• Asian-Australasian Journal of Animal Sciences
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• 제10권4호
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• pp.402-407
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• 1997

This study was conducted to investigate the effects of effects of enprostil, a prostaglandin $E_2$, analogue, on liver triacylglycerol content and factors that regulate liver lipid metabolism in mice. Mice received vehicle or $10{\mu}g$ enprostil/kg body weight intraperitoneally every 6 h, and were killed at 0, 6, 12, 18 and 24 h after the first injection. Enprostil significantly lowered liver triacylglycerol content after 12 h of the first injection. However, the peroxisomal ${\beta}$-oxidation activity was inconsistent with the result of liver triacylglycerol content, because its activity was lovered by enprosil. In another experiment, the effect of enprostil on lipid metabolism in mice was investigated in a short period. Mice received $10{\mu}g$ enprostil/kg body weight intraperitoneally, and were killed after 0, 5, 10, 30 and 60 min. After 30 min, malic enzyme activity was significantly increased by the administration of enprostil compared with the activity at 5 min after. No significant changes in liver carnitine palmitoyltransferase and peroxisomal ${\beta}$-oxidation activities were observed. Plasma free fatty acid concentrations were markedly reduced from 5 through 60 min after the administration of enprostil. Consequently, enprostil suppressive effect on liver triacylglycerol concentration might result from the decreased entry of free fatty acid into liver.

• Journal of Power Electronics
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• 제18권1호
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• pp.147-159
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• 2018

In this paper, the voltage tracking control of a conventional DC-DC boost converter affected by unknown, time-varying circuit parameter perturbations is investigated. Based on the fundamental property of incremental passivity, a passivity based control law is designed. Then, to obtain a better disturbance rejection property, two generalized proportional integral (GPI) observers are employed to estimate the time-varying uncertainties in the output voltage and inductor current channels, and the estimated values are applied as feedforward compensation. Moreover, the global trajectory tracking performance of a system with disturbances is ensured under the composite controller. Finally, simulation and experiment studies are provided to demonstrate the feasibility and effectiveness of the proposed method. The results show that the proposed controller delivers a promising disturbance rejection capability as well as a good nominal tracking performance.

• Smart Structures and Systems
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• 제15권1호
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• pp.227-244
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• 2015

This study develops a two stage procedure to identify the structural damage based on the optimized artificial neural networks. Initially, the modal strain energy index (MSEI) is established to extract the damaged elements and to reduce the computational time. Then the genetic algorithm (GA) and artificial neural networks (ANNs) are combined to detect the damage severity. The input of the network is modal strain energy index and the output is the flexural stiffness of the beam elements. The principal component analysis (PCA) is utilized to reduce the input variants of the neural network. By using the genetic algorithm to optimize the parameters, the ANNs can significantly improve the accuracy and convergence of the damage identification. The influence of noise on damage identification results is also studied. The simulation and experiment on beam structures shows that the adaptive parameter selection neural network can identify the damage location and severity of beam structures with high accuracy.

• 대한의생명과학회지
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• 제16권3호
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• pp.179-185
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• 2010

Benzene is known as a ubiquitous air pollutant and has a carcinogenic influence on the human body. Benzene is also metabolized to other volatile organic compounds (VOCs) in the body such as phenol and hydroquinone (HQ). The metabolites are accumulated and further oxidized by myeloperoxidase in bone marrow. They act as toxic agents and cause a variety of diseases, including cancer, atopic dermatitis and asthma. In this study, we examined the effects of benzene and its metabolites on proliferation, differentiation and chemotaxis of EoL-1 cells, the human eosinophilic leukemia cell line. These chemicals had no effect on the proliferation of EoL-1 cells. Benzene decreased the differentiation of EoL-1 cells induced by butyric acid. HQ was induced the cell death during butyric acid-induced EoL-1 cell differentiation. In a chemotaxis experiment, benzene, phenol and HQ enhanced the cell migration induced by Lkn-1 but not by MCP-1, eotaxin, MIP-$1{\alpha}$ and RANTES. These findings provide the effect of VOCs on the regulation of eosinophil-involved immune response.

• Nuclear Engineering and Technology
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• 제54권2호
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• pp.579-588
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• 2022

In order to meet the needs of domestic reactor severe accident analysis program, a MIDAC (Module Invessel Degraded severe accident Analysis Code) is developed and maintained by Xi'an Jiaotong University. As the accuracy of the calculation results of the analysis program is of great significance for the formulation of severe accident mitigation measures, the article select three experiments to evaluate the updated severe accident models of MIDAC. Among them, QUENCH-06 is the international standard No.45, QUENCH-16 is a test for the analysis of air oxidation, and FROMA is an out-of-pile fuel rod melting experiment recently carried out by Xi'an Jiaotong University. The heating and melting model with lumped parameter method and the steam oxidation model with Cathcart-Pawel and Volchek-Zvonarev correlations combination in MIDAC could better meet the needs of severe accident analysis. Although the influence of nitrogen still need to be further improved, the air oxidation model with NUREG still has the ability to provide guiding significance for engineering practice.

• Nuclear Engineering and Technology
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• 제53권10호
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• pp.3217-3228
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• 2021

Flow blockage of the fuel assembly in the lead-based fast reactor (LFR) may produce critical local spots, which will result in cladding failure and threaten reactor safety. In this study, the flow blockage characteristics were analyzed with the sub-channel analysis method, and the circumferentially-varied method was employed for considering the non-uniform distribution of circumferential temperature. The developed sub-channel analysis code SACOS-PB was validated by a heat transfer experiment in a blocked 19-rod bundle cooled by lead-bismuth eutectic. The deviations between the predicted coolant temperature and experimental values are within ±5%, including small and large flow blockage scenarios. And the temperature distributions of the fuel rod could be better simulated by the circumferentially-varied method for the small blockage scenario. Based on the validated code, the analysis of blockage characteristics was conducted. It could be seen from the temperature and flow distributions that a large blockage accident is more destructive compared with a small one. The sensitivity analysis shows that the closer the blockage location is to the exit, the more dangerous the accident is. Similarly, a larger blockage length will lead to a more serious case. And a higher exit temperature will be generated resulting from a higher peak coolant temperature of the blocked region. This work could provide a reference for the future design and development of the LFR.

• Journal of the Optical Society of Korea
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• 제19권4호
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• pp.415-420
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• 2015

A novel method to measure the scale factor for the all-optical atomic spin inertial measurement device (ASIMD) is demonstrated in this paper. The method can realize the calibration of the scale factor by a self-consistent method with small errors in the quiescent state. At first, the matured IMU (inertial measurement unit) device was fixed on an optical platform together with the ASIMD, and it has been used to calibrate the scale factor for the ASIMD. The results show that there were some errors causing the inaccuracy of the experiment. By the comparative analysis of theory and experiment, the ASIMD was unable to keep pace with the IMU. Considering the characteristics of the ASIMD, the mismatch between the driven frequency of the optical platform and the bandwidth of the ASIMD was the major reason. An all-optical atomic spin magnetometer was set up at first. The sensitivity of the magnetometer is ultra-high, and it can be used to detect the magnetization of spin-polarized noble gas. The gyromagnetic ratio of the noble gas is a physical constant, and it has already been measured accurately. So a novel calibration method for scale factor based on the gyromagnetic ratio has been presented. The relevant theoretical analysis and experiments have been implemented. The results showed that the scale factor of the device was $7.272V/^{\circ}/s$ by multi-group experiments with the maximum error value 0.49%.

• Journal of Microbiology and Biotechnology
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• 제30권7호
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• pp.996-1004
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• 2020

Various genetically engineered microorganisms have been developed for the removal of heavy metal contaminants. Metal biosorption by whole-cell biosorbents can be enhanced by overproduction of metal-binding proteins/peptides in the cytoplasm or on the cell surface. However, few studies have compared the biosorption capacity of whole cells expressing intracellular or surface-displayed metal-adsorbing proteins. In this study, several constructs were prepared for expressing intracellular and surface-displayed Ochrobactrum tritici 5bvl1 ChrB in Escherichia coli BL21(DE3) cells. E. coli cells expressing surface-displayed ChrB removed more Cr(VI) from aqueous solutions than cells with cytoplasmic ChrB under the same conditions. However, intracellular ChrB was less susceptible to variation in extracellular conditions (pH and ionic strength), and more effectively removed Cr(VI) from industrial wastewater than the surface-displayed ChrB at low pH (<3). An adsorption-desorption experiment demonstrated that compared with intracellular accumulation, cell-surface adsorption is reversible, which allows easy desorption of the adsorbed metal ions and regeneration of the bioadsorbent. In addition, an intrinsic ChrB protein fluorescence assay suggested that pH and salinity may influence the Cr(VI) adsorption capacity of ChrB-expressing E. coli cells by modulating the ChrB protein conformation. Although the characteristics of ChrB may not be universal for all metal-binding proteins, our study provides new insights into different engineering strategies for whole-cell biosorbents for removing heavy metals from industrial effluents.

• 고려인삼학회:학술대회논문집
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• 고려인삼학회 1993년도 학술대회지
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• pp.110-112
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• 1993

Acidic polysaccharide from Korean red ginseng was found to inhibit pancreatic lipase activity and cause reduction of plasma triglyceride level after oral administration of corn oil emulsion to rats. Thus acidic polysaccharide may reduce plasma triglyceride through its inhibitory action on pancreatic lipase and successive inhibition of intestinal absorption of fat due to reduction of lipolysis. In the course of this experiment, we found an unknown ninhydrin positive substance in Korean red ginseng. The unknown substance was identified to be arginyl-fructosyl glucose(Arg - Fru - Glc). Coment of this new compound was $5.37\%$ in Korean red ginseng powder. Sucrase and maltase activities in mucous layer of rat jejunum were found to be inhibited by Arg-Fru-Glc. Physiological significance of the new compound was discussed based on these experimental results.

• Korean Chemical Engineering Research
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• 제43권6호
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• pp.668-674
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• 2005

카본블랙을 이용한 프로판 분해는 메탄보다 분해가 용이하여 효과적인 수소생산방법으로 알려졌다. 특히, 프로판 직접 분해 반응에 의한 수소생산은 CO나 $CO_2$와 같은 부산물이 생성되지 않으므로 환경친화적인 수소 생산기술이다. 본 연구에서는 국내에서 상용화되어 시판되고 있는 활성탄 및 카본블랙을 탄소계 촉매로 사용하여 프로판 직접 분해반응특성을 조사하였다. 프로판의 직접 분해반응은 대기압 하, $500{\sim}1,000^{\circ}C$ 온도영역에서 실험이 수행되었으며, 프로판 분해반응에 의한 생성물로 수소뿐만 아니라 메탄, 에틸렌, 에탄, 프로필렌 등의 부산물의 생성이 확인되었다. 이러한 부산물들은 고온으로 갈수록 줄어들어 상대적으로 수소 수율이 증가함을 알 수 있었다. 다양한 상용촉매를 프로판 분해 반응에 적용하여 본 결과로서 DCC N330을 촉매로 이용하였을 경우, $750^{\circ}C$에서 22.47％의 수소 수율을 얻었다.