• Bulletin of the Korean Chemical Society
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• 제17권2호
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• pp.168-172
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• 1996

The variations of the structural detail of layered perovskite-type oxides, Na2Ln2Ti3O10 (Ln=La, Nd, Sm, Gd), have been refined by Rietveld analyses of their powder X-ray diffraction data. Although the c-axis strongly decreases from Ln=La to Nd, Sm, or Gd, the length of Na-O bond along the c-axis that is regarded as the sodium layer spacing is not dependent on the unit cell parameter. Such a behavior is explained by the fact that Na-O bond is in competition with Ti-O one of the perovskite slab. Increased covalency of this Ti-O bond by the lattice contraction leads to weakening of the attaching strength of Na ion. This picture is consistent with the experimental observation that Na ion conductivity of Na2Ln2Ti3O10 increases from Ln=La to Nd, Sm, or Gd despite strong contraction of the unit cell volume.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2003년도 추계학술발표대회 요약집
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• pp.246.2-246.2
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• 2003

• Asian-Australasian Journal of Animal Sciences
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• 제31권5호
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• pp.658-671
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• 2018

Objective: Nandrolone decanoate (ND) is an anabolic-androgenic steroid frequently used for clinical treatment. However, the inappropriate use of ND results in the reduction of serum testosterone level and sperm production. The suppressive effect of ND on testosterone production has not been investigated in detail. The present study was designed to examine the effect of ND on the expression of steroidogenic enzymes in the rat testis. Methods: Male Sprague Dawley rats at 50 days of age were subcutaneously administrated with either 2 or 10 mg of ND/kg body weight/week for 2 or 12 weeks. The changes of transcript and protein levels of steroidogenic enzymes in the testis were determined by real-time polymerase chain reaction and western blotting analyses, respectively. Moreover, immunohistochemical analysis was employed to determine the changes of immunostaining intensity of these enzymes. The steroidogenic enzymes investigated were steroidogenic acute regulatory protein, cytochrome P450 side chain cleavage enzyme, $17{\alpha}-hydroxylase$, $3{\beta}-hydroxysteroid$ dehydrogenase, and cytochrome P450 aromatase. Results: The treatment of ND resulted in depletion of Leydig cells and sloughing of germ cells in the testis. The ND treatment caused significant expressional decreases of steroidogenic enzymes at transcript and protein levels, and the destructive effects of ND on the testis were more apparent with a higher dose and a longer period of the treatment. Evident reduction of immunostaining intensity present in Leydig cells was clearly detected by the ND treatment. Conclusion: The exposure to ND in young male results not only in histological changes of the testis but also in aberrant gene expression of testicular steroidogenic enzymes, consequently leading into the reduction of testosterone production in the testis and thus likely disruption of spermatogenesis.

• 한국광학회지
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• 제14권1호
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• pp.85-91
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• 2003

비평면 고리형 공진기에서의 내부 공진기 주파수 배가를 이용한 단일 모드 Nd:YAG 레이저를 제작하였다. 비평면 고리형 공진기는 두 개의 구면경과 Nd:YAG 결정, KIP 결정으로 구성되어 있다. Nd:YAG 결정의 양단면은 상대적인 비틀림 각을 갖고 있으면서 브루스터 각이 되도록 연마되었으며, 비틀림 각에 의해 형성된 비평면 고리 공진기가 가역적인 편광 회전기 역할을, 자기장이 가해진 Nd:YAC 결정 자체가 비가역적 편광 회전기 역할을, 브루스터 각을 갖고 있는 양단면이 편광자 역할을 각각 담당하여 전체적으로 광 다이오드를 형성하고 있다. 이러한 구조에서 단 방향 발진이 일어날 수 있는 비틀림 각이 이론적으로 추정되었다. 1.2 W, 809 nm 다이오드 레이저로 펌핑하여 532 nm 파장에서 22 ㎽의 단 방향, 단일 모드 출력을 얻었으며, 이것은 약 1.8%의 변환 효율에 해당한다.

• 한국자기학회지
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• 제5권1호
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• pp.34-37
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• 1995

단롤법 급속응고장치를 이용하여 비정질 $Nd_{x}Fe_{77}B_{23-x}(x=4,\;6,\;8,\;11,\;13)$ 합금을 제작하고 $650^{\circ}C$ 이상에서 결정화 시키어 자기적 특성을 조사하였다. 열처리 후의 결정상을 조사한 결 과 x=8 조성에서 준안정상 $Nd_{2}Fe_{23}B_{3}$가 단일상에 가깝게 생성되며 연자기특성을 나타냄 을 알았다. 자기특성 조사결과 $8{\leq}x{\leq}13$ 조성범위에서 Nd 함유량이 증가할수록 보자력은 증가하나 잔류자속밀도는 감소함을 알았다. 그러나, $4{\leq}x{\leq}6$ 합금의 경우 Nd 함유량이 감소할수록 보자 력과 잔류자속밀도가 함께 증가하였다. x=4 합금의 경우 연자성:경자성=70:30의 혼합조직이 얻어지며 $96kJ/m^{3}(12MGOe)$의 높은 에너지적을 나타냈다.

• 한국수소및신에너지학회논문집
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• 제10권3호
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• pp.177-184
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• 1999

The charge-discharge characteristics of the $Mg_2Ni-x$ wt.%Nd (x = 0~3) electrodes were investigated. The electrodes were prepared by the mechanical grinding of the induction-melted $Mg_2Ni$ alloy powders with Ni and/or Nd using planetary ball mill apparatus. The discharge capacity of the $Mg_2Ni$ alloy increased with the increase in the nickel content. The electrode possessing 100 wt.% nickel powder showed the initial capacity of 760 mAh/g and the capacity decay with the cycle number was less than that of the 55 wt.% nickel powder. The Nd was added to this composition. It was found that the $Mg_2Ni-100$ wt.%Ni -0.2 wt.%Nd alloy showed an excellent charge-discharge cycle characteristics compared with the other reported Mg-Ni alloy system. The discharge capacity was 400 mAh/g after 70 cycles. Such an improved cycle life seems to be attributed to the improvement in the corrosion characteristics of the alloy. The anodic polarization curve of the $Mg_2Ni-100$ wt.%Ni-0.2 wt.%Nd alloy exhibited better passivating behavior than that of the $Mg_2Ni-100$ wt.%Ni.

• 농업과학연구
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• 제40권2호
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• pp.87-91
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• 2013

The major characteristics of the developed corn hybrids were compared at each different planting time; 1st time(April 28) and 2nd time(August 20), respectively. Among traits surveyed, stem height showed highly at 1st time than 2nd, while ear height, stem diameter and ear length were similar at two times. Sugar content of the used hybrids showed highly at 2nd planting time than 1st. Pericarp thickness was also high at 2nd planting time. Especially, among hybrids CNU99 was the highest in stem height and ear length, CNU11 and CNU56 were high in sugar content, and CNU51 and CNU124 were thiner than other hybrids in pericarp thickness. Accordingly, these hybrids will be planted and recognized in 2nd yield trial for superior corn hybrid selection.

• E2M - 전기 전자와 첨단 소재
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• 제7권4호
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• pp.306-311
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• 1994

In this study, the influence of the powder sintering, the 2nd sinteiing and the grinding time on the Superconducting properties in the Bi(Pb)SiCaCuO Superconductor has been studied. From the analysis of SEM and XRD patterns, it was known that the sample prepared by the process of powder sintering has a porous microstructure with the critical temperature(Tc) below 77K, while the sample prepared by the 2nd sintering has a highly oriented microstructure with the Tc above 100K. The Critical Current Density(Jc) of the sample prepared by the 2nd sintering was better than the sample prepared by the process of powder sinteiing, but it's Jc, was low in practical use. Also, the effect of grinding time from 0[min] to 120[min] was investigated. As the grinding time is increased, the samples degraded from high-Tc phase to low-Tc phase and nonsuperconducting phases.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 초전도 자성체 연구회
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• pp.42-45
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• 2003

The phase transformation of $REBa_2Cu_3O_{7-x}$ (RE=Nd, Gd, Dy) was investigated using isothermal heat-treatment and continuous cooling in air. During continuous cooling, the $REBa_2Cu_3O_{7-x}$ (RE=123) superconducting phase with well-distributed $REBa_2Cu_3O_{7-x}$ (RE-211) was obtainde at a cooling rate of $0.001^{\circ}C$/s. Single phase RE-123 (Nd, Gd, Dy) was stable at $1050^{\circ}C$, $1050^{\circ}C$, and $950^{\circ}C$ during isothermal heat-treatment, respectively. Above these temperatures the RE-211 phase existed within the RE-123 grains. The RE-123, RE-211, $BaCu_2Od_2$, and CuO phases coexisted at $50^{\circ}C$ below the partial melting temperature for each respective rare-earth RE-123.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.672-675
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• 2010

본 연구에서는 저주파영역의 가진분무에 대하여 추가적인 내부가진을 수행함으로써 변조분사되는 분무특성에 대한 연구를 수행하였다. 회전식 가진장치를 사용하여 1차 가진을 생성한 후 2차 가진원인 마그네틱 밸브를 사용하여 변조하였다. 변조분무의 FFT결과와 분무패턴의 가시화를 통하여 관찰한 결과, 2차 가진 제어가 있는 변조분사의 경우 1차 가진만 있는 분사보다 분무의 상하 운동 진폭이 작으며 분무 하단류의 침투깊이가 증가하는 경향성이 발견되었다.