• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.175-181
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• 2019

In the case of a conventional single stage decompression regulator used for large depressurization in the hydrogen fuel cell system of a fuel cell electric vehicle (FCEV), problems can arise, such as pulsation, slow response, hydrogen brittleness, leakage, high weight, and high cost due to high decompression. Most of these problems can be overcome easily using two decompression mechanisms (two-stage structures). In addition, a wide outlet-pressure control range can be secured if an electronic solenoid is applied to the second decompression. Accordingly, it is necessary to improve the precision of the outlet pressure of a two-stage pressure-reducing regulator and develop techniques, such as leakage prevention, durability, light weight, and price reduction. Therefore, to improve the outlet pressure accuracy and prevent leakage, the structural part before and after decompression to improve the air tightness were divided and the analysis was carried out assuming that the valve part was closed (open ratio: 0%) after each initial internal pressure application.

• Preventive Nutrition and Food Science
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• v.2 no.4
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• pp.338-347
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• 1997

Apo E polymorphism(e2, e3, e4) was among the first reported genetic polymorphism that explained part of the normal vairation in plasma cholesterol concentrations. Both alleles E2 and E4 are significantly more frequent in patients with mixed forms of hyperlipidemia and contribute on the observed differences in CHD risk among different populations. Effects of apo E polymorphism on the distribution of plasma lipid profiles were studied in 89 normolipidemic healthy females, aged 19 up to 22 years. The relative frequencies of E3/3 was 0.787, E3/2 was 0.101, E3/4 allele was 0.112 and no E2/2, E2/4 and E4/4 were found. Weight, height and %LBM were elevated in E2 than those in E3&E4. No differences in the blood pressure among apo E isomers were found, otherwise the pulsation was higher in E4 than that in the others. There were no differences in plasma total-, total DL-, HDL$_3$-, HDL$_2$ cholesterol, apo B-100 and apo A-I, However, phenotype means rank E3/2>E3/3>E3/4 in average TG levels(p<0.0001) significantly, and rank E3/4>E3/3>E3/2 in LDL cholesterol levels. These results were related to the correlation between atherogenic indiced (AI) such as LDL/HDL, (TC-HDL)/HDL, HDL$_3$/HDL$_2$. The ratio of HDL$_3$& HDL$_2$was significantly increased in E2 & E4 than that in E3(P=0.043). LCAT activity was not different between E2 and E3 but was highly increased in E4 (p<0.0001 among apo E isomers), but CETP was not different. Since the negative correlation between LCAT and CETP in apo E2(r=-0.491) was stronger than that in apo E3, E2 allele impacts the clearance of plasma apo E mediated lipoproteins. In conclusion firstly, E4 mediated alteration through LDL or E receptors results in lower TG or higher $\beta$-lipoprotein levels and E2 shows reciprocal effects of E4, respectively. Second, E4 allele was more atherogenic than E2 allele because the higher levels of AI such as HDL$_3$/HDL$_2$ were criticized.

• Journal of Nutrition and Health
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• v.29 no.6
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• pp.642-650
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• 1996

Apo E polymorphism (e2, e3, e4) was among the first reported genetic polymorphism that explained part of the normal variation in plasma cholesterol concentrations. Both alleles E2 and E4 are significantly more frequent in patients with mixed forms of hyperlipidemia and contribute on the observed differences in CHD risk among different populations. Effects of apo E polymorphism on the distribution of plasma lipid profiles were studied in 105 normolipidemic healthy women. The relative frequencies of common alleles for gene locus of apo E in this study were that E3 allele was 0.848, E4 allels was 0.087, and E2 allele was 0.067. SBP and DBP were slightly more elevated in E2 allele than those in E3 and E4. The pulsation was also significantly (p<0.016) increased by E2 allele with excess body fat % in E2 allele. There were no differences in total-, total HDL-, VLDL+LDL-, VLDL- and LDL cholesterol among the apo E alleles. However, apo E2 allele subject had lower level of total HDL and HDL2 cholesterol (P<0.047) and significantly higher lev디 of HDL3 cholesterol (P<0.05) than those in apo E3 and E4 allele subject. The conclusion is that first, it seems that apo E4-mediated alteration through LDL B/E receptors or E receptors in cholesterol metabolism results in lower plasma TG or remanate particles and in higher levels of VLDL+LDL or LDL. Second, apo E2 allele shows reciprocal effects of E4 on the plasma lipid metabolism, respecitvely. Third, apo E2 allele was more atherogenic than apo E4 because the higher levels of HDL3/HDL2 ratio and atherogenic index[(TC-HDL)/HDL]were criticized.