• 한국초지조사료학회지
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• 제8권2호
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• pp.92-98
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• 1988

山地초지에 고토와 함유된 有機質複合비료의 施用이 목장의 건물수량, 수량구성요소 및 식생변화에 마치는 影響을 究明코자 비종과 시비수준을 달리한 5處理를 亂塊法 3反復으로 團場配置하여 1984年 9月부터 1986年 10月까지 水原 근교의 신 개척지에서 本 試餘을 수행하였던 바 그 결과를 요약하면 다음과 같다. 1. 목장의 耐冬性, 生育勢 및 被覆率 等 初期生 育狀態는 有機質複함포료 施用區가 단비시용에 比해 良好하였다. 2. 2年평균 목장의 乾物收量은 시비水準間에는 有意差있는 增收했果가 있었으며, 少肥施用水準에서 단비구의 乾物수량 7,930.6kg/ha에 比해 有機質 複合비료 施用區는 8,693.1kg/ha로서10%, 普肥施 用水準에서는 單肥區의 11,122.6kg/ha에 比해 有機 質複合肥料 施用區는 12,758.7kg/ha를 生産하여 15% 회수되었으나 有意性은 없었다. 3. 植牛別 건물수량은 未本科 救草의 경우 施肥量이 많아짐에 따라 有意差있게 증가하였으며 (P<0.01), 荳科救草의 收量은 無肥區는 施肥區(少肥, 普肥)에 比해 顧著히 회수되었으나(P< 0.01), 少肥와 普肥施用水準 問에는 有意性이 없었다. 한편 肥種問에서는 有機質複合肥料 施用區가 單肥에 比해 未本科 목초는 8-14%, 荳科는 26-29% 增收되었으나 有意性은 없었다. 4.. 植生構成比率은 草地管理時에 施肥 하지 않은 곳은 荳科의 優古現象이 나타났으나, 3要素 施用區는 植生比率 및 목초율이 적합하였으며, 유기質複合비료 施用區의 荳科比率은 單肥施用區에 比해 漸次 增加되는 碩向이였다. 5. 試嚴後 士壞의 化學成分은 試餘前에比해 顯 著히 높아졌으나 施肥水準을 平均하여 볼때 有機質 複合nE料 施用區는 單肥에 比해 有機物과 有郊憐嚴含量은 높았고, pH 및 置換性 醒基는 若千 낮은 碩向이었다.

• Bulletin of the Korean Chemical Society
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• 제27권5호
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• pp.759-761
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• 2006

The compound B(C6F5)3 and its variations have been widely employed as alkyl carbanion abstracting reagents to produce metallocene cations for olefin polymerization.1-3 Weakly coordinating anions containing boron can greatly improve the activity of metallocene catalysts used in industrial olefin polymerization4 and thus group IV and V metallocene complexes of the organohydroborate anions have been intensively investigated.5 Recently, many organohydroborate metallocene complexes have been reported by Shore and co-workers.6-8 A common structural feature of those complexes is the three-center two electron M-H-B bond, like that observed in transition metal tetrahydroborate complexes but the reactivity and fluxional behavior of organohydroborate complexes are unlike those of the tetrahydroborate analogues.6 Although many of those metallocenes have been synthesized, few complexes could be used in the olefin polymerization and then this laboratory has been involved in the chemistry of the cyclic organohydroborate anions, and their group IV metallocene derivatives for the catalyst.9 Described here is recent work that led to the preparation of a novel cyclic organohydroborate hafnocene complex (h5-C5H5)2Hf ？(μ-H)2BC8H14 ,Cl. The hafnocene complex contains the three-center two electron bond Hf-H-B10 in which the hydride abstraction for olefin polymerization may occur.

• 자원리싸이클링
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• 제22권1호
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• pp.48-54
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• 2013

LCD용 편광필름에 핵심적으로 사용되어진 요오드화칼륨 (KI, Potassium Iodide) 폐용액으로부터 분별결정법을 이용하여 고순도의 요오드화칼륨 결정을 제조하는 실험을 행하였다. 본 연구에서는 붕소, 나트륨 및 PVA 등의 불순물을 포함한 1.3% 요오드화칼륨 폐액을 3회에 걸쳐 농축하였으며, 용해도 차이를 이용하여 최대 불순물인 붕소화합물을 제거하고, 여과지를 이용하여 유기물을 제거하였다. 또한 24시간 숙성을 통하여 $K_2SO_4$ 형태로 불순물을 제거하여 99.5% 이상의 고순도 요오드화칼륨 결정을 제조하였으며, 재결정을 통하여 농축되어진 불순물을 약 70% 제거할 수 있었다.

• 한국재료학회지
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• 제17권3호
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• pp.142-146
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• 2007

Vacuum brazing method has been coming to an important process as one of the new fabricating techniques of metals and alloys. In this study, a vacuum brazing of SUS304 stainless steel with BNi-2 filler metal was carried out in $1{\times}10^{4}$ Torr of vacuum atmosphere. The formation of brittle intermetallic compounds in brazed joints between SUS304 stainless steel and BNi-2 filler metal is a major concern, since they considerably degrade the mechanical properties of joints. To obtain enough stable joining strength, it is necessary to understand the unique properties of brazing process with Ni-based filler metals containing boron. So, in this research we investigated the performance of SUS304/BNi-2 brazed system and the brazed joint properties were evaluated at room temperature by using tensile test. Metallurgical and fractographic analysis were used to characterize the microstructure, the mechanisms of brazing, and joint failure modes.

• Journal of Welding and Joining
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• 제33권1호
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• pp.49-53
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• 2015

An experimental study was conducted to investigate the effect of carbon nanotubes on the zinc corrosion resistance of sealing layer formed on the Tungsten Carbide spray coating. Using the nanotubes, a sealing agent in the form of solid-liquid suspensions was made and applied to the surface of spray coating. A series of experiments, consisted of three stages such as preparation of test piece, molten-pot immersion test, and evaluation of micro structure, were undertaken to demonstrate complicated interaction existing between zinc ions and sealing layer containing the nanotubes. Experimental results showed newly developed sealing layer were less susceptible to corrosion and thus coated layer was well protected even in the case of 10 days exposure. Comparison of the micro structure after molten pot test also indicated that carbon nanotubes still remained in the matrix and organized more reliable frame work constituted with boron nitride and chromium compound. It was revealed that carbon nanotubes in the sealing layer played positive role to enhance zinc corrosion resistance in the perspective of both fibrous structure and inherent chemical stability.

• Mass Spectrometry Letters
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• 제1권1호
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• pp.9-12
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• 2010

Trimethylboroxine (TMB) is a six-membered ring compound containing Lewis acidic boron and Lewis basic oxygen atoms that can bind halide anion and alkali metal cation, respectively. We employed Fourier transform ion cyclotron resonance spectroscopy to study the gas-phase binding of $LiBrLi^+$ and $F^-(KF)_2$ to TMB. TMB forms association complexes with both $LiBrLi^+$ and $F^-(KF)_2$ at room temperature, providing direct evidence for the ditopic binding. Interestingly, the $TMB{\cdot}F^-(KF)_2$ anion complex is formed 33 times faster than the $TMB{\cdot}Li^+BrLi$ cation complex. To gain insight into the ditopic binding of an ion pair, we examined the structures and energetics of $TMB{\cdot}Li^+$, $TMB{\cdot}F^-$, $TMB{\cdot}LiF$ (the contact ion pair), and $Li^+{\cdot}TMB{\cdot}F^-$ (the separated ion pair) using Hartree-Fock and density functional theory. Theory suggests that $F^-$ binds more strongly to TMB than $Li^+$ and the contact ion-pair binding ($TMB{\cdot}LiF$) is more stable than the separated ion-pair binding ($Li^+{\cdot}TMB{\cdot}F^-$).

• 연구논문집
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• 통권24호
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• pp.161-174
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• 1994

The Ni-Al intermetallic compound that has the greatest potential to be commercialized shows the high ductility at room temperature with the addition of boron, but has extremely low ductility at high temperature and oxidation environment. On this research work, the changes of microstructure and compressive fracture properties were studied in ($NiAl+Ni_3Al$) two-phase alloys. The precipitation behavior of $Ni_3Al$ after solution treatment at $1300^\circC$ for 14hrs and aging treatment at $800^{\circ}C$ for 14hrs was varied with Al content in ($NiAl+Ni_3Al$) two-phase alloys. These microstructure could be modified dramatically by suitable heat treatments. Martensite or martensite plus $Ni_3Al$ microstructure was obtained upon oil quenching from $1300^\circC$. Aging of Martensite at $800^\circC$ resulted in the $Ni_3Al$ plus NiAl phase. The compressive fracture strength and compressive fracture strain were improved by the $Ni_3Al$ plus NiAl phase mixtures at room temperature and $1100^\circC$. Microcracks are observed mostly in the region of NiAl and the interface of $NiAl-Ni_3Al$ phase after compressive test at room temperature. In the case of high temperature compressive test, microcracks are formed in the region of $Ni_3Al$ phase.

• Nuclear Engineering and Technology
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• 제56권4호
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• pp.1425-1430
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• 2024

This study develops superheated emulsion detectors that are both sensitive to fast neutrons, and thermal neutrons owing to the exergonic ⁶₃Li(n, α)³₁H capture reaction caused by the ⁶Li-containing compound dispersed throughout the gel-like medium. The experimental research was conducted on two SEDs. One detector was an ordinary Freon-12 detector and the other was a Freon-12 detector containing 3.4 % (by weight) LiCl. In order to investigate the sensitivity of lithium-containing SEDs to thermal neutrons, two types of SEDs were simultaneously exposed to various flux levels of thermal neutrons from ²⁴¹Am-Be neutron source inside a cylindrical tank filled with water. A Boron-lined proportional counter was used to estimate the thermal neutron flux and the relevant MCNP code was developed for flux and dose calculations in the prepared set-up around ²⁴¹Am-Be source. The results demonstrate that there is a proportional relationship between the variations of SED response and the change in thermal neutron flux and dose. Also, the sensitivity of SED was estimated.

• 한국초지조사료학회지
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• 제8권3호
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• pp.92-98
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• 1988

山地초지에 고토와 함유된 有機質複合비료의 施用이 목장의 건물수량, 수량구성요소 및 식생변화에 마치는 影響을 究明코자 비종과 시비수준을 달리한 5處理를 亂塊法 3反復으로 團場配置하여 1984年 9月부터 1986年 10月까지 水原 근교의 신 개척지에서 本 試餘을 수행하였던 바 그 결과를 요약하면 다음과 같다. 1. 목장의 耐冬性, 生育勢 및 被覆率 等 初期生 育狀態는 有機質複함포료 施用區가 단비시용에 比해 良好하였다. 2. 2年평균 목장의 乾物收量은 시비水準間에는 有意差있는 增收했果가 있었으며, 少肥施用水準에서 단비구의 乾物수량 7,930.6kg/ha에 比해 有機質 複合비료 施用區는 8,693.1kg/ha로서10%, 普肥施 用水準에서는 單肥區의 11,122.6kg/ha에 比해 有機 質複合肥料 施用區는 12,758.7kg/ha를 生産하여 15% 회수되었으나 有意性은 없었다. 3. 植牛別 건물수량은 未本科 救草의 경우 施肥量이 많아짐에 따라 有意差있게 증가하였으며 (P<0.01), 荳科救草의 收量은 無肥區는 施肥區(少肥, 普肥)에 比해 顧著히 회수되었으나(P< 0.01), 少肥와 普肥施用水準 問에는 有意性이 없었다. 한편 肥種問에서는 有機質複合肥料 施用區가 單肥에 比해 未本科 목초는 8-14%, 荳科는 26-29% 增收되었으나 有意性은 없었다. 4.. 植生構成比率은 草地管理時에 施肥 하지 않은 곳은 荳科의 優古現象이 나타났으나, 3要素 施用區는 植生比率 및 목초율이 적합하였으며, 유기質複合비료 施用區의 荳科比率은 單肥施用區에 比해 漸次 增加되는 碩向이였다. 5. 試嚴後 士壞의 化學成分은 試餘前에比해 顯 著히 높아졌으나 施肥水準을 平均하여 볼때 有機質 複合nE料 施用區는 單肥에 比해 有機物과 有郊憐嚴含量은 높았고, pH 및 置換性 醒基는 若千 낮은 碩向이었다.

• 한국주조공학회지
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• 제2권3호
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• pp.2-15
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• 1982

In this study, the influenced of graphite shape on the boriding of cast iron and boride structure was investigated. Gray cast iron, ferritic and pearlitic ductile cast iron were borided at 750,850,900 and $950^{\circ}C$ for 1,3 and 5 hours by powder pack method with the mixture of $B_4C_9\;Na_2B_4O_7$, $KBF_4$ and Shc. The boride layer was consisted of FeB(little), $Fe_2B$ (main) and graphite. Some possibility of the existence of unknown Fe-B-C compound in the boride layer was suggested. And precipitates in the diffusion zone was $Fe_3(B,C)$. The concentration of Si and precipitation of $Fe_3(B,C)$ in the ${\alpha}$ layer raised the hardness of this Zone. The depth and hardness of boride layer increased with the increase of treating temperature and tim. But high temperature (over $950^{\circ}C)$ caused pore at graphite position and long treating time (5hrs) sometimes caused formation of graphite layer beneath the boride layer. So, for the practical application of borided cast iron, treating in short time and at low temperature was recommended. And for ductile cast iron, ferritizing or pearlitizing heat treatment was seemmed to be possible at the same time with boriding. The graphite in the boride layer was deeply concerned with the qualitx and characteristics of the boride layer. And it greatly influenced on the shape of the boride phase, structure of the boride layer. Generally speaking, the existance of graphite restrained the growth of the boride phase. But the boundary between the gsaphite and the matrix acted as the shortcut of boron diffusion. So, for gray cast iron, the graphite layed length-wise led the formation of boride layer.