• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.1
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• pp.86-92
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• 2008

Recently, the use of tubes in the manufacturing of the automobile parts has increased and therefore many automotive manufactures have tried to use hydro-forming technology. The hydro-forming technology may cause many advantages to automotive applications in terms of better structural integrity of the parts, lower cost from fewer part count, material saving, weight reduction, lower spring-back, improved strength and durability and design flexibility. In this study, the whole process of front engine cradle (or front sub-frame) parts development by tube hydro-forming using steel material having tensile strength of 440MPa grade is presented. At the part design stage, it requires feasibility study and process design aided by CAE (Computer Aided Design) to confirm hydro-formability in details. Effects of parameters such as internal pressure, axial feeding and geometry shape on automotive sub-frame by hydro-forming process were carefully investigated. Overall possibility of hydro-formable sub-frame parts could be examined by cross sectional analyses. Moreover, it is essential to ensure the formability of tube material on every forming step such as pre-bending, preforming and hydro-forming. At the die design stage, all the components of prototyping tools are designed and interference with press is examined from the point of geometry and thinning.

• Journal of IKEEE
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• v.2 no.2 s.3
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• pp.309-315
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• 1998

This paper describes an 8b 52 MHz CMOS subranging analog-to-digital converter (ADC) for Integrated Services Digital Network (ISDN) applications. The proposed ADC based on the improved time-interleaved architecture removes the holding time which is typically observed in the conventional double-channel subranging ADCs to increase throughput rate. Moreover, the ADC employs the interpolation technique in the back-end subranging ADCs far residue signal processing to minimize die area and power consumption. The fabricated and measured prototype ADC in a 0.8 um n-well double-poly double-metal CMOS process typically shows a 52 MHz sampling rate at a 5 V supply voltage with 230 mW, and a 40 MHz sampling rate at a 3 V power supply with 60 mW power consumption.

• The Plant Pathology Journal
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• v.19 no.3
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• pp.181-183
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• 2003

Corky root symptoms caused by Pyrenochaeta lycopersici were observed on the roots and stem base of tomato plants in Korea. Symptoms on infected plants typically appeared as stunting and generally lacking vigor, and infected plants die back from the foliage tips after fruits have set. Brown lesions appearing with bands around the roots were characteristic symptoms of the disease. The lesions become swollen and cracked along the length of the root with corky appearance. Based on cultural and morphological characteristics, the fungus from the diseased plants was identified as Pyrenochaeta lycopersici. Pycnidia were solitary, globose to subglobose, brown to black, darker around the neck region, and measured 173-215 $\mu\textrm{m}$ in diameter with septate setae up to 102-132$\times$6.5 $\mu\textrm{m}$. Conidia were hyaline, unicellular, and 4.2-4.7$\times$l.5-2.0 $\mu\textrm{m}$ long. Optimum temperature for mycelial growth of the p. lycopersici isolates ranged from $20^{\circ}C$ to $25^{\circ}C$. Fifteen isolates off lycopersici were tested for pathogenicity to susceptible and tolerant cultivars of tomato plants by artificial inoculation. Three isolates of P. lycopersici induced typical corky root discoloration on susceptible tomato cultivars but not on tolerant tomato. This is the Erst report in Korea of tomato corky root disease caused by P. lycopersici.

• Journal of Sericultural and Entomological Science
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• v.44 no.1
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• pp.9-12
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• 2002

The agronomic characteristics and fertility of Morus tiliaefolia growing wild in Korean peninsula are as follows. The possibility of seed formation is 46∼80% and that of germination is 19∼28%. The height period of making flower is April 4-May 3, it means that is later than Morus bombycis, faster than Kaeryangppong. Green tip sprouting stage in spring is April 21∼24. This is later than Morus bombycis and faster than Kaeryangppong. The leaf has very big width and the ratio of leaf length to leaf width is 1.05. The thickness of leaf is thicker than Morous bombycis. There are a lot of matter of soluble nitrogen free, crude ash, and are little crude protein, crude fat and crude fiber in chemical contents of maturation leaf. The attitude of low cutting is spread out type and the branch is long type. The internord length is long. It is weak against cold and die-back.

• Journal of Sericultural and Entomological Science
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• v.44 no.1
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• pp.22-27
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• 2002

The Yongcheonppong was cultured in the form of a dense mulberry field coverd with polyethylene film and was tested in Suwon and Chunchon. The agronomic characteristic and some consideration on the result of the silkworm rearing were as follows. The Yongcheonppong was the medium budding variety and was longer in length of young shoots than the Kaeryangppong. The Yongcheonppong was higher in leaf yield in spring than the Kaeryangppong and was lower in leaf yield in autumn than the Kaeryangppong to the contrary. The Yongcheonppong was a little higher in the number of branches and was longer in the length of the branch than the Kaeryangppong and so was appropriate for rearing with mulberry shoots. Yongcheonppong was more resistant to twig blight and die-back and was a little susceptible to dwarf disease. As the Yongcheonppong was most resistant to the freezing injury, it was appropriate for the cold region and enabled the farmers to rear some amount of silkworms every year. In Chunchon, The Yongcheonppong increased by 11% in cocoon yield than the Kaeryangppong when the freezing injury occurred 1 year out of 2 years and produced about the same as the Kaeryangppong in cocoon yield when the freezing injury occurred 1 year out of 3 years.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.12
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• pp.1373-1377
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• 2014

Hot-stamping is a method of obtaining ultrahigh-strength steel by simultaneously forming and cooling boron steel in a press die after it has been heated at $900^{\circ}C$ or above. After heat treatment, boron steel has a strength of 1500 MPa or more. This material ensures a high level of quality because it overcomes the spring-back phenomenon, which is a problem associated with high-strength steel materials, and the degree of dimensional precision is improved by 90 or more because of the good formability compared with existing types of steel. In this study, the welding characteristics were identified through the butt and lap welding of hot-stamped steel using a disk laser. Full penetration was obtained at a faster speed with butt welding compared to lap welding, and a white band was observed in every specimen.

• Korean Journal of Soil Science and Fertilizer
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• v.13 no.2
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• pp.71-76
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• 1980

Effect of soil moisture on growth of 2 year old Pan ax ginseng was investigated by pot culture using clay loam and sandy loam soils. In clay loam soil emergence rate of new shoot and stem growth were greatly decreased below 40% of field capacity. In sandy loam soil the growth of stem and leaf were greatly affected below 40% moisture. Root yield showed maximum at 60% moisture and significantly coorelated with stem diameter and root length. Rotten root rate and die back rate of top were least at 60% and gradually increased with either increase or decrease of soil moisture.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.2
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• pp.98-107
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• 2013

This work describes a 13b 100 MS/s 0.13 um CMOS four-stage pipeline ADC for 3G communication systems. The proposed SHA-free ADC employs a range-scaling technique based on switched-capacitor circuits to properly handle a wide input range of $2V_{P-P}$ using a single on-chip reference of $1V_{P-P}$. The proposed range scaling makes the reference buffers keep a sufficient voltage headroom and doubles the offset tolerance of a latched comparator in the flash ADC1 with a doubled input range. A two-step reference selection technique in the back-end 5b flash ADC reduces both power dissipation and chip area by 50%. The prototype ADC in a 0.13 um CMOS demonstrates the measured differential and integral nonlinearities within 0.57 LSB and 0.99 LSB, respectively. The ADC shows a maximum signal-to-noise-and-distortion ratio of 64.6 dB and a maximum spurious-free dynamic range of 74.0 dB at 100 MS/s, respectively. The ADC with an active die area of 1.2 $mm^2$ consumes 145.6 mW including high-speed reference buffers and 91 mW excluding buffers at 100 MS/s and a 1.3 V supply voltage.

• Journal of Forest and Environmental Science
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• v.23 no.2
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• pp.93-100
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• 2007

This study was carried out to select the utilizable vegetations for the stabilization of slopes and river banks, landscape creation and water quality cleansing in dams, lakes and streams. In this study, 4 species were investigated for their survival and growth characteristics in the complete and partly flooding conditions with various flooding periods. The results are as followings; Acorus calamus var. angustatus showed the highest flooding tolerance based on survival rate and growth condition. Equisetum hyemale, Acorus gramineus and Salix gracilistyla followed after Acorus calamus var. angustatus in the order of flooding tolerance. Particularly, A. calamus var. angustatus and E. hyemale showed higher survival rate and grew well even when they were completely submerged in the water up to 120 days. As they were partially submerged longer, they grew better. This ascertained that they had strong flooding tolerance. When A. gramineus were completely submerged in the water, their growth was disturbed but they did not die in the complete submergence up to 120 days. A. gramineus had a small growth disturbance and showed the highest vitality of leaves among the species. Though S. gracilistyla showed somewhat low growth rate in the complete water submergence and died in 90 days, it also can grow back to normal with some changes of water level.

• The Journal of Advanced Prosthodontics
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• v.7 no.2
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• pp.146-150
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• 2015

PURPOSE. This in vitro study aimed to compare the failure load and failure characteristics of two different zirconia framework designs of premolar crowns when subjected to static loading. MATERIALS AND METHODS. Two types of zirconia frameworks, conventional 0.5 mm even thickness framework design (EV) and 0.8 mm cutback of full contour crown anatomy design (CB), were made for 10 samples each. The veneer porcelain was added on under polycarbonate shell crown made by vacuum of full contour crown to obtain the same total thickness of the experiment crowns. The crowns were cemented onto the Cobalt-Chromium die. The dies were tilted 45 degrees from the vertical plane to obtain the shear force to the cusp when loading. All crowns were loaded at the lingual incline of the buccal cusp until fracture using a universal testing machine with cross-head speed 0.5 mm/min. The load to fracture values (N) was recorded and statistically analyzed by independent sample t-test. RESULTS. The mean and standard deviations of the failure load were $1,170.1{\pm}90.9$ N for EV design and $1,450.4{\pm}175.7$ N for CB design. A significant difference in the compressive failure load was found (P<.05). For the failure characteristic, the EV design was found only cohesive failures within veneering porcelain, while the CB design found more failures through the zirconia framework (8 from 10 samples). CONCLUSION. There was a significant difference in the failure load between two designs, and the design of the framework influences failure characteristic of zirconia crown.