• Journal of Integrative Natural Science
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• v.9 no.4
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• pp.275-280
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• 2016

Intensity modulated photovoltage spectroscopy (IMVS) analysis of organic solar cells (OSCs) with a bulk-heterojunction (BHJ) film composed of P3HT and $PC_{61}BM$ was performed. The dynamic response of charge recombination by the post-annealing approach in $P3HT/PC_{61}BM$ BHJ solar cells characterized by IMVS demonstrated that post-annealing reduced the recombination of electron carriers in the device. The recombination times of $P3HT/PC_{61}BM$ BHJ solar cells post-annealed at room temperature, 80, 120, and $140^{\circ}C$ were 0.009, 0.020, 0.024, and 0.030 ms, respectively, at a short-circuit current of 0.18 mA. The results indicated that the IMVS analysis can be effectively used as powerful.

• Archives of Plastic Surgery
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• v.46 no.2
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• pp.140-146
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• 2019

Background Thoracodorsal vessels (TDVs) and internal mammary vessels (IMVs) have both been widely employed as recipient vessels for use in free muscle-sparing transverse rectus abdominis myocutaneous (MS-TRAM) flaps. However, whether TDVs or IMVs are preferable as recipient vessels for autologous breast reconstruction with a free MS-TRAM flap remains controversial. The purpose of this study was to compare the clinical outcomes when TDVs were used as recipient vessels to those obtained when IMVs were used as recipient vessels for autologous breast reconstruction with a free MS-TRAM flap. Methods A retrospective matched-cohort study was performed. We retrospectively reviewed data collected from patients who underwent a free MS-TRAM flap for autologous breast reconstructions after mastectomy between March 2003 and June 2013. After a one-to-one matching using age, 100 autologous breast reconstructions were selected in this study. Of the 100 breast reconstructions, 50 flaps were anastomosed to TDVs and 50 to IMVs. Patient demographics and clinical outcomes including operation time, length of hospital stay, postoperative complications, and aesthetic score were compared between the two groups. Results No statistically significant differences were found between the two groups in patient demographics and clinical outcomes, including the complication rates and aesthetic scores. There were no major complications such as total or partial flap loss in either group. Conclusions The results of our study demonstrate that both TDVs and IMVs were safe and efficient as recipient vessels in terms of the complication rates and aesthetic outcomes.

• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.469-472
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• 2012

Intensity modulated photocurrent spectroscopy and intensity modulated photovoltage spectroscopy were investigated to measure the dynamic response of charge transfer and recombination in the standard, $TiCl_4$-treated and the combined scattering layer electrode dye-sensitized solar cells (DSSCs). IMPS and IMVS provided transit time ($\tau_n$), lifetime ($\tau_r$), diffusion coefficient ($D_n$) and effective diffusion length ($L_n$). These expressions are derived that generation, collection, and recombination of electrons in a thin layer nanocrystalline DSSC under conditions of steady illumination and with a superimposed small amplitude modulation. In this experimental, IMPS/IMVS showed that the main effect of $TiCl_4$ treatment is to suppress the recombination of photogenerated electrons, thereby extending their lifetime. And the Diffusion coefficient of combined scattering layer electrode is $6.10{\times}10^{-6}$ higher than that of the others, resulting in longer diffusion length.

• Progress in Medical Physics
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• v.23 no.2
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• pp.91-98
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• 2012

Verification of internal organ motion during treatment and its feedback is essential to accurate dose delivery to the moving target. We developed an offline based internal organ motion verification system (IMVS) using cine EPID images and evaluated its accuracy and availability through phantom study. For verification of organ motion using live cine EPID images, a pattern matching algorithm using an internal surrogate, which is very distinguishable and represents organ motion in the treatment field, like diaphragm, was employed in the self-developed analysis software. For the system performance test, we developed a linear motion phantom, which consists of a human body shaped phantom with a fake tumor in the lung, linear motion cart, and control software. The phantom was operated with a motion of 2 cm at 4 sec per cycle and cine EPID images were obtained at a rate of 3.3 and 6.6 frames per sec (2 MU/frame) with $1,024{\times}768$ pixel counts in a linear accelerator (10 MVX). Organ motion of the target was tracked using self-developed analysis software. Results were compared with planned data of the motion phantom and data from the video image based tracking system (RPM, Varian, USA) using an external surrogate in order to evaluate its accuracy. For quantitative analysis, we analyzed correlation between two data sets in terms of average cycle (peak to peak), amplitude, and pattern (RMS, root mean square) of motion. Averages for the cycle of motion from IMVS and RPM system were $3.98{\pm}0.11$ (IMVS 3.3 fps), $4.005{\pm}0.001$ (IMVS 6.6 fps), and $3.95{\pm}0.02$ (RPM), respectively, and showed good agreement on real value (4 sec/cycle). Average of the amplitude of motion tracked by our system showed $1.85{\pm}0.02$ cm (3.3 fps) and $1.94{\pm}0.02$ cm (6.6 fps) as showed a slightly different value, 0.15 (7.5% error) and 0.06 (3% error) cm, respectively, compared with the actual value (2 cm), due to time resolution for image acquisition. In analysis of pattern of motion, the value of the RMS from the cine EPID image in 3.3 fps (0.1044) grew slightly compared with data from 6.6 fps (0.0480). The organ motion verification system using sequential cine EPID images with an internal surrogate showed good representation of its motion within 3% error in a preliminary phantom study. The system can be implemented for clinical purposes, which include organ motion verification during treatment, compared with 4D treatment planning data, and its feedback for accurate dose delivery to the moving target.

• Archives of Plastic Surgery
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• v.47 no.4
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• pp.333-339
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• 2020

Background The purpose of this study was to compare the anatomical features of the internal mammary vessels (IMVs) at the second and third intercostal spaces (ICSs) with regard to their use as recipient vessels in deep inferior epigastric artery perforator (DIEP) flap breast reconstruction. Methods A total of 38 consecutive DIEP breast reconstructions in 36 patients were performed using IMVs as recipient vessels between March 2017 and August 2018. The intraoperative findings and postoperative complications were analyzed. Anatomical analyses were performed using intraoperative measurements and computed tomography (CT) angiographic images. Results CT angiographic analysis revealed the mean diameter of the deep inferior epigastric artery to be 2.42±0.27 mm, while that of the deep inferior epigastric vein was 2.91±0.30 mm. A larger mean vessel diameter was observed at the second than at the third ICS for both the internal mammary artery (2.26±0.32 mm vs. 1.99±0.33 mm, respectively; P=0.001) and the internal mammary vein (IMv) (2.52±0.46 mm vs. 2.05±0.42 mm, respectively; P<0.001). Similarly, the second ICS was wider than the third (18.08±3.72 mm vs. 12.32±2.96 mm, respectively; P<0.001) and the distance from the medial sternal border to the medial IMv was greater (9.49±2.28 mm vs. 7.18±2.13 mm, respectively; P<0.001). Bifurcations of the IMv were found in 18.4% of cases at the second ICS and in 63.2% of cases at the third ICS. Conclusions The IMVs at the second ICS had more favorable anatomic features for use as recipient vessels in DIEP flap breast reconstruction than those at the third ICS.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.483.2-483.2
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• 2014

In this study, we describe a simple selective etching method that produces noncurling, freestanding, large-area, aligned $TiO_2$ nanotube (NT) with doubly ends opened. The novel selective etching process only removed the thin 2nd bottom layer from the physically and chemically stable thick amorphous 1st top layer under thermal treatment at $250^{\circ}C$, yielding ordered doubly open-ended NT (DNT) that could be easily transferred to an FTO substrate for the fabrication of front-illuminated dye sensitized solar cells (DSCs). The DNT-DSCs yielded a higher PCE (8.6%) than was observed from $TiO_2$ nanoparticle (TNP)-based DSCs (7.3%), for comparable film thicknesses of $16{\mu}m$, despite of 20% decreased amount of dye. Intensity-modulated photocurrent and photovoltage spectroscopy (IMPS and IMVS, respectively) revealed that the DNT-DSCs exhibited electron lifetimes that were 10 times longer than those of TNP-DSCs, which contributed to high device performances.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.196-196
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• 2012

염료감응 태양전지는 실리콘 태양전지에 비해 단가가 낮고 반투명하며 친환경적 특성으로 차세대 태양전지로 주목을 받았으나 염료의 안정성의 문제와 특정 파장대의 빛만 흡수하는 단점을 가지고 있다. 이러한 문제점을 해결하기 위하여 양자구속 효과에 의해 크기에 따라 밴드갭 조절이 용이하여 다양한 파장대의 빛을 흡수 할 수 있는 양자점 감응태양전지가 많은 관심을 받고 있다. 하지만 양자점 감응 태양 전지의 활성층으로 사용되는 반도체 산화물인 이산화티타늄의 두께는 $13{\sim}18{\mu}m$로 짧은 확산거리로 인해 전하수집의 한계를 가지고 있다. 이를 극복하기 위해 인듐 주석 산화물 나노선을 합성하여 전자가 광전극에 직접유입이 가능하도록 해 빠른 전하이동 및 전하수집을 가능하게 한다. 인듐 주석 산화물 나노선은 증기수송 방법(VTM)을 이용하여 인듐 주석 산화물 유리 기판 위에 $5{\sim}30{\mu}m$ 길이로 합성하였다. 전해질과 전자가 손실되는 것을 방지하기 위해 원자층 증착법(ALD)을 이용하여 이산화 티타늄 차단층을 20 nm 두께로 코팅한 후 화학증착방법(CBD)을 이용하여 인듐 주석 산화물 나노선-이산화 티타늄 코어-쉘 구조를 만든다. 마지막으로 황화카드뮴, 카드늄셀레나이드, 황화아연을 증착시킨 후 다황화물 전해질을 이용하여 양자점 감응 태양전지를 제작하였다. 특성 평가를 위해 전계방사 주사전자현미경, X-선 회절, 고분해능 투과 전자 현미경을 이용하며 intensity modulated photocurrent spectroscopy (IMPS), intensity modulated voltage spectroscopy (IMVS)를 이용하여 전하수집 특성평가를 하였다.

• Journal of Drive and Control
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• v.17 no.2
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• pp.45-54
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• 2020

The IMV is a combination of four two-way valve systems which replace a conventional four-way spool valve to improve efficiency mostly in excavator hydraulics. As the environmental regulations for construction equipment have tightened, some overseas advanced companies have released commercial excavators in which the MCV is implemented with the IMVs. Development of the IMV type MCV relies on the control algorithm as well as the robust performance of proportional flow control valves. In this study, the IMV controller was designed and verified with experiments for the excavator working unit, which determines the IMV mode of operation and the extent of the valve opening in consideration of the load conditions on hydraulic actuators. First, the open-loop controller was designed with a joystick command vs. a PSV reference current map comprising several control parameters in to compensate for the different flow characteristics and non-linearities of two-way flow control valves. Second, the closed-loop controller was designed with the PI control fed by the actuator displacement and outputs actuator percent effort equivalent to the operator's joystick command. Finally, the performance of the IMV type MCV was verified with the trajectory control of position references derived from the energy consumption test standard. Experimental results showed the control performance of the IMV developed in this study, and suggest that future studies to be conducted to advance technical progress.

• Rapid Communication in Photoscience
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• v.2 no.3
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• pp.82-84
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• 2013

We fabricated dye-sensitized solar cells (DSSCs) with $TiO_2$ nanowire (NW)/nanoparticle (NP) composite and solidified nanogel as the photoelectrode and electrolyte, respectively. $TiO_2$ NWs were generated via pore-infiltration of titanium (IV) isopropoxide (TTIP) into a track-etched polycarbonate membrane with a pore diameter of 100 nm, followed by calcination at $500^{\circ}C$. Energy conversion efficiency of $TiO_2$ NW/NP-based DSSCs was always higher than that of NP-based cells. We attributed this to improved light scattering and electron transport by $TiO_2$ NWs, as verified by intensity modulation photocurrent spectroscopy (IMPS) and intensity modulation photovoltage spectroscopy (IMVS) analyses. Quasi-solid-state DSSCs with NW/NP composites exhibited 5.0% efficiency at 100 $mW/cm^2$, which was much greater than that of NP-based cells (3.2%).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.5
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• pp.380-384
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• 2013

In this paper, we have developed a low temperature process to make two type of paste by using $TiO_2$ nanoparticles(P25). The interconnections between substrate and $TiO_2$ films or link between particles of free-binder paste(FP1, FP2, FP3) is very poor. Therefore, the Titanium(IV) isopropoxide was added to the TP paste to improve the interconnection. Electron transport time (${\tau}_t$) and recombination time (${\tau}_r$) are analyzed by IMPS (intensity-modulated photocurrent spectroscopy) and IMVS(Intensity-modulated photovoltage spectroscopy). In the results, ${\tau}_t$ of TP paste based DSSCs (about $4.3{\times}10^{-3}$) is faster than other samples. ${\tau}_r$ is longer from $2.7{\times}10^{-2}$ s of FP2 to $3.0{\times}10^{-2}$ s of TP. A solar conversion efficiency (DSSCs) of TP is 3.54% for an incident solar energy of 100 mW $cm^{-2}$(meanwhile, 2.70% for DSSCs with FP2). The conversion efficiency is increased by 1.3 times.