수증기 개질 반응에서 Ni-La2O3-Ce0.8Zr0.2O2 촉매의 La2O3 함량이 촉매의 성능에 미치는 영향

유성연,김학민,김범준,장원준,노현석 한국수소및신에너지학회 2018 한국수소 및 신에너지학회논문집 Vol.29 No.5

Ni-La2O3-Ce0.8Zr0.2O2 catalysts with various La2O3 loading were investigated for hydrogen production from steam reforming of methane (SRM). The La2O3 loading influenced the physicochemical properties of Ni-La2O3-Ce0.8Zr0.2O2 catalysts such as BET surface area, Ni dispersion, Ni size and reducibility. Among the prepared catalysts, Ni-70La2O3-Ce0.8Zr0.2O2 catalyst showed the highest activity and stability at a very high gas hourly space velocity (GHSV) of 932,556 h-1. This is mainly due to high Ni dispersion, small Ni size and high reducibility.

Clarifying the basic phase structure and magnetic behavior of directly quenched (Ce,La)2Fe14B alloys with various Ce/La ratios

X.F. Liao,L.Z. Zhao,J.S. Zhang,G. Ahmed,A.J. Khan,H.X. Zeng,H.Y. Yu,X.C. Zhong,Z.W. Liu,G.Q. Zhang 한국물리학회 2019 Current Applied Physics Vol.19 No.6

To improve the performance/cost ratio of NdFeB based permanent magnets, Ce or/and La substitutions for Nd have been suggested. To better understand the effects of these substitutions, the fundamental behavior of (Ce,La)-Fe-B alloys has to be clearly understood. Here, we reported a systematic investigation on the phase structure, microstructure, and magnetic properties of melt-spun (Ce,La)2Fe14B alloys. The results confirm that partial substitution of Ce by La can effectively enhance the hard magnetism and thermal stability of (Ce1- xLax)2Fe14B alloys, while over 80% La substitution leads to the decomposition of 2:14:1 phase. The lattice parameters a, c and the Curie temperature Tc of 2:14:1 phase increase linearly with the increasing La content. La substitution can effectively refine the grain, resulting in the enhancement of inter-grain exchange coupling. The (Ce0.7La0.3)2Fe14B alloy with a mean grain size of 25 nm exhibits high remanence, maximum energy product and intrinsic coercivity up to 0.69 T, 6.2 MGOe and 217 kA/m, respectively. The present work provides a good understanding on the melt-spun (Ce,La)-Fe-B system for further developing low cost rare earth permanent magnets.

Influence of rare earth elements on porosity controlled synthesis of MnO₂ nanostructures for supercapacitor applications

Rajagopal, Rajesh,Ryu, Kwang-Sun Pergamon Press 2018 Electrochimica Acta Vol. No.

<P><B>Abstract</B></P> <P>Nanostructured MnO<SUB>2</SUB> was synthesized using a facile hydrothermal technique with potassium permanganate as a precursor. Rare earth elements, lanthanum and cerium, were used to control the porosity of the MnO<SUB>2</SUB> nanostructures. Nanorod-, nanoflower-, nanoneedle-, and nanoneedles/nanopetal-shaped MnO<SUB>2</SUB> nanostructures were synthesized by changing the concentration of the rare earth elements. The as-synthesized MnO<SUB>2</SUB> nanorods, La – MnO<SUB>2</SUB> nanoneedles, Ce – MnO<SUB>2</SUB> nanoflowers, and La/Ce – MnO<SUB>2</SUB> nanoneedles/nanopetals were examined using a range of physico chemical characterization techniques. Scanning electron microscopy and transmission electron microscopy – energy dispersive X-ray spectroscopy confirmed the morphology of the MnO<SUB>2</SUB> nanostructures and the elemental distribution. The porous natures of the synthesized MnO<SUB>2</SUB> nanostructures were analyzed by nitrogen adsorption technique. The electrochemical behavior of the MnO<SUB>2</SUB> nanostructures was examined by cyclic voltammetry, charge – discharge and electrochemical impedance spectroscopy tests. The La/Ce – MnO<SUB>2</SUB> nanoneedles/nanopetals electrode exhibited a high specific capacitance of 825 F g<SUP>−1</SUP> at an applied current density of 10 A g<SUP>−1</SUP>. The La/Ce – MnO<SUB>2</SUB> nanoneedles/nanopetals were also mixed with 5, 10, 15 and 20 wt% of rGO nanosheets to enhance the electrochemical behavior. The 20 rGO@La/Ce – MnO<SUB>2</SUB> sample showed extraordinary electrochemical behavior; the calculated specific capacitance was 1165 F g<SUP>−1</SUP> at an applied current density of 10 A g<SUP>−1</SUP>. A 20 rGO@La/Ce – MnO<SUB>2</SUB> and activated carbon asymmetric supercapacitor coin cell device exhibited ∼93% capacitance retention after 1000 cycles. These results highlight the potential of 20 rGO@La/Ce – MnO<SUB>2</SUB> as an electrode material for supercapacitor applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Manganese oxide nanostructures were synthesized by hydrothermal process. </LI> <LI> Lanthanum and cerium used to control the porosity of manganese oxide. </LI> <LI> La/Ce mixed MnO<SUB>2</SUB> nanoneedles/nanopetals showing good electrochemical behavior. </LI> <LI> rGO mixed La/Ce – MnO<SUB>2</SUB> was prepared to improve the storage capacity. </LI> <LI> 20rGO@ La/Ce – MnO<SUB>2</SUB> electrode exhibited high specific capacitance of 1165 F g<SUP>−1</SUP>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

프랑수아 모리악과 몸의 문제

김모세(Mose KIM) 프랑스학회 2018 프랑스학연구 Vol.0 No.85

Cette étude a pour but d’analyser la corporéité dans les oeuvres littéraires de François Mauriac, l un des romanciers chrétiens les plus éminents de la France du XXe siècle. La vision mauriacienne sur le corps a subi un certain nombre de changements. Il avait une perception largement négative de la corporéité au début de sa carrière littéraire. En fait, durant cette période, il a même déclaré que “le christianisme n a rien à voir avec le corps; plutôt, le christianisme le supprime”. Mauriac croyait que la pensée chrétienne est incompatible avec le corps car il représente la nature sensuelle du désir. Ce sont les caractéristiques narcissiques et égocentriques du corps qui lui ont donné une impression négative. Le corps est aussi un moyen d exprimer la volonté de puissance. Mauriac est ensuite passé à la deuxième étape, où il a commencé à adoucir sa vision négative du corps. Un certain moment de révélation lui a fait adopter une position plus inclusive sur le corps. Mauriac a commencé à explorer attentivement l harmonie possible entre la grâce et le corps. Il met davantage l accent sur l émotion que sur la raison comme moyen d embrasser la grâce. Mauriac en vint à croire qu il serait plus approprié que la doctrine chrétienne fixe une limite appropriée au désir et à l usage du corps plutôt que de l écarter complètement comme tabou. La troisième étape de la perspective mauriacienne de la corporéité est marquée par son effort pour placer le corps au centre de sa pensée chrétienne. La pensée chrétienne est centrée sur le sacrifice - par-dessus tout, le sacrifice du corps. Le christianisme est essentiellement l histoire de l’Être absolu qui s est incarné dans la chair humaine et a sacrifié son propre corps pour sauver les hommes. Cette perspective se traduit par des personnages qui se sacrifient pour des autres. Les êtres altruistes, par souci de l autre, sont sensibles à la souffrance des autres et portent le fardeau de sacrifier leur propre corps comme moyen de substituer la souffrance de l autre.

Electrode properties of porous La2NiO4+δ layers screen-printed on a Ce0.8Sm0.2O2-δ electrolyte

Qing Xu,Bok-Hee Kim,Kai Zhao,Duan-Ping Huang,Min Chen,Hong Wang 한양대학교 세라믹연구소 2009 Journal of Ceramic Processing Research Vol.10 No.2

A La2NiO4+δ/Ce0.8Sm0.2O2-δ/La2NiO4+δ symmetrical cell was prepared using a screen-printing method by sintering at 1100℃. The electrochemical properties of the cell were examined by the impedance spectroscopy technique under zero dc bias in air between 500-700℃. The La2NiO4+δ electrodes displayed satisfactory chemical and thermodynamic compatibilities with the Ce0.8Sm0.2O2-δ electrolyte. A comparatively low area specific resistance of 0.18 Ω cm2 at 700℃ was determined for the La2NiO4+δ electrodes. Scanning electron microscope (SEM) observation revealed that the La2NiO4+δ electrodes showed a reasonable porosity, a well-necked connection among fine grains and a tight adhesion to the electrolyte support. The desired microstructure is regarded to be responsible for the superior electrode properties of the La2NiO4+δ layers. A La2NiO4+δ/Ce0.8Sm0.2O2-δ/La2NiO4+δ symmetrical cell was prepared using a screen-printing method by sintering at 1100℃. The electrochemical properties of the cell were examined by the impedance spectroscopy technique under zero dc bias in air between 500-700℃. The La2NiO4+δ electrodes displayed satisfactory chemical and thermodynamic compatibilities with the Ce0.8Sm0.2O2-δ electrolyte. A comparatively low area specific resistance of 0.18 Ω cm2 at 700℃ was determined for the La2NiO4+δ electrodes. Scanning electron microscope (SEM) observation revealed that the La2NiO4+δ electrodes showed a reasonable porosity, a well-necked connection among fine grains and a tight adhesion to the electrolyte support. The desired microstructure is regarded to be responsible for the superior electrode properties of the La2NiO4+δ layers.

paṃsukūlaについて

青野道彦 불교학연구회 2016 불교학연구 Vol.46 No.-

초기 불교의 출가유행자들은 “분소의(糞掃衣)”라는 초라한 옷을 입고 있었다고 한다. 본 논문은 그 원어의 하나인 빨리어 paṃsukūla의 의미를 빨리율을 중심으로 한 빨리문헌의 관련 용례를 조사함으로써 고찰한다. paṃsukūla는 아베지온 (阿部慈園) 에 따르면 “오물 또는 쓰레기나 먼지처럼 불필요하고 가치없는 곳곳에 버려진 천 조각을 기어서 만든 옷”이라고 한다. 또한 J. Dantinne에 따르면 “쓰레기 더미, 길거리, 묘지에서 찾은 버려진 천 조각으로 만든 옷”이라고한다. 여기에서 볼 수 있는 것처럼 paṃsukūla는 일반적으로 “불필요한 천 조각으로 만든 옷” 으로 이해되는 경우가 많다. 그런데 paṃsukūla와 그 파생어인 paṃsukūlika의 용례를 살펴보면 이러한 일반적인 이해는 충분하지 않다. paṃsukūla는 “불필요한 천 조각으로 만든 옷”이 아니라 그소재인 “불필요한 천 조각”의 의미로 사용되는 경우가 있기 때문이다. 또한 paṃsukūla는 옷뿐만 아니라 다양한 것을 가리켜 사용되기 때문에, 원래의 의미를 감안하여 “주인없는 버려진 것”이라는 뜻으로 이해하는 것이 더 적절한 경우가 있기 때문이다. 본 논문은 이러한 paṃsukūla의 의미를 설명하기 위해 paṃsukūla와 paṃsukūlika의 용례를 빨리문헌에서 인용하고 제시한다. This paper examines the meaning of the term paṃsukūla as found in the Theravāda Tipiṭaka, especially the Vinayapiṭaka. It is thought that the early Buddhist monks wore paṃsukūla, described by Jion Abe as a “robe made of rags which were discarded here and there as useless and worthless things like filth.” This description is commonly accepted in foreign countries as well as in Japan. Jean Dantinne views it as “un vêtement fait de haillons, trouvés sur un tas d’ordures, en rue, dans un cimetière,” while Reginald A. Ray calls them/it “clothes made from cast-off rags.” The popular definition of paṃsukūla in the Theravāda Tipiṭaka, is accurate in many cases, but the term does not always mean “robe made of rags.” It can also mean “refuse rags,” which are materials of robe. In addition, it is used to describe an ownerless “lump of refuse” or “heap of waste,” which is an original meaning of the term. This article provides examples of paṃsukūla and its derivative, paṃsukūlika, from the Theragāthā and the Vinayapiṭaka to validate the meanings described above.

$Ce_{0.8}Gd_{0.2}O_{1.9}$ 전해질에서 $La_{0.5}Sr_{0.5}MnO_{3-\delta}$ 양극의 과전압특성

윤희성,노의범,김병호 한국세라믹학회 1998 한국세라믹학회지 Vol.35 No.9

$La_{0.5}Sr_{0.5}MnO_{3-\delta}$ as air electrode for soild oxide fuel cell was synthesized by a citrate process and its cathodic polarization was determinated by the current interruption method on the Gd-doped ceria as electrolyte. The addition of citric acid increased the exothermic heat for the formation of $La_{0.5}Sr_{0.5}MnO_{3-\delta}$ perovskite oxide. The degree of the initial particle agglomeration was affected by the exothermic heat. Also the increase of cal-cination temperature enlarged the particle size and the higher sintering temperature accelerated the den-sification of $La_{0.5}Sr_{0.5}MnO_{3-\delta}$ layer after its being painted on $Ce_{0.8}Gd_{0.2}O_{1.9}$ electrolyte. In this study $La_{0.5}Sr_{0.5}MnO_{3-\delta}$ synthesized by citrate process of which the molar ratio of citric acid to metal nitrate was 2 calcined at $650^{\circ}C$ for 2hr and sintered at 1100 at $1200^{\circ}C$ for 4 hrs after slurry coating on Ce0.8Gd0.2O1.9 electrlyte showed the lowest cathodic polarization.

(La0.7-xCex)Sr0.3MnO3 세라믹스의 구조적, 전기적 특성

인태연,임정은,박병준,이삼행,이명규,박주석,이성갑 한국전기전자재료학회 2023 전기전자재료학회논문지 Vol.36 No.3

La0.7-xCexSr0.3MnO3 specimens were fabricated by a solid state reaction method and structural and electrical properties with variation of Ce4+ contents were measured. All specimens exhibited a polycrystalline rhombohedral crystal structure, and the (110) peaks were shifted to low angle side with increasing the amount of Ce4+ contents. As Ce4+ ions with different ion radii and charges are substituted with La3+ ions, electrical properties are thought to be affected by changes in the double exchange interaction between Mn3+-Mn4+ ions due to distortion of the unit lattice, a decrease in oxygen vacancy concentration, and an increase in lattice defects. Resistivity gradually decrease as the amount of Ce4+ added increased, and negative temperature coefficient of resistance (NTCR) properties were shown in all specimens. In the La0.5Ce0.2Sr0.3MnO3 specimens, electrical resistivity, TCR and B-value were 31.8 Ω-cm, 0.55%/℃ and 605 K, respectively.

Ni-coated La2Ce2O7/SiC Membrane via DC Magnetron Sputtering

송다회,정미원 대한화학회 2016 Bulletin of the Korean Chemical Society Vol.37 No.6

La2Ce2O7 powder was synthesized through hydrolysis and polycondensation processes. A La2Ce2O7 /SiC composite membrane was fabricated using SiC and La2Ce2O7 powder with phenolic resin. For surface modification, Ni metal was coated onto the membrane via DC magnetron sputtering. The membranes were characterized by X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), and pore size distribution analyses. Hydrogen and CO gas permeation experiments were performed through the use of Sievert's type equipment. Both fluxes decreased with increasing temperature and followed the Knudsen and surface diffusion mechanisms. The hydrogen permeability of the membrane was determined as 1.17 × 10−5 mol/m2sPa with a permselectivity (H2 /CO) of 2.30 at 303 K.

Influencing factors on low-temperature deNOx performance of Mn–La–Ce–Ni–Ox/PPS catalytic filters applied for cement kiln

She-Min Zhu,Da-Hai Zheng,Yuesong Shen,Yun-Shun Qiu,Bing Li,Yan-Wei Zeng,Shubao Shen,Shemin Zhu 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.24 No.-

Effects of catalyst loading amount, reaction temperature, O2 concentration, NH3/NO molar ratio and SO2 on low-temperature catalytic performance of the Mn–La–Ce–Ni–Ox (Mn/La/Ce/Ni = 2.5:2.5:1:1 in mol)/ PPS for NH3-SCR of NO were mainly studied. Results showed that the filter with catalyst loading amount of 250 g/m2 obtained more than 95% NO removal efficiency at 200 8C under filtration velocity of 1 m/min. The NO removal efficiency was still above 85% by injecting 300 ppm SO2 at 200 8C. Anyway, the Mn–La– Ce–Ni–Ox/PPS catalytic filter is promising to achieve the expectation of simultaneous removing particulate and NOx from low-sulfur flue gas in cement kiln.