• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.139.2-139.2
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• 2015

In this study, We applied the magnetic field that has CW frequency and AM frequency to heating magnetic nano powder. For this experiment, We set up the devices flat-type magnetic field generator with CW frequency and AM frequency. We supplied the current to encircling coil by adjusting the power of generating of magnetic field device for AC voltage through Slidacs and using way of LC resonance circuit and SMPS(Switching Mode Power Supply). Above the encircling coil, We covered the circular flat insulator like glass. And we located the well plate containing the magnetic nano powder liquor above the circular flat insulator and exposed the magnetic field to this well plate. Using the flat-type magnetic field generator with CW and AM frequency and the magnetic field measurement sensor(Magnetic pick up coil or Hall sensor), We measured the strength of the magnetic field of circular flat insulator's surface in each position. The temperature of the magnetic nano powder in the well plate was quantitatively measured by the magnetic field strength through the Fluoroptic thermometer.

• Natural Product Sciences
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• 제21권2호
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• pp.111-121
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• 2015

The root of Panax ginseng, is a Korea traditional medicine, which is used in both raw and processed forms due to their different pharmacological activities. As part of a continued chemical investigation of ginseng, the focus of this research is on the isolation and identification of compounds from Panax ginseng root by open column chromatography, medium pressure liquid chromatography, semi-preparative-high performance liquid chromatography, Fast atom bombardment mass spectrometric, and nuclear magnetic resonance. Dammarane-type triterpenoid saponins were isolated from Panax ginseng root by open column chromatography, medium pressure liquid chromatography, and semi-preparative-high performance liquid chromatography. Their structures were identified as protopanaxadiol ginsenosides [gypenoside-V (1), ginsenosides-Rb1 (2), -Rb2 (3), -Rb3 (4), -Rc (5), and -Rd (6)], protopanaxatriol ginsenosides [20(S)-notoginsenoside-R2 (7), notoginsenoside-Rt (8), 20(S)-O-glucoginsenoside-Rf (9), 6-O-[$\alpha$-L-rhamnopyranosyl(1$\rightarrow$2-$\beta$-D-glucopyranosyl]-20-O-$\beta$-D-glucopyranosyl-$3\beta$,$12\beta$, 20(S)-dihydroxy-dammar-25-en-24-one (10), majoroside-F6 (11), pseudoginsenoside-Rt3 (12), ginsenosides-Re (13), -Re5 (14), -Rf (15), -Rg1 (16), -Rg2 (17), and -Rh1 (18), and vinaginsenoside-R15 (19)], and oleanene ginsenosides [calenduloside-B (20) and ginsenoside-Ro (21)] through the interpretation of spectroscopic analysis. The configuration of the sugar linkages in each saponin was established on the basic of chemical and spectroscopic data. Among them, compounds 1, 8, 10, 11, 12, 19, and 20 were isolated for the first time from P. ginseng root.

• Bulletin of the Korean Chemical Society
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• 제32권6호
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• pp.1907-1911
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• 2011

A kinetic study is reported for nucleophilic substitution reactions of 4-pyridyl X-substituted benzoates 7a-e with a series of alicyclic secondary amines in H2O. The Br${\o}$nsted-type plot for the reactions of 4-pyridyl benzoate 7c is linear with ${\beta}_{nuc}$ = 0.71. The corresponding reactions of 2-pyridyl benzoate 6, which is less reactive than 7c, resulted in also a linear Br${\o}$nsted-type plot with ${\beta}_{nuc}$ = 0.77. The fact that the more reactive 7c results in a smaller ${\beta}_{nuc}$ value appears to be in accord with the reactivity-selectivity principle. The aminolysis of 7c has been suggested to proceed through a stepwise mechanism in which breakdown of the intermediate is the rate-determining step (RDS). The Hammett plot for the reactions of 7a-e with piperidine consists of two intersecting straight lines, i.e., ${\rho}_X$ = 1.47 for substrates possessing an electron-donating group (EDG) and ${\rho}_X$ = 0.91 for those possessing an electron-withdrawing group (EWG). In contrast, the corresponding Yukawa-Tsuno plot exhibits excellent linear correlation with ${\rho}_X$ = 0.79 and r = 0.56. Thus, it has been concluded that the nonlinear Hammett plot is not due to a change in the RDS but is caused by stabilization of the ground state of the substrates possessing an EDG through resonance interaction between the EDG and the C=O bond of the substrates.

• Journal of Microbiology and Biotechnology
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• 제27권8호
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• pp.1386-1391
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• 2017

The bioactivities of boxthron fruits, a source of oriental medicine, are well known, whereas phytochemical studies of the boxthorn stem are rare. In this study, the stem extract of boxthorn (Lycium chinense Miller) and its subfractions were evaluated for their effects on nitric oxide (NO) inhibition and procollagen type I peptide (PIP) synthesis. A phenolic amide isolated from the stem extract was also assayed for these effects. The compound, N-trans-feruloyltyramine, was identified by $^1H$, $^{13}C$, and 2D-nuclear magnetic resonance analyses. In NO inhibition, the chloroform fraction (CF) exhibited the strongest inhibitory activity ($MIC_{50}=24.69{\mu}g/ml$) among the subfractions of the ethanol extract (EE). N-trans-feruloyltyramine isolated from the CF showed strong NO inhibitory activity, presenting with an $MIC_{50}$ of $31.36{\mu}g/ml$. The EE, CF, and N-trans-feruloyltyramine shown to have NO inhibition activity were assayed for the activity of PIP synthesis. The EE and CF showed relatively high PIP values of 38.8% and 24.21% at $100{\mu}g/ml$, respectively. The PIP value for $20{\mu}g/ml$ N-trans-feruloyltyramine showed a 36% increase compared with the non-treated control, whereas that treated with $20{\mu}g/ml$ ascorbic acid as a positive control showed a 13% increase. The results suggest that the proper stem extract of boxthorn stem could be efficiently used to produce good cosmetic effects.

• Smart Structures and Systems
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• 제26권2호
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• pp.195-211
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• 2020

Among anti-seismic technologies, base isolation is a very effective means of mitigating damage to structural and nonstructural components, such as equipment. However, most seismic isolation systems are designed for mitigating only horizontal seismic responses because the realization of a vertical isolation system (VIS) is difficult. The difficulty is primarily due to conflicting isolation stiffness demands in the static and dynamic states for a VIS, which requires sufficient rigidity to support the self-weight of the isolated object in the static state, but sufficient flexibility to lengthen the isolation period and uncouple the ground motion in the dynamic state. To overcome this problem, a semi-active VIS, called the piezoelectric inertia-type vertical isolation system (PIVIS), is proposed in this study. PIVIS is composed of a piezoelectric friction damper (PFD) and a leverage mechanism with a counterweight. The counterweight provides an uplifting force in the static state and an extra inertial force in the dynamic state; therefore, the effective vertical stiffness of PIVIS is higher in the static state and lower in the dynamic state. The PFD provides a controllable friction force for PIVIS to further prevent its excessive displacement. For experimental verification, a shaking table test was conducted on a prototype PIVIS controlled by a simple controller. The experimental results well agree with the theoretical results. To further investigate the isolation performance of PIVIS, the seismic responses of PIVIS were simulated numerically by considering 14 vertical ground motions with different characteristics. The responses of PIVIS were compared with those of a traditional VIS and a passive system (PIVIS without control). The numerical results demonstrate that compared with the traditional and passive systems, PIVIS can effectively suppress isolation displacement in all kinds of earthquake with various peak ground accelerations and frequency content while maintaining its isolation efficiency. The proposed system is particularly effective for near-fault earthquakes with long-period components, for which it prevents resonant-like motion.

• Bulletin of the Korean Chemical Society
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• 제35권2호
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• pp.471-476
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• 2014

A kinetic study on aminolysis of 2-chloro-4-nitrophenyl X-substituted-benzoates (2a-k) in 80 mol % $H_2O/_20mol%$ DMSO at $25.0^{\circ}C$ is reported. The Br${\emptyset}$nsted-type plot for the reactions of 2-chloro-4-nitrophenyl benzoate (2g) with a series of cyclic secondary amines curves downward (e.g., ${\beta}_1=0.25$, ${\beta}_2=0.85$ and $pK_a^o=10.3$), which is typical of reactions reported to proceed through a stepwise mechanism with a change in ratedetermining step (RDS). The Hammett plot for the reactions of 2a-k with piperidine consists of two intersecting straight lines, while the corresponding Yukawa-Tsuno plot exhibits an excellent linear correlation with ${\rho}_X=1.15$ and r = 0.59. Thus, it has been concluded that the nonlinear Hammett plot is not due to a change in RDS but is caused by stabilization of substrates through resonance interactions between the electron-donating substituent and the C=O bond. Substrates possessing a substituent at the 2-position of the leaving aryloxide deviate negatively from the curved Br${\emptyset}$nsted-type plot for the reactions of Y-substituted-phenyl benzoates (3a-i), implying that the steric hindrance exerted by the substituent at the 2-position is an important factor which governs the reactivity of Y-substituted-phenyl benzoates.

• Bulletin of the Korean Chemical Society
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• 제35권4호
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• pp.1128-1132
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• 2014

A kinetic study on aminolysis of 4-chloro-2-nitrophenyl X-substituted-benzoates (6a-i) in MeCN is reported. The Hammett plot for the reactions of 6a-i with piperidine consists of two intersecting straight lines, while the Yukawa-Tsuno plot exhibits an excellent linear correlation with ${\rho}_X$ = 1.03 and r = 0.78. The nonlinear Hammett plot is not due to a change in rate-determining step (RDS) but is caused by the resonance stabilization of substrates possessing an electron-donating group in the benzoyl moiety. The Br${\phi}$nsted-type plot for the reactions of 4-chloro-2-nitrophenyl benzoate (6e) with a series of cyclic secondary amines is linear with ${\beta}_{nuc}$ = 0.69, an upper limit for reactions reported to proceed through a concerted mechanism. The aminolysis of 6e in aqueous medium has previously been reported to proceed through a stepwise mechanism with a change in RDS on the basis of a curved Br${\phi}$nsted-type plot. It has been concluded that instability of the zwitterionic tetrahedral intermediate ($T^{\pm}$) in MeCN forces the reaction to proceed through a concerted mechanism. This is further supported by the kinetic result that the amines used in this study are less reactive in MeCN than in $H_2O$, although they are more basic in MeCN over 7 $pK_a$ units.

• 척추신경추나의학회지
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• 제9권1호
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• pp.15-26
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• 2014

Objectives : The purpose of this study was to evaluate the effect of Korean medicicine treatment in patients with Spondylolisthesis and Lumbar Herniated Intervertebral Disc(HIVD). Methods : This clinical study was carried out on 62 patients who were diagnosed as spondylolisthesis and lumbar herniated intervertebral disc(HIVD) on L-spine X-ray and L-spine magnetic resonance imaging(MRI), who had been admitted from Feb. 2013 to Apr. 2014. All of 62 patients were treated with acupuncture, chuna treatment and herbal medicine during the whole admission period. Numerical rating scale(NRS) was used to evaluated the effectiveness of the oriental medical treatment. Results : 1. Distribution showed female predominance in general. 2. Degenerative type is the most common in this study. 3. In the duration of symptoms, the largest group was" Subacute"(32.26%). 4. Almost of patients had radiation pain, but in SLR test and valsalva test, more patients had no significant sign. 5. Spondylolytic type involved the 5th lumbar vertebra in 80% and degenerative type involved the 4th lumbar vertebra in 53.84%. 6. Most of case were grade 1(93.54%) in degree of slipping. 7. By the oriental medical treatment, NRS reduction in spondylolytic spondylolisthesis, was better than degenerative spondylolisthesis. Conclusions : The result of treatment by Korean medical is satisfactory for the tretment of spondylolisthesis.

• Bulletin of the Korean Chemical Society
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• 제34권8호
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• pp.2455-2460
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• 2013

Second-order rate constants ($k_N$) have been measured spectrophotometrically for the nucleophilic displacement reactions of 4-nitrophenyl X-substituted-cinnamates (4a-4e) and Y-substituted-phenyl cinnamates (5a-5e) with Z-substituted-phenoxide anions in 80 mol % $H_2O$/20 mol % DMSO at $25.0{\pm}0.1^{\circ}C$. The Hammett plot for the reactions of 4a-4e with 4-chlorophenoxide (4-$ClPhO^-$) consists of two intersecting straight lines, which might be taken as a change in the rate-determining step (RDS). However, it has been concluded that the nonlinear Hammett plot is not due to a change in the RDS but is caused by stabilization of the ground state of substrates possessing an electron-withdrawing group in the cinnamoyl moiety through resonance interactions, since the Yukawa-Tsuno plot exhibits an excellent linear correlation with ${\rho}X=0.89$ and r = 0.58. The Br${\o}$nsted-type plot for the reactions of 4-nitrophenyl cinnamate (4c) with Z-substituted-phenoxides is linear with ${\beta}_{nuc}=0.76$. The Br${\o}$nsted-type plot for the reactions of Y-substituted-phenyl cinnamates (5a-5d) with 4-chlorophenoxides (4-$ClPhO^-$) is also linear with ${\beta}_{lg}=-0.72$. The Hammett plot correlated with ${\sigma}^-$ constants for the reactions of 5a-5d results in a much better linear correlation than that correlated with ${\sigma}^o$ constants, indicating that a partial negative charge develops on the O atom of the leaving aryloxide. Thus, the reactions have been concluded to proceed through a concerted mechanism.

• 한국추진공학회지
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• 제21권1호
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• pp.26-35
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• 2017

원심압축기 운전 중에 발생하는 고주기 피로균열이나 공진 등은 임펠러 파손의 주된 원인이다. 이러한 파손을 회피하기 위해 공진영역 운전에서도 견딜 수 있는 충분한 강도의 임펠러를 설계하거나, 공진이 발생하지 않도록 임펠러를 튜닝 한다. 이러한 회피설계는 임펠러 내부유동 및 성능특성 변화를 야기하게 된다. 본 연구에서는 밀폐형 임펠러에 대해 블레이드 두께를 증가시킨 모델과 스켈럽을 적용한 모델에 대한 유동 및 성능특성을 파악하기 위해 전산해석을 수행하였다. 전산해석 결과, 블레이드 두께 증가 모델 경우는 기본모델 대비 압력계수가 0.5% 감소하였으며, 전효율은 0.1% 감소하였다. 스켈럽 적용모델은 압력계수가 0.4% 증가하였으며, 전효율은 1.6% 감소하였다.