• Korean Journal of Veterinary Research
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• v.21 no.1
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• pp.51-58
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• 1981

Two experiments were conducted to establish a program for the prevention of swine parakeratosis occurred recently in Korea. In the first experiment, 11 rations which were considered to be related clinico-pathologically to the incidence of parakeratosis and 5 rations not to be related were collected at farms during the period from June, 1979 to December, 1980. In addition, 23 commercial rations and 10 ingredients were also collected at feed dealers or farms. The feed samples were analyzed for calcium, zinc and unsaturated fatty acid. In the second experiment, the efficiencies of adding zinc carbonate (150mg/kg diet) with or without soybean oil (5ml/kg diet) to two control rations were tested using 20 weanling pigs. One of the control rations had low zinc (41mg/kg) and normal calcium (0.64%) and the other low zinc (57mg/kg) and high calcium (1.42%). The results obtained are as follow: 1. Content of zinc in the rations induced parakeratosis ranged from 35 to 80mg/kg with a mean of 49mg/kg; whereas those of rations not induced ranged from 97 to 182mg/kg with a mean of 182mg/kg. The difference between two means was highly significant (p<0.01). 2. The calcium content in rations related to parakeratosis was ranged from 0.56 to 1.80% with a mean of 1.30% whereas that of not related was ranged from 0.63 to 1.37% with a mean of 1.07%. The highly significant difference of calcium content between two rations were recognized (p<0.01). The calcium contents of both rations were markedly higher than that of generally recommended value of 0.40~0.80%. 3. The contents of unsaturated fatty acid in induced rations was a mean of 4.42% and it was significantly lower (p<0.01) compared with those in not induced rations with a mean of 6.70%. The content of unsaturated fatty acid of commercial rations was ranged from 5.25 to 7.81% with a mean of 6.29%. 4. Zinc content of 15 commercial ration samples among 23 were less than 97mg/kg and 21 rations contained more than 1.03% of calcium. 5. Addition of zinc carbonate to the two control rations which are low in zinc content or high in calcium content were resulted in preventive effect on the incidence of swine parakeratosis. 6. It may be concluded that the incidence of swine parakeratosis was closely related to the low zinc, excess calcium and low unsaturated fatty acid in rations, most of the commercial rations contained low in zinc and high in calcium as compared with the recommended contents. Content of Unsaturated fatty acids in the commercial rations, however, were sufficient for the prevention of parakeratosis in swine.

• Journal of the Korean Electrochemical Society
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• v.6 no.3
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• pp.203-207
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• 2003

Zinc Air batteries obtain their energy density by utilizing ambient oxygen as the cathode materials. And specific capacity of zinc powder is as high as 820 mAh/g. When Zinc Air battery discharged at low current, then discharge voltage profile has very flat pattern until reach to end of voltage. But, when Zinc Air battery discharged at high current, then discharge voltage and energy becomes very low. So we focused on resistance and porosity of cathode with contents of PTFE. Wf studied on the effects of PTFE on performance of Zinc Air batteries. So we have got optimum contents of PTFE binder.

• Korean Journal of Community Nutrition
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• v.5 no.2
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• pp.152-160
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• 2000

The purpose of this study was to investigate zinc and copper metabolism and risk factors of chronic diseases in 20 normal adults women. The daily intake, excretions in urine and feces, and serum levels of zinc and copper were determined by 24-hr food records and chemical analysis. The results were summarized as follows. mean age, body weight and BMI were 22.88 years, 54.65kg and 21.28kg/$m^2$ respectively. Mean daily intakes of energy and protein were 1578.84㎉(79% of RDA) and 52.05g (87% of RDA). The zinc and copper intake, excrestion in urine and feces were 7093.23$\mu\textrm{g}$(59% of RDA/2093.87$\mu\textrm{g}$, 203.50$\mu\textrm{g}$/39.87$\mu\textrm{g}$ and 3416.41$\mu\textrm{g}$/857.62$\mu\textrm{g}$, respectively. The serum levels of fasting glucose, insulin, total cholesterol, HDL-cholesterol, LDL-cholesterol, triglyceride, zinc and copper were 76.60mg/㎗, 15.66IU/㎗, 160.30mg/㎗, 50.95mg/㎗, 89.80mg/㎗, 89.79mg/㎗, 95.65$\mu\textrm{g}$/㎗ and 73.28$\mu\textrm{g}$/㎗ respectively. Dietary ratio of Zn to Cu was shown to have significant positive correlations with serum insulin, total cholesterol, LDL-cholesterol. The urinary ratio of Zn to Cu was shown to have significant positive correlations with triglyceride. The serum copper level was shown to have significant negative correlations with serum total cholesterol and LDL-cholesterol. In summary, Zn consumption of adult women in their normal diet does not meet the Zn requirement for Koreans. Also, intakes of Zn and Cu may effect the glucose metabolism and cardiovascular diseases. Therefore, to increase the Zn intake and to maintain an appropriate intake ratio of Zn to Cu, nutrition education needs to be implemented.

• Journal of Preventive Medicine and Public Health
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• v.16 no.1
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• pp.19-24
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• 1983

In order to study the effects of iron and zinc on the lead poisoning of rats, lead with iron and zinc, or lead alone were administered orally to a total of 98 adult rats of Sprague-Dawley Species. The concentrations of lead, zinc, and iron were measured by atomic absorption spectrophotometer at every 20 days intervals of 20th, 40th, 60th, 80th and 120th day as a final measurement. Those datas were analysed and compared with those of control groups. The results were summarized as follows; 1. The concentration of lead in blood, bone. and liver tissues kept increasing in case of lead exposure group whereas it started decreasing at 60-80th day when concentration of zinc started increasing in case of combined exposure group. However, in kidney tissue, the concentration of lead in combined exposure group kept increasing up to the end of observation showing special high concentration at the final measurement at 120th day. 2. Concentration of zinc in blood and liver tissues had increased from 60-80th day in case of combined exposure group. 3. Concentration of iron in blood showed decreasing from $44.15{\pm}9.67\;to\;32.44{\pm}2.69{\mu}g/ml$ in case of lead exposure group, whereas it showed constant level of $47.50{\sim}45.65{\mu}g/ml$. However, in liver tissue it kept constant as control did from 40th to 60th days, but from 100th day on it started increasing to show much higher concentration than control.

• Journal of Nutrition and Health
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• v.25 no.7
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• pp.608-616
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• 1992

Using the hematofluiorometer normal values of the erythrocyte zinc protoporphyrin(ZPP) and ZPP/Heme ratio were measured in 312 males and 163 females aged from 6 month to 73 years old and compared with those of anemic persons. The mean$\pm$SD values of ZPP of normal Koreans were 28.5$\pm$6.4($\mu\textrm{g}$/dl) in males and 3.18$\pm$7.7 in females. the mean$\pm$SD of ZPP/Heme ratio were 49.5$\pm$12.3($\mu$mol/mol heme) in males and 62.0$\pm$15.8 in females. The difference in the mean ZPP and ZPP/Heme ratio values between male and female subjects were statistically signficant(p<0.0001) In male subjects the mean ZPP and ZPP/Heme ratio of the age groups less than 15 years old were higher than adult groups and the difference between age groups was significant(p<0.005 and p<0.0001 respecti-vely) The normal upper limit of the mean$\pm$2SD in normal male and female subjects were 41.3 and 47.2 for ZPP and 74.1 and 93.6 for ZPP/Heme ratio respectively. The mean values of ZPP and ZPP/Heme ratio measured in the anemic persons were higher than those of normal subjects and did not show any significant difference by the sex and age groups except in 6-14 years male groups. The test specificity(positivity) analyzed in the anemic persons by the cut-off values calculated from the normal data were 50.6% for ZPP and 73.0% for ZPP/Heme ratio. The correlation analysis between blood hemoglobin and erythrocyte ZPP or ZPP/Heme ratio in the total 801 normal and anemic subjects showed that there are very high logarithmic correlation between the hemoglobin levels and ZPP/Heme ratio (r=-0.8339) and high correla-tion between the hemoglobin levels and ZPP concentrations(r=-0.6372) These results suggested that the measurement of the erythrocyte ZPP and ZPP/Heme ratio with the hematofluorometer can be a usuful screening method for iron deficiency anermin because they provide a reliable immediate results with a small amount of sample and are relatively simple and inexpensive.

• Proceedings of the KAIS Fall Conference
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• 2011.05a
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• pp.327-331
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• 2011

Zinc oxide (5, 10 and 15 wt%) impregnated NaZSM-5 zeolite synthesized using rice husk ash as silica source was tested for $CO_2$ adsorption. The materials were characterized by XRD, SEM-EDS, $CO_2$-TPD and BET techniques. The heat of the reaction (${\Delta}$Hr) derived from DSC for ZnO(10%)/NaZSM-5 was found to be 495 Btu/lb and the maximum $CO_2$ adsorption capacity of ZnO(10%)/NaZSM-5 is 140 mg/g of sorbent. Extraction of silica from the agricultural waste, rice husk and its use in the zeolite synthesis is an added advantage in this study. Hence, from the study it is concluded that zinc oxide impregnated NaZSM-5 could be treated as novel material for $CO_2$ adsorption as they were found to be regenerable, selective and recyclable.

• Korean Journal of Crystallography
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• v.15 no.2
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• pp.69-73
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• 2004

The hydro(solve)thermal reaction of zinc(II) nitrate $(Zn(NO_3)_2{\cdot}6H_2O)$ with $1,3-BDCH_2\;(1,3-BDC= 1,3-benzenedicarboxylate)$ in the presence of pyridine a gave 1-dimensional zinc polymer $[Zn(1,3- BDC)({\mu}_4-O)\;(pyridine)_2]$ (1). X-ray structure determination revealed that polymer 1 has a quadruply bridging oxygen $({\mu}_4-O)$ ligand. This polymer consists of two strands linked by 1,3-BDC ligands, and each strand is formed by connecting the monomer units by 1,3-DBC ligands.

• Transactions on Electrical and Electronic Materials
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• v.16 no.3
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• pp.135-138
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• 2015

A manganese dioxide (MnO₂) layer and zinc (Zn) layer are used as the cathode and the anode to develop filmtype manganese battery, in which a stack of a MnO₂ layer, gel electrolyte, and Zn layer are sandwiched between two plastic layers. This paper describes the chemical equation of swelling control upon the film-type manganese battery. We examined the reduction of hydrogen formation, by using calcium hydroxide Ca(OH)₂ as an additive in the electrolyte of film-type manganese battery. The phenomena or an effect of reduced hydrogen gas was proven by cyclic voltammogram, X-ray photoelectron spectra (XPS), and volume of hydrogen formation. The amount of H₂ gas generation in the presence of Ca²⁺ ion was reduced from 4.81 to 4.15 cc/g-zinc (14%), and the corrosion of zinc electrode in the electrolyte was strongly inhibited as time passed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.292-293
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• 2006

$ZnNb_2O_6$ ceramics were sintered under the presence of zinc-borosilicate(ZBS) glass and resultant microwave dielectric properties were investigated with a view to applying the composition to LTCC technology. The addition of 10~30 wt% ZBS glass ensured successful sintering below $900^{\circ}C$. In general, increased addition of ZBS glass increased sinterability but it decreased the dielectric properties significantly due to the formation of an excessive liquid and second phases. The sintered $ZnNb_2O_6$ ceramics at $900^{\circ}C$ with 25 wt% ZBS glass demonstrated 15.8 in dielectric constant(${\varepsilon}_r$), 5,400 in quality factor($Q{\times}f_0$), and $-98\;ppm/^{\circ}C$ in temperature coefficient of resonant frequency(${\tau}_f$).

• Journal of the Korean institute of surface engineering
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• v.20 no.4
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• pp.144-153
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• 1987

In the case of dipping the Ni-Resist cast iron into molten aluminum with iron content, the thickness of intermetallic compound was remarkably increased with increasing iron content. The thickness was shown by following equation in the range of 1-3% iron content; $x=22.5t^{1/2}+4.47{\cdot}t{\cdot}(Fe%)$. where, x is thickness(${\mu}m$), t the time (minute), Fe% the iron w/o. When the Ni-Resist cast iron was dipped into the molten aluminum containing zinc content, the intermetallic compound thickness was also increased with increasing zinc contents. And thickness was represented by the following equation in the range of 2-10% zinc content; $x=3.46t^{1/2}+0.27{\cdot}t{\cdot}(Zn%)$. However, in the case of dipping the Ni-resist cast iron into molten aluminum with silicon content, the thickness of intermetallic compound was decreased with increasing silicon content, as shown in the following equation; $x=7.17t^{1/2}-0.15{\cdot}t{\cdot}(Si%)$. The intermetallic compound formed onto Ni-Resist cast iron was identified to be $FeAl_3\;and\;Fe_3Al$. As the result of hardness measurement, the peak hardness appeared in the intermetallic compound at near interface of the cast iron and the compound.