliography 37Maste

The Effects of User Engagements for User and Company Generated Videos on Music Sales: Empirical Evidence From YouTube

With the growth of social network services, users have been able to freely create and share music in ways that were once thought unimaginable. Sharing a music video through such platforms can now be done simply by anyone with access to a computer or smart phone. Online music content can be divided into two major categories—user-generated content (UGC) and company-generated content (CGC). While previous studies on the content of online music videos have examined the impact of this content on, for example, a company's marketing effectiveness and brand image, they have given little attention to the different effects of user engagement of UGC and user engagement of CGC. This study attempts to address this lack by examining how these two kinds of user engagement differently influence user music choices. We will also examine the differing levels of impact on users across the initial, middle, and final periods after a song is released. In order to examine the different impacts of user engagement, we apply an estimation of generalized least squares (GLS) with a panel dataset of 1,035 songs found on Gaon, the official South Korean music ranking chart. We use the number of music video shares generated by users and firms as proxy variables of user engagement in UGC and CGC, respectively. We find that user engagement of UGC and CGC positively influence music sales. We also find that the effects are not static, but rather change in the initial, middle, and final periods after a song is released. In particular, this study finds that the effect of user engagement of UGC on sales is greater than the effect of user engagement of CGC in the initial period but that the effect of the latter becomes similar to that of former at the end of this period. This finding suggests that managers of digital music providers should encourage consumers to create their own content in the initial period, as potential consumers are more likely to buy songs with more UGC content and shares in the initial period