• 한국산업보건학회지
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• 제6권2호
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• pp.301-312
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• 1996

This study was performed to search a optimal analyzing method of cadmium in whole-blood. Cadmium was determined by graphite furnace atomic absorption spectrometry(GFAAS). We investigated the effect of ashing temperature on the absorbance of cadmium in a simple dilution(ten-fold) method with triton X-100 and matrix modifier methods treated with $NH_4H_2PO_4$(1 and 3%) and $Pd(NO_3)_2$(0.00l and 0.005%) as matrix modifier. We also compared the reported reference values of standard blood with values resulted from optimal analyzing conditions of this study. In case of a simple dilution method, when ashing temperature was set at $450^{\circ}C$, the absorbance of sample and background were $0.334{\pm}0.012$ and $1.382{\pm}0.245$, respectively. Background level was higher than the value(0.8) that can be corrected by $D_2$ background correction method. As ashing temperature was rised to $500^{\circ}C$, the absorbance of sample and background were $0.178{\pm}0.008$ and $0.711{\pm}0.223$ respectively. The higher ashing temperature($450^{\circ}C-650^{\circ}C$) was, the lower the absorbance of sample was. In case of a matrix modifier method with $NH_4H_2PO_4$(1 and 3%), when ashing temperature was rised from $500^{\circ}C$ to $650^{\circ}C$, the absorbance of sample slightly changed. The absorbances of sample at $600^{\circ}C$ were $0.230{\pm}0.017$ and $0.137{\pm}0.012$, respectively. These values were larger than that of simple dilution method. But the absorbance of background was higher than the level that can be corrected by $D_2$ method. In case of a matrix modifier method with $Pd(NO_3)_2$(0.001 and 0.005%), the absorbance of sample and background were higher than those of other methods and were stable and reproducible. When ashing temperature was over $550^{\circ}C$, the absorbance of sample was significantly decreased. In case of 0.005% $Pd(NO_3)_2$ carbon residue remained in graphite tube affected the absorbance of sample and background. From these results, We propose that in case of a simple dilution(ten-fold) method with triton X-100 ashing temperature must be maintained below $400^{\circ}C$. In order to diminish the absorbance of background, the alternative method is attenuation of injection volume or multiplication of dilution ratio. We recommend $Pd(NO_3)_2$ than $NH_4H_2PO_4$ as a matrix modifier. In case of a matrix modifier method with $Pd(NO_3)_2$ ashing temperature might be maintained below $550^{\circ}C$.

• Membrane and Water Treatment
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• 제13권2호
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• pp.97-104
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• 2022

With a small particle size, specific surface area and chemical nature, Pd/Cu-Fe nanocomposites can efficiently remove the organic compounds. In order to understand the applicability for in situ remediation of contaminated groundwater, the degradation of p-nitrophenol by Pd/Cu-Fe nanoparticles was investigated. The degradation results demonstrated that these nanoparticles could effectively degrade p-nitrophenol and near 90% of degradation efficiency was achieved by Pd/Cu-Fe nanocomposites for 120 min treatment. The efficiency of degradation increased significantly when the Pd content increased from 0.05 wt.% and 0.10 wt.% to 0.20 wt.%. Meanwhile, the removal percentage of p-nitrophenol increased from 75.4% and 81.7% to 89.2% within 120 min. Studies on the kinetics of p-nitrophenol that reacts with Pd/Cu-Fe nanocomposites implied that their behaviors followed the pseudo-first-order kinetics. Furthermore, the batch experiment data suggested that some factors, including Pd/Cu-Fe availability, temperature, pH, different ions (SO42-, PO43-, NO3-) and humic acid content in water, also have significant impacts on p-nitrophenol degradation efficiency. The recyclability of the material was evaluated. The results showed that the Pd/Cu-Fe nanoparticles have good recycle performance, and after three cycles, the removal rate of p-nitrophenol is still more than 83%.

• 동력기계공학회지
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• 제20권4호
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• pp.69-74
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• 2016

Recently, in order to meet the stricter emission regulations, the proportion of after-treatments for vehicle and vessel is increasing gradually. The purpose of this study is to investigate the de-$CH_4$ characteristics of NGOC in front of proposed combined system according to additive catalyst and support ratio. In the case of Pd addition, the de-$CH_4$ performance of 2Pt-2Pd-3MgO/$Al_2O_3$ NGOC was improved by approximately 10 to 20% for the HC components. The de-$CH_4$ performance of 2Pt-2Pd-3Cr-3MgO/$Al_2O_3$ NGOC was higher compared to five kinds of NGOC catalysts, because Cr particle was smaller and dispersion of Pd was increased. The NGOC(Zeolite:$Al_2O_3$(80%:20%)｝catalyst according to support ratio, was improved performance at low temperature region on CO and NO conversion rate.

• 센서학회지
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• 제6권5호
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• pp.369-375
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• 1997

$SnO_{2}$에 $V_{2}O_{5}/ThO_{2}/Pd$를 도핑하여 제조된 센서는 약 $500^{\circ}C$의 높은 센서 온도에서 CO에 대해 우수한 선택도와 안전성 및 빠른 응답특성을 보였다. 특히, $V_{2}O_{5}$를 약 3.0 wt.% 첨가하여 선택도에 있어서 CO 감도에 대해 $NO_{x}$, $C_{3}H_{8}$, $CH_{4}$ 및 $SO_{2}$같은 많은 간섭가스들의 영향이 적음을 알았다. 센서 제조는 $V_{2}O_{5}$(3.0 wt.%), $ThO_{2}$(1.5wt.%), Pd(1.0 wt.%)의 촉매물질과 함께 기존에 잘 알려진 후막기술을 이용하였다. 일반적으로 연소배가스처럼 $NO_{x}$와 CO가 혼합되어 있는 복합가스의 경우, $SnO_{2}$계 반도체 센서로는 CO만의 검지는 $NO_{x}$ 간섭 때문에 대단히 어렵다. 본 센서는 공연비제어를 요하는 자동차나 보일러 시스템의 연소배가스의 측정과 감시에 사용할 수 있을 것이다.

• Bulletin of the Korean Chemical Society
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• 제34권7호
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• pp.2099-2104
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• 2013

We present here an efficient and simple method for preparation of highly active Pd heterogeneous catalyst (CNT-Pd), specifically by reaction of dichlorobis(triphenylphosphine)palladium ($Pd(PPh_3)_2Cl_2$) with thiolated carbon nanotubes (CNTs). The as-prepared CNT-Pd catalysts demonstrated an excellent catalytic activity for the carbon-carbon (C-C) cross-coupling reactions (i.e. Suzuki, Stille, and decarboxylative coupling reactions) under mild conditions. The CNT-Pd catalyst could easily be removed from the reaction mixture; additionally, in the decarboxylative coupling of iodobenzene and phenylpropiolic acid, it showed a six-times recyclability, with no loss of activity. Moreover, once its activity had decreased by repeated recycling, it could easily be reactivated by the addition of phosphine ligands. The remarkable recyclability of the decarboxylative coupling reaction is attributable to the high degree of dispersion of Pd catalysts in CNTs. Aggregation of the Pd catalysts is inhibited by their strong adhesion to the thiolated CNTs during the chemical reactions, thereby permitting their recycling.

• 한국자동차공학회논문집
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• 제3권2호
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• pp.95-101
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• 1995

Experiments have been conducted to investigate the characteristics of formaldehyde and nitrous oxide formation from the catalytic reaction of methane. Catalysts used in the experiment were Pd. Pd/Pt/Rh loaded on ${\gamma}-Al_2O_3$ and ${\gamma}-Al_2O_3-La_2O_3$ monolith. In the catalytic reaction of methane. as the concentration of NO, $O_2$ and $CH_4$ increased, the formaldehyde emission was increased. The concentration of $N_2O$ increased as NO and CO increased. It was also found that the formaldehyde emission was produced by the gas reaction of methane in high temperature above 950K.

• 한국작물학회지
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• 제32권3호
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• pp.369-374
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• 1987

풍기와 금산지방의 백삼포장을 대상으로 인삼의수량, 재식본수, 결주율, 근중엽면적 수확근수간의 상호관계를 조사하였다. 1. 금산지방은 풍기지역보다 재식본수가 거의 2배나 되며 박엽을 및 결주율이 높고 수량은 낮았다 2. 수량이 밀식재배에서는 근수에 의존하고 소식재배에서는 근중에 의존하였다. 결주율이 수량에 주는 영향은 밀식재배에서 더욱 현저하였으며 재식본수는 유의성은 없으나 수량과 부상관이였다. 결주율과 재식본수와는 무관하였다. 3. 채굴본수는 재식본수에 의존하고 특히 결주율에 의해 제한되었다. 4. 수량은 수확기 엽면적지수(LAI) 특히 생육 최성기 LAI 에 의존하였으며 LAI는 밀식재배에서는 채를 본수에만 소식재배에서는 주엽면적에만 의존하였고 LAI 는 밀식과 소식재배간 차이가 없었으며 MR에 의하여 제한되었다. 5. 주엽면적은 근중에 고도로 의존하였으며 밀식에 의하여 LAI 가 증대하지 않는 원인이고 모든 포장은 최적 LAI 이하였다.

• Molecules and Cells
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• 제41권7호
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• pp.653-664
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• 2018

The RNA-binding protein tristetraprolin (TTP) binds to adenosine-uridine AU-rich elements in the 3'-untranslated region of messenger RNAs and facilitates rapid degradation of the target mRNAs. Therefore, it regulates the expression of multiple cancer and immunity-associated transcripts. Furthermore, a lack of TTP in cancer cells influences cancer progression and predicts poor survival. Although the functions of TTP on cancer cells have previously been researched, the mechanism of TTP on the interaction between cancer cells with their micro-environment remains undiscovered. In this study, we admed to determine the role of cancer cell TTP during the interaction between tumor and immune cells, specifically regulatory T cells (Tregs). We evaluate the capability of TTP to modulate the antitumor immunity of GC and explored the underlying mechanism. The overexpression of TTP in GC cells dramatically increased peripheral blood mononuclear lymphocyte (PBML) -mediated cytotoxicity against GC cells. Increased cytotoxicity against TTP-overexpressed GC cells by PBMLs was determined by Treg development and infiltration. Surprisingly, we found the stabilization of programmed death-ligand 1 (PD-L1) mRNA was declining while TTP was elevated. The PD-L1 protein level was reduced in TTP-abundant GC cells. PD-L1 gas been found to play a pivotal role in Treg development and functional maintenance in immune system. Taken together, our results suggest the overexpression of TTP in GC cells not only affects cell survival and apoptosis but also increases PBMLs -mediated cytotoxicity against GC cells to decelerate tumor progression. Moreover, we identified PD-L1 as a critical TTP-regulated factor that contributes to inhibiting antitumor immunity.

• 센서학회지
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• 제5권5호
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• pp.39-46
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• 1996

$WO_{3}$에 미량의 Pd 또는 Pt가 첨가된 박막을 이용한 NOx 센서를 제조하였다. $WO_{3}$계 박막은 고진공, 저항가연식 evaporator를 이용하여 분위기온도에서 증착한 다음 $500^{\circ}C$에서 열처리하였다. 5 ppm의 $NO_{2}$가스에 대하여 $200^{\circ}C$에서 측정한 가스감도($R_{gas}/R_{air}$)는 0.5 wt.% $Pt-WO_{3}$ 센서에서 50으로서 최대값을 가졌다.

• 한국대기환경학회지
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• 제23권6호
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• pp.699-707
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• 2007

This study was carried out to investigate the reaction characteristics of corona/catalyst hybrid $DeNO_x$ process. The experiments were performed by using the multi-staged pin-to-hole type corona reactor which is enable to control the pin-to-hole gap and to insert the catalyst. Also, used for this study, were catalysts which commercially used Pt, Pd and $TiO_2$, and oxygen and hydrocarbon ($C_2H_4$) as reagents. In the syn-gas test, at high temperatures in the range of $100{\sim}200^{\circ}C$, the corona-only $DeNO_x$ process did not reduce the $NO_x$ concentration effectively. However in the presence of ethylene and oxygen as reagents, the $NO_x$ removal efficiency was better at these high temperatures than corona-only $DeNO_x$ process. In addition, coronal catalyst hybrid process with $TiO_2$ showed more efficiency of $NO_x$ removal than Pt and Pd catalyst, because the $TiO_2$ catalyst was more active than Pt and Pd catalyst to converse the $NO_2$ to $HNO_3$. Furthermore, at the condition of real diesel exhaust gas, the $DeNO_x$ efficiency of corona/catalyst hybrid process was not good at higher reaction temperature and plasma density.