• 대한기계학회논문집A
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• 제24권3호
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• pp.710-717
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• 2000

Tensile and fracture toughness tests of the cold-rolled STS 304 steel plate for membrane material of LNG storage tank were performed at wide range of temperatures, 11 IK(boiling point of LNG), 153K , 193K and 293K(room temperature). Tensile strength significantly increases with a decrease in temperature, but the yield strength is relatively insensitive to temperature. Elongation at 193K abruptly decreases by 50% of that at 293K, and then decreases slightly in the temperature range of 193K to 111K. Strain hardening exponents at low temperatures are about four times as high as that at 293K. Elastic-plastic fracture toughness($J_c$) and tearing modulus($T_{mat}$) tend to decrease with a decrease in temperature. The $J_c$ values are inversely related to effective yield strength in the temperature range of 111K to 293K. These phenomena result from a significant increase in the amount of transformed martensite in low temperature regions.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.1077-1080
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• 1998

In this paper, a simple low-power current-mode CMOS wotage reference circuit is proposed. The reference circuit of enhancement-mode MOS transistors and resistors. Temperature compensation is made by adding a current component proportional to a thermal voltage to a current component proportional to a threshold voltage. The designed circuit has been simulated using a $0.65\mu\textrm{m}$ n-well CMOS process parameters. The simulation results show that the reference circuit has a temperature coefficient less than $7.8ppm/^{\circ}C$ and a power-supply(VDD) coefficient less than 0.079%/V for a temperature range from $-30^{\circ}C$ to $130^{\circ}C$ and a VDD range from 4.0V to 12V. The power consumption is 105㎼ for VDD=5V and $T=30^{\circ}C.$ The proposed reference circuit can be designed to generate a wide range of reference voltages owing to its current-mode operation.

• Bulletin of the Korean Chemical Society
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• 제32권spc8호
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• pp.3057-3062
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• 2011

We have synthesized and characterized the first cyclic co-oligomeric ferroelectric liquid crystals (FLCs) based on cyclic siloxanes and found that the co-oligomer containing two different mesogenic units exhibits $SmC^*$ mesophase over a wide temperature range from $65^{\circ}C$ to $135^{\circ}C$, much wider than those of the monomer counterparts and the cyclic homo-oligomers. The cyclic co-oligomeric liquid crystal readily filled the display cell and exhibited fast switching times in the range of 4 ms to 6 ms over the entire $SmC^*$ phase. Moreover, the practical absence of layer shrinkage, attributed to de Vries-type transition, shows an additional significant advanage for cyclic co-oligomeric FLCs in LCD applications.

• 열처리공학회지
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• 제15권1호
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• pp.9-15
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• 2002

Deformation behavior of nickel-rich Ti-51.5at.%Ni single crystals was investigated over a wide range of temperatures(77 to 440K) and strain levels(up to 9%) in compression. These alloys combined superior strength with wide range of pseudoelasticity temperature interval(~200K). The slip deformation in [001] orientation did not occur due to the prevailing slip system, and consequently, exhibited pseudoelastic deformation at temperatures ranging from 77 to 283K and 273 to 440K for the solutionized and over-aged cases, respectively. The critical transformation stress levels were in the range of 800 to 1800MPa for the solutionized case, and 200 to 1000MPa for the over-aged case depending on the temperature and specimen orientation. These stress levels are considerably higher compared to these class of alloys having lower Ni contents. The maximum transformation strains, measured from incremental straining experiments in compression, were lower compared to the phenomenological theory with Type II twinning. A compound twinning model depending on the successive austenite(B2) to intermediate phase(R) to martensite(B19') transformation predicts lower transformation strains compared to the Type II twinning case.

• 동력기계공학회지
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• 제5권3호
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• pp.80-87
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• 2001

Decorative properties of chromium depositions from oxalic acid bath containing chromium oxide and ammonium sulfate have been examined over a wide range of bath compositions and plating conditions. The obtained results from this experiment are summarized as follow: The followings were determined as a optimum conditions, bath compositions; $CrO_3\;200{\sim}250\;g/{\ell},\;H_2C_2O_4{\cdot}2H_2O\;500{\sim}700\;g/{\ell},\;(NH_4)_2SO_4\;40{\sim}120\;g/{\ell}$, and operation conditions; pH $2.0{\sim}2.5$, current density $15{\sim}250\;A/dm^2$ at bath temperature range of $30{\sim}80^{\circ}C$. Bright chromium deposits were obtained over a wide range of ammonium sulfate concentration and bath temperature. Decorative property for chromium deposition was adopted to apply stoichiometric ratio of $CrO_3$ concentration and $H_2C_2O_4{\cdot}2H_2O$.

• JSTS:Journal of Semiconductor Technology and Science
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• 제13권2호
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• pp.152-156
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• 2013

This paper presents a fast-lock dual-loop successive approximation register-controlled duty-cycle corrector (SARDCC) circuit using a mixed (binary+sequential) search algorithm. A wider duty-cycle correction range, higher operating frequency, and higher duty-cycle correction accuracy have been achieved by utilizing the dual-loop architecture and the binary search SAR that achieves the fast duty-cycle correcting property. By transforming the binary search SAR into a sequential search counter after the first DCC lock-in, the proposed dual-loop SARDCC keeps the closed-loop characteristic and tracks variations in process, voltage, and temperature (PVT). The measured duty cycle error is less than ${\pm}0.86%$ for a wide input duty-cycle range of 15-85 % over a wide frequency range of 0.5-2.0 GHz. The proposed dual-loop SARDCC is fabricated in a 0.18-${\mu}m$, 1.8-V CMOS process and occupies an active area of $0.075mm^2$.

• 대한전기학회논문지:시스템및제어부문D
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• 제51권7호
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• pp.317-322
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• 2002

This paper presents a linear temperature/voltage relation over a temperature range(0~100$^{\circ}C$) with high-resolution, reasonably god response linearity, reliability, and overall improved performance. A notable feature of the proposed method is that the whole temperature span is divided by 16 subbands thus the variation span of measured voltage is narrowed. Therefore noise characteristic has been improved. The output voltage is amplified after the uniformed DC voltage component is eliminated by offset. We proposed circuit using median value and mean value of digital signal in order to reduce the noise effect. The proposed circuit offers linear temperature/voltage conversion over a wide dynamic range using DSP(TMS320C31) and steinhart equation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 B
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• pp.766-768
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• 1998

Optical Temperature Distribution measurement System (OTDS) is completely different from conventional electric point sensor in that it uses the optical fiber itself as the sensor. This new concept in temperature measuring system requires only one fiber to be laid. The use of optical fiber also gives the advantage of small diameter, light weight, explosion resistance, and electromagnetic noise resistance. The OTDS is a sensor which is capable of making a precise measurement over a wide range of areas using only a single optical fiber. Since current temperature sensors, such as the thermocouple, are only used to measure temperaturea of point, they are almost impractical for measuring a wider range because of the extremely high cost. In comparision with current sensors, the optical fiber distributed temperature sensor can make much quicker and more precise measurements at a comparatively low cost.

• 대한전자공학회논문지SD
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• 제47권2호
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• pp.87-93
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• 2010

이 글은 공정, 전압, 온도 변화를 극복하기 위한 2단계 자동 트랜스컨덕턴스 조절 기능을 가진 저전력, 광대역 전압제어발진기의 설계에 관한 논문이다. 광대역에서 전압제어발진기를 발진시키기 위해, 디지털 자동 트랜스컨덕턴스 조절 루프와 아날로그 자동 진폭조절 루프가 사용되었다. 전압제어발진기의 출력 스윙 크기에 따라 트랜지스터의 바디전압을 조절하는 기능도 저전력 구현을 위해 설계되었다. 소모전류는 1.2 V 공급전압에서 2 mA에서 6 mA까지 1 mA 단위로 조절된다. 전압제어발진기의 튜닝 범위는 2.35 GHz에서 5 GHz까지 2.65 GHz로써 72%이다. 위상잡음은 중심주파수 3.2 GHz를 기준으로 1MHz 떨어진 지점에서 -117 dBc/Hz 이다.

• 대한의용생체공학회:의공학회지
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• 제4권1호
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• pp.21-28
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• 1983

The opjective of this research is to derelop the linearijed digital temperature monitor based on EPROM. The advantages associated with this proposod monitor as Compared with the conventional temperature montor is very high accuracy in wide range The accuracy of this monitor was evaluated by the experimental system which was consisted of the water-bath controller. mercury thermometor, and YSI-400 series probes.