• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.5
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• pp.63-71
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• 2021

Windbreak forests, which have a windproof effect against strong winds, are known to be effective in reducing the spread of odors and dust emitted from livestock farms. The effect of reducing the spread of odors and dust can be estimated through numerical models such as computational fluid dynamics, which require aerodynamic coefficients of the windbreaks for accurate prediction of their performance. In this study, we aimed to evaluate the aerodynamic coefficients, Co, C₁, C₂, and α, of two windbreaks, Thuja occidentalis and a mesh net, through wind tunnel experiments. The aerodynamic coefficients were derived by the relation between the incoming wind speed and the pressure loss due to the windbreaks which was measured by differential pressure sensors. In order to estimate the change in the aerodynamic coefficient concerning various leaf density, the experiments were conducted repeatedly by removing the leaves gradually in various stages. The results showed that the power law regression model more suitable for coefficient evaluation compared to the Darcy-Forchheimer model.

• International Area Studies Review
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• v.14 no.3
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• pp.86-107
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• 2010

Prior research on the relationship between output volatility and growth has produced mixed results, failing to provide clear empirical evidence on the sign of the relationship. In this paper, we raise the possibility that such failure is due to misspecification in empirical models previously used, i.e., not taking into account the business cycle dependence of the volatility-growth relation. We set off with the conjecture that higher volatility exerts qualitatively different effect on growth depending on whether the economy is in expansion or contraction. We estimate a series of ARCH-type models with the monthly industrial production data of the U.K., and find strong evidence suggesting that the volatility-growth relation is positive when the economy is in expansion, while higher volatility lowers growth rate in the contraction phase. We also find evidence supporting that the volatility-growth relation estimated in the paper captures a a causal relation, not a bidirectional correlation.

• Cross-Cultural Studies
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• v.38
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• pp.297-329
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• 2015

Since 1989 about one million Jews from Former Soviet Union have immigrated to Israel. Now Russian speaking Jews are the second largest ethnic groups after the Israeli Jews who were born in Israel. Although FSU Jews have returned to their ethnic homeland, they continue to live as 'foreigners' due to a cultural distance between sending and receiving society, such as, lack of knowledge about Jewish tradition and religious practice and low level of Hebrew proficiency. Because of this reason FSU immigrants tend to continue remain strong ties with Russian language and culture. There are several reasons for such a relatively slow process of language shift of FSU Jewish immigrants, the language shift to Hebrew. Firstly, majority of FSU immigrants moved to Israel since the 1990s are older than 45. Secondly, their first residences in Israel are mostly located in small and mid-sized cities, where the proportion of Russian speaking immigrants is more than 30%. And finally they consider Russian culture is 'superior' to Israel's Levantine culture. For many Jewish diasporic communities, Judaism was a dominant factor for self-consciousness, but because of Soviet regime, aimed to break all the religious institution including Jewish, Soviet Jewry was uprooted from their religious traditions. Besides about 30% of FSU immigrants are not defined as Jews by the Jewish religious law(Halakhah). And many of them are reluctant to convert to Judaism. FSU Jewish immigrant agree that Israel must be a Jewish state, but for them 'Jewish' does not include religious elements. FSU immigrants consider that religious affiliation of citizens of Israel should not affect their civic rights.

• Cross-Cultural Studies
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• v.35
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• pp.97-122
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• 2014

Since the arrival of Chinese immigrants in the 1850s, many Euro-American writers tended to project their fears, contempt, desires and fantasy onto the Other race and perceived Chinese Americans in stereotypes-dangerous villains, unassimilated aliens, quiet and passive servants, sexually submissive women, or seductive prostitutes. However in the 1970s and the 1980s Euro-American novels expressed varying attitudes towards Chinese Americans. Many earlier EuroAmerican writers began portraying positive characterizations of Chinese Americans. The purpose of this study is to examine the ways one of the Euro-American writers, Howard Fast characterized Chinese Americans in The Immigrants. Part of the novel concerns a Chinese American family. Fast gave a favorable portrayal of Chinese Americans. Unlike many Euro-American novelists who dealt only with Chinese American villains and prostitutes and view Chinese Americans as the lowest class of American society, Fast, on the other hand, portrayed Chinese Americans as law-abiding and useful citizens. Thus, I will discuss how Howard Fast subverted the familiar negative characterization of Chinese Americans and placed Chinese American experiences in the context of American immigration history. Many white Americans tended to notice only the lurid and sensational aspects in the Chinese American community. They seldom regarded Chinese Americans as people with homes and families and seldom saw Chinese Americans as individuals, as human beings with feelings, pain, and joy. To counter this racist view, Fast described the family life of Chinese Americans and depicted Chinese Americans as individuals with a full range of human emotions and with strong family and cultural ties. Though Fast debunked some myths about Chinese Americans, he also reinforces other stereotypes or some stereotypical illusions about them. In conclusion, I'll demonstrate Fast's work remains an incomplete representation of Chinese Americans.

• Earthquakes and Structures
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• v.17 no.2
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• pp.233-244
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• 2019

In this work, we have studied the effects of different soil thicknesses, haunch heights, reinforcement forms and construction technologies on the seismic performance of a composite precast fabricated utility tunnel by pseudo-static tests. Five concrete specimens were designed and fabricated for low-cycle reciprocating load tests. The hysteretic behavior of composite precast fabricated utility tunnel under simulated seismic waves and the strain law of steel bars were analyzed. Test results showed that composite precast fabricated utility tunnel met the requirements of current codes and had good anti-seismic performance. The use of a closed integral arrangement of steel bars inside utility tunnel structure as well as diagonal reinforcement bars at its haunches improved the integrity of the whole structure and increased the bearing capacity of the structure by about 1.5%. Increasing the thickness of covering soil within a certain range was beneficial to the earthquake resistance of the structure, and the energy consumption was increased by 10%. Increasing haunch height within a certain range increased the bearing capacity of the structure by up to about 19% and energy consumption by up to 30%. The specimen with the lowest haunch height showed strong structural deformation with ductility coefficient of 4.93. It was found that the interfaces of haunches, post-casting self-compacting concrete, and prefabricated parts were the weak points of utility tunnel structures. Combining the failure phenomena of test structures with their related codes, we proposed improvement measures for construction technology, which could provide a reference for the construction and design of practical projects.

• The Journal of the Korea Contents Association
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• v.19 no.9
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• pp.242-253
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• 2019

There has been a large literature on bank liquidity risk since the 2008 global financial crisis because liquidity risk was at the heart of the crisis. However, there is no study that investigates whether the level of investor protection influences liquidity risk-taking behavior of banks. Therefore, this study aims to explore the relationship between investor protection and liquidity risk as well as to provide policy implications. Using a panel dataset of commercial banks in 21 OECD countries, we found that strong investor protection encourages banks to take lower liquidity risk. Furthermore, this positive role of shareholder protection is more prominent during a crisis, implying that legal protection of investors plays an essential role in bank stability while market discipline is largely ineffective due to extensive government guarantees in turbulent times.

• Bulletin of the Korean Chemical Society
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• v.9 no.6
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• pp.345-349
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• 1988

The polycrystalline powder of (CaLa) (MgMo)$O_6$ has been prepared at $1350^{\circ}C$ in $H_2/H_2O$ and $N_2$ flowing atmosphere. The powder X-ray diffraction pattern indicates that (CaLa) (MgMo)$O_6$ has a monoclinic perovskite structure with the lattice constants $a_0=b_0=7.901(1){\AA}$, $c =7.875(1){\AA}\;and\;{\gamma}=89^{\circ}$16'(1'), which can be reduced to orthorhombic unit cell, a = 5.551(1) ${\AA}$, b = 5.622(1) ${\AA}$ and c = 7.875(1) ${\AA}$. The infrared spectrum shows two strong absorption bands with their maxima at 590($ν_3$) and 380($ν_4$) cm, which are attributed to $2T_{1u}$ modes indicating the existence of highly charged molybdenum octahedron $MoO_6$ in the crystal lattice. According to the magnetic susceptibility measurement, the compound follows the Curie-Weiss law below room temperature with the effective magnetic moment 1.83(1)$_{{\mu}B}$, which is well consistent with that of spin only value (1.73 $_{\mu}_B$) for $Mo^{5+}$ with $4d^1$-electronic configuration within the limit of experimental error. From the thermogravimetric analysis, it has been confirmed that (CaLa) (MgMo)$O_6$ decomposes gradually into $CaMoO_4,\;MoO_3,\;MgO,\;La_2O_3$ and unidentified phases due to the oxidation of $Mo^{5+}$ to $Mo^{6+}$.

• Computers and Concrete
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• v.28 no.5
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• pp.521-532
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• 2021

Present paper focuses on the modeling of size effect on the compressive strength of normal concrete with the application of Discrete Element Method (DEM). Test specimens with different size and shape were cast and uniaxial compressive strength test was performed on each sample. Five different concrete mixes were used, all belonging to a different normal strength concrete class (C20/25, C30/37, C35/45, C45/55, and C50/60). The numerical simulations were carried out by using the PFC 5 software, which applies rigid spheres and contacts between them to model the material. DEM modeling of size effect could be advantageous because the development of micro-cracks in the material can be observed and the failure mode can be visualized. The series of experiments were repeated with the model after calibration. The relationship of the parallel bond strength of the contacts and the laboratory compressive strength test was analyzed by aiming to determine a relation between the compressive strength and the bond strength of different sized models. An equation was derived based on Bazant's size effect law to estimate the parallel bond strength of differently sized specimens. The parameters of the equation were optimized based on measurement data using nonlinear least-squares method with SSE (sum of squared errors) objective function. The laboratory test results showed a good agreement with the literature data (compressive strength is decreasing with the increase of the size of the specimen regardless of the shape). The derived estimation models showed strong correlation with the measurement data. The results indicated that the size effect is stronger on concretes with lower strength class due to the higher level of inhomogeneity of the material. It was observed that size effect is more significant on cube specimens than on cylinder samples, which can be caused by the side ratios of the specimens and the size of the purely compressed zone. A limit value for the minimum size of DE model for cubes and cylinder was determined, above which the size effect on compressive strength can be neglected within the investigated size range. The relationship of model size (particle number) and computational time was analyzed and a method to decrease the computational time (number of iterations) of material genesis is proposed.

• Journal of Electrochemical Science and Technology
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• v.13 no.4
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• pp.453-461
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• 2022

A chemically sintered and binder-free paste of TiO₂ nanoparticles (NPs) was prepared using a binary-liquid mixture of 1-octanol and CCl₄. The 1:1 (v/v) complex of CCl₄ and 1-octanol easily interacted chemically with the TiO₂ NPs and induced the formation of a highly viscous paste. The as-prepared binary-liquid paste (P_BL)-based TiO₂ film exhibited the complete removal of the binary-liquid and residuals with the subsequent low-temperature sintering (~150℃) and UV-O₃ treatment. This facilitated the fabrication of TiO₂ photoanodes for flexible dye-sensitized solar cells (f-DSSCs). For comparison purposes, pure 1-octanol-based TiO₂ paste (P_O) with moderate viscosity was prepared. The P_BL-based TiO₂ film exhibited strong adhesion and high mechanical stability with the conducting oxide coated glass and plastic substrates compared to the P_O-based film. The corresponding low-temperature sintered P_BL-based f-DSSC showed a power conversion efficiency (PCE) of 3.5%, while it was 2.0% for P_O-based f-DSSC. The P_BL-based low- and high-temperature (500℃) sintered glass-based rigid DSSCs exhibited the PCE of 6.0 and 6.3%, respectively, while this value was 7.1% for a 500℃ sintered rigid DSSC based on a commercial (or conventional) paste.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.45.1-45.1
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• 2021

The polarization degree as a function of phase angle (the Sun-target-observer's angle), so-called the polarimetric phase curves (PPC), have provided priceless information on asteroids' albedos since B. Lyot (1929). Succeeding experimental works in 1970s have confirmed the Umow law: There is a universal and strong correlation between the albedo and the PPC slope (slope of the tangential line at the zero of the PPC at phase angle ~ 20 degrees). Experiments in 1990s (ref [1]), on the other hand, have demonstrated that the negative branch of PPC is dependent on the size parameter (X ~ π * particle-size / wavelength), especially when X <~5. The change in particle size changed the minimum polarization degree, location of the minimum, and the width of the negative branch (called the inversion angle). From polarimetry[2] and spectroscopy[3], large asteroids are expected to be covered with fine (<~ 10 ㎛ size) particles due to the gravity. The size parameters are X ~ 30 at the optical wavelength (λ ~ 0.5 ㎛) and X ~ 10 in near-infrared (J, H, Ks bands; λ ~ 1.2-2.2 ㎛), if the representative particle size of 5 ㎛ is considered. Accordingly, the near-infrared polarimetry has a great potential to validate the idea in ref[1]. We conducted near-infrared photopolarimetry of the large asteroid (4) Vesta using the Nishiharima Infrared Camera (NIC) at Nishi-Harima Astronomical Observatory (NHAO). NIC allows simultaneous polarimetric measurements in J, H, and Ks bands, and thus the change of PPC is obtained for three different size parameters. As a result, we found a signature of the change in the negative branch in the PPC of asteroid (4) Vesta. We will introduce our observation and the results and give an interpretation of the regolith on Vesta.