• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1999년도 제30회 추계학술대회
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• pp.213-218
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• 1999

Friction and wear characteristics of novolac resin-based friction materials reinforced with aramid pulp and potassium titanate were investigated by using a pad-on-disk type friction tester. Friction properties such as friction stability, surface morphology, and wear rate varied according to the relative amount of aramid pulp and potassium titanate. The friction materials reinforced with both aramid pulp and potassium titanate showed superior friction stability and wear resistance due to the formation of durable transfer layer.

• Tribology and Lubricants
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• 제15권4호
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• pp.314-320
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• 1999

Friction and wear characteristics of phenolic resin-based friction materials reinforced with aramid pulp and potassium titanate were investigated using a pad-on-disk type friction tester. Friction characteristics such as friction stability, thermal stability, and wear rate varied according to the type of phenolic resins and the relative amount of aramid pulp and potassium titanate. The modified novolac resin-based friction materials showed better heat resistance and friction stability than those with the unmodified(straight) novolac resin. Compared with friction materials filled with potassium titanate or aramid pulp only, the friction materials reinforced with both aramid pulp and potassium titanate showed good friction stability and wear resistance. Increment of aramid pulp from 10 to 20 vol.% however, showed little difference in friction stability.

• 한국세라믹학회지
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• 제35권12호
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• pp.1241-1248
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• 1998

$\beta$-C2S and C4A3 were synthesized separately and potassium oxalate was added to each system. The ad-ditive caused calcium ions in solution to decrease at early time in hydration and promoted hydration reac-tion. And then clinker which is mainly composed of $\beta$-C2S and C4A3 was synthesized at 130$0^{\circ}C$ After ad-ding potassium oxalate to it behavior of hydration was observed. It showed that the additive promoted et-tringtie formation at early time and C-S-H formation as time went on.

• 상하수도학회지
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• 제25권5호
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• pp.643-649
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• 2011

Degradation of benzothiophene(BT) in the aqueous phase by potassium ferrate(VI) was investigated. Potassium ferrate(VI) was prepared by the wet oxidation method. The degradation efficiency of BT was measured at various values of pH, ferrate(VI) dosage and initial concentration of BT. BT was degraded rapidly within 30 seconds by ferrate(VI). While the highest degradation efficiency was achieved at pH 5, the lowest degradation efficiency was achieved at pH 9. Also, the initial rate constant of BT increased with decreasing of the BT initial concentration. In addition, the intermediate analysis for the reaction of BT and ferrate(VI) has been conducted using GC-MS. Benzene, styrene, benzaldehyde, formaldehyde, benzoic acid, formic acid, and acetic acid were identified as reaction intermediates, and ${SO_4}^{2-}$ was identified as an end product.

• 한국산업보건학회지
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• 제20권4호
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• pp.236-240
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• 2010

This study demonstrates the use of a chemical containing potassium superoxide (KO2) to convert carbon dioxide (CO$_2$) in air to oxygen (O$_2$). A oxygen generating closed-circuit SCBA (self contained breathing apparatus) removes carbon dioxide by a chemical reaction with potassium dioxide that consumes the carbon dioxide and produces oxygen. Considering the disasters, there is a need to develop strategies to enable the introduction of self-contained self rescuers (SCSR). The potassium superoxide reacts with the wears breath to produce oxygen and absorb carbon dioxide. If the respiration rate of a person is 5 MET (metabolic equivalent), to say 30 L/min, at disaster such as fire, mass of potassium superoxide was evaluated as 33.3 g with yield and safety factor. Four researchers tested on a laboratory treadmill breathing through SCSRs in a closed circuit, it appears useable for 9 minutes.

• 한국작물학회지
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• 제22권2호
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• pp.42-47
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• 1977

사역토에 대한 질소분시와 가리분시 질소, 가리 혼합분시가 수도의 수량형질 및 생리적 특성에 미치는 영향을 구명하고자 시험한 결과를 요약하면 다음과 같다. 1. 수도 생육기간 동안 관행에 비하여 실소분시하였을 경우 20%, 가리분시하였을 경우 18%, 질소, 가리혼합분시하였을 경우 22%의 증수 효과가 있었다. 2. 수도근의 생리적활력은 가리분시에 의하여 높았다. 3. 엽신 엽연소함양과 미분함량은 질소분시에 의하여 증가되였다. 4. $\alpha$-naphthylamine에 의한 상위근 산화력과 엽록소함량과는 정의 상관관계가 있었다. 5. 수도체 가리합량과 미분함량과는 부의 상관관계가 있었다. 6. 무기영양함량은 관행에 비하여 질소, 가리 혼합분시에 의하여 수도체내 영양균형을 이루어 수도생육에 좋은 영향을 미치고 있었다.

• Journal of Nutrition and Health
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• 제28권7호
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• pp.612-619
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• 1995

This study was to investigate the intake of human milk, sodium and potassium of breast-fed infants at 7, 15, 30, 60 and 90 days postpartum. Milk samples were obtained from 20 healthy lactating women living in In-Cheon area. Milk intakes of 20 breastfed infants were determined by the test-weighing method and soldium and potassium contents of human milk were analyzed by Atomic Absorptin Spectrophotometer after Wet-Digestion. Infant milk intakes per day tended to increase during lactation. The mean($\pm$SD) intakes at 7, 15, 30, 60 and 90 day were 460(164), 547(202), 626(199), 718(139) and 688(162)g/day, respectively. The sodium contents decreased significantly from 9.7(1.1)mEq/kg at 7 day to 6.3(1.8)mEq/kg at 90 day(p<0.05). The sodium intakes of infants were 100.8(39.6), 103.3(46.7), 107.2(47.9), 115.5(41.5) and 105.2(41.2)mg/day, respectively and average intake was 107.2(43.9)mg/day. The potassium contents were ranged from 10.5(1.3) to 13.3(2.3) mEq/kg and the potassium intakes of infants were 241.8(11.2), 267.8(98.8), 314.1(98.6), 318.0(66.1) and 276.1(62.6)mg/day, respectively and average intake was 288.3(91.8)mg/day. The mean sodium and potassium intakes of infants between boys and girls were not significantly different at 5% level.

• The Korean Journal of Physiology and Pharmacology
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• 제7권2호
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• pp.73-77
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• 2003

The effects of nitric oxide on the vestibular function recovery following unilateral labyrinthectomy (UL) were studied. Sprague-Dawley male rats, treated with nitric oxide liberating agent sodium nitroprusside (SNP) and NOS inhibitor $N^G$-nitro-L-arginine methyl ester (L-NAME), were subjected to destruction of the unilateral vestibular apparatus, and then spontaneous nystagmus was observed in the rat. To explore the effects of nitric oxide on the neuronal excitability, whole cell patch clamp technique was applied on isolated medial vestibular nuclear neurons. The frequency of spontaneous nystagmus in SNP treated rats was lesser than that of spontaneous nystagmus in control animals. In contrast, pre-UL treatment with L-NAME resulted in a significant increase in spontaneous nystagmus frequency. In addition, SNP increased the frequency of spontaneous action potential in isolated medial vestibular nuclear neurons. Potassium currents of the vestibular nuclear neurons were inhibited by SNP. After blockade of calcium dependent potassium currents by high EGTA (11 mM) in a pipette solution, SNP did not inhibit outward potassium currents. 1H-[1,2,4] oxadiazolo [4,3-a] quinozalin-1-one (ODQ), a specific inhibitor of soluble guanylyl cyclase, inhibited the effects of SNP on the spontaneous firing and the potassium current. These results suggest that nitric oxide after unilateral labyrinthectomy would help to facilitate vestibular compensation by inhibiting calcium-dependent potassium currents through increasing intracellular cGMP, and consequently would increase excitability in ipsilateral vestibular nuclear neurons.

• The Korean Journal of Physiology
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• 제10권2호
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• pp.23-28
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• 1976

Author have already reported that urinary aldosterone excretion of the Korean who usually eat high sodium diet is significantly lower comparing with the American, although the plasma aldosterone concentration is identical in the former with that of the latter. Measurement of urinary aldosterone excretion and Plasma concentration only is insufficient to establish the pressence and/or mode of evolution of the Korean. In this experiments, aldosterone secretion rate(ASR) was measured in normotensive Korean during high and low dietary sodium intake with or without additional potassium supply. Results were as follows; 1) In normal Korean, dietary sodium restriction resulted in appreciable increase in ASR, and a sustained increase in urinary aldosterone excretion with an increase in plasma level. 2) Oral potassium loading easily stimulated the adrenal cortex of the Korean who already adapted to a high sodium diet when dietary sodium is still identical with not·mal American. 3) Quantitative relationships between aldosterone secretion rate, plasma concentration and urinary excretion of aldosterone were altered by potassium loading. 4) Urinary aldosterone excretion didn't reflect concurrent increase aldosterone secretion in subjects with Potassium intake. It was discussed that the changes of tile relationships and of adrenal hyper response on Potassium Beading in the Korean will be elucidated by measuring the metabolic clearance rate.

• KSBB Journal
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• 제30권3호
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• pp.97-102
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• 2015

This study aimed to evaluate the potential plantgrowth promoting effects of potassium polyacrylate, a superabsorbent polymer, and Bacillus sp. SH1RP8, a family of plant-growth-promoting bacteria. Potassium polyacrylate was selected as the polymer for use due to its high molecular weight and its ability to retain and continuously supply moisture. Plant-growth-promoting rhizobacteria (PGPR) were isolated from the soil and applied to plants growing in dry environments, such as saline conditions. The moisture absorption and retention abilities of potassium polyacrylate were evaluated at a high temperature ($50^{\circ}C$) and in a dry condition, during which time the polymer showed a water retention potential of 19606.07% after 29 days. To overcome the reaming problem in the soil environment, natural polymers (such as cellulose) were mixed with the potassium acrylate. The shoot growths of Peucedanum japonicum Thunb and Arundo donax were significantly enhanced when treated with the mixture of the isolated rhizosphere bacterium SH1RP8 and potassium polyacrylate (63.5 and 124.3%, respectively).