인접 Pd-MILC가 Ni-MILC에 미치는 영향

김영수,김민선,오현욱,최성희,주승기 한국세라믹학회 2004 한국세라믹학회지 Vol.41 No.8

본 연구에서는 Palladium-Metal Induced Lateral Crystallization(Pd-MILC)과 Nickel-Metal Induced Lateral Crystallization (Ni-MILC)을 동시에 사용하여 Ni-MILC의 결정화 속도를 향상시키는 방법을 제안하였다 이 방법을 사용하여 기존의 Ni-MILC 보다 거의 4배나 빠른 결정화 속도인 15 $\mu$m/h를 얻을 수 있었다. Ni과 Pd의 간격이 좁을수록 Ni-MILC의 결정화 속도가 더 빨라졌으며 Pd두께, Ni두께에, 비정질 실리콘 너비와는 큰 의존관계가 없었다. 하지만 Pd이 Ni에 의해 덮혀져 Pd-MILC가 일어나지 못하는 경우에는 이러한 현상이 발견되지 않았다. 이는 Pd물질 그 자체가 Ni-MILC를 향상시키는 것이 아니라 Pd MILC가 진행되면서 발생하는 tensile stress에 의해 향상되는 것임을 의미한다. 이와 같은 현상들을 새로운 MILC mechanism으로 설명하였다. In this study, we proposed the novel method that can crystallize the amorphous silicon by adjacent Pd-MILC enhanced Ni-MILC. With this method, the MILC rate was about 15 ${\mu}$m/h at 550$^{\circ}C$ which is four times faster than conventional MILC rate. The crystallization rate increased rapidly with the spacing between Ni and Pd decreased. And it was independent on Ni and Pd layer thickness and amorphous silicon active width. However, when Pd was capped by a Ni layer, there's no enhancement on Ni-MILC. This phenomenon implies that the enhancement of Ni-MILC rate comes from not Pd material itself but Pd-MILC induced tensile stress. We can explain these phenomena with a novel MILC mechanism.

PD저널리즘 실현 수단으로서의 유튜브 경험 : 어느 20년 차 지역방송 PD의 자기민속지학

송철민 ( Song Chulmin ),최낙진 ( Choi Nakjin ) 한국지역언론학회 2022 언론과학연구 Vol.22 No.1

이 연구는 20년 차 지역방송 PD인 나의 유튜브 경험을 자기민속지학적으로 고찰한 것이다. 연구자의 유튜브 이용동기는 제주 제2공항이라는 지역 이슈에 대해 언론인으로서의 역할을 하지 못하는 상황에 대한 반성이다. 지역방송의 경영난 심화로 PD에 의한 탐사 프로그램이 하나둘 사라지는 현실에서 유튜브를 PD저널리즘의 실현을 위한 대안매체로 이용해본 것이다. 유튜브는 누구나 제작자가 되어 자신의 목소리를 낼 수 있다는 저널리즘적 장점과 가치에도 불구하고 확증편향과 가짜뉴스 확산의 주범으로 취급받고 있다. 이로 인해 유튜브를 저널리즘으로 분류하는 데 대해 반대 목소리 또한 높다. 연구자 본인 역시 그런 목소리를 내는 쪽에 속하여 있었으나 유튜브 경험을 통해 현실의 벽에 가로막혀 욕구로서만 존재하던 PD저널리즘을 구현할 수 있었으며, 언론인으로서 PD의 정체성을 돌아보는 기회가 되었다. 그리고 이러한 결과를 토대로 지역방송들로 하여금 유튜브 시스템을 활용한 PD저널리즘 활성화를 제안하였다. 본고에서 연구방법으로 사용한 자기민속지학은 연구자 본인의 개인적 경험을 성찰함으로써 자신이 속한 사회와 문화를 이해하고자 한다. 연구자의 유튜브 경험이 비록 개인적인 것이긴 하나 그것을 분석하는 것은 연구자가 소속된 지역방송, 특히 지역방송 PD의 현실을 제대로 이해하는 과정이기도 한 것이다. 이러한 자기민속지학 연구는 다른 보조적인 분석방법을 접목해 수행되기도 하는데 본고에서는 ‘이용과 충족’ 이론을 적용해보았다. ‘이용과 충족’ 이론에 따르면 수용자들은 자신의 욕구를 충족하기 위해 여러 경쟁적인 미디어들 중 특정 미디어를 선택하고, 욕구 충족이 강화될수록 그 선택은 반복된다. 이러한 과정을 5단계, 즉 [욕구-동기-기대-이용-충족]으로 제시할 수 있는데 이 5단계 모형을 자기민속지학적 기술에 있어 구성의 틀로 사용한 결과 자신의 미디어 경험을 드러내는 데 유익하다는 것을 확인할 수 있었다. This study is a auoo-ethnographic examination of my YouTube experience as a local TV producer with 20 years of experience. The researcher’s motivation to use YouTube is to reflect on the situation in which he can’t play a role as a journalist on the local issue of Jeju Second Airport. In the reality that exploration programs by PDs disappear one by one due to the deepening financial difficulties of local broadcasting, YouTube was used as an alternative medium to realize PD journalism. Despite the merits and values of journalism that anyone can become a producer and have their own voice, YouTube is being treated as a major culprit in the spread of confirmation bias and fake news. For this reason, there are also strong voices against classifying YouTube as journalism. Although the researcher’s opinion was same, but through the YouTube experience, I was able to realize PD journalism, which existed only as a desire because I was blocked by the wall of reality, and it was an opportunity to reflect on the identity of the PD as a journalist. And based on these results, it was suggested that local broadcasters activate PD journalism using the YouTube system. Auto-ethnography, used as a research method in this paper, seeks to understand the society and culture to which the researcher belongs by reflecting on his/her own personal experiences. Although the researcher’s YouTube experience is personal, analyzing it is also a process of properly understanding the reality of the local broadcaster to which the researcher belongs, especially the local broadcaster PD. Such auto-ethnographic studies are sometimes conducted by grafting other auxiliary analysis methods, but in this paper, the ‘use and fulfillment’ theory is applied. According to the ‘use and gratification’ theory, in order to satisfy their needs, recipients select a specific media among competing media, and the selection is repeated as the satisfaction of their needs is strengthened. This process can be presented in five stages, that is, [needs-motivation-expectation-use-fulfillment]. As a result of using this five-stage model as a frame of composition in autoethnographic description, it is confirmed that it is beneficial for revealing one’s own media experience.

Effect of sulfur aging and regeneration on low temperature NO adsorption over hydrothermally treated Pd/CeO₂ and Pd/Ce_0.58Zr_0.42O₂ catalysts

Ryou, Y.,Lee, J.,Lee, H.,Kim, C.H.,Kim, D.H. Elsevier Science Publishers 2017 CATALYSIS TODAY - Vol.297 No.-

Various treatments such as hydrothermal aging (HTA), sulfur aging (SA), and regeneration (DeSOx) were applied to Pd/CeO<SUB>2</SUB> and Pd/Ce<SUB>0.58</SUB>Zr<SUB>0.42</SUB>O<SUB>2</SUB> (Pd/Ce58) catalysts to understand the effect of sulfur aging and regeneration on the changes in NO adsorption ability and physicochemical properties of catalysts. The addition of Pd to Ce-based supports results in the larger amount of NO adsorbed at higher desorption temperature (250-500<SUP>o</SUP>C) than CeO<SUB>2</SUB>. Also, Pd/CeO<SUB>2</SUB> has larger amount of NO adsorbed than Pd/Ce58, indicating that ceria is the active site for NO adsorption at low temperature. However, SA treatment on both catalysts gives rise to the negligible NO adsorption ability since it leads to form thermodynamically more stable Ce(SO<SUB>4</SUB>)<SUB>2</SUB>. Structural and textural analysis after regeneration shows that Pd/Ce58 maintains the pore size distribution with the similar crystalline size, whereas Pd/CeO<SUB>2</SUB> does not, despite the similar amount of residual sulfur over two samples. In addition, Pd dispersion is recovered completely over the former sample, although the latter does not. However, the fact that both regenerated catalysts do not recover the NO adsorption ability to the level of HTA ones implies that either textural property or Pd dispersion cannot account for the degradation of NO adsorption at low temperature. Instead, H<SUB>2</SUB>-TPR analysis indicates that the intimate interaction Pd and ceria is lost for both samples after regeneration, as evidenced by the disappearance of the simultaneous reduction of CeO<SUB>2</SUB> and PdO below 20<SUP>o</SUP>C. Hence, it can be concluded that the exposure of SO<SUB>2</SUB> and the subsequent regeneration significantly affects the interaction between PdO and CeO<SUB>2</SUB>, resulting in the irreversible decrease in the NO adsorption ability at low temperature.

Pd/TiO2 광촉매를 이용한 폐수중의 NO3- 제거

최경희 ( Choe Gyeong Hui ),김서경 ( Kim Seo Gyeong ),전민수 ( Jeon Min Su ),신형식 ( Sin Hyeong Sig ),양오봉 ( Yang O Bong ) 한국공업화학회 2003 공업화학 Vol.14 No.6

졸-겔법에 의하여 제조된 TiO₂와 Pd가 담지된 Pd/TiO₂광촉매를 이용한 폐수중의 NO₃^(-)제거에 관한 연구로 UV 조사 하에 회분식 반응장치에서 진행하였다. 제조된 촉매들은 X-선회절기(X-ray diffraction, XRD), 적외선분광기(Fourier transform infrared spectroscopy, FT-IR), 전자현미경(scanning electron microscopy, SEM)과 비표면적(BET)으로 특성화하였다. 루타일 구조를 가지고 표면에 OH group의 양이 적은 750℃에서 소성시킨 TiO₂가 NO₃^(-)제거율이 우수하였다. 또한 TiO₂에 Pd를 담지한 Pd/TiO₂ 경우 NO₃^(-)제거율이 크게 향상되었다. 이것은 NO₃^(-)제거가 환원 반응이기 때문에 환원성금속인 Pd을 도입하고 아나타제와 OH group이 적을수록 환원 반응에 유리하기 때문으로 설명할 수 있다. 반응에 희생시약을 첨가하면 NO₃^(-) 제거능이 크게 향상되었으며, 메탄올 > 에탄올 > 페놀 > 프로판올의 순서로 NO₃^(-)의 제거율을 향상시켰다. 최적의 NO₃^(-) 제거율을 보이는 실험조건은 메탄올 : NO₃^(-)의 비가 2:1일 때, 폐수 리터당 촉매 3 g을 사용하였을 때, Pd의 담지량이 0.5 wt%일 때이었다. Pd/TiO₂는 NO₃^(-)의 75% 이상이 N₂로 완전 환원되는데 비하여 TiO₂는 35%만이 N₂로 완전환원되는 생성물 분포를 보여 Pd/TiO₂의 우수한 환원성을 확인할 수 있었다. The removal of NO? from waste water was studied in a batch system under ultra-violet (UV) irradiation, using TiO_(2) and Pd/TiO_(2) photocatalysts that were prepared by sol-gel method. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FR-IR) and specific surface area measurement (BET). The TiO_(2) photocatalyst calcined at 750 ℃, which had mainly rutile structure and less amount of OH group, has shown a superior NO_(3)^(-) removal efficiency. Also, the photocatalytic decomposition of NO_(3)^(-) was enhanced significantly using Pd/TiO_(2), which was prepared by impregnating Pd as the reducing metal. These results would suggest that the removal of NO_(1), which is reduction reaction, may be improved by increasing the amount of Pd as the reducing metal and by decreasing the amount of anatase phase and OH group as the oxidizing agents. The removal efficiency of NO_(3)^(-) was improved significantly with addition of an additive, in the following decreasing order: methanol > ethanol > phenol. The optimal reaction conditions for the removal of NO_(3)^(-) were as following: the ratio of methanol to NO_(3)^(-) was 2.0, 3 g catalyst per liter of waste water, and 0.5 wt% Pd loading on TiO_(3) 75% of NO_(3) was reduced completely to N_(2) gas over Pd/TiO_(2) indicating the superior reducing power of Pd/TiO_(2) in comparison with naked TiO_(2) that showed only 35% of NO_(3) reduced to N_(2) gas.

Pd/Ti-SPK과 Pd/Zr-SPK 촉매상에서 수소 생산을 위한 메탄의 부분산화반응과 촉매의 특성화

서호준 ( Ho Joon Seo ),강웅일 ( Ung Il Kang ) 한국공업화학회 2010 공업화학 Vol.21 No.6

고정층 상압 흐름 반응기에서 메탄의 부분산화반응을 수행하여 메탄으로부터 수소제조 위한 촉매의 활성도를 평가하였고, BET, XPS, XRD를 사용하여 촉매의 특성을 분석하였다 Pd(5)Ti-SPK과 Pd(5)/Zr-SPK 촉매의 BET 표면적, Horvath-Kawaze의 기공부피와 기공폭, t-플롯 미세기공 면적과 부피는 각각 284 m2/g, 0.233 cm3/g, 3.9 nm, 30 m2/g, 0.015 cm3/g과 396 m2/g, 0.324 cm3/g, 3.7 nm, 119 m2/g, 0.055 cm3/g이었다. 촉매는 히스테리시스가 잘 발달된 IV형 임을 N(2)-흡착등온선으로부터 확인할 수 있었다. XPS분석으로부터 SPK에 Ti와 Zr이 부분 치환된 Ti-SPK과 Zr-SPK의 Si 2p과 O Is 피크는 SPK의 Si 2p와 O Is 피크 보다 낮은 결합에너지 쪽으로 화학 이동함을 알 수 있었고, 촉매표면의 Pd의 산회상대는 Pd(0)와 Pd(+2)이었다. XRD의 결정 피크는 반응 전에 무정형인 촉매가 반응 후에는 결정상으로 변함을 보여주었다. Pd(5)Ti-SPK과 Pd(5)/Zr-SPK 촉매의 메탄의 전화율과 수소의 선택도는 973 K, CH(4)/O(2) = 2, GHSV = 8.4 x 10(4) mL/g(cat)·h 반응조건에서 각각 77,84%와 78,72%이었고, 반응 시작 후 3일까지도 촉매의 활성이 거의 일정하게 유지되었다 Pd(5)/Ti-SPK과 Pd(5)/Zr-SPK 촉매는 메탄의 부분산화반응에서 활성도와 열 안정성 및 물리화학적 성질이 우수하였다. Catalytic activities of the partial oxidation of methane (POM) to hydrogen were investigated over Pd(5)Ti-SPK and Pd(5)Zr-SPK in a fixed bed flow reactor (FBFR) under atmosphere, and the catalysts were characterized by BET, XPS, XRD. The RET surface areas, pore volume and pore width of Horvath-Kawaze, micro pore area and volume of t-plot of Pd(5)Ti-SPK and Pd(5)Zr-SPK were 284 m2/g, 0.233 cm3/g, 3.9 nm, 30 m2/g, 0.015 cm3/g and 396 m2/g, 0324 cm3/g, 3.7 nm, 119 m2/g, 0.055 cm3/g, repectively. The nitrogen adsorption isotherms were type IV with hysteresis. XPS showed that Si 2p and O Is core electronlevels of Ti-SPK and Zr-SPK substituted Ti and Zr shifted to slightly lower binding energies than SPK. The oxidation states of Pd on the surface of catalysts were Pd(0) and Pd(+2). XRD patterns showed that crystal structures of fresh catalyst changed amorphous into crystal phase after reaction. The conversion and selectivity of POM to hydrogen over Pd(5)/Ti-SPK and Pd(5)/Zr-SPK were 77,84% and 78,72%, respectively, at 973 K, CH(4)/O(2) = 2, GHSV = 8.4 × 10(4) mL/g(cat)·h and were kept constant even after 3 days in stream. These results confirm superior activity, thermal stability, and physicochemical properties of catalyst in POM to hydrogen.

Pd 첨가량 및 첨가방법이 알코올 센서용 SnO₂ 반도체 후막 특성에 미치는 영향 연구

김준형(Jun-Hyung Kim),김형관(Hyeong-Gwan Kim),이호년(Ho-Nyun Lee),김현종(Hyun-Jong Kim),이희철(Hee-Chul Lee) 한국표면공학회 2017 한국표면공학회지 Vol.50 No.5

In this paper, two methods of making the Pd-added SnO₂ (Pd-SnO₂) powder with pure tetragonal phase by the hydrazine method were suggested and compared in terms of crystal structure, surface morphology, and alcohol gas response. One of the addition methods is to use PdCl₂ as a Pd source, the other is to use Pd-based organic with oleylamine (OAM). When Pd concentration was increased from 0 to 5 wt%, the average grain size of Pd-SnO₂ made with Pd-OAM were decreased from 32 to 12 nm. In the case of using with PdCl2, grain size of the PdCl₂ fell to less than 10 nm. However, agglomerated and extruded surface morphology was observed for the films with Pd addition over 4 wt%. The crack-free Pd-SnO₂ thick films were able to successfully fill the 30 μm gap of patterned Pt electrodes by optimized ink dropping method. Also, the 2 wt% Pd-SnO₂ thick film made with PdCl₂ showed gas responses (Rair/Rgas) of 3.7, 5.7 and 9.0 at alcohol concentrations of 10, 50 and 100 ppm, respectively. On the other hand, the prepared 3 wt% Pd-SnO₂ thick film with Pd-OAM exhibited very excellent responses of 3.4, 6.8 and 12.2 at the equivalent measurement conditions, respectively. The 3 wt% Pd-SnO₂ thick film with Pd-OAM has a specific surface area of 31.39 m²/g.

X-선 광전자분광법을 이용한 MgO/Mg 표면에 증착된 Pd의 분석

태위승,서현욱,김광대,김영독,Tai, Wei-Sheng,Seo, Hyun-Ook,Kim, Kwang-Dae,Kim, Young-Dok 한국진공학회 2009 Applied Science and Convergence Technology Vol.18 No.4

본 연구에서는 고진공 조건에서 열기화 증착 방법으로 산화막으로 덮인 Mg 리본(MgO/Mg) 위에 Pd을 증착하였다. 고진공 속에서 만든 시료의 전자구조를 in-situ X-선 광전자 분광법 (XPS)을 통하여 분석하였고, 분석 후, FE-SEM을 통해 증착량의 증가에 따른 표면구조의 변화를 확인하였다. Pd 증착량이 1 나노미터 (nm) 이하인 경우에는 증착량 증가에 따른 Pd 나노입자 크기의 증가를 확인하였으며, Pd을 1 nm 이상의 두께로 증착시킨 경우에는 Pd 입자들의 뭉침에 의해 얇은 필름이 형성됨을 관찰하였다. Pd과 기판사이의 전하이동에 의하여 산화물/금속 계면의 Pd 원자들은 부분적으로 양전하를 띔을 확인하였다. Pd was deposited on magnesium-oxide-covered magnesium ribon substrate by metal thermal evaporation method in high vacuum. The electronic and chemical properties of Pd samples with different coverages were studied using in-situ X-ray Photoelctron Spectroscopy (XPS) and Field Emission Scanning Electron Microscopy (SEM). For relatively lower amounts of Pd deposited(< 1nm), separate Pd particles could be observed, whereas at higher Pd coverages, Pd thin films caused by agglomeration of Pd nanoparticles was found. The metal support interaction with Pd-support was observed. The Pd atoms on the metal oxide/metal interface were partially negative charged by charge transfer.

PD-L1 (SP142) Expression in Primary and Recurrent/Metastatic Triple-Negative Breast Cancers and Its Clinicopathological Significance

한은경,우지원,서경진,김세현,김지현,박소연 대한암학회 2024 Cancer Research and Treatment Vol.56 No.2

Purpose The programmed death-ligand 1 (PD-L1) SP142 assay identifies patients with triple-negative breast cancer (TNBC) who are most likely to respond to the anti–PD-L1 agent atezolizumab. We aimed to compare PD-L1 (SP142) expression between primary and recurrent/metastatic TNBCs and elucidate the clinicopathological features associated with its expression. Materials and Methods Primary and recurrent/metastatic TNBCs tested with PD-L1 (SP142) were collected, and clinicopathological information of these cases was obtained through a review of slides and medical records. Results PD-L1 (SP142) positivity was observed in 50.9% (144/283) of primary tumors and 37.8% (31/82) of recurrent/metastatic TNBCs with a significant difference. Recurrent or metastatic sites were associated with PD-L1 positivity, with high PD-L1 positivity in the lung, breast, and soft tissues, and low positivity in the bone, skin, liver, and brain. When comparing PD-L1 expression between primary and matched recurrent/metastatic TNBCs using 55 paired samples, 20 cases (36.4%) showed discordance; 10 cases revealed positive conversion, and another 10 cases revealed negative conversion during metastatic progression. In primary TNBCs, PD-L1 expression was associated with a higher histologic grade, lower T category, pushing border, and higher tumor-infiltrating lymphocyte infiltration. In survival analyses, PD-L1 positivity, especially high positivity, was found to be associated with favorable prognosis of patients. Conclusion PD-L1 (SP142) expression was lower in recurrent/metastatic TNBCs, and substantial cases showed discordance in its expression between primary and recurrent/metastatic sites, suggesting that multiple sites may need to be tested for PD-L1 (SP142) when considering atezolizumab therapy. PD-L1 (SP142)–positive TNBCs seems to be associated with favorable clinical outcomes.

Pd/Al2O3, Pd/Ag/Al2O3 분리막의 제조와 수소 투과 성능 평가

박정훈,이정인,신민창,장학룡,황재연,김억용,정창훈 한국막학회 2022 멤브레인 Vol.32 No.2

본 실험에서는 α-Al2O3 세라믹 중공사를 지지체로 사용하였고, 무전해 도금을 통해 Pd 및 Pd-Ag가 도금된 수소 분리막을 제조하였다. Pd-Ag 분리막은 Pd와 Ag 합금 형태로 만들기 위하여 500°C, 10 h 동안의 annealing 과정을 거쳤으며, EDS (Energy Dispersive X-ray Spectroscopy) 분석을 통해 Pd-Ag 합금이 되었다는 것을 확인하였다. 또한, SEM (Scanning Electron Microscope) 분석을 통해 제조된 Pd 및 Pd-Ag 도금층의 두께는 약 8.98, 9.29 µm으로 측정되었다. 제조된 수소 분 리막은 350~450°C, 1-4 bar의 범위에서 수소 단일 가스, 혼합가스(H2, N2)를 이용하여 수소 투과 실험을 진행하였다. 수소 단 일 가스에서 Pd와 Pd-Ag 분리막은 최대 각각 21.85, 13.76 mL/cm2⋅min의 flux를 가지며, 혼합가스에서는 450°C, 4 bar의 조건일 때, 1216, 361의 separation factor가 각각 나오는 것을 확인하였다.

Pd–Fe bimetallic nanoparticles anchored on N‑doped carbon‑modified graphene for efficient catalytic organic reactions

Yue Zhang,Jie Huang,Zixuan Dong,Yu Zhan,Jiangbo Xi,Jian Xiao,Shaohua Huang,Fan Tian 한국탄소학회 2023 Carbon Letters Vol.33 No.1

A promising approach to enhance catalytic performance of supported heterogeneous nano-metal catalysts is to uniformly disperse active nanoparticles on the support. In this work, N-doped carbon-modified graphene (G@NC) nanosheet is designed and prepared to anchor Pd–Fe bimetallic nanoparticles (Pd–Fe/G@NC). The N-doped carbon modification on graphene surface could construct a sandwich-like structure (G@NC), which not only prevented the re-stacking of graphene nanosheets but also provided confined space for stable anchoring of bimetallic Pd–Fe nanoparticles. Benefitted from the unique structural property and synergetic effect of metal Pd and Fe species, the as-obtained Pd–Fe/G@NC composite displays excellent catalytic activity toward 4-nitrophenol reduction reaction with a turnover frequency of 613.2 min? 1, which is far superior to that of the mono-metal counterparts (Fe/G@NC and Pd/G@NC). More importantly, Pd–Fe/G@NC catalyst also exhibits favorable catalytic performance in the reduction of other nitroaromatic compounds (nitrobenzene, 4-nitrotoluene, 4-chloronitrobenzene, and so on). In addition, Pd–Fe/G@NC can catalyze the oxidation of furfuraldehyde to furoic acid with a high yield of 88.64%. This work provides a new guide for rationally designing and developing advanced supported heterogeneous bimetallic catalyst.