• Bulletin of the Korean Chemical Society
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• 제35권8호
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• pp.2299-2303
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• 2014

Two diastereoisomers of cyclo(Pro-Tyr) have been synthesized simultaneously. The crystal structures and conformations of both cyclo($\small{L}$-Pro-$\small{L}$-Tyr) and a racemic mixture of cyclo($\small{D}$-Pro-$\small{L}$-Tyr) and cyclo($\small{L}$-Pro-$\small{D}$-Tyr), abbreviated as rac-cyclo($\small{D}$-Pro-$\small{L}$-Tyr/$\small{L}$-Pro-$\small{D}$-Tyr), have been determined by a single-crystal X-ray diffraction study at low temperature. The crystals of rac-cyclo($\small{D}$-Pro-$\small{L}$-Tyr/$\small{L}$-Pro-$\small{D}$-Tyr) belong to orthorhombic space group $Pna2_1$ with a = 10.755 (1), b = 12.699 (1), c = 9.600 (1) ${\AA}$ and Z = 4. The tyrosine side chain is folded towards the diketopiperazine (DKP) ring. The DKP ring adopts a twist boat conformation with pseudo symmetry $C_{2v}$. The pyrrolidine ring has an envelope conformation with the N5, C4, C7 and C8 atoms in a plane. The crystal of rac-cyclo($\small{D}$-Pro-$\small{L}$-Tyr/$\small{L}$-Pro-$\small{D}$-Tyr) is stabilized by hydrogen bonds between amide N2-H2 and carbonyl oxygen O2 in the neighbor. The hydroxyl group of tyrosine residue is also hydrogen bonded to the oxygen of the carbonyl group of the DKP ring in the next molecule. The spectroscopic properties of both isomers are also described.

• 충청수학회지
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• 제24권4호
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• pp.617-630
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• 2011

Let X, Y be vector spaces, and let r be 2 or 4. It is shown that if an odd mapping $f:X{\rightarrow}Y$ satisfies the functional equation $${\hspace{50}}rf(\frac{\sum_{j=1}^{d}\;x_j} {r})+\;{\sum\limits_{\iota(j)=0,1 \atop {\sum_{j=1}^{d}}\;{\iota}(j)=l}}\;rf(\frac{\sum_{j=1}^{d}{(-1)^{\iota(j)}x_j}}{r}) \\({\ddag}){\hspace{160}}=(_{d-1}C_l-_{d-1}C_{l-1}+1)\;{\sum\limits_{j=1}^{d}\;f(x_j)}$$ then the odd mapping $f:X{\rightarrow}Y$ is additive, and we prove the Cauchy-Rassias stability of the functional equation in Banach modules over a unital $C^*$-algebra. As an application, we show that every almost linear bijection $h:{\mathcal{A}}{\rightarrow}{\mathcal{B}}$ of a unital $C^*$-algebra ${\mathcal{A}}$ onto a unital $C^*$-algebra ${\mathcal{B}}$ is a $C^*$-algebra isomorphism when $h(2^nuy)=h(2^nu)h(y)$ for all unitaries $u{\in}{\mathcal{A}}$, all $y{\in}{\mathcal{A}}$, and $n=0,1,2,{\cdots}$.

• Wind and Structures
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• 제26권5호
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• pp.331-341
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• 2018

A numerical study on the flow over a square cylinder in the vicinity of a wall is conducted for different Couette-Poiseuille-based non-uniform flow with the non-dimensional pressure gradient P varying from 0 to 5. The non-dimensional gap ratio L (=$H^{\ast}/a^{\ast}$) is changed from 0.1 to 2, where $H^{\ast}$ is gap height between the cylinder and wall, and $a^{\ast}$ is the cylinder width. The governing equations are solved numerically through finite volume method based on SIMPLE algorithm on a staggered grid system. Both P and L have a substantial influence on the flow structure, time-mean drag coefficient ${\bar{C}}_D$, fluctuating (rms) lift coefficient ($C_L{^{\prime}}$), and Strouhal number St. The changes in P and L leads to four distinct flow regimes (I, II, III and IV). Following the flow structure change, the ${\bar{C}}_D$, $C_L{^{\prime}}$, and St all vary greatly with the change in L and/or P. The ${\bar{C}}_D$ and $C_L{^{\prime}}$ both grow with increasing P and/or L. The St increases with P for a given L, being less sensitive to L for a smaller P (< 2) and more sensitive to L for a larger P (> 2). A strong relationship is observed between the flow regimes and the values of ${\bar{C}}_D$, $C_L{^{\prime}}$ and St. An increase in P affects the pressure distribution more on the top surface than on bottom surface while an increase in L does the opposite.

• ALGAE
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• 제19권4호
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• pp.303-309
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• 2004

The laboratory culture study of Porphyra seriata Kjellman from Korea was conducted at different conditions of temperatures (5, 10, 15, 20, 25 and 30${^{\circ}C}$), photon flux densities (10, 20, 40 and 80 $\mu$mol $^{-2}s^{-1}$) and photoperiods (14L: 10D and 10L:14D). Conchocelis filaments grew fast at 15-20${^{\circ}C}$ and 20-80 $\mu$mol $^{-2}s^{-1}$ under both photoperiods. Concho sporangial branches were produced at 5-25${^{\circ}C}$, and abundant when the conchocelis filaments were cultured at higher temperatures of 20-25${^{\circ}C}$ under both photoperiods. Foliose thalli grew well at 15-20${^{\circ}C}$ under 10L:14D and at 20${^{\circ}C}$ under 14L:10D. At 30${^{\circ}C}$, the foliose thallus failed to survive. No archespores were observed at any culture conditions. Spermatangia and zygotosporangia were formed in squarish patches at the upper marginal portion of mature thalli. Anatomical examination revealed that the mature spermatangia were 64 (a/4, b/2, c/8) and 128 (a/4, b/4, c/8), and that of zygotosporangium was 16 (a/2, b/2, c/4) according to the Hus' formula.

• 한국식품과학회지
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• 제37권6호
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• pp.861-865
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• 2005

본 연구는 일반적으로 사용되고 있는 vitamin C 분석방법인 2,4-dinitrophenylhydrazine(DNP), indophenol, 그리고 HPLC법을 이용하여 시판중인 다양한 제품을 이용하여 보존조건($10^{\circ}C,\;20^{\circ}C$)에 따른 vitamin C 함량을 세 가지 방법으로 비교 검토함으로서 가장 이상적인 분석방법을 조사하였다. $10^{\circ}C$ 보존시 요쿠르트 A 제품에서의 vitamin C 변화 추세를 살펴보면, DNP법은 초기와 말기 TAA 함량이 각자 26.7과 22.8mg/100mL로 측정되었으나, 저장 3일째와 10일째에 오히려 증가하는 현상을 보였으며, 또만 indophenol법은 초기와 말기에 각각 28.6과 9.5mg/100mL로, HPLC법은 30.5와 14.6mg/100mL로 확인되었다. 그리고 본 실험에서는 indophenol법과 HPLC법은 일정한 감소 추세를 보였다. 따라서, 가장 이상적인 vitamin C 분석 방법은 HPLC법이며, 저장 초기에 간단하게 vitamin C 함량을 측정할 경우에는 indophenol법을 이용하여도 신뢰할 수 있는 결과를 얻을 수 있는 것으로 사료된다.

• 한국수산과학회지
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• 제3권3호
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• pp.187-198
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• 1970

1970년 7월 11일에 꽃게 Portunus trituberculatus (MIERS)의 인공 부화를 실시하여 조이야 유생으로부터 성체형 꽃게 새끼로 된 후 9회 탈피할 패까지의 성장 과정을 조사하였다. 1. 어미 게의 갑폭(C)과 포란수(E)와의 관계는 E=27.9049C-281.8155의 식으로 표시되었고, 체(W)과 포란수 (E)와는 E=0.5682W-116.4606의 관계식으로 표시되었다. 2. 조이야 유생은 수온 $21.4\~25.2^{\circ}C$ 범위에서 5회를 탈피하여 $13\~14$일만에 메갈로파 유생기로 변태하였고, 조이야 유생기의 1회 탈피 기간은 평군 $2\~$일이 소요되었다. 3. 메갈로파 유생의 배갑폭 평균 길이는 1.70mm였고, 배갑 후면에서부터 전두극 끝까지의 길이는 평균 2.78mm였으며 메갈로파 유생기에서 탈피하여 성체형 게로 되는 데까지는 수온 $25.3\~26.9^{\circ}C$범위에서 $5\~6$일이 소요되었다. 4. 최초의 성체형 꽃게 새끼로 변태한 것은 부화 후 18일째였고, 이 때의 평균 갑폭은 4.48mm, 평균 갑장은 2.62mm 였다. 5. 성체형으로 변태한 새끼 꽃게는 $4\~5$일만에 첫회의 탈피를 하였으며, 탈피 후의 평균 갑폭은 6.47mm, 평균 갑장은 4.66mm 였다. 6. 유생 사육은 염분 농도가 높은 실내 수조보다 낮은 야외 탱크가 효과적이었고, 유생 기간의 폐사율은 조이야 1기에서 2기로 탈피할때 가장 높았으며, 새끼 꽃게로 된 후 9회 탈피기까지의 잔존율은 $55\~65\%$였다. 7. 성체형으로 변태한 후 40일간의 경과 일순(D)에 대한 각 수조별 성장식은 다음과 같이 표시되었다. 갑폭(C)은 실내 수조에서 C=1.1250D+1.7227 야외 수조에서 C=1.3465D-0.2449 갑장(L)은 실내 수조에서 L=0.6654D+1.6712 야외 수조에서 L=0.7893D+0.6919 이상과 같이 회귀 직선으로 표시되었고, 체중(W)은 야외 수조에서 $W=1.15e^{0.12423D}$, 실내 수조에서는 새끼 게 변태 후 9일부터 19일까지는 $W=6.759\times10^{-2}D^{1.2598}$이었고, 21일부터 40일 까지에서는 $W=4.136\times10^{-2}D^{1.6024}$ 등 의지수 곡선으로 표시되었다. 8. 성체형으로 변태한 후 9회의 탈피 기간 중 탈피 회수(N)에 따른 갑폭(C)과 갑장(L) 및 체중(W)과의 성장 관계는 $C=5.2e^{0.28119N}$ $L=3.65e^{0.26372N}$ $W= 0.14e^{0.7037N}$ 등의 지수 곡선으로 표시되었다. 9. 성체형으로 변태한 후 9회 탈피까지의 갑장(L)에 대한 갑폭(C)과 체중(W)과의 상대 성장식은 갑장 2.62mm부터 27.17mm(변태 후 40일)까지는 L=1.6864C-1.0387의 회귀 직선으로 표시되었고, 체중은 갑장 7.47mm부터 18.53mm까지(새끼 게 변태 후 23일)는 $W=9.367\times10^{-5}C^{3.5567}$였고, 갑장 22.11mm부터 27.17mm까지(새끼 게 변태 후 40일)는 $W=3.406\times10^{-5}C^{3.8571}$ 등의 지수 곡선으로 표시되었다.

• 대한수학회지
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• 제59권5호
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• pp.843-867
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• 2022

Maynard proved that there exists an effectively computable constant q1 such that if q ≥ q1, then $\frac{{\log}\;q}{\sqrt{q}{\phi}(q)}Li(x){\ll}{\pi}(x;\;q,\;m)<\frac{2}{{\phi}(q)}Li(x)$ for x ≥ q8. In this paper, we will show the following. Let 𝛿1 and 𝛿2 be positive constants with 0 < 𝛿1, 𝛿2 < 1 and 𝛿1 + 𝛿2 > 1. Assume that L ≠ ℚ is a number field. Then there exist effectively computable constants c0 and d1 such that for dL ≥ d1 and x ≥ exp (326n𝛿1L(log dL)1+𝛿2), we have $$\|{\pi}_C(x)-\frac{{\mid}C{\mid}}{{\mid}G{\mid}}Li(x)\|\;{\leq}\;\(1-c_0\frac{1og\;d_L}{d^{7.072}_L}\)\;\frac{{\mid}C{\mid}}{{\mid}G{\mid}}Li(x)$$.

• 한국항공우주학회지
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• 제30권3호
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• pp.87-95
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• 2002

원주의 항력 감소와 원주 주위 유동의 제어에 대하여 실험적으로 연구하였다. 원주 주위 유동을 제어하기 위하여 작은 제어봉을 원주 전방에 설치하였다. 실험시 원주 직경(D=30mm)에 기초한 레이놀즈수는 $Re=2 {/times} 10^4$이었다. 제어봉의 직경(d)은 4mm, 5mm, 6mm, 7mm로 변화시켰으며, 원주와 제어봉 사이의 거리(L)를 조절하면서 원주의 표면압력분포와 후류속도를 측정하였다. 제어봉으로부터의 와 유출이 사라지는 임계거리 (critical distance) $ L_C$는 $ L_C$ /D=1.5+0.83d이었는데, $ L_C$를 전후로 유동특성과 항력값이 크게 바뀌었다. 특히 원주와 제어봉 사이의 거리가 임계거리보다 짧은 경우에는 항력이 감소하다가 $ L_C$보다 크게 되면 증가하는 경향을 보였다. 제어봉의 직경이 d/D=0.233인 경우, L/D=2.013의 조건에서 원주는 약 29%의 항력 감소를 보였고, 전체 항력은 L/D=1.833조건에서 약 25% 항력이 감소하였다.

• 한국수산과학회지
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• 제48권1호
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• pp.76-81
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• 2015

The effects of temperature, photon irradiance, and photoperiod on the growth of Sargassum horneri embryos were examined for female plants collected at Chokpo in Tongyeoung, Gyeongnam Prefecture, Korea on 27 December 2011. Mature plant receptacles were detached, and fertilized eggs were cultured in the laboratory at temperatures of $5-25^{\circ}C$ with photon irradiances of $10-80{\mu}mol\;m^{-2}s^{-1}$ under 14L:10D and 10L:14D photoperiods. Germination and embryo growth were rapid at $20-25^{\circ}C$ and $40{\mu}mol\;m^{-2}s^{-1}$ under 14L:10D. The number of rhizoids in the germinated young thalli was high at high photon irradiances ($40-80{\mu}mol\;m^{-2}s^{-1}$) and $15-20^{\circ}C$. At $20^{\circ}C$ and 14L:10D, vigorous growth of main and lateral branches was observed; however, at $5^{\circ}C$ under both photoperiods, plant growth decreased markedly. In the present study, S. horneri grew well at high temperatures ($20-25^{\circ}C$) and high photon irradiances ($40-80{\mu}mol\;m^{-2}s^{-1}$) with a 14L:10D photoperiod.

• 핵의학기술
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• 제13권3호
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• pp.143-146
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• 2009

Purpose: We use the centrifugation of refrigeration state in separation of blood serum, Anti-ds-DNA, Vitamin $B_{12}$/Folate and GAD-Ab assay. However, Cortisol urine and 25-Hydroxyvitamin $D_3$ ($25OHD_3$) are conducted centrifuge at room temperature. This is troublesome that change centrifugation temperature into room temperature due to using of most assays at cold temperature. Therefore when using centrifuge after extraction of Cortisol urine and $25OHD_3$, we conducted researches on effect of the centrifugation temperature in assay results. Materials and Methods: In Cortisol urine, add dichloromethane 1.0 mL in urine $500\;{\mu}L$, mix for 15 minutes, and then centrifuge for 8 minutes at 2600rpm. In $25OHD_3$ add acetonitrile 0.5 mL in serum $200\;{\mu}L$, and then centrifuge for 8 minutes at 2600rpm. Those experiments were conducted centrifuge at room temperature and $4^{\circ}C$. And experiments conducted immediately after centrifugation at $4^{\circ}C$ and standing for 20 minutes after centrifugation $4^{\circ}C$. Results: In Cortisol urine, room temperature result in 1.93, 2.18, 2.43, 9.45, 14.2 (${\mu}g/dL$). Experiments of performing immediately after centrifuge at $4^{\circ}C$ result in 1.8, 2.0, 2.3, 8.1, 13.7 (${\mu}g/dL$). Experiments of performing after 20 minutes result in 2.1, 2.1, 2.7, 9.95, 14.35 (${\mu}g/dL$). On the other hand, the $25OHD_3$ tests conducted at room temperature result in 7.13, 26.6, 35.8, 48.2, 74.8 (ng/dL). Experiments were conducted immediately by pipetting after $4^{\circ}C$ centrifugation result in 7.53, 30.9, 40.3, 61.5, 89.1 (ng/dL) as results are higher than experiments at room temperature. The experiments that conducted centrifuge at $4^{\circ}C$ and then left at room temperature for 20 minutes result in 7.40, 32.4, 41.3, 51.6, 85.6 (ng/dL). Conclusions: Experiments were conducted by using centrifuge at $4^{\circ}C$ are higher or lower than room temperature. The differences between results of standing for 20 minutes after centrifuge at $4^{\circ}C$ and those of centrifuge at room temperature are less than conducting immediately. It is concerned that experiments conducted immediately after centrifuge at $4^{\circ}C$ are incorrect, because tubes become dim due to temperature differences between $4^{\circ}C$ and room temperature. Therefore, it is desirable to centrifuge at room temperature as manual and we should pipet promptly without stopping.