• Computers and Concrete
• /
• 제25권2호
• /
• pp.145-154
• /
• 2020

For the influence of the propagation law of stress wave at the coal-rock interface during the pre-blasting of the top coal in top coal mining, the ANSYS-LS/DYNA fluid-solid coupling algorithm was used to numerical calculation and the life-death element method was used to simulate the propagation of explosion cracks. The equation of the crushing zone and the fracturing zone were derived. The results were calculated and showed that the crushing radius is 14.6 cm and the fracturing radius is 35.8 cm. With the increase of the angles between the borehole and the coal-rock interface, the vibration velocity of the coal particles and the rock particles at the interface decreases gradually, and the transmission coefficient of the stress wave from the coal mass into the rock mass decreases gradually. When the angle between the borehole and the coal-rock interface is 0°, the overall crushing degree is about 11% and up to the largest. With the increase of the distance from the charge to the coal-rock interface, the stress wave transmission coefficient and the crushing degree of the coal-rock are gradually decreased. At the distance of 50 cm, the crushing degree of the coal-rock reached the maximum of approximately 12.3%.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2008년도 제34회 동계학술대회 초록집
• /
• pp.161-161
• /
• 2008

• Transactions on Electrical and Electronic Materials
• /
• 제15권2호
• /
• pp.73-76
• /
• 2014

$Pt/Al_2O_3/La_2Si_5O_x/SiO_2/Si$ charge trap memory capacitors were prepared, in which the $La_2Si_5O_x$ film was used as the charge trapping layer, and the effects of post annealing atmospheres ($NH_3$ and $N_2$) on their memory characteristics were investigated. $La_2O_3$ nanocrystallites, as the storage nodes, precipitated from the amorphous $La_2Si_5O_x$ film during rapid thermal annealing. The $NH_3$ annealed memory capacitor showed higher charge storage performances than either the capacitor without annealing or the capacitor annealed in $N_2$. The memory characteristics were enhanced because more nitrogen was incorporated at the $La_2Si_5O_x/SiO_2$ interface and interfacial reaction was suppressed after the $NH_3$ annealing treatment.

• 대한전기학회논문지
• /
• 제44권4호
• /
• pp.483-489
• /
• 1995

To investigate the mechanism generated by irradiation in the insulator layer irradiated MIS (Metal - Insulator - Semiconductor) device, the various types of MIS capacitors depending on insulator thickness, insulator types and implanted impurities are fabricated on the P-type wafer. MIS capacitors exposed by 1Mrad Co$^{60}$ .gamma.-ray are measured for flat band voltage and charge density shifts pre- and post-irradiation. The measuring results of post-irradiation show the flat band voltage shifting toward negative direction and charge density increasing regardless of parameters. This results have a good agreement with calculated data by computer simulation. Si$_{3}$N$_{4}$ layers have a good radiation-hardness than SiO$_{2}$ layers compared to the results of post-irradiation. Also, radiation-induced negative trap is discovered in the implanted insulator layer. Using numerical analysis, four continuty equations (conduction-band electrons continuity equation, valence-band holes continuity equation, trapped electrons continuity equation, trapped holes continuity equation) are solved and charge distributions according to the distance and Si-Insulator interface states are investigated.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2011년도 추계학술대회
• /
• pp.875-877
• /
• 2011

본 논문에서는 개선된 charge pump 회로를 이용하여 구성한 터치스크린 패널 드라이버를 소개한다. 터치 패널 드라이버는 크게 터치를 감지하는 아날로그 센싱 부분과 감지된 신호를 처리하는 디지털 신호 처리 부분으로 이루어진다. 제안된 터치스크린 드라이버의 동작을 확인하기 위하여 혼성 모드로 회로를 구성하고 Cadence Spectre를 이용하여 그 동작을 검증하였다. 디지털 회로 부분은 Verilog-A 모델링하여 아날로그 부분과의 인터페이스가 가능하게 하여, 그 동작을 검증함으로써 동작의 신뢰성을 확보하였고 시뮬레이션 시간을 줄일 수 있었다. 시뮬레이션 결과 ADC가 없는 간단한 구조의 디지털 신호 변환으로 터치 패널 드라이버의 안정적인 동작을 확인하였다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
• /
• pp.69-69
• /
• 2013

In the area of artificial photosynthesis, particularly for the generation of hydrogen form water, much attention has been paid on organic-inorganic hybrid system. Most of all, a dye/TiO2-combined system has been suggested and its potential utility was well manifested. However, due to its complicated nature of charge interactions in between dye and TiO2 -interface there remains a great challenge to establish the charge-activity relationship, per se light driven charge generation and recombination kinetics with respect to the amount of hydrogen produced. Further complexity of that hybrid system has been witnessed when sacrificial donor and aqueous media are considered. To unveil the operating mechanism on such a dye/TiO2-combined system, we have prepared organic dyes suitable to account for the effect of sacrificial donor as well as water interactions, and prepared the typical dye-grafted TiO2 films to investigate charge-activity relationship. Femtosecond flash photolysis clearly defined the dye effects anchored on to the TiO2 platform. In addition, photodynamic data contemplated well to the dye orientation proposed by the DFT calculations. Recent findings provide fundamental understanding on the dye-grafted TiO2 system and establish a firm background how future dye-sensitized organic-inorganic hybrid system can be designed for the light driven hydrogen generation from water.

• 센서학회지
• /
• 제31권4호
• /
• pp.218-227
• /
• 2022

Triboelectric nanogenerators (TENGs), a new green energy, that have various potential applications, such as energy harvesters and self-powered sensors. The output performance of TENGs has been improving rapidly, and their output power significantly increased since they were first reported owing to improved triboelectrification materials and interfacial material engineering. Because the operation of a TENG is based on contact electrification in which electric charges are exchanged at the interface between two materials, its output can be increased by increasing the contact area and charge density. Material surface modification with microstructures or nanostructures has increased the output performance of TENGs significantly because not only does the sharp micro/nano morphology increases the contact area during friction, but it also increases the charge density. Chemical treatment in which ions or functional groups are added has also been used to improve the performance of TENGS by modifying the work functions, charge densities, and dielectric constants of the triboelectric materials. In addition, ultrahigh output power from TENGs without using new materials or treatments has been obtained in many studies in which special structures were designed to control the current release or to collect the charge current directly. In this review, we discuss physical and chemical treatments, bulk modifications, and interfacial engineering for enhancing TENG performance by improving contact electrification and electrostatic induction.

• 한국결정성장학회지
• /
• 제12권6호
• /
• pp.304-310
• /
• 2002

실리콘 기판 위의 초기 산화막을 NO 열처리 및 재산화 공정방법으로 성장한 재산화된 질화산화막을 게이트 유전막으로 사용한 새로운 전하트랠형 기억소자로의 응용가능성과 계면트랩특성을 조사하였다. 0.35$\mu$m CMOS 공정기술을 사용하여 게이트 유전막은 초기산화막을 $800^{\circ}C$에서 습식 산화하였다 전하트랩영역인 질화막 층을 형성하기 위해 $800^{\circ}C$에서 30분간 NO 열처리를 한 후 터널 산화막을 만들기 위해 $850^{\circ}C$에서 습식 산화방법으로 재산화하였다. 프로그램은 11 V, 500$\mu$s으로 소거는 -l3 V, 1 ms의 조건에서 프로그래밍이 가능하였으며, 최대 기억창은 2.28 V이었다. 또한 11 V, 1 ms와 -l3 V, 1 ms로 프로그램과 소거시 각각 20년 이상과 28시간의 기억유지특성을 보였으며 $3 \times 10^3$회 정도의 전기적 내구성을 나타내었다. 단일접합 전하펌핑 방법으로 소자의 계면트랩 밀도와 기억트랩 밀도의 공간적 분포를 구하였다. 초기상태에서 채널 중심 부근의 계면트랩 및 기억트랩 밀도는 각각 $4.5 \times 10^{10}/{cm}^2$ 와 $3.7\times 10^{1R}/{cm}^3$ 이었다. $1 \times 10^3$프로그램/소거 반복 후, 계면트랩은 $2.3\times 10^{12}/{cm}^2$으로 증가하였으며, 기억트랩에 기억된 전하량은 감소하였다.

• 한국정보처리학회논문지
• /
• 제4권4호
• /
• pp.1100-1105
• /
• 1997

세로 검은 줄무늬 전하 결합 소자 결점의 하나이다. 세로 검은 줄무늬는 수직 전하 전송부에서 수평 전하 전송부로 넘어가지 못하는 신호 전하량에 의하여 나타난 것이다. 신호 전하의 불완전한 전송은 수직-수평 채널 경계 영역 구조에서 좁은 폭 효과에 의하여 발생한 전위 장벽 때문이다. 세로 검은 줄무늬는 저 조도하에서 전하 전송 효율이 99.2% 이하로 전송될 때 나타난다. 본 논문은 새로운 수직-수평 채널 경계 영역 구조를 전위 장벽이 발생하지 않도록 부채꼴 형태로 설계 제작하여 세로 검은 줄무늬를 제거하였다.

• Tribology and Lubricants
• /
• 제30권5호
• /
• pp.247-255
• /
• 2014

Charged polymer chains, i.e., polyelectrolytes, are known to show superior aqueous lubricating properties compared to those of neutral polymer chains, especially in brush conformation. This is primarily because of the incorporation of a large amount of counterions within the polymer layers and the consequently increased osmotic pressure. However, this effect is active only when the polymer chains remain immobilized even under tribostress, which is not realistic for high-contact pressure tribological applications, especially when they are irreversibly immobilized on tribopair surfaces. In contrast, with free polymers, which can be included as surface-active additives in the base lubricant (water), long-term lubricating performance based on "self-healing" properties is readily expected. In order to assess whether the superior aqueous lubricating properties of polyelectrolyte chains are valid for free polymers too, this study reviews recent studies on the tribological properties of many charged biopolymer and synthetic copolymers at a nonpolar, hydrophobic interface. In contrast to the irreversibly immobilized polyelectrolyte chains, free polyelectrolyte chains show inferior aqueous lubricating properties compared to their neutral counterparts owing to charge accumulation and the consequently impeded surface adsorption on the nonpolar surface. Nevertheless, bovine submaxillary mucin (BSM), a representative biopolymer, shows a sufficiently effective surface adsorption and aqueous lubricating capabilities even at neutral pH without losing the polyanionic characteristics.