• Proceedings of the KIEE Conference
• /
• 1989.07a
• /
• pp.633-636
• /
• 1989

The simulation results of the third harmonic conversion with 1.064 um Nd :YAG laser using polarization mismatch method are reported. The third harmonic conversion efficiency was over 65% for the Gaussian incident pulse of $300{\sim}400MW/cm^2$ peak intensity, and over 80% for $3{\sim}4GW/cm^2$ peak intensity pulse. The dependence of the third harmonic conversion efficiency' on the variation of incident polarization angle ${\theta}_p$ and angular discrepancy ${\Delta}{\theta}$ of phase matched angle ${\theta}_m$ is discussed.

• Polymer(Korea)
• /
• v.29 no.4
• /
• pp.418-421
• /
• 2005

Three-dimensional (3D) microfabrication process using two-photon polymerization (TPP) is developed to fabricate the curved microstructures in a layer, which can be applied potentially to optical MEMS, nano/micro-devices, etc. A 3D curved structure can be expressed using the same height-contours that are defined by symbolic colors which consist of 14 colors. Then, the designed bitmap figure is transformed into a multi-exposure voxel matrix (MVM). In this work a multi-exposure voxel matrix scanning method is used to generate various heights of voxels according to each laser exposure time that is assigned to the symbolic colors. An objective lens with a numerical aperture of 1.25 is employed to enlarge the variation of a voxel height in the range of 1.2 to 6.4 um which can be controlled easily using the various exposure time. Though this work some 3D curved micro-shapes are fabricated directly to demonstrate the usefulness of the process without a laminating process that is generally required in a micro-stereolithography process.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2015.10a
• /
• pp.397-400
• /
• 2015

In this paper a solar energy harvesting system with low-cost MPPT control for low duty-cycled sensor nodes is proposed. The targeted applications are environment, structure monitoring sensor nodes that are not required successively to operate, and MPPT(Maximum Power point Tracking) control using simple circuits is low-cost differently than existing MPPT control. The proposed MPPT control is implemented using linear relationship between the open-circuit voltage of a solar cell. The designed MPPT circuit traces the maximum power point by sampling periodically the open circuit voltage of the solar cell and delivers the maximum available power to the load. The proposed circuit is designed in 0.35um CMOS process. The designed chip area is $975um{\times}1025um$ including pads. Measured results show that the designed system can track the MPP voltage by sampling periodically the open circuit voltage of solar cell.

• Journal of the Semiconductor & Display Technology
• /
• v.3 no.3
• /
• pp.1-4
• /
• 2004

Fabrication and electrical and mechanical properties of piezoelectric micro bending actuators (PMBA) using sol-gel-multi-coated thick PZT films and MEMS processes were investigated. PMBA could be used for design and fabrication of micro fluidic devices, for example, micro-pumps, micro dispensers, and so on. PMBA were fabricated using 2 um thick PZT films on Pt (350 nm)/$SiO_2$ (500 nm)/Si ($300\mu\textrm{m}$) substrates and MEMS processes. 7 types of PMBA were fabricated with areas of silicon diaphragms, PZT films and top electrodes. When the sizes of silicon diaphragms, PZT films and Pt top electrodes were reduced from 3000$\times$$1389\mu\textrm{m}$, 4000$\times$$1000\mu\textrm{m}$ and 4000$\times$$900\mu\textrm{m}$ down to 14%, 14% and 11 % of them, respectively, the center displacements of PMBA were decreased from 0.68 um to 0.10 um at 5 Hz and 12 Vpp. So, PMBA with large areas showed larger displacements than PMBA with small areas and experimental results were also good agreement with the plate and shell theory.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2007.04a
• /
• pp.469-472
• /
• 2007

최근 많은 광대역 유무선 통신 응용분야에서 OFDM(Orthogonal Frequency Division Multiplexing) 방식을 표준기술로 채택하고 있다 OFDM 방식의 고속 무선 데이터 통신를 위한 FFT 프로세서는 일반적으로 DSP(Digital Signal Processing)로 구현되었으나, 큰 전력 소비를 필요로 한다. OFDM의 단점인 전력문제를 보안하기 위해서 Current-mode FFT LSI가 제안되었다. 본 논문에서는 Current-mode FFT LSI의 구현을 위한 저전력 IVC를 설계하였다. 설계된 IVC는 FFT Block의 출력이 $13.65{\mu}A$ 이상일 때에 3V 이상의 전압을 출력하고, FFT Block의 출력이 $0.15{\mu}A$ 이하일 때에 0.5V 이하의 전압을 출력한다. 그리고 IVC의 총 소모전력은 약 1.65mW이다. $0.35{\mu}A$ 공정에서의 저전력 IVC를 설계함으로서, $0.35{\mu}A$ 공정에서의 Current-mode FFT LSI의 설계가 가능해졌다. 저전력 OFDM 통신용 Current-mode FFT LSI는 무선통신의 발전에 기여할 것으로 전망한다.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2004.08a
• /
• pp.249-257
• /
• 2004

Drying and curing characteristics of PCM resins using the induction heater and short-wave infrared emitter module was studied to develop a compact oven system for the high speed CCL and post-treatment equipment. Drying of the polyester resins using the induction heater and infrared heater showed that the blistering tendency of polyester resin coating increased regardless of additives and colors of resins as the heating rate and/or dry film thickness increased. The blistering of polyester resin coating layer occurred when the heating speed was over than $25^{\circ}C/sec$ for the dry film thickness of $19\~20um$, which is the typical thickness of finish coating in CCL. So did it when the heating speed was over than $40^{\circ}C/sec$ for the dry film thickness over than 10 um. The heating efficiency of paint coated steels by the infrared heating was strongly dependent on the colors of paint coating and generally increased for the dark surface and/or coating. But the faster drying of the PCM resin coatings increased the blistering tendency of coating layer. The blistering limit for the typical finish coating by the infrared heating was estimated as the heating rate slower than $20^{\circ}C/sec$ regardless of colors of PCM resins.

• The Journal of Korean Medicine
• /
• v.15 no.2 s.28
• /
• pp.132-142
• /
• 1994

Paraquat has been widely used as a herbicide in Korea since 1970. Human ingestion results in transient impairment of liver and kidney function and a characteristically respiratory failure with a high mortality rate. Clinical investigation and Oriental Medical Treatment were done on 3 cases of paraquat poisoning admitted to the department of 1st Internal Medicine. Kyung San University Oriental Medical Hospital from August 1991 to December 1992. and following results were obtained. The symptoms of paraquat poisoning can be regarded as Sim hua chi song(心火熾盛), Kan hua sang yom(肝火上炎). um hu hua wang(陰虛火旺), Kan tam sup yol(肝膽濕熱), Yang myong yol tok(陽明熱毒) in Oriental Medicine. and the principle of treatment for paraquat poisoning can be applicable to Chong yol Ii sop(淸熱利濕), Chong yol hae tok(淸熱解毒). Sa ha hae tok(瀉下解毒). Ja um kang hua(滋陰降火) and so on. Three cases were treated by HuangYonHaeTokTang(黃蓮解毒湯) and KamDuTang(甘豆湯): all of them have survived without complications. According to the result above, it suggests that determination of treatment based on the differentiation of symptoms and signs(Pyon jung si chi ;辨證施治) of Oriental Medicine may prove to be helpful in saving lives of patients with paraquat poisoning.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.45 no.3
• /
• pp.54-59
• /
• 2008

A highly accurate wide swing BiCMOS cascode current mirror is proposed. It uses the base-current compensated BJT current mirror. It increases both output impedance and output voltage range by using the npn-NMOS cascode instead of the NMOS-NMOS cascode. The npn transistor copies the input current and the NMOS transistor increases the output impedance for the accurate current mirroring. The proposed current mirror achieves highly constant current for wide output voltage range. Simulation results were verified with measurements performed on a fabricated chip using a 5/16V 0.5um BCD process. It has only $-2.5%{\sim}1.0%$ current error for $0.3V{\sim}16V$ output voltage range.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.4 no.2
• /
• pp.93-100
• /
• 2002

Cocoon production, which is a representative of traditional sericulture shifted into silkworm powder production in the spring of 1995. This, infect, signifies the change from the dress-centered textile business to the bio-industry and the functional resource industry. One of the most outstanding shifting is utilization of silkworm larvae for anti-diabetic agent. In Asian countries including Korea, silkworm powder derived from the domestic silkworm (Bombyx mori L.) has long been favored for anti-diabetic agent, but its efficacy was not tested until last decade by modern scientific methods. In this article, we reviewed the major researches on the silkworm powder as a blood glucose-lowering substance. After the beginning test of the efficacy of silkworm powder by a cooperative research between Department of Sericulture and Entomlogy, NIAST, RDA and Kyung Hee University, substantial data have been accumulated so far, In a serial experiment to select best condition, the fifth instar larvae prepared by freeze dry method turned out to have the best blood glucose-lowering effect. In the pharmacological experiment to understand the mechanism of silkworm powder in small intestine, the silkworm powder turned out to inhibit the activity of ${\alpha}$-glucosidase, by competitively binding to $\alpha$-type disaccharides. The animal experiment showed that the extract of silkworm powder prevents a rapid increase of blood glucose level after meal and prevents hunger and law blood glucose level during empty stomach. In the experiment to isolate the major component of silkworm powder, which exerts blood glucose-lowering effect, 1-deoxynojirimy-cin (DNJ) was eventually mass-purified, and it turned out that DNJ isolated from silkworm powder was excellent in its blood glucose-lowering effect. In the experiment to understand the personal difference of the efficacy of the silkworm powder, clinical candidates were divided on the basis of the criterion of traditional Chinese medicine: Tae-Yang, Tae-Um, So-yang, and So-Um. The result showed that silkworm powder has a tendency to reduce blood glucose level at fasting and at 2 hours after meal, and this trend was somewhat obvious in the Tae-Um body type. In summary, we reviewed scientific papers on the efficacy of silkworm powder and its purified DNJ as a blood glucose-lowering agent. These suggest that silkworm powder truly possesses blood glucose-lowering effect as documented in the traditional Chinese medicine, although further researches will be required to develop them as "medical" resource instead of functional food.

• Journal of Sasang Constitutional Medicine
• /
• v.9 no.2
• /
• pp.301-312
• /
• 1997

Since new continental was discovered, potatoes and sweet potatoes originated from America have been known worldwide. Through literary consideration about potatoes and sweet potatoes, several conclusons were obtained as enumerated below. 1. Based on work done by taxonomist in Orient, both of sweet potatoes and potatoes which were classified to the families of Convovulaceae and Solansceae repectively were included in Seo-rue(薯類). In contrast, both plants' identities were differed systematically. 2. Because potatoes fulfilled with like-cold keep warm, potatoes help So-um-in(少陰人) achieve Yang-nan-ji-gi(陽煖之氣). Meanwhile, the characteristic of sweet potatoes typically in wild living style assists Tae-um-in(太陰人) to own Ho-san-ji-gi(呼散之氣). That sweet potatoes affect on bodies as much as Mar(山藥=마) does makes this pant be defined as good food. 3. The inside contents of Nam-bang-bon-cho-sang(南方本草狀) cited from sweet potatoes chapter in the book of Bon-cho-gang-mok(本草綱目) indicated that the word of sweet potatoes was not found, but called as a kind of Mar(山藥=마) which lived wildly in a mountain Unfortunately, due to that medical scientist cited contents of Nam-bang-bon-cho-sang(南方本草狀) without pursuing carefully, sweet potatoes have been misunderstood. 4. According to the book of Sasang Constitutional medicine, sweet potatoes are good for Tae-um-in(太陰人) who has constipation, and potatoes are good for So-um-in(少陰人) who suffers form stomach illnesses like ulcer and hotburn. Therefore two plants have been used for curing those illness. ln addition, the taking oriental medicine with those plants are recommenced for dietary treatment according to the Constitution.