• Korean Journal of Soil Science and Fertilizer
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• v.17 no.3
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• pp.232-241
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• 1984

For the purpose of investigating the effect of chemical composition of nitrogenous fertilizers such as urea, ammonium sulfate, ammonium phosphate(dibasic) and aqua-ammonia on growth, yield, efficiency and chemical properties of paddy soil this study was carried out at the same nitrogen concentration through field experiment. The results obtained was summarized as follows. 1. Nitrogenous fertilizers had an effect on plant height at heading stage, plant weight at harvest and No. of spikelet per panicle of rice plants in decreasing order: Ammonium sulfate > Diammonium phosphate > Urea > Ammonia water. But they didn't effect on culm length, spike length, dry matter weight, No. of grain per spike, ripening ratio and weight of 1000 grains of rice plants. 2. The absorbed amount of nitrogen and that of sulfur and nitrogen availability were highest in ammonium sulfate application and lowest in ammonia water application and these were positively correlated with yield. 3. The influence of nitrogenous fertilizers on nitrogen and sulfur efficiency and translocation efficiency was insignificant but that of ammonium sulfate on nitrogen efficiency was higher than that of the others. 4. The effect of nitrogenous fertilizers on a basic chemical properties of paddy soil experimented such as pH, C.E.C, exchangeable cation and organic matter was insignificant. But the sulfur content of ammonium sulfate application and phosphorous content of diammonium phosphate application were higher than that of the others.

• Resources Recycling
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• v.28 no.3
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• pp.15-20
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• 2019

The recovery of struvite using nitrogen and phosphorus in wastewaters is useful for prevention of eutrophication and use as fertilizer, but there are theoretical and technical issues to be resolved. Through the detailed literature review, this study discusses the possible reasonable prediction of struvite formation reaction by setting a feasible reaction equation with some theoretical considerations. In a technical aspect, the purity of struvite in solid precipitates can be promoted by excluding Ca in an effective way. As for the struvite reaction prediction issue, selection of proper equilibrium reaction as well as its reaction equilibrium coefficient is significant in the neutral and basic pH regions. The equilibrium reaction agrees well with the experimental batch test results. Considering the charge balance of the ions, the pH drop along struvite formation in a diluted solution can be predicted. Also, improvement of struvite purity through elimination of Ca can be expected by providing a highly concentrated ${NH_4}^+-N$ relative to ${HPO_4}^{2-}-P$ because ${NH_4}^+$ can enhance the thermodynamic driving force toward favorable struvite formation. Even though the phosphate reacts rapidly with Ca to form a solid precipitate, the thermodynamic driving force due to the high ${NH_4}^+$ activity can dissociate the phosphate-calcium precipitates and produce struvite.

• Journal of the Korean Wood Science and Technology
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• v.13 no.4
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• pp.3-57
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• 1985

This research was conducted to examine the feasibility of developing fire retardant particleboard and complyboard. Particleboard were manufactured using meranti particle(Shorea spp.)made with Pallmann chipper, and complyboard meranti particle and apitong veneer (Dipterocarpus spp.). Particles were passed through 4mm (6 mesh) and retained on 1mm (25 mesh). Urea formaldehyde resin was added 10 percent on ovendry weight of particle. Face veneer for complyboard was 0.9, 1.6 and 2.3mm in thickness and spread with 36 g/(30.48 cm)$^2$ glue on one side. Veneers were soaked with 10 percent solution of five fire retardant chemicals (diammonium phosphate, ammonium sulfate, monoammonium phosphate, Pyresote and Minalith), and particles with 5, 10, 15 and 20 percent solution of five chemicals. Particleboard and complyboard were evaluated on physical and mechanical properties, and fire retardancy. The results obtained were summarized as follows. 1. Among five fire retardant chemicals treated to particleboard and complyboard, the retention of ammonium sulfate in 5 percent solution showed the lowest as 1.39 kg/(30.48 cm)$^3$ exceeding the minimum retention of 1.125 kg/(30.48 cm)$^3$ recommended by Forest Products Laboratory and Koch. 2. Particleboard and complyboard treated with diammonium phosphate showed higher modulus of rupture (MOR), modulus of elasticity (MOE), internal bond strength and screw holding power than those with the other chemicals. 3. MOR and MOE of complyboard treated with fire retardant chemicals were greater than those of fire retardant particleboard. 4. Thickness swelling of fire retardant complyboard was lower than that of fire retardant particleboard. 5. The moisture content of the boards treated with Pyresote and Minalith increased and with monoammonium phosphate reduced. 6. Fire retardant particleboard showed no ignition, and fire retardant complyboard started ignition, but time required to ignite was prolonged comparing the controlboard. Complyboard with only shell veneer treated showed ignition and lingering flame, but lingering flame time was shorter than controlboard. Complyboard with treated both core and veneer showed ignition but not lingering flame. 7. Flame length, carbonized area and weight loss were smaller than controlboard but had no significant difference among chemicals treated. 8. Temperature of unexposed surface of fire retardant particleboard was lowered with the increasing concentration of five chemicals. 9. Temperature of unexposed surface of fire retardant particleboard was lowered with the highest in Pyresote and the lowest in Minalith. 10. Temperature of unexposed surface of fire retardant complyboard was lower than that of controlboard.

• Journal of the Korea Institute of Building Construction
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• v.17 no.1
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• pp.23-30
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• 2017

The aim of the research is to suggest an economical and sustainable method of reducing pH of recycled aggregate as an embanking and a covering materials. Because of the unhydrated cement based materials on the surface of the recycled aggregate, it causes a severe problem on environment with leaked high alkali water from embankment and covering by using recycled aggregate. In this research, to reduce the pH of recycled aggregate, regarding the recycled fine aggregate, eight different methods were tested and analyzed with three different categorized: natural treatment, artificial treatment, and chemical treatment. From the results of experiment, it was considered that the most efficient method of reducing pH of recycled aggregate was the chemical treatment using acid such as $CO_2$ acceleration or monoammonium phosphate (MAP), and diammonium phosphate (DAP). Especially, using MAP and DAP, fertilizers, is the most efficient method of reducing pH with its time duration and performance.

• Applied Chemistry for Engineering
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• v.8 no.5
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• pp.749-755
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• 1997

Molybdenum phosphate(P/Mo = 0.6) has been synthesized with ammonium molybdate and phosphoric acid under aqueous solution. The kinetics of the ammoxidation of methylpyrazine over molybdenum phosphate catalyst was investigated with the variation of reaction temperature and partial pressure of methylpyrazine, oxygen and ammonia, respectively at atmospheric pressure. The catalytic activity was constant for 300hrs operation under our experimental conditions. Under the steady-state condition, the rate equation of methylpyrazine was shown as $-r=kP_{MP}P_{NH3}{^0}P_{O2}{^{\gamma}}({\gamma}=2.2;1.3{\leq}P_{O2}(kPa){\leq}4)$. The apparent activation energy was 29.6kcal/mol below 623K. The main product obtained in the ammoxidation of methylpyrazine is cyanopyrazine whose selectively was kept always over 90% regardless of conversion.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.84-87
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• 2009

본 연구는 건축용 바닥재로 널리 이용되는 PVC 상재의 표면을 열에 의한 손상으로부터 보호하기 위하여 기존에 사용하는 광경화형 우레탄-아크릴 수지에 내열성(anti-cigar burning)을 향상시킨 광경화형 수성도료 개발에 관한 것이다. PVC 바닥상재용으로 사용되는 내열기능성이 없는 우레탄-아크릴 수지에 인계화합물을 주원료로 합성한 내열재, 구아니딘을 주원료로 합성한 내열재, 일시적 방염제로 사용되는 제 2인산암모늄을 수지의 양 대비 함량(wt%)을 10, 20, 30%로 변화하여 첨가한 후 배합하여 수지의 내열성을 향상시킨 코팅액을 제조하였다. 제조한 코팅액은 코팅층의 두께조절이 가능한 Bar-coating을 사용하여 PVC 바닥상재에 코팅한 후, 내열성, 부착력, 내화학성, 코팅두께 등의 코팅층 표면물성을 평가하였다. 연구결과, 수지에 인계화합물을 주원료로 합성한 내열재 30%를 혼합하여 제조한 코팅액을 Bar-coater No.12로 코팅한 코팅표면이 열에 의한 손상이 가장 적고, 부착력 100%, 내화학성 양호로 가장 좋은 물성을 보였다. 전반적으로 내열재 함량이 높고 코팅 두께가 두꺼울수록 내열성이 우수한 것으로 나타났다.

• The Korean Journal of Food And Nutrition
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• v.10 no.1
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• pp.44-52
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• 1997

Nephrolithiasis is the most common disorder of the urinary tract in hospitalized patients, more frequently increased in 30~50 years of age, more common in males than in females, prior right stone to left side, and than upper ureteral stone is found in cultural country, while lower ureteral stone is increased in uncultural country. Stone components are classified as calcium oxalate, calcium phosphate, magnesium ammonium phosphate, uric acid, cystine, and their mixed stone, respectively. According to the pathophysiology of urinary stones, supersaturation/crystalization of inorganic salt concentration in urine, organic matrix, inhibitor deficiency, and epitaxy theory could be based on the stone formation. Not only hypercalciuria, hyperparathyroidism, hyperoxaluria, hyperuricosuria, and cystinuria, but also renal tubular acidosis, hypervitaminosis D, and peptic ulcer, are significantly associated with nephrolithiasis. In this study upper ureteral stone component were analyzed with chemical analysis, infrared spectrum, and image analyzer from K43 patient wit erosive gastritis. As the results, mixed stone of calcium oxalate dihydrate and calcium phosphate apatite was identified, the values of clinical test in blood and urine maintained normal revels. The relapsing urinary stone from K43 have no correlation between factors for stone formation reported early, also have no evidence for risk from erosive gastritis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.2
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• pp.608-613
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• 2010

This study is on development of UV-cured water soluble coating composition which have more improved anti-cigar burning to prevent a surface of PVC tile from damage of heat. To make an anti-cigar burning coating solution, thermostable agent that synthesize main materials phosphorus compound, guanidine and ammonium phosphate dibasic used temporary flame retardants, changing their contents from 10 to 30wt% against quantities of resin and compounded. After coating PVC tiles using bar-coating method that can adjust a thickness, we estimated surface properties of coated layer such as anti-cigar burning, adhesive power, chemical resistance, thickness of coating, and so on. Results showed that a coating composition added 30 wt% of phosphorus compound and coated with No.12 bar-coater had the best optimized surface property in anti-cigar burning effect, adhesive power and chemical resistance. Also, we could find anti-cigar burning effect was improved as thermostable agents content and coating thickness increased.

• Korean Journal of Organic Agriculture
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• v.15 no.2
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• pp.219-228
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• 2007

강원도 고랭지는 채소 재배지로 그 이용 면적이 매년 급속히 증가하고 있다. 금한 경사와 집중적으로 발생하는 장마철의 폭우는 토양 유실은 물론이고 토양 비옥도의 심각한 저하를 초래할 위험이 경작의 강도와 범위가 넓어짐에 따라 더욱더 증가하고 있다. 또한 험한 지형에 따른 기계화 영농의 어려움과 이에 수반하는 노동력의 낭비로 문제점을 제기한다. 채소 작물 재배를 위해 많이 사용하는 요소 비료, 황산암모늄 비료와 함께 특별히 수지(resin)를 피막 처리한 복합비료를 가지고 배추의 생장과 토양에 미치는 영향을 조사하였다. 수지 피막처리는 각각 7, 10, 15%의 비율로 혼합했다. 배추의 수량은 실험에 사용된 비료간에 큰 차이가 없었다. 요소와 황산암모늄은 기본 시비와 함께 2차례 추비를 하였고 수지 피막 복합 비료는 단 한번 초기에 시비하였다. 따라서 이 경우 노동력 절감과 토양 환경 교란의 최소화를 달성할 수 있었으므로 완효성의 수지 피막 처리 비료가 바람직한 것으로 나타났다. 토양에 미치는 효과는 비료의 종류간에 별다른 차이가 없었으나 인산$(P_2O_5)$의 토양내 축적 현상이 t지 피막 처리 복합 비료 시용 구에서 뚜렷하게 조사되었다. 일반적으로 화학 비료의 시용은 토양 반응(pH)의 저하를 초래하였다.

• Microbiology and Biotechnology Letters
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• v.10 no.2
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• pp.133-144
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• 1982

The distribution of acid phosphatase activity was investigated with 141 microorganisms from the type culture collection of Chong Kun Dang laboratory and the 41 strains isolated from natural sources. The phytase activity was detected mainly with fungal strains. A fungus isolated from soil and identified as Aspergillus niger had shown the highest phytase activity. The environmental conditions for the enzyme formation by the isolate and some properties of the enzyme were also studied. The results obtained were as follows: (1) The highest phytase production was observed when the fungus was cultivated at 28$^{\circ}C$ for 5 days in the corn starch based medium using the cells incubated at 34$^{\circ}C$ for 3 days as a seed. (2) The optimal initial pH of the culture medium was found to around 2 for the formation of phytase. (3) Sucrose was proved to be one of the most effective carbon sources tested for the enzyme production. (4) As an inorganic nitrogen source, potassium nitrate was found to give a good result in the production of phytase. (5) Synthesis of phytase was significantly increased by the supplement with 0.2 % corn steep liquor to the basal medium as an organic nitrogen source. (6) At the concentration of 40-80 mg inorganic phosphate per liter of the culture medium, the enzyme formation revealed the highest level. But as the phosphate was increased above this optimum concentration the phytase activity was drastically decreased although the cell density showed to be still increasing