• The Korean Journal of Ceramics
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• 제3권3호
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• pp.187-190
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• 1997

The aluminum-magnesium (Al-Mg) aklloys have been proved to be an effective solvent for synthesis of cubic-phase boron nitride (cBN) from hexagonal-phase boron nitride (hBN) at the conditions of high pressures and high temperatures (HP/HT). Various kinds of hBN powders having different crystallinity have been tested for cBN synthesis with Al-Mg solvents. The conversion ratio from hBN to cBN and the shape of synthesized cBN crystals appeared to be affected strongly by chemical composition and added amount of Al-Mg solvents as well as crystallinity of BN powders. As the magnesium content increased in the Al-Mg solvents, the conversion ratio increased and the size of cBN crystals became larger. The crystal facets developed well in the specimens with solvents having high Mg content. It was observed that a hBNlongrightarrowcBN transformation occurred more easily in the specimens having well crystallized hBN powders. Amorphous BN having much $B_2O_3$ impurity exhibited a low threshold temperature for transformation to cBN, which was attributed to crystallization of amorphous BN to well crystallized hBN prior to transformation into cBN with help of $B_2O_3$.

• Nuclear Engineering and Technology
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• 제45권1호
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• pp.61-66
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• 2013

Among the radioactive wastes generated from the nuclear power plant, a radioactive nuclide such as $^{129}I$ is classified as a difficult-to-measure (DTM) nuclide, owing to its low specific activity. Therefore, the establishment of an analytical procedure, including a chemical separation for $^{129}I$ as a representative DTM, becomes essential. In this report, the adsorption and recovery rate were measured by adding $^{125}I$ as a radio-isotopic tracer ($t_{1/2}$ = 60.14 d) to the simulation sample, in order to measure the activity concentration of $^{129}I$ in a pressurized-water reactor primary coolant. The optimum condition for the maximum recovery yield of iodine on the anion exchange resins (AG1 x2, 50-100 mesh, $Cl^-$ form) was found to be at pH 7. In this report, the effect of the boron content in a pressurized-water reactor primary coolant on the separation process of $^{129}I$ was examined, as was the effect of $^3H$ on the measurement of the activity of iodine. As a result, no influence of the boron content and of the simultaneous $^3H$ presence was found with activity concentrations of $^3H$ lower than 50 Bq/mL, and with a boron concentration of less than 2,000 ${\mu}g/mL$.

• 열처리공학회지
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• 제8권1호
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• pp.75-83
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• 1995

The purpose of this study is to investigate the effect of heat treatments on the martensite transformation and tensile deformation behavior in Ti-Ni-B alloys with various boron concentration. Three types of heat treatment are given to the specimens; i) solution treatment ii) aging iii) thermo-mechanical treatment. In solution treated specimens. R-phase transition which is related to abnormal increase of electrical resistance prior to martensitic transformation has been formed at a boron content of 0.2at % and the $M_s$ temperature has been decreased with the increasing of boron content. However. It has not been affected by aging, while that of thermo-mechanically treated specimens has been remarkably increased in the vicinity of recrystallization temperature. The thermo-mechanically treated specimen has showed a good thermal fatigue characteristics, shape memory effect and superelasticity in comparison with the solution treated specimen.

• 소성∙가공
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• 제32권3호
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• pp.160-165
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• 2023

As the supply of eco-friendly vehicles increases, the application rate of hot stamping components is rising to reduce vehicle weight and improve safety. Although Al-Si coated steel sheets are commonly used in hot stamping processes, their manufacturing costs are elevated due to process patents and royalties. Various hot stamping studies have been conducted to reduce these production costs. In this study, we derived a process control method for suppressing the oxide layer of hot stamping parts using uncoated boron steel sheets. Firstly, hat-shaped parts were hot stamped under atmospheric conditions to analyze the tendency of oxide layer formation by location. Then, the Gleeble system was used to observe oxide layer formation based on oxygen content under various atmospheric conditions. Finally, the oxide layer thickness was quantitatively measured using SEM images.

• 한국토양비료학회지
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• 제16권1호
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• pp.72-76
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• 1983

무우의 붕소결핍증(硼素缺乏症)으로 알려진 근부흑변현상(根部黑変現象)의 발생원인(発生原因)과 품종별(品種別) 발생율차이(発生率差異) 및 붕소(硼素) 시용효과(施用効果)를 검토(検討)하기 위하여 수용성붕소함량(水溶性硼素含量)이 0.20ppm인 사질양토(砂質壤土)에서 6개(個)의 봄무우품종(品種)을 공시(供試)하여 붕소무시용구(硼素無施用区), 엽면살포구(葉面撒布区)(붕소(硼素) 0.5ppm, 3회살포(回撒布)), 토양(土壤) 시용구(施用区)(붕사(硼砂) 1.5kg/10a)를 설정(設定)하여 실시(実施)한 시험결과(試験結果)를 요약(要約)하면 다음과 같다. 1. 무우의 근흑변(根黑変) 개체발생률(個体発生率)은 평균(平均) 무시용구(無施用区) 70%, 엽면살표구(葉面撒布区) 52%, 토양시용구(土壤施用区) 4%이였고 품종간(品種間) 발생률(発生率)은 각(各) 구별(区別)로 각각 45~90%, 30~85%, 0~l5% 범위(範圍) 내(內)에 있었다. 2. 엽중(葉中)의 평균(平均) 붕소함량(硼素含量)(파종후(播種後) 65일(日))은 무시용구(無施用区) 16.8ppm 엽면살포구(葉面撒布区) 20.3 ppm 토양시용구(土壤施用区) 36.2ppm 이였다. 3. 무우의 급격한 근비대(根肥大) 시기(時期)는 파종후(播種後) 55일(日)에서 65일(日) 사이었으며 이 기간중(期間中)의 엽중(葉中) 붕소함량(硼素含量)은 무시용구(無施用区)와 엽면살포구(葉面撤布区)에서는 근비대(根肥大)와 더불어 감소(減少)하는 경향(傾向)을 보여 이 시기(時期)에 붕소(硼素)의 공급량(供給量) 부족(不足)으로 흑변현상(黑変現象)이 발생(発生)되는 것으로 나타났다. 이와 반대(反対)로 토양시용구(土壤施用区)에서는 이 시기(時期)에 엽중(葉中) 붕소함량(硼素含量)이 약간 증가(増加)하였다. 4. 근흑변발생률(根黑変発生率)은 엽중붕소함량(葉中硼素含量)과 높은 상관(相関) ($r=-0.755^{**}$)이 있었으나 품종간(品種間) 근흑변발생률(根黑変発生率) 차이(差異)는 붕소함량(硼素含量)과는 일정(一定)한 관계(関係)가 없었다.

• Nuclear Engineering and Technology
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• 제13권4호
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• pp.229-236
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• 1981

중성자포획 감마선 방사화분석법을 이용하여 원자로급 알루미늄중 붕소를 분석하였다. 실험에 의한 검출한계는 10% 불확실도의 경우 5.7ppm 이었다. 함량이 더욱 미량인 경우를 위하여 양이온 교환수지를 이용하며 알루미늄으로 부터 붕소를 사전분리하는 농축법을 개발하였다. 이 두 방법 즉 직접 측정하는 방법과 농축후 측정하는 두가지 방법의 정확도를 첨가법으로 조사하였다. 그 결과 5% 편차 이내에서 잘 일치하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제12권6호
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• pp.1002-1008
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• 1999

Essential metabolic functions have been identified for seven macrominerals (calcirum, phosprorus, magnesium, sodium, potassium, chloride, and sulfur), and eight microminerals (cobalt, copper, iodine, iron, manganese, molybdenum, selenium, and zinc). Major functions for each of these minerals are summarized. Considerable research suggests that chromium is also essential and that it functions by facilitating insulin activity. Studies are reviewed which indicate that chromium supplementation of animal diets may: 1) increase glucose removal from blood, 2) reduce carcass fat and increase lean in nonruminants, 3) alter egg cholesterol content, and 4) enhance immunity and disease resistance in ruminants. A number of other minerals including nickel, boron, vanadium, arsenic, silicon, lithum, and lead have been reported to be essential, but specific metabolic functions have not been defined for any of these elements. Limited research in poultry suggests that boron may be of practical significance in some instances.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2009년 추계학술발표대회
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• pp.205-209
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• 2009

Wetting properties between silver-copper-titanium braze alloys with different titanium contents up to 2.8 mass% and hexagonal boron nitride ceramics were investigated using sessile drop method at 1123K in Argon. The final contact angle is less than $30^{\circ}$ when the Ti content was over 0.41 mass%. Meanwhile, the contact angle curves show different behavior. In case of using braze alloy containing 2.8 mass% of titanium, the initial contact angle is acute angle just after the melting of braze. In case of brazes containing titanium less than 2.26 mass%, the contact angle is larger than $90^{\circ}$ at the beginning and slowly decreases to acute angle. The reaction layer of titanium nitride is observed at the interface. In addition, the reaction of Ti in the braze and N in the bulk h-BN seemed to show diffusion limited spreading.

• Nuclear Engineering and Technology
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• 제16권1호
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• pp.18-20
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• 1984

붕소의 사전 농축후 포획감마선 계측법에서 자연 리티움 벽돌을 Ge(Li) 검출기 앞에 설치하므로서 붕소의 검출한계를 더욱 낮출 수 있었다. 실험상 검출한계는 알루미늄, 철강, 이산화우라늄 그리고 그라파이트 시료에 대해서 각각 0.30ppm, 0.18ppm, 0.045ppm 고리고 0.090ppm이었다. 또한 계측 중 중성자 속의 변화에 의한 오차를 없애기 위하여 교대로 계측하는 방법을 사용하였다.

• 한국세라믹학회지
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• 제26권3호
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• pp.381-389
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• 1989

Effects of annealing temperature, time, and atmospehre on the flow characteristics of Atmospheric Pressure Chemical Vapor Deposition-borophosphosilicate glass were investigated. Stable step coverage can be obtained by annealing the BPSG film at 90$0^{\circ}C$ for 30 minutes in N2 atmosphere, but further heat treatment isnot effective. Flow characteristics of the BPSG film was better in steam atmosphere than in N2 atmosphere, and the factors which cause it were analyzed. The concentration of boron in the BPSG film was measured pretty accurately by FTIR spectrum. Boron content in the BPSG film was reduced by annealing treatment. The decrement of boron was greater in steam atmosphere than in the N2 atmosphere. Also it was found from the FTIR spectroscopic analysis that PH3 inhibited the oxidation of B2H6.