• Journal of the Society of Cosmetic Scientists of Korea
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• v.29 no.2 s.43
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• pp.131-147
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• 2003

In the 21st century, the development of cosmetics is led to pursue the high functionality of cosmetics with excellent effectiveness and safety. As Cosmetic Act took effect in 2000, functional cosmetics is provided in the law. As a result, the research and development of functional cosmetics has continually increased, and the number of patent applications in functional cosmetics has also rapidly increased as a plan for preoccupying in the functional cosmetics age. Now, the cosmetic industry has a great interest in developing anti-wrinkle cosmetics among functional cosmetics, because women's desire for having young resilient skin has increased since Korea entered an aging society thanks to the advanced medical technology. The patent application trends of anti-wrinkle cosmetics at home since 2000 particularly show the rapid increase in the applications in natural plant extracts. It may be because Korean consumers preference of vegetable cosmetics has resulted in the development of raw materials based on the traditional medicine. As for the existing preparation such as Retinoid or Ascorbic acid, the patent application itself will be an essential technical element in the future because patent applications are filed in the field of a preparation of cosmetics for stabilizing ingredients, reducing skin irritability or promoting absorbance, and in the field of cosmetic formulation technology. As there are many studies on the causes of skin wrinkles, it is expected that new raw materials of cosmetics can be developed due to new mechanisms, and that the number of patent applications in new technologies will increase due to a change in the thought of cosmetics accompanied by the integration of cosmetics with biotechnology using Genetic Engineering, including the practical application of the medicine previously used far treating skin diseases to an anti-wrinkle agent and the mass production of active ingredients of cosmetics.

• Journal of the Korean Society of Safety
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• v.37 no.2
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• pp.1-9
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• 2022

Most factories deal with toxic or flammable chemicals in their industrial processes. These hazardous substances pose a risk of leakage due to accidents, such as fire and explosion. In the event of chemical release, massive casualties and property damage can result; hence, quantitative risk prediction and assessment are necessary. Several methods are available for evaluating chemical dispersion in the atmosphere, and most analyses are considered neutral in dispersion models and under far-field wind condition. The foregoing assumption renders a model valid only after a considerable time has elapsed from the moment chemicals are released or dispersed from a source. Hence, an initial dispersion model is required to assess risk quantitatively and predict the extent of damage because the most dangerous locations are those near a leak source. In this study, the dispersion model for initial consequence analysis was developed with three-dimensional unsteady advective diffusion equation. In this expression, instantaneous leakage is assumed as a puff, and wind velocity is considered as a coordinate transform in the solution. To minimize the buoyant force, ethane is used as leaked fuel, and two different diffusion coefficients are introduced. The calculated concentration field with a molecular diffusion coefficient shows a moving circular iso-line in the horizontal plane. The maximum concentration decreases as time progresses and distance increases. In the case of using a coefficient for turbulent diffusion, the dispersion along the wind velocity direction is enhanced, and an elliptic iso-contour line is found. The result yielded by a widely used commercial program, ALOHA, was compared with the end point of the lower explosion limit. In the future, we plan to build a more accurate and general initial risk assessment model by considering the turbulence diffusion and buoyancy effect on dispersion.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4A
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• pp.659-675
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• 2006

Recently, significant progress has been made in performance-based engineering methods that rely mainly on nonlinear static seismic analysis procedures. The Capacity Spectrum Method (CSM) and the Displacement Coefficient Method (DCM) are the representative nonlinear static seismic analysis procedures. In order to evaluate the applicability of the procedures to the seismic evaluation and design process of new and existing structures, the accuracy of both CSM and DCM should be evaluated in advance. The accuracy of seismic responses by the nonlinear static procedures is evaluated in comparison with the shaking table test results for the structural wall specimen subjected to the far field and near field earthquakes. Also conducted are comparative studies where the shaking table test results are compared with those from nonlinear dynamic analysis procedures, i.e., Single-Degree-of-Freedom (SDOF), equivalent SDOF and Multi-Degree-of-Freedom (MDOF) systems.

• Earthquakes and Structures
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• v.26 no.1
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• pp.17-30
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• 2024

Earthquakes can lead to substantial damage to buildings, with long-period ground motion being particularly destructive. The design of high-performance building structures has become a prominent focus of research. The double-story isolated structure is a novel type of isolated structure developed from base isolated structure. To delve deeper into the building performance of double-story isolated structures, the double-story isolated structure was constructed with the upper isolated layer located in different layers, alongside a base isolated structure for comparative analysis. Nonlinear elastoplastic analyses were conducted on these structures using different ground motion inputs, including ordinary ground motion, near-field impulsive ground motion, and far-field harmonic ground motion. The results demonstrate that the double-story isolated structure can extend the structural period further than the base isolated structure under three types of ground motions. The double-story isolated structure exhibits lower base shear, inter-story displacement, base isolated layer displacement, story shear, and maximum acceleration of the top layer, compared to the base isolated structure. In addition, the double-story isolated structure generates fewer plastic hinges in the frame, causes less damage to the core tube, and experiences smaller overturning moments, demonstrating excellent resistance to overturning and a shock-absorbing effect. As the upper isolated layer is positioned higher, the compressive stress on the isolated bearings of the upper isolated layer in the double-story isolated structure gradually decreases. Moreover, the compressive stress on the isolated bearings of the base isolated layer is lower compared to that of the base isolated structure. However, the shock-absorbing capacity of the double-story isolated structure is significantly increased when the upper isolated layer is located in the middle and lower section. Notably, in regions exposed to long-period ground motion, a double-story isolated structure can experience greater seismic response and reduced shock-absorbing capacity, which may be detrimental to the structure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.6
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• pp.342-347
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• 2016

We investigated the effect of $Bi_{1/2}(Na_{0.82}K_{0.18})_{1/2}TiO_3$ (BNKT) modification on the ferroelectric and electric-field-induced strain (EFIS) properties of lead-free $0.97Bi_{1/2}(Na_{0.82}K_{0.18})_{1/2}TiO_3-0.03LaFeO_3$ (BNKTLF) ceramics as a function of BNKT content (x= 0, 0.1, 0.2, 0.3, 0.5, and 1). BNKT-modified BNKTLF powders were synthesized using a conventional solid-state reaction method. As the BNKT content x increased from 0 to 1 the normalized electric-field-induced strain ($S_{max}/E_{max}$) was observed to increase at relatively low fields, i.e., below the poling field. Moreover, BNKTLF-30BNKT showed about 460 pm/V as low as at 3 kV/mm, which is a considerably high value among the lead-free systems reported so far. Consequently, it was confirmed that ceramic-ceramic composite, a mixture of an ergodic relaxor matrix and embedded ferroelectric seeds, is a salient way to make lead-free piezoelectrics practical with enhanced EFIS at low field as well as less hysterical.

• Journal of Korea Water Resources Association
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• v.45 no.9
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• pp.853-860
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• 2012

It is well-known that loop effect of the stage-discharge relationship is formulated based on many field observations especially for the sand rivers. Theoretical understandings of the loop effect for the sand rivers have been widely provided, based on the facts that it is driven by the flood wave propagation and bed form changes over the given flood period. However, very few theoretical studies or field observations associated with loop-rating curves in the gravel or rock-bed mountain streams have been attempted so far, due particularly to the difficulties in the accurate discharge measurement during the flood in such field conditions. The present paper aims to report a unique loop-rating curve measured at a gravel and rock-bed mountain stream based on the flood discharge observation acquired during the typhoon, Muifa that passed nearby Jeju Island in summer of 2011. As velocity instrumentation, a non-intrusive Surface Velocity Doppler Radar to be suitable for the flood discharge measurement was utilized, and discharges were consecutively measured for every hour. Interestingly, the authors found that the hysteresis of the loop-rating curve was adverse compared to the typical trend of the sand bed streams, which means that the discharge of the rising limb is smaller than the falling limb at the same stage. We carefully speculate that the adverse trend of the loop-rating curve in the gravel bed was caused by the bed resistance change that works differently from the sand bed case.

• Research in Plant Disease
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• v.8 no.3
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• pp.184-188
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• 2002

An antagonistic bacteria, Bacillus licheniformis Nl strain which effectively inhibited mycelial growth of gray mold rot pathogen, Botrytis cinerea was isolated from the rhizosphere of perilla crop. Powder soy formulation by B. lichentfomis Nl strain as a biocontrol agent was developed far the first time and estimated its control effect on perilla leaves in this study. First of all, far the mass production of antifungal metabolites of B. lichentfomis Nl strain in flask liquid culture, the most effective carbon and nitrogen source were selected as glucose and tryp-tone, respectively, For the formulation, vegetative biomass of B. licheniformis Nl strain from 5-day-old liquid culture in nutrient broth added glucose and tryptone was mixed with soy flour, rice flour glucose, FeSo$_4$~7$H_2O$, and MnCl$_2$. 4$H_2O$, and dried and pulverized. In plastic house test, powder soy formulation effectually controlled gray mold rot as the control value of 93.1 %, was more effective than chemical fungicide, benomyl showing the control value of 86.1%. Thus, development of powder soy formulation of B. lichentfomis Nl will aid large-scale application of biological control in field trials.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.131-131
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• 2009

Silicon Carbide (SiC) is a material with a wide bandgap (3.26eV), a high critical electric field (~2.3MV/cm), a and a high bulk electron mobility ($\sim900cm^2/Vs$). These electronic properties allow high breakdown voltage, high-speed switching capability, and high temperature operation compared to Si devices. Although various SiC DMOSFET structures have been reported so far for optimizing performances, the effect of channel dimension on the switching performance of SiC DMOSFETs has not been extensively examined. This paper studies different channel dimensons ($L_{CH}$ : $0.5{\mu}m$, $1\;{\mu}m$, $1.5\;{\mu}m$) and their effect on the the device transient characteristics. The key design parameters for SiC DMOSFETs have been optimized and a physics-based two-dimensional (2-D) mixed device and circuit simulator by Silvaco Inc. has been used to understand the relationship. with the switching characteristics. To investigate transient characteristic of the device, mixed-mode simulation has been performed, where the solution of the basic transport equations for the 2-D device structures is directly embedded into the solution procedure for the circuit equations. We observe an increase in the turn-on and turn-off time with increasing the channel length. The switching time in 4H-SiC DMOSFETs have been found to be seriously affected by the various intrinsic parasitic components, such as gate-source capacitance and channel resistance. The intrinsic parasitic components relate to the delay time required for the carrier transit from source to drain. Therefore, improvement of switching speed in 4H-SiC DMOSFETs is essential to reduce the gate-source capacitance and channel resistance.

• Journal of the Korean Geotechnical Society
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• v.17 no.6
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• pp.53-67
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• 2001

In this study the pilot test of CGS as injection method by low slump mortar was performed and the results were analyzed in order to find out the application of this method and effect of settlement restraint. The site far pilot test is adjacent to apartments supported by pile foundations. Sand drain method was performed previously as countermeasures against settlement, but settlement occur continuously because this ground is very soft. Site investigations such as SPT, DCPT and vane shear test were performed to determine the characteristics of ground improvement. Field measurements and FDM analysis were performed on purpose to find out the displacement of ground during injection works. From the results of this study, CGS method can be optimized by the control of diagram, space, depth, injection material, and injection pressure. CGS improved soft ground compositely by the bearing effect of CGS columns and reinforcement of adjacent ground. Considering that increase of N value is about 2.1, CGS can be considered as an effective method to increase the bearing capacity as well as to stop the settlement of soft ground. It is also expected to be economic and effective in improvement of ground when it is used in applicable sites.

• Journal of the Korea Safety Management & Science
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• v.3 no.3
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• pp.11-21
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• 2001

Domestic construction industry has considerable level of construction performance and technology thanks to the economic development and as the result of performing diverse oversea construction project. However, construction disasters have been steadily increasing, and do severe disasters at faster pace. Most of such disasters happen at small and small medium-sized construction fields, which contract size is less than 10 billion won. small and medium-sized construction fields are not obliged to designate a safety manager, and have limitations in engaging self-regulating disaster prevention activities due to reduced budget for safety facilities. For the small and medium-sized construction sites with less than 10 billion won, the Ministry of Labor has been carrying out mobile inspections of construction safety. However, the effect so far is insignificant and an improvement plan is required. Therefore, in the present thesis, we derive problems appearing in the current construction safety mobile inspection system, investigate and study systems in foreign countries, and suggest an efficient and effective plan to operate safety technology inspections. First of all, we establish a standard to select sites to be inspected that are high in construction risk and disaster occurrence probability In addition, we suggest a plan to take administrative and judiciary measures based on the total score for disaster factors considering the disaster occurrence probability and the illegal practices. Furthermore, a scheme to maximize the effect of disaster prevention is sought by building an organic cooperative system between the Ministry of Labor, Korea Occupational Safety ＆ Health Agency and other organizations specialized in instruction of construction disaster prevention. Finally, we induce a research conclusion that leads to self-regulating safety management through checking and instructing systematic management on mobile inspections.