• 한국간담췌외과학회지
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• 제27권3호
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• pp.292-300
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• 2023

Backgrounds/Aims: Current literature presents limited data regarding outcomes following conversion at the time of minimally invasive pancreaticoduodenectomy (MI-PD). Methods: The National Cancer Database was queried for patients who underwent pancreaticoduodenectomy. Patients were stratified into three groups: MI-PD, converted to open pancreaticoduodenectomy (CO-PD), and open pancreaticoduodenectomy (O-PD). Multivariable modeling was applied to compare outcomes of MI-PD and CO-PD to those of O-PD. Results: Of 17,570 patients identified, 12.5%, 4.2%, and 83.4% underwent MI-PD, CO-PD, and O-PD, respectively. Robotic pancreaticoduodenectomy (R-PD) resulted in a higher lymph node yield (n = 23.2 ± 12.2) even when requiring conversion (n = 22.4 ± 13.2, p < 0.001). Margin positivity was higher in the CO-PD group (26.6%) than in the MI-PD group (21.3%) and the O-PD (22.6%) group (p = 0.017). Length of stay was shorter in the MI-PD group (laparoscopic pancreaticoduodenectomy 10.4 ± 8.6, R-PD 10.6 ± 8.8) and the robotic converted to open group (10.7 ± 6.4) than in the laparoscopic converted to open group (11.2 ± 9) and the O-PD group (11.5 ± 8.9) (p < 0.001). After adjusting for patient and tumor characteristics, both MI-PD (odds ratio = 1.40; p < 0.001) and CO-PD (odds ratio = 1.24; p = 0.020) were significantly associated with an increased likelihood of long-term survival. Conclusions: CO-PD does not negatively impact perioperative or oncologic outcomes.

• 한국대기환경학회지
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• 제14권1호
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• pp.25-33
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• 1998

We have studied the reduction of NO by propane over perovskite-type oxides prepared by malic acid method. The catalysts were modified to enhance the activity by substitution by substitution of metal into A or B site of perovskite oxides. In addition, the reaction conditions, such as temperature, $O_2$ concentration, space velocity have been studed. In the $LaCoO_3$ type catalyst, the partial substitution of Ba, Sr into A site enhanced the catalytic activity in the reduction of NO. In the $La_{0.6}Sr_{0.4}Co_{1-x}Fe_xO_3(x=0 \sim 1.9)$ catalyst, the partial substitution of Fe into B site enhanced the conversion of NO, but excess amount of Fe decreased the conversion of NO. The surface area and catalytic activity of perovskite catalysts prepared by malic acid method showed higher values than those of solid reaction method. In the $La_{0.6}Sr_{0.4}Co_{1-x}Fe_xO_3$ catalyst, the conversion of NO increased with increasing $O_2$ concentration and contact time. The introduction of water into reactant feed decreased the catalytic activity.

• 전력전자학회논문지
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• 제19권2호
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• pp.99-105
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• 2014

This paper proposes the reliability improvement of H-Bridge Multi-level (HBM) inverter. This reliability can be implemented through modularization of power circuit, distribution of controller, duplication of controller and communication, and continuous operation method in case of power cell failure for driving medium-voltage & high-power induction motor. It is shown that the modularization and expansion characteristics of the HBM inverter are improved since the individual inverter modules operate more independently when using the proposed concept. Also the fault tolerance is increased by using power cell bypass. The proposed design and control methods are described in detail and the validity of the proposed system is verified experimentally in various industrial fields.

• Journal of Advanced Marine Engineering and Technology
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• 제30권8호
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• pp.870-876
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• 2006

In proportion to the increase of industrial development, emission troubles were concerned as global issue. For these reasons, so many researchers and associated institutes effort to reduce pollution with new technology and various devices. As a kind of these methods, we used catalysts as a after-treatment system. At first, we made equipment of model furnace. And various catalysts were equipped at exhaust duct of combustion system, and excess air ratio(a), change cell numbers catalyst materials(Pt, Pd) were changed as experimental conditions. With these various condition, temperature. NOx, CO, HC, $CO_2$ and $O_2$ concentration were measured. As a result, NOx conversion increased with increasing of cell number in Pd catalyst. And Pt catalyst became 100% conversion at 200 and 300 cell. Also, Pt catalyst was better than Pd catalyst at a=1.5 in this condition. In addition, CO and HC concentrations were decreased at a = 1.5 with Pd catalyst.

• 한국응용과학기술학회지
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• 제31권2호
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• pp.313-319
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• 2014

This study was performed to obtain high conversion efficiency of $NH_3$ and minimize generation of nitrogen oxides using metal-supported catalyst with Ag : Cu ratio. Through structural analysis of the prepared catalyst with Ag : Cu ratio ((10-x)Ag-xCu ($0{\leq}x{\leq}6$)), it was confirmed that the specific surface area was decrease with increasing metal content. A prepared catalysts showed Type II adsorption isotherms regardless of the ratio Ag : Cu of metal content, and crystalline phase of $Ag_2O$, CuO and $CuAl_2O$ was observed by XRD analysis. In the low temperature($150{\sim}200^{\circ}C$), a conversion efficiency of AC_10 recorded the highest(98%), whereas AC_5 (Ag : Cu = 5 : 5) also showed good conversion efficiency(93.8%). However, in the high temperature range, the amounts of by-products(NO, $NO_2$) formed with AC_5 was lower than that of AC_10. From these results, It is concluded that AC_5 is more environmentally and economically suitable.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.154-159
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• 2005

In proportion to the increase of industrial development, emission troubles were concerned as global issue. For these reasons, so many researchers and associated institutes effort to reduce pollution with new technology and various devices. As a kind of these methods, we used catalysts as a after-treatment system. At first, we made equipment of model furnace. And various catalysts were equipped at exhaust duct of combustion system, and excess air ratio( ), change cell numbers, catalyst materials(Pt, Pd) were changed as experimental conditions. With these various condition, temperature, NOx, CO, HC, $CO_2$ and $O_2$ concentration were measured. As a result, NOx conversion were increased with increasing of cell number in Pd catalyst. And Pt catalyst were became 100% conversion at 200 and 300 cell. Also, Pt catalyst was better than Pd catalyst ${\alpha}$=1.5 in this condition. In addition, CO and HC concentrations were decreased${\alpha}$=1.5 with Pd catalyst.

• 공업화학
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• 제3권4호
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• pp.588-594
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• 1992

Potassium octoate 촉매 존재하에 toluene diisocyanate(TDI)를 사용하여 polyisocyanurate를 합성할 때 용매에 포함된 수분과 부탄올이 반응물의 점도 변화율, 반응시간(생성물의 점도가 5 poise가 될 때까지의 반응시간), 생성물의 분자량 분포 및 TDI전환율에 미치는 영향을 고찰하였다. Butyl acetate용매에 포함된 수분의 양이 0.1%인 반응 조건에서 uretidione이 생성되었으며 이때 가장 높은 TDI전환율이 얻어졌다. Uretidione은 butanol을 용매에 첨가할 때는 생성되지 않았다. 첨가된 butanol양이 증가할수록 TDI전환율은 증가하고 분자량 분포도 넓어졌다.

• 한국자동차공학회논문집
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• 제14권1호
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• pp.8-16
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• 2006

The research was conducted to characterize of Rh-Pd-Pt TWC with a double-layer washcoat for gasoline vehicle. The physical characteristics on surface of catalyst were inspected by BET, SEM and TEM. The characteristics of catalytic reaction were examined by the TPD/TPR and CO-pulse chemisorption. The catalyst $6Hx(0.35\times11\times3)$ showed superior conversion performance after hydrothermal aging process, which was due to small difference of the surface area between. the fresh and the aged catalyst. The CO-chemisorption and surface area were superior in the 600 cpsi catalyst than other catalysts, this catalyst also shown the higher conversion efficiency of the exhaust emissions. From the TPR test, the conversion performance of the aged catalyst was decreased by the agglomeration and sintering of the PM and metal oxides. From the TPD result, it was found that the NO chemisorption was happed on the bottom-layer washcoat with Pd, and the NO chemisorption was re-happened on the upper-layer washcoat with Pt and Rh in the desorption process.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2006년도 학술논문요약집
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• pp.144-145
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• 2006

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 추계학술대회
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• pp.83-86
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• 2006

In this study, the syngas producing facility that consists of pulverized coal feeding/gasification and hot gas clean-up system was tested for Indonesian subbituminous coal. And the DME conversion facilities have been developed and tested for converting syngas to DME by reactions with catalysts. So, the entrained-bed slagging type pi lot scale coal gasifier was operated normally in the temperature range of $1,400{\sim}1,450^{\circ}C,\;7{\sim}8kg/cm^2$ pressure. And Roto middle coal produced syngas that has a composition of $36{\sim}38%$ CO, $14{\sim}16%\;H_2,\;and\;5{\sim}8%\;CO_2$. Particulates in syngas were 99.8% removed by metal filters. $H_2S$ composition in syngas was also desulfurized by the Fe chelate system to yield less than 0.1 ppm level. When the clean syngas $70{\sim}100 Nm^3/h$ was provided to DME conversion rector, normally operated in the temperature range of $230{\sim}250^{\circ}C$ and $60kg/cm^2$ pressure, 4.5% DME was yielded.