• Journal of Animal Science and Technology
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• 제57권3호
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• pp.14.1-14.7
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• 2015

A feeding trial was carried out to determine the effects of chromium methionine (Cr-Met) chelate and forage level over two years, $1^{st}$ fattening and $2^{nd}$ fattening period on growth parameters, carcass characteristics and blood metabolites of 46 Korean native (Hanwoo, Bos Taurus, $BW=183{\pm}44kg$) steers. Treatments were: 1) Steers in the low forage (LF) group were fed diets that consisted of 60% concentrate and 40% forage; 2) Steers in the high forage (HF) group were fed diets that consisted of 40% concentrate and 60% forage. Following the $1^{st}$ fattening period, steers ($BW=480{\pm}37.6kg$) were randomly assigned to four treatment groups: LF (40 F plus no Cr-Met supplementation in the $2^{nd}$ fattening period), LFCM (40LF plus added 400 ppb of Cr-Met during the $2^{nd}$ fattening period), HF (60 F plus no added Cr-Met during the $2^{nd}$ fattening period) and HFCM (60 F plus added 400 ppb of Cr-Met in the $2^{nd}$ fattening period). Dry matter intake of the treatment diets did not differ during the raising and $1^{th}$ fattening period (P > 0.05). The ADG in the raising period showed no difference between the 40 F and 60 F groups (P > 0.05). Carcass characteristics including rib-eye area and meat yield index were higher in HF than the other treatment groups (P < 0.05). The HF group tended to show a higher (P = 0.08) marbling score than the LF group whereas the HFCM group showed a higher marbling score than the LFCM group (P < 0.05). HDL was higher and LDL lower in groups fed with Cr-Met than in other groups whereas glucose showed the lowest value in HF group (P < 0.05). Triglyceride (TG), Cholesterol, PUN and total protein (TP) were the same among all treatment groups (P > 0.05). The Insulin concentration in the blood was significantly higher for the HFCM group than for the LF, LFCM and HF groups (P < 0.05). It is concluded that supplementation of chromium-methionine chelate could improve meat quality in beef steers.

• 한국자기학회지
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• 제23권5호
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• pp.149-153
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• 2013

이 연구에서는 방사광 연 X선 광흡수 분광법(soft x-ray absorption spectroscopy: XAS)을 이용하여 $TCr_2O_4$(T = Fe, Co, Ni) 스피넬 산화물들의 전자 구조를 연구하였다. 전이금속 이온들의 2p 준위의 흡수에 의한 XAS 측정으로부터 T(T = Fe, Co, Ni) 이온들의 원자가는 공통적으로 2가($T^{2+}$)이며, Cr 이온의 원자가는 3가 ($Cr^{3+}$) 임을 발견하였다. 그리고 T 이온들은 정사면체 대칭성을 가진 A 사이트에 주로 위치하고, Cr 이온은 정팔면체 대칭성을 가진 B 사이트에 주로 위치함을 알 수 있었는데, 이러한 발견을 통하여 $TCr_2O_4$는 정상 스피넬에 가까운 구조를 가지고 있다고 결론지을 수 있다. 또한 $FeCr_2O_4$와 $NiCr_2O_4$에서는 얀-텔러 변형이 중요한 역할을 하지만, $CoCr_2O_4$는 얀-텔러 변형이 없는 입방체 구조를 유지하는 원인을 알 수 있었다. 그러므로 $TCr_2O_4$에서 $Cr^{3+}$ 상태의 이온들과 $T^{2+}$ 상태의 이온들 간의 반강자성 결합이 이 산화물들의 자성 특성을 결정하는데 중요한 역할을 한다고 생각된다.

• Radiation Oncology Journal
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• 제36권3호
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• pp.192-199
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• 2018

Purpose: Use of radiotherapy combined with chemotherapy is increasing in hypopharyngeal cancer. However, many show residual tumor after radiotherapy. Timing for treatment evaluation and salvage therapy is essential. However, optimal timing for salvage surgery has not been suggested. In this study, we tried to evaluate optimal timing for salvage surgery. Methods and Materials: Patients who were diagnosed with hypopharyngeal squamous cell carcinoma between 2006 and 2015 were retrospectively analyzed. All patients received definitive radiotherapy with or without chemotherapy. Response of all treated patients were analyzed at 1, 3, and 6 months after radiotherapy. Any patients with progression before 6 months were excluded. Results: A total of 54 patients were analyzed. Complete remission (CR) rates at 1 month (CR₁), 3 months (CR₃) and 6 months (CR₆) were 66.7%, 81.5%, and 90.7%, respectively. Non-CR at 1 month (NCR₁), 3 months (NCR₃), and 6 months (NCR₆) showed poor locoregional recurrence-free survival rates (1-year rates of 63.7%, 66.7%, and 0.0%, respectively) compared to CR₁, CR₃, and CR₆ (1-year rates 94.3%, 88.0%, and 91.5%, respectively). Particularly significant differences were seen between CR₆ and NCR₆ (p < 0.001). Of 10 patients with NCR₃, 5 showed CR at 6 months (NCR₃/CR₆). There was no statistical difference in locoregional recurrence-free survival between CR₃ and NCR₃/CR₆ group (p = 0.990). Conclusion: Our data suggest half of patients who did not show CR at 3 months eventually achieved CR at 6 months. Waiting until 6 months after radiotherapy may be appropriate for avoiding additional salvage therapy.

• Journal of Magnetics
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• 제20권3호
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• pp.211-214
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• 2015

$Cr_2O_3$ nanoparticles were prepared via one-step reactive laser ablation of Cr in oxygen. The metastable $CrO_2$ phase was obtained through the subsequent oxidation of $Cr_2O_3$ nanoparticles under $O_2$ with gas pressures of up to 40 MPa. The as-prepared $Cr_2O_3$ nanoparticles are spherical or rectangular in shape with sizes ranging from 20 nm to 50 nm. High oxygen pressure annealing is effective in producing meta-stable $CrO_2$ from as-dried $Cr_2O_3$ nanoparticles, and the $Cr_2O_3$ nanoparticles exhibit a weak ferromagnetic behavior with an exchange bias of up to 11 mT that can be ascribed to the interfacial exchange coupling between uncompensated surface spins and the antiferromagnetic core. The $Cr_2O_3/CrO_2$ nanoparticles exhibit an enhanced saturation magnetization and a reduced exchange bias with an increasing faction of $CrO_2$ due to the elimination of uncompensated surface spins over the $Cr_2O_3$ nanoparticles when exposed to a high pressure of $O_2$ and/or possible phase segregation that results in a smaller grain size for both $Cr_2O_3$ and $CrO_2$.

• 충청수학회지
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• 제23권1호
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• pp.11-27
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• 2010

Let $\Omega$ be a domain with smooth boundary in ${\mathbb{C}}^{n+1}$ and let $p{\in}{\partial}{\Omega}$. Suppose that $\Omega$ is Kobayashi hyperbolic and p is of Catlin multi-type ${\tau}=({\tau}_0,{\ldots},{\tau}_n)$. In this paper, we show that $\Omega$ admits a $C^{k}$ contraction at p with $k{\geq}\mid{\tau}\mid+1$ if and only if $\Omega$ is biholomorphically equivalent to a domain defined by a weighted homogeneous polynomial.

• 한국재료학회지
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• 제4권6호
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• pp.704-709
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• 1994

Crystal Structure and Magnetic Properties of $(LaS)_xCrS_2(x \approx 1.20$)가 1273K에서 $La_S_3$ , Cr, S의 혼합물의 반응으로부터 합성되었다. $(LaS)_xCrS_2( x\approx 1.20$)의 XRD회절 pattern은 monoclinic의 LaS-부격자, triclinic의 $CrS_{2}$-부격자와 그들의 초격자로서 해석되었다. 부격자의 온도의존성을 저온에서 X-선 회절분석으로 조사하였다. 77K~실온의 온도역에서 $(LaS)_xCrS_2(x \approx 1.20$)의 자기자화율을 Faraday balance법으로 측정하였다. $(LaS)_xCrS_2(x \approx 1.20$)은 실온 $\sigma$ -H plot에서 paramagnetic한 거동을 나타내었다. 관측된 유효자기 moment($\mu_{eff}$)는 $Cr^{3+}$을 spin-only에 의한 것과 $La^{3+}$을 spin-only와 orbital에 의한 것으로 계산할 경우 잘 일치되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제23권8호
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• pp.1007-1012
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• 2010

The aim of the present study was to describe whether abnormal cervical mucus discharge (A-CMD) or pathogens in cervical mucus discharge (CMD) have effects on reproductive performance of cows and heifers in estrus. Animals having clear discharges (68 cows, 38 heifers) with normal viscosity and without bad odor were grouped as normal cervical mucous discharge (N-CMD) group. The other animals (84 cows, 32 heifers) were grouped as A-CMD group. Microorganisms isolated from samples were divided into three groups as uterine pathogens (UP), potential uterine pathogens (PUP) or opportunistic uterine pathogens (OUP). Presence of PUP was associated with A-CMD for both cows (p<0.01) and heifers (p<0.02). First service conception rates (FS-CR) were lower in cows positive for PUP (p<0.01). Moreover, presence of PUP and OUP affected FS-CR in heifers (p<0.01). Although A-CMD significantly affected FS-CR in cows (p<0.04), it did not affect FS-CR in heifers. Differences in average open day for cows (p<0.02) and first service age for heifers (p<0.01) were significant between N-CMD and A-CMD groups, respectively. The current study suggested that CMD should be evaluated more carefully when there are infertility problems. In addition to the known microorganism that causes sterility and infertility in the UP group, pathogens in the PUP group should be considered for their potential to cause infertility.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.247.1-247.1
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• 2016

Low-cost, high efficiency solar cells are tremendous interests for the realization of a renewable and clean energy source. ZnTe based solar cells have a possibility of high efficiency with formation of an intermediated energy band structure by impurity doping. In this work, ZnO/ZnTe:Cr and ZnO/i-ZnTe structures were fabricated by pulsed laser deposition (PLD) technique. A pulsed (10 Hz) Nd:YAG laser operating at a wavelength of 266 nm was used to produce a plasma plume from an ablated a ZnTe target, whose density of laser energy was 10 J/cm2. The base pressure of the chamber was kept at approximately $4{\times}10-7Torr$. ZnTe:Cr and i-ZnTe thin films with thickness of 210 nm were grown on p-Si substrate, respectively, and then ZnO thin films with thickness of 150 nm were grown on ZnTe:Cr layer under oxygen partial pressure of 3 mTorr. Growth temperature of all the films was set to $250^{\circ}C$. For fabricating ZnO/i-ZnTe and ZnO/ZnTe:Cr solar cells, indium metal and Ti/Au grid patterns were deposited on back and front side of the solar cells by using thermal evaporator, respectively. From the fabricated ZnO/ZnTe:Cr and ZnO/i-ZnTe solar cell, dark currents were measured by using Keithley 2600. Solar cell parameters were obtained under Air Mass 1.5 Global solar simulator with an irradiation intensity of 100 mW/cm2, and then the photoelectric conversion efficiency values of ZnO/ZnTe:Cr and ZnO/i-ZnTe solar cells were measured at 1.5 % and 0.3 %, respectively.

• 한국세라믹학회지
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• 제39권7호
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• pp.663-668
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• 2002

폐기물 함유 세라믹 재료의 성형과정에서 일차적인 중금속의 안정화를 알아보기 위하여 중금속(Cd, Cr, Cu, Fe, Pb, Zn) 표준용액의 농도를 각각 5, 10, 15, 20ppm으로 조절하여 점토, 백토와 제올라이트에 대해 회분식 흡착실험을 행하였다. 중금속 표준용액의 농도가 증가할수록 모든 시료에서 중금속 흡착률은 감소하는 경향을 보였다. 점토와 백토는 Cr을 제외한 모든 중금속에서 평균 80% 이상의 흡착률을 보였고, Fe와 Pb에서는 99% 이상의 우수한 흡착률을 보였다 점토와 백토를 혼합한 경우, Cr에 대한 흡착률이 점토와 백토에 비해 우수하였으나 Zn에 대한 흡착률은 상대적으로 작았다. Cr, Zn은 다른 중금속에 비해 낮은 중금속 흡착률을 보이는데, 이것은 낮은 pH에서 용액 내 수소이온과 이온교환경쟁을 벌이기 때문인 것으로 사료된다.

• 한국도로학회논문집
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• 제9권3호
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• pp.75-82
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• 2007

터널 내 축적된 다양한 오염원들은 간헐적으로 수행되는 세척과정 중에 폐수로 배출되게 되며, 서울 시내 3개 터널 지점에서 수행된 수질분석결과 SS, $COD_{Cr}$, T-N, $NH_3-N$, $NO_3-N$, Zn, Cu, Cr(+6). Mn, Mg, Phenol. $CN^-$, E-Coli 등이 고농도 형태로 배출되는 것으로 나타났다. 한편, 이러한 오염수질의 배출농도 특성은 터널 세척 폐수의 채취 방법, 세척횟수, 세척수량, 터널내벽 특성, 통행량, 배수 특성 등에 따라 다양한 농도범위를 보여주는 것으로 나타났다. 한편, 수집된 터널 세척폐수를 단순 중력침전을 이용하여 저감실험을 수행한 결과, $COD_{Cr}$는 80%, T-N, T-P는 각각 30, 90% 제거됨을 확인하였고, 중력침전 분리를 통하여 제거되지 않은 잔여 오염물질에 대하여 GAC 소재를 통한 흡착실험(터널 세척폐수 $1{\ell}$에 대하여 GAC를 50g을 투입) 결과, $COD_{Cr}$, T-N, Zn, Cu, Mn, Phenol, CN 항목에서 80% 이상 제거됨을 확인하였다.