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Herein, an integrated device that comprises inorganic kesterite solar cells and Li-ion batteries (LIBs) has been proposed for application in fast photo-charging power systems. LiFePO4 and Li4Ti5O12 were selected as the battery electrode materials and six kesterite solar cells connected in series were fabricated to satisfy the charging voltage required for LIBs. Photo-charging was conducted at the rate of 1C (1.790 mAh g−1) at 2.1 V. An energy conversion and storage efficiency of 3.87% was acquired in the integrated device, and a storage efficiency of over 70% was observed in LIBs. Furthermore, by synchronizing the charging voltage of the solar cell and LIB, over 70% of the capacity was obtained at the rate of 1C, while preventing overvoltage during long-term charging.

The fringe-field switching (FFS) mode that uses liquid crystals (LCs) with negative dielectric anisotropy is used in high-resolution FFS liquid crystal display owing to its higher transmittance over positive LC, although its response time becomes slow and operating voltage (Vop) becomes high. In the device, reduction of the cell gap is required to achieve fast response time, which results in increase in Vop in general. In this paper, we propose the FFS mode with electrode width 1 µm and distance between the electrodes 1.5 µm. In such an electrode structure, Vop decreases with decreasing cell gap to 2 µm so that a proper Vop, high LC's light efficiency of 90%, a high color temperature, and a fast response time less than 10 ms, can be achieved, which maximizes electro-optic performance of the FFS mode.

The fringe-field switching (FFS) mode that uses liquid crystals (LC) with negative dielectric anisotropy is used in high resolution FFS-LCD owing to its higher transmittance over positive LC. In this paper, the FFS mode with electrode width 1 µm and distances between the electrodes 1.5 µm is proposed. In such an electrode structure, operating voltage (Vop) decreases with decreasing cell gap to 2 µm so that a proper Vop, high LC's light efficiency of 90%, and a fast response time less than 10 ms, can be achieved, which maximizes electro-optic performance of the FFS mode. In addition, the color temperature of a white state becomes higher in the fine patterned FFS cell.

In-plane field driven vertical alignment device using a liquid crystal with positive dielectric anisotropy has been studied. In the device, the distance between inter-digital electrodes needs to be increased to achieve higher transmittance; however, such a design results in an increase in operating voltage and slower response time. In this work, we use polymer stabilisation technique, which generates surface tilt angle other than 90o, to improve upon these drawbacks. As a result, the proposed device shows lower operating voltage and faster response time while keeping transmittance at the same level, compared to those prior to polymer stabilisation.

Performance and anti-corrosion of cold forged fuel pumps and die-casting fuel pumps have been tested in this study. Ethanol with 10 ppm of acetic acid is applied for the anti-corrosion test for 250 hours. Performance test result shows that the pumping efficiency of the cold forged fuel pump is equivalent to that of the die-casting fuel pump. The cold forged lower housing has better quality against corrosiveness and finer metallic structure than the die-casting lower housing does. Key Words : Fuel Pump, Cold Forging, Lower Hosing, Anti-Corrosion, Die-Casting * 교신저자 : 박성영(sungyoung@kongju.ac.kr)접수일 11년 11월 07일 수정일 12년 01월 03일 게재확정일 12년 01월 05일 1. 서론 현재까지 자동차용 연료펌프의 설계법, 성능예측 및 향상에 대해서 연구가 다수 이루어졌지만 자동차용 연료펌프의 효율 향상과 신뢰성 있는 설계법이 아직도 만족할 만한 결과를 보이지 못하고 있다. 특히 연료펌프에 대한 국내 연구는 연료 펌프 생산업체 위주로 소극적 개발이 진행되어 왔으며, 다양한 형상 및 인자에 따른 실험 결과에 근거한 설계법 및 성능 예측법은 실제 제품에 적용하기에 무리가 있다[1]. 자동차용 연료펌프는 국내 시판되는 가솔린 자동차의 거의 대부분에 사용되고 있음에도 불구하고 설계기술을 포함하는 핵심 기술들은 외국의 소수 자동차부품 전문 기술업체만이 보유하고 있다. 국내시장을 차지하는 대부분의 국내업체들도 이들 외국기업의 자본으로 이루어졌기 때문에 국내업체들은 독자적으로 기술개발을 수행하기 어려운 환경에 처해져 있으며, 생산 및 제조 기술에서 경쟁력이 있음에도 해외 판매 및 제품 개발에 한계를 가지고 있다. 세계적으로 완성차업체들의 글로벌 소싱이 현실화되고, 그에 따른 연료펌프의 시장이 확대되고 있는 상황에서 펌프의 효율 향상 및 신뢰성 있는 설계법의 확보는 기업의 글로벌 경쟁력을 확보하는데 필수적인 요소라 할 수 있다[2,3].가솔린 자동차의 연료펌프는 차량의 연료탱크 내부에 설치되어 연료탱크에서 엔진으로 연료를 공급하는 장치이다. 초기 용적형 연료펌프의 토출압 맥동, 소음․진동 등의 문제점을 해결하기 위하여 재생펌프(Regenerative Pump)가 도입되었으며, 현재 대부분의 가솔린 자동차용

The device characteristics of a gradual hole injection dual-gate lateral insulated gate bipolar transistor (GHI-LIGBT) is analyzed with the experiment and two-dimensional (2-D) numerical simulation. The hole injection mechanism in the GHI-LIGBT is investigated in detail and the device characteristics of the GHI-LIGBT are studied in terms of the various device parameters such as the p/sup +/ injector length and the injection gate length. The hole injection characteristics and latch-up characteristics in the GHI-LIGBT are also presented as a function of temperature. The experimental results demonstrate that an on-state voltage drop in GHI-LIGBT is reduced by 1 V, compared with the conventional SA-LIGBT and the negative resistance regime is eliminated since the injection of holes is initiated at the lower anode voltage. It is also found that the low on-state voltage drop in the GHI-LIGBT can be achieved without sacrificing the inherent high switching speed in shorted anode (SA) LIGBT structures.

We have firstly demonstrated a hybrid flash including both NOR and NAND cell in a single chip using 90 nm logic technology for S-SIM (Super-Subscriber Identity Module) application. The memory sizes are 16 MB NAND and 768 kB NOR flash, respectively. The flash memory cells exhibited over 10 k-cycle endurance and 10-year retention for the successful smart card application.

We propose and fabricate a new base resistance-controlled thyristor (BKT) employing a self-aligned corrugated p-base. The new device, entitled CB-BRT, suppresses the snap-back effectively and increases the maximum controllable current. Experimental results show that the snap-back of the CB-BRT is reduced significantly when compared with that of the conventional BRT. Also, the maximum controllable current of the CB-BRT increases as compared with the conventional BRT.

A new shorted-anode lateral insulated gate bipolar transistor (SA-LIGBT), entitled gradual hole injection dual gate LIGBT (GHI-LIGBT), is proposed and fabricated. The new device employs a dual gate and p/sup +/ injector in order to initiate the hole injection gradually from the anode electrode into the drift region so that the negative differential resistance (NDR) regime may be eliminated. The experimental results show that the NDR regime, which may cause undesirable device characteristics, is completely eliminated in the GHI-LIGBT, and the forward voltage drop is reduced by 1 V at the current density of 200 A/cm/sup 2/ in comparison with the conventional SA-LIGBT.

A new shorted-anode lateral IGBT with dual gate and p/sup +/ injector (DG-SALIGBT) is proposed and fabricated in order to eliminate the negative differential resistance (NDR) regime, which is the inherent characteristic of SALIGBTs, by modulating the drift region conductivity gradually. The experimental results show that the NDR regime is eliminated completely and the forward voltage drop is reduced considerably in the DG-SALIGBT when compared with the conventional SALIGBT, without sacrificing the switching speed. We have analyzed the device operation mechanism, such as hole injection phenomena, by 2D numerical simulation.

A Hybrid Schottky INjector Field Effect Transistor (HSINFET) which increases the forward conduction current without sacrificing the latch-up capability and turn-off characteristics, is proposed. The feature of the structure is that the hybrid Schottky injector is implemented by the trench sidewall Schottky contact and p-n junction injector at the bottom of a trench. The device characteristics of the proposed HSINFET are numerically simulated and compared with conventional devices. The proposed HSINFET exhibits a lower forward voltage drop than the conventional HSINFET by 0.4 V at 100 A/cm/sup 2/.

We proposed a method to reduce the operating voltage and the grey-to-grey switching time of a vertically aligned liquid crystal display using a mixture of planar and vertical polyimide alignment materials. The surface anchoring energy of the two-polyimide mixture was smaller than that of the pure vertical polyimide and consequently, liquid crystal molecules were easily switched to a planar state with an electric field, resulting in a greater maximum retardation than that of the pure polyimide at the same applied voltage. Rising time was also significantly reduced due to the suppressed optical bouncing effect in the mixed planar polyimide, and the decaying time showed negligible change. With the proposed approach, we can reduce the cell gap to obtain half-wave retardation allowing for faster response time while keeping a low operating voltage. (Some figures may appear in colour only in the online journal)

We developed a robust measurement recipe for six layer SOI film stack. Both spectrometer and BPR were combined to characterize the plate and storage polysilicons. A new global optimization method was developed to find the best solution in parameter spaces with up to 12 parameters. Such a recipe was applied to production wafers with over 50 site die mapping. The 5 day repeatability shows the measurements were stable and robust.

An internal hernia is a rare cause of small bowel obstruction, ranging from 0.5% to 4.1% of all hernia cases (1). This condition is rarely diagnosed preoperatively because of the nonspecific signs and symptoms. An internal hernia may be congenital or acquired as well as persistent or intermittent. More than 50% of internal hernias reported in the literature are paraduodenal (left and right), while the other types are quite rare (1, 2). Pelvic internal hernias include hernias through the broad ligament, perirectal fossa, and pouch of Douglas (1). An internal hernia through a peritoneal defect of the pouch of Douglas is extremely rare, with only two cases reported in the English literature to date (3, 4). We report a case of small bowel obstruction due to an internal hernia through a peritoneal defect of the pouch of Douglas in a 25-year-old woman with computed tomography (CT) findings, which correlated with the intraoperative findings and review of previous reports.

Bizarre parosteal osteochondromatous proliferation (BPOP) is a rare benign lesion arising from the surface of cortical bone which usually occurs in the small bones of distal extremities and shows exophytic growth. Such a lesion can be cured by local excision. BPOP can be confused with some benign and malignant diseases such as osteochondroma, paraosteal osteosarcoma, or chondrosarcoma, both radiologically and pathologically (1). We illustrate imaging features including simple radiograph and magnetic resonance imaging of BPOP in the proximal phalanx of the hand with unusual cortical erosion and bone marrow edema accompanied by soft tissue enhancement.

The maximum controllable current of an EST, which employs the segmented p-base (SB-EST), is investigated with the various design parameters, such as p-base surface doping concentration, segmented gate length and carrier lifetime, by performing 2-dimensional numerical simulation. The simulation results show that the maximum controllable current of the SB-EST with the p-base surface doping concentration of 5 × 1017 cm-3 is 900 A/cm2, while that of the conventional EST is 540 A/cm2. The SB-EST shows 52% higher maximum controllable current that the conventional EST independent of the carrier lifetime (0.1 µs to 0.5 µs).

A new dual gate shorted anode silicon on insulator (SOI) lateral insulated gate bipolar transistor (LIGBT), which suppresses effectively the snap back without sacrificing the forward voltage drop, the switching speed and the breakdown voltage, is proposed and verified by numerical simulation. The numerical simulation results show that the snap-back is reduced less than the anode voltage of 2.5 V while the snap-back occurs at anode voltage of about 4 V for the conventional structure with the drift length of 35 µ m. We have verified that the snap-back is suppressed due to the enhancement of the hole injection and investigated the snap-back as a function of the device parameters such as the n- drift region doping concentration and drift region length.

A trench-gate silicon-on-insulator (SOI) lateral insulated gate bipolar transistor (LIGBT) with the p+ cathode well is proposed to improve the latch-up characteristics, and the improved characteristics are verified numerically by MEDICI simulation. It is found that the trench-gate SOI LIGBT exhibits at least 6 times larger latch-up capability than the conventional devices. The enhanced latch-up capability of the trench-gate SOI LIGBT is obtained due to the fact that the hole current in the device bypasses the resistance of the p body region which is the source of the latch-up and reaches the cathode via the p+ cathode well.

A novel insulated gate bipolar transistor (IGBT) structure, which employs the self aligned deep p+ buried region enveloping all the area under the n+ source, is proposed and verified by SUPREM IV and PISCES-IIB simulation. The simulation results show that the latch-up current is found to increase up to about 10 times compared with the conventional structure when the implantation dose of the p+ buried region and the p-body are 1×1015 cm-2 and 1×1014 cm-2, respectively. The variation of the threshold voltage is within 0.1 V although the implantation dose of the p+ buried region increases from 1×1014 cm-2 to 1×1015 cm-2.