• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.430-430
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• 2008

Using multi plasma enhanced chemical vapor deposition system (Multi-PECVD), p-a-Si:H deposition layer as a $p^+$ region which was annealed by laser (Q-switched fiber laser, $\lambda$ = 1064 nm) on an n-type single crystalline Si (100) plane circle wafer was prepared as new doping method for single crystalline interdigitated back contact (IBC) solar cells. As lots of earlier studies implemented, most cases dealt with the excimer (excited dimer) laserannealing or crystallization of boron with the ultraviolet wavelength range and $10^{-9}$ sec pulse duration. In this study, the Q-switched fiber laser which has higher power, longer wavelength of infrared range ($\lambda$ = 1064 nm) and longer pulse duration of $10^{-8}$ sec than excimer laser was introduced for uniformly deposited p-a-Si:H layer to be annealed and to make sheet resistance expectable as an important process for IBC solar cell $p^+$ layer on a polished n-type Si circle wafer. A $525{\mu}m$ thick n-type Si semiconductor circle wafer of (100) plane which was dipped in a buffered hydrofluoric acid solution for 30 seconds was mounted on the Multi-PECVD system for p-a-Si:H deposition layer with the ratio of $SiH_4:H_2:B_2H_6$ = 30:120:30, at $200^{\circ}C$, 50 W power, 0.2 Torr pressure for 20 minutes. 15 mm $\times$ 15 mm size laser cut samples were annealed by fiber laser with different sets of power levels and frequencies. By comparing the results of lifetime measurement and sheet resistance relation, the laser condition set of 50 mm/s of mark speed, 160 kHz of period, 21 % of power level with continuous wave mode of scanner lens showed the features of small difference of lifetime and lowering sheet resistance than before the fiber laser treatment with not much surface damages. Diode level device was made to confirm these experimental results by measuring C-V, I-V characteristics. Uniform and expectable boron doped layer can play an important role to predict the efficiency during the fabricating process of IBC solar cells.

• Journal of Korea Foresty Energy
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• v.20 no.2
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• pp.81-116
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• 2001

The flora of vascular plants investigated in civilian control line area was 730 taxa consisting of 104 families, 331 genera, 631 species, 2 subspecies, 90 varieties, 7 formae. The forest was comparatively well conserved by Pteridophyta calculation(Pte-Q), 1.27. Among the investigated vascular plants, Korean endemic plants(Carex okamotoi, Salix koriyanagi, Clematis chisanensis, Aconitum pseudo-laeve var. erectum, Viola diamantiaca etc.) were 31 taxa; rare and endangered plants(Disporum ovale, Lilium distichum, Trillium kamschaticum, Gastrodia elata etc.) were 35 taxa; naturalized plants(Dactylis glomerata, Poa pratensis, Rumex acetosella, Gypsophila oldamiana, Lepidium apetalum etc.) were 26 taxa. The forest vegetation was classified into 1 order, 1 alliances, 6 communities; Rhododendro-Quercetalia mongolicae Kim 1990(신갈나무-철쭉군목), Lindero-Quercion mongolicae Kim 1990(신갈나무-생강나무군단), A. Carex humilis v. nana- Phinus densiflora Community 소나무-산거울군락, B. Acer pseudo-sieboldianum-Quercus mongolica Community 당단풍-신갈나무군락, C. Styrax obassia-Quercus mongolica Community 쪽동백-신갈나무군락, D. Acer palmatum-Quercus mongolica Community 단풍나무-신갈나무군락, E. Rheodendron mucronulatum-Quercus mongolica Community 진달래-신갈나무군락, F. Betula schmiditii-Quercus mongolica Community 박달나무-신갈나무군락

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.5
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• pp.24-32
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• 2017

In this paper, a low power 4th order delta-sigma modulator was designed with a high resolution of 12 bits or more for the biological signal processing. Using time-interleaving technique, 4th order delta-sigma modulator was designed with one operational amplifier. So power consumption can be reduced to 1/4 than a conventional structure. To operate stably in the big difference between the two capacitor for kT/C noise and chip size, the variable-stage amplifier was designed. In the first phase and second phase, the operational amplifier is operating in a 2-stage. In the third and fourth phase, the operational amplifier is operating in a 1-stage. This was significantly improved the stability of the modulator because the phase margin exists within 60~90deg. The proposed delta-sigma modulator is designed in a standard $0.18{\mu}m$ CMOS n-well 1 poly 6 Metal technology and dissipates the power of $354{\mu}W$ with supply voltage of 1.8V. The ENOB of 11.8bit and SNDR of 72.8dB at 250Hz input frequency and 256kHz sampling frequency. From measurement results FOM1 is calculated to 49.6pJ/step and FOM2 is calculated to 154.5dB.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.6
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• pp.39-47
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• 1998

A fourth-order $\Sigma$-$\Delta$ modulator is designed and implemented in 0.6 $\mu\textrm{m}$ CMOS technology. The modulator is verified by introducing nonlinear factors such as DC gain and slew rate in system model that determines the transfer function in S-domain and in time-domain. Dynamic range is more than 110 dB and the peak SM is 102.6 dB at a clock rate of 2.8224 MHz for voiceband signal. The structure of a ∑-$\Delta$ modulator is a modified fourth-order ∑-$\Delta$ modulator using direct feedback loop method, which improves performance and consumes less power. The transmission zero for noise is located in the first-second integrator loop, which reduces entire size of capacitors, reduces the active area of the chip, improves the performance, and reduces power dissipation. The system is stable because the output variation with respect to unit time is small compared with that of the third integrator. It is easy to implement because the size of the capacitor in the first integrator, and the size of the third integrator is small because we use the noise reduction technique. This paper represents a new design method by modeling that conceptually decides transfer function in S-domain and in Z-domain, determines the cutoff frequency of signal, maximizes signal power in each integrator, and decides optimal transmission-zero frequency for noise. The active area of the prototype chip is 5.25$\textrm{mm}^2$, and it dissipates 10 mW of power from a 5V supply.

• Journal of the Korean Wood Science and Technology
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• v.37 no.1
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• pp.105-113
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• 2009

The freezed Mulberry (10 kg) was extracted with 80% EtOH, concentrated, and fractionated with a series of n-hexane, ethyl acetate, and water on a separatory funnel. A portion of ethyl acetate soluble (22 g) was chromatographed on a Sephadex LH-20 column using a series of aqueous methanol as eluents. The isolated compounds were identified by cellulose TLC, $^1H-$,$^{13}C$-NMR, FAB, and EI-MS. Quercetin-3-O-${\beta}$-D-glucopyranoside (Compound I), protocatechuic acid (Compound II), p-hydroxybenzoic acid (Compound III) were isolated from the ethyl acetate soluble fraction. In antioxidative activities of the fractionated extractives using DPPH radical scavenging test, EtOAc and water soluble fractions indicated better than BHT as contro and in in vitro tests using MTT assay, there was no cytotoxicity. Also, tyrosinase inhibition and anticancer activities were not so good, but there may be a potential as a cosmetic raw material because the cell extension effect was excellent.

• Korean Journal of Food Science and Technology
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• v.34 no.5
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• pp.787-791
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• 2002

Optimal extraction, separation, and capillary rinsing conditions for capillary electrophoresis (CE) were established to identify the cultivation site (domestic vs. foreign) of Job's-tears (Coix lachrymajobi var. mayuen) using 240 samples (domestic sample n = 121, foreign sample n = 119). Job's-tears was extracted with 30% ethanol and separated on a $50-{\mu}m-I.D.$ untreated fused-silica capillary. Optimal analytic conditions were: temperature, $45^{\circ}C$; voltage, 15 kV; detector rise time, 0.1 sec; and pressure injection, 20 sec. Separation of peak investigated using 0.1 M phosphate buffer (pH 2.5) containing 0.05% hydroxypropylmethylcellulose (P buffer) revealed the optimal separation buffer was P buffer containing 26 mM hexane sulfonic acid with 30% methanol. Under the optimal conditions established for CE, the average correct identification percentage of domestic or foreign Job's-tears was 82%.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.5
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• pp.738-746
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• 2011

We manufactured rice-whole soybean curd by a microbial transglutaminase (MTGase) with a mixture of hydrolyzed rice and micronized whole soybean powder (MWSP) and analyzed its rheological properties, including texture, viscoelasticity, protein cross-linking, and surface structure. A 40% rice suspension digested with a Termamyl enzyme at $85^{\circ}C$ for 20 min showed a 9.0% reducing sugar and a consistency of $1.27\;Pa{\cdot}s^n$, resulting in a great reduction in consistency. A MWSP suspension with 22% solid content was transformed into a typical tofu texture. MWSP curd fortified with 7.5% rice showed enhanced texture properties, with a hardness of 639.6 dyne/$cm^2$, and a springiness of 0.96. In a MWSP suspension (18~22% w/v) treated with 5% MTGase, viscoelasticity increased dependently with MWSP concentration, and a 22% MWSP indicated a G' value of 5.1 Pa and a G'' value of 9.0 Pa. Furthermore, soybean proteins present in the 22% MWSP curd largely disappeared or formed polymers with a high molecular weight by MTGase reaction within 30 min. MWSP (22%) fortified with 7.5% rice showed similar polymerization patterns on SDS-PAGE. The surface structure of the rice-MWSP curds was more dense and homogeneous network due to the addition of hydrolyzed rice. However, the surface structure of all rice-MWSP curds became rough and showed a non-homogeneous network after cold storage.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.33 no.2
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• pp.79-86
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• 2007

The aim of this study was to investigate the inhibitory effects of Forsythia suspensa fruit extracts (FSfE) ($0.1{\sim}1.0%$) and their active component on melanogenesis. FSfE dose-dependently inhibited melanin synthesis (up to $63.1{\pm}3.1%$ at the concentration of 1.0%) without cell cytotoxicity. We purifed one active compound from FSfE and identified its structure. It was identified as 4-[(3,4-Dimethoxyphenyl)methyl)]dihydro-3-[(4-hydroxy-3-methoxyphenyl)methyl]-2(3H)-furanone (arctigenin) by $^1H-NMR,\;^{13}C-NMR$, and Mass analysis. Arctigenin also inhibited melanin synthesis in a dose dependent manner (up to $52.7{\pm}3.1%$ at the concentration of $3.0{\mu}g/mL$). In order to verify the whitening activity of the cream containing 3% FSfE, we performed the clinical test with twenty five female volunteers for 8 weeks. Bioengineering analyses and visual assessment by doctors at the initial time point and 8 weeks after applications showed that cream containing FSfE have significant whiteining effect (paired t-test). From the results, we conclude that the FSfE can be used as a useful whitening agent.

• Journal of Acupuncture Research
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• v.17 no.2
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• pp.153-168
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• 2000

Introduction : In spite of the use of Bee Venom aqua-acupuncture in the clinics, the scientific evaluation on effects is not enough. Bee Venom aqua-acupuncture is used according to the stimulation of acupuncture point and the chemical effects of Bee Venom. The aims of this study is to investigate the analgegic effects of the Bee Venom aqua-acupuncture, through the change of writhing reflex and the change of c-fos in secondary neurons in the spinal cord. Materials and Methods : Pain animal model was used acetic acid method. The changes of writhing reflex of the mice which were derived pain by injecting acetic acid into the abdomen, after stimulating Bee Venom aqua-acupuncture on Chungwan(CV12) were measured. We used Fos immunohistochemical technique to study the neuronal activity in the spinal cord. Results : 1. Expression of c-fos in superficial dorsal horn(SDH), nucleus proprius(NP) and neck of dorsal hom(N) on 6~9th thoracic spine decreased significantly at $2.5{\times}10-4$g/kg Bee Venom aqua-acupuncture, compared with saline-acetic acid group. 2. The numeral change of Fos-LI neurons on the NP, N, and ventral gray(V) on 6-9th thoracic spine, SDH on 9-11th thoracic spine, and SDH and V on 11~13th thoracic spine decreased significantly at Chungwan(CV12) Bee Venom aqua-acupuncture, compared with saline-acetic acid group. 3. The correlation between the numbers of writhing refleax and Fos-LI neurons in T6-13 segment was statistically statistically significant at Chungwan(CV12) Bee Venom aqua-acupuncture. Conclusion : This study shows that the Bee Venom aqua-acupuncture on Chungwan(CV12) decreases the numbers of Fos-LI neurons. As the analgegic effects of Bee Venom aqua-acupuncture is recognized. Bee Venom aqua-acupuncture treatment is expected for pain modulation. In order to use it in many ways, more researches are needed for the dose and stability of Bee Venom aqua-acupuncture.

• The Korean Journal of Physiology and Pharmacology
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• v.8 no.1
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• pp.7-15
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• 2004

Nitric oxide (NO) system has been implicated in a wide range of physiological functions in the nervous system. However, the role of NO in regulating the neural activity in the gustatory zone of nucleus tractus solitarius (NTS) has not been established. The present study was aimed to investigate the role of NO in the gustatory NTS neurons. Sprague-Dawley rats, weighing about 50 g, were used. Whole cell patch recording and immunohistochemistry were done to determine the electrophysiological characteristics of the rostral gustatory nucleus of the tractus solitaries and distribution of NO synthases (NOS). Neuronal NOS (nNOS) immunoreactivity was strongly detected along the solitary tract extending from rostral to caudal medulla. Resting membrane potentials of NTS neurons were $-49.2{\pm}2\;mV$ and action potential amplitudes were $68.5{\pm}2\;mV$ with a mean duration measured at half amplitude of $1.7{\pm}0.3\;ms$. Input resistance, determined from the response to a 150 ms, -100 pA hyperpolarizing current pulse, was $385{\pm}15\;M{\Omega}$, Superfusion of SNAP or SNP, NO donors, produced either hyperpolarization (68%), depolarization (5%), or no effect (27%). The hyperpolarization was mostly accompanied by a decrease in input resistance. The hyperpolarization caused by SNAP or SNP increased the time to initiate the first action potential, and decreased the number of action potentials elicited by current injection. SNP or SNAP also markedly decreased the number of firing neural discharges of the spontaneous NTS neural activity under zero current. Superfusion of L-NAME, a NOS inhibitor, slightly depolarized the membrane potential and increased the firing rate of NTS neurons induced by current injection. ODQ, a soluble guanylate cyclase inhibitor, ameliorated the SNAP-induced changes in membrane potential, input resistance and firing rates. 8-Br-cGMP, a non-degradable cell-permeable cGMP, hyperpolarized the membrane potential and decreased the number of action potentials. It is suggested that NO in the gustatory NTS has an inhibitory role on the neural activity of NTS through activating soluble guanylate cyclase.