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ผศ.ดร.กิจจา จิตรภิรมย์
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Category Archives: วิทยาศาสตร์สุขภาพ สาธารณสุขศาสตร์ และอาชีวอนามัย และความปลอดภัย
การฟื้นฟูตัวเร่งปฏิกิริยาซีโอไลต์จากกระบวนการย่อยสลาย PMMA ด้วยแก๊สโอโซน
อ.สุภาภรณ์ คางคำ
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Regeneration of Coked Zeolite from PMMA Cracking Process by Ozonation
อ.สุภาภรณ์ คางคำ
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Contents lists available at SciVerse ScienceDirect Applied Catalysis B: Environmental jo ur nal home p ag e: www.elsevier.com/locate/apcatb |
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| Regeneration of coked zeolite from PMMA cracking process by ozonation |  |
Supaporn Khangkhama,c, Carine Julcour-Lebiguea,b,∗, Somsak Damronglerdc,
Chawalit Ngamcharussrivichaic, Marie-Hélène Maneroa, Henri Delmasa
a Université de Toulouse, Laboratoire de Génie Chimique, 4 allée Emile Monso – BP 84234, 31030 Toulouse Cedex 4, France
b CNRS, Laboratoire de Génie Chimique, 31030 Toulouse, France
c Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| A R T I C L E I N F O
Article history: Keywords: |
A B S T A C T
Regeneration of coked ZSM-5 zeolite was performed by oxidation with ozone at low temperature range (<150 ◦C) so that to restore catalytic activity. Physicochemical properties of the samples were characterized by several techniques: thermogravimetry (nature of coke deposit), elemental analysis (carbon content), porosimetry (surface area and pore size), ammonia temperature-programmed desorption and pyridine adsorption followed by infrared spectroscopy (acidity). Reactions were carried out at various temperatures, gas hourly space velocities and inlet concentrations of ozone. They showed that partially coked samples (containing 3 wt.% of C) can be successfully regenerated by ozone with carbon removal up to 80%. Carbon removal is improved by increasing the inlet ozone concentration in the range 16–50 g/m3, with almost linear trend, and by increasing time on stream until it plateaus after 2 h. Coke oxidation with O3 starts at low temperature and exhibits an optimum at about 100 ◦C. At higher temperatures, the rate of ozone decomposition becomes much faster than its pore diffusion rate, so that radical species are no longer available for the coke deposit within the particles and the overall oxidation yield decreases. Indeed, catalytic decomposition of ozone is found to occur significantly above 100 ◦C: O3 decomposition reaches 90% with fresh ZSM-5 catalyst. Thus regeneration of coked zeolite particles involves both complex chemical reactions (coke oxidation and O3 decomposition to active but unstable species) and transport processes (pore diffusion to the internal coked surface). © 2013 Elsevier B.V. All rights reserved. |
| 1. Introduction
Zeolites are used in many industrial and petrochemical processes because of their unique properties of molecular sieving, acidity, high thermal stability, and shape selectivity [1]. For example, FAU-type zeolite, e.g. Y and Ultrastable Y zeolite, is extensively applied as catalyst in fluid catalytic cracking (FCC). In this process, MFI-type zeolite, e.g. ZSM-5, is frequently used as FCC catalyst additive either in the form of separate particles or within a composite to control product yield and/or to improve octane number [2]. Moreover, zeolites, and ZSM-5 in particular, are also applied
|
in recycling of plastic wastes to provide more valuable products: monomer and/or gas and liquid which can be reutilized as chemical reagents or fuels [3,4]. Previous results showed that MMA recovery by cracking of PMMA was successfully achieved on a zeolite fixed bed at temperatures below 300 ◦C [5]. Such temperature is of significant advantage as compared to conventional thermal processes (400–450 ◦C), as proposed by Kaminsky et al. [6–8] using fluidized bed reactors or more recently by Lopez et al. [9] using a spouted bed reactor.
Even if zeolite catalysts produce less coke than other materials, it is still a common feature which requires efficient and low-cost regeneration techniques for the process economy. Deposition of carbonaceous residues blocks the access of pores to the reacting molecules and/or poisons active acid catalytic sites [10–15]. Besides the loss of activity and/or selectivity, coking can also reduce heat transfer in the reactor, while increasing pressure drop and possibly even plugging the reactor. |
Effect of AG2O Doping on some Physical Properties Y145 Superconductor
รัตนสุดา สุภคนัยสร
Theerathawan Panklang 1, a *, Rattanasuda Supadanaison 1, b, Chalit Wanichayanan 1, c, Adullawich Kaewkao 2, d, Tunyanop Nilkamjon2, e,
Pongkaew Udomsamuthirun2, f, Somporn Tiyasri3, g, Wirat Wongphakdee3, h, Thitipong Kruaehong4, i, Piyamas Chainok5, j“
1Bansomdejchaopraya Rajabhat University, 1061 Soi Itsaraphap 15, Hiranruchi, Thon Buri, Bangkok 10600, Thailand
2Prasarnmit Physics Research Unit, Department of Physics, Faculty of Science, Srinakharinwirot University, Bangkok 10110, Thailand
3Department of Chemistry, Faculty of Science, Srinakharinwirot University, Bangkok 10110, Thailand
4Department of Physics, Faculty of Science and Technology, Suratthani Rajabhat University, Surat Thani 84100, Thailand
5Department of General Education, Faculty of Science and Technology, Pathumwan Institute of Technology, Bangkok 10330, Thailand
a[email protected], b[email protected], c[email protected], d[email protected], e[email protected], f[email protected] g[email protected], h[email protected], i[email protected], j[email protected]
Keywords : Y145 Superconductor, Solid state reaction, Silver-doped.
Abstract. In this paper, the Y145 superconductor doped Ag2O were synthesized by solid state reaction. The calcinations and sintering temperature were at 920 0C and annealing temperature was at 550 0C. The highest critical temperature was in Y145+0.1Ag sample with Tc onset at 96 K and the lowest was found in pure Y145 at 95 K. We found that the surface of Y145 superconductor was improved by Ag adding on the porous structure.
Introduction
The Y123 (YBa2Cu3O7-x) is the first superconductor having critical temperature higher than the boiling point of liquid nitrogen that was synthesized by Chu and coworkers [1] in 1987. After this discovery, the YBaCuO superconductor has spurred a lot of interest by scientist all around the world because of the low cost of using that make it easier for applied in various areas. There are two importance properties of superconductor in superconductivity state i.e. zero resistance and magnetic levitation that can be used for the supermagnet and high speed train etc.”
The critical temperature (Tc) of this high temperature superconductor sensitively depends on both the holes concentration in the CuO2 planes and the relative concentration of the oxygen within the planes [2]. After that the various elements are added in YBaCuO system for the proposal to increasing the critical temperature (Tc) and critical current density (Jc) that can be applied in [3-5]. To improve the electrical properties of superconductor, Ag is one of the candidates because it can be filled in the intergranular space that can enhance the critical current density without changing the critical temperature [6, 7].
Shao et al. [8] prepared the Y123 superconductor by using Y2O3, BaCO3, CuO as starting materials. The Ag, Ag2O, AgNO3 were added into Y123 power to investigate the effect of Ag on Y123 superconductor. They found that the Ag-doping does not cause any district microstructure change of Y123 superconductor that Ag located at the pores contributes to strengthening and improving the critical current density of material. Rani, Jha and Awana [9] prepared Y123 and reported the effect of Ag addition on superconducting performance of Y123 superconductor. The powder of Y2O3, BaCO3, CuO and Ag2O was used as the starting materials. The calcination at 870°C, 890°C, and 910°C with sintering temperature at 920°C were done. They found that the grain size is increase with Ag doping until the maximum value then decrease. Recently, the new formula of YBaCuO superconductor were synthesized as Y5-6-11, Y7-9-16,Y358, Y5-8-13, Y7-11-18, Y156, Y3-8-11, and Y13-20-23, where the numbers indicate Y, Ba, and Cu atoms respectively [10, 11]. After this, Chainok et.al [12] studied the YBaCuO superconductors having one Yttium atom that Y123 (YBa2Cu3O7-y), Y134 (YBa3Cu4O9-y), Y145 (YBa4Cu5O11-y) and Y156 (YBa5Cu6O13-y). The sintering temperature at 950oC and 980oC were used for synthesized their samples. The critical temperature in range 88-94°C was found. Chainok et.al [13] synthesized and characterized the physical properties of YBa2Cu3Ox (Y123) and YBa4Cu5Ox (Y145) superconductors by solid state reaction and melt process. They found that the critical temperature onset of Y145 is 94 K and 96 K for solid state reaction and melt process, respectively. The peritectic temperature of Y145 is 1018°C.
There are four formula of YBaCuO that having one Yttium atom in unit cell i.e. Y123, Y134, Y145 and Y156 proposed by Chainok et al. [13]. The Y123 superconductor has been investigated completely. We use the data from Y123 to be our guideline. There was little data from Y145 then we interested in Y145 superconductor. We synthesized Y134 superconductor doped Ag2O by solid state reaction and investigated the effect of Ag2O addition on the critical temperature of Y134 superconductor.
Experimental Details
We synthesized the YBa4Cu5AgxO9-δ (x = 0, 0.05, 0.10) by standard solid state reaction method with the appropriate amount of 0Y2O3, CuO, Ag2O and BaCO3. After mixed and ground with mortar and pestle, the powder was kept in alumina crucible and heated at 9200C for the calcination process. Although the peritectic temperature of Y145 superconductor is about 1080°C but the melting point of silver oxide is about 280°C. However, the research of Rani, Jha and Awana [9] studied the effect of silver on Y123 superconductor by using Ag2O addition with the calcination temperature at 870°C, 890°C, and 910°C and sintering temperature at 920°C. They also found some effect of silver on Y123 superconductor. Then we used the calcination and sintering temperature at 920°C. After calcinations the materials was ground to enhance chemical homogeneity. The homogeneous powder was pressed to form of pellets before sintering. These pellets sintered in air at 920°C and the final annealing at 550°C was done. The surface morphology of as samples obtained had been investigated by scanning electron microscope (JSM-5600). The electrical resistivity has been measured by standard four probe method.
Fig. 1. Shown the normalized resistivity versus temperature of Y145 and Y145 with Ag-doped superconductors
Results and Discussion
The resistivity measurement depending on temperature of our samples obtained was conducted with four-point probe technique in range 78-120 K as shown in Fig. 1. And the summation of Tc onset and Tc offset were shown in Table 1. Here, the Tc onset temperature was taken as the temperature at which the tangent of the resistivity versus temperature curve intersects with the tangent of the part where resistivity dropped abruptly and Tc offset was defined as the temperature at which the resistivity readings reached zero.
The highest critical temperature was in Y145+0.1Ag sample with Tc onset at 96 K and the lowest was found in pure Y145 at 95 K. Our critical temperature found was in the same range of YBaCuO superconductor [10-13]. Here, Chainok et.al [13] found the critical temperature onset of Y145 superconductors at 94 K and 96 K prepared by solid state reaction and melt process.
Fig. 2. The SEM images of Y145 and Y145 doped silver.
From Fig. 2, we found that the surface of Y145 superconductor was improved by Ag adding on the porous structure.
Conclusions
The Y145 superconductor doped Ag2O were synthesized by solid state reaction. The calcinations and sintering temperature were at 920°C and annealing temperature was at 550°C. The highest critical temperature was in Y145+0.1Ag sample with Tc onset at 96 K and the lowest was found in pure Y145 at 95 K. We found that the surface of Y145 superconductor was improved by Ag adding on the porous structure.
Reference
[1] K. Wu, J. R. Ashburn, C. J. Torng, P. H. Hor, R. L. Meng, L. Gao, Z. J. Huang, Y. Q. Wang, C. W. Chu, Effect of compaction on the superconducting transition of YBa2Cu3O9-y compound, Phy. Rev. Lett. 58 (1987) 908.
[2] M. Karppinen, H. Yamauchi, Hole-doping routes for understanding the relationship between atomic arrangements and superconductivity properties in multi-layered copper oxides, J. Inorg. Mater. 2(6) (2000) 589-599.
[3] K. Salama, V. Selvamanickan, L. Gao, K. Sun, High current density in bulk YBa2Cu3Ox superconductor, Appl. Phys. Lett. 54 (1989) 2352.
[4] S. Ravi, V. Seshu Bai, ac-susceptibility study of the 110-K superconducting phase of Bi-Sr-Ca-Cu-O, Phys. Rev. B. 49(18) (1994) 13082.
[5] D. X. Chen, R. B. Goldfarb, J. Nogues, K. V. Rao, Magnetic susceptibility of sintered and powdered Y‐Ba‐Cu‐O, J. Appl. Phys. 63 (1988) 980.
[6] T. Nishio, T. Y. Itoh, Y. F. Ogasawara, M. Suganuma, Y. Yamada, U. Mizutani, Superconducting and mechanical properties of YBCO-Ag composite superconductors, J. Mater. Sci. 24, (1989) 3228-3234
[7] A. P. Li, Q. N. Ni, Q. P. Kong, Mechanical properties of Ag-doped YBa2Cu3O7−y superconductors, Phys. Status Solidi a 27 (1991) 187-193.
[8] B. Shao, A. Liu, Y. Zhou, J. Zhang, J. Wang, Effect of Ag-doping on critical current densities in high Tc superconducting materials of YBa2Cu3O7-x, Mat. Res. Bull. 24(11) (1989) 1369-1373.
[9] P. Rani, R. Jha, V. P. S Awana, AC Susceptibility Study of Superconducting YBa2Cu3O7: Agx Bulk Composites (x = 0.0–0.20): The Role of Intra and Intergranular Coupling, J. Supercond. Nov. Magn. 26 (2013) 2347–2352.
[10] P. Udomsamuthirun et al. The new superconductors of YBaCuO materials, J. Supercond. Nov. Magn. 23 (2010) 1377-1380.
[11] A. Aliabadi et al. A new Y-based HTSC with Tc above 100 K, Physica. C. 469(22) (2009) 2012-2014.
[12] P. Chainok, T. Khuntak, S. Sujinnapram, S. Tiyasri, W. Wongphakdee, T. Kruaehong, T. Nilkamjon, S. Ratreng, P. Udomsamuthirun, Some properties of YBam Cu 1+m Oy (m = 2, 3, 4, 5) superconductors, Int. J. Mod. Phys. B 29(9) (2015) 1550060.
[13] P. Chainok, S. Sujinnapram, T. Nilkamjon, S. Ratreng, K. Kritcharoen, P. Butsingkorn, P. Ruttanaraksa, P. Udomsamuthirun, The preparation and characterization of Y145 superconductor, Adv. Mat. Res. 770 (2013) 295-298.
การแตกสลายเชิงเร่งปฏิกิริยาของพอลิเมทิลเมทาคริเลตด้วยตัวเร่งปฏิกิริยาซีโอไลต์
สุภาภรณ์ คางคำ
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Investigate Effect of Ag2O Adding on Y134 Superconductor
Napaporn Sripawatakul1,a* , Rattanasuda Supadanaison2,b,
Theerathawan Panklang2,c, Chalit Wanichayanan2,d, Adullawich Kaewkao1,e,
Tunyanop Nilkamjon1,f Piyamas Chainok5,i, Somporn Tiyasri3,j,
Wirat Wongphakdee3,g, Thitipong Kruaehong4,h,
Pongkaew Udomsamuthirun1,j
1Prasarnmit Physics Research Unit, Department of Physics, Faculty of Science, Srinakharinwirot University, Bangkok 10110, Thailand.
2Bansomdejchaopraya Rajabhat University 1061 Soi Itsaraphap 15, Hiranruchi, Thon Buri, Bangkok 10600, Thailand.
3Department of Chemistry, Faculty of Science, Srinakharinwirot University,Bangkok 10110, Thailand.
4Department of Physics, Faculty of Science and Technology, Suratthani Rajabhat University,Surat Thani 84100, Thailand.
5Department of General Education, Faculty of Science and Technology,Pathumwan Institute of Technology, Bangkok 10330, Thailand.
[email protected], [email protected], [email protected],
[email protected], [email protected], [email protected], [email protected],
[email protected], [email protected], [email protected],
Keywords: Y134 superconductor, Solid state reaction, Critical temperature
Abstract. In this paper, we synthesized Y134 superconductor doped Ag2O by solid state reactionand investigated the effect of Ag2O addition on the critical temperature of Y134 superconductor and SEM micrographs shown Y134 doped Ag2O has rather smooth and small pores feature. The maximum critical temperature found at an optimal doping, 0.1 Ag, with Tc onset =97 K.
Introduction
Since the discovery of high temperature superconductors of Bednorz and Muller [1] in 1986 and the discovery of Y123 (YBa2Cu3O7-x) by Chu and coworkers [2] in 1987, increasing critical temperature and current of superconductors has been the aim of intensive research. The critical temperature above liquid nitrogen boiling point of these materials means that YBaCuO compounds can exhibit a high critical temperature enough for application in various areas. The critical temperature (Tc) of this high temperature superconductor sensitively depends on both the hole concentration in the CuO2 planes and the relative concentration of the oxygen within the planes [3]. After the discovery of Y123 (YBa2Cu3O7-x), various elements are added in YBaCuO system for increasing the critical temperature (Tc) and critical current density (Jc) [4-6]. Numerous studied have shown that Ag-doping of Y123 superconductor caused in improved superconducting properties [7-11]. As Ag fills the intergranular spaces, it improves the electrical properties of samples, enhancing the critical current density without changing the critical temperature [12]. In the studies of Ag admixing has been reported to result in enhancement of the critical current density in cuprate superconductors [13-15]. Shao et al. [16] prepared the YBa2Cu3O7-x by using Y2O3, BaCO3, CuO in the appropriate amounts. Then the Ag, Ag2O, AgNO3 were added into Y123 power separately. The sintering temperature of 830 – 930 °C were used to form the bulk samples. They found that the Ag-doping does not cause any district microstructure change of Y123 superconductor. Ag dopants located at the pores contributes to strengthening and improving the critical current density of material. Zheng et al. [17] study the Y124 superconductor and the effectof Ag2O addition prepared by solid-state reaction method. The Y2O3, CaCO3, Ba(NO3)2, CuI and Ag2O were mixed and heated at 815 °C. The obtained samples had a remarkable increase in critical current density by optimum silver addition. Reduction of porosity in the Y124 superconductor was found to be the origin of critical current density enhancement. Rani, Jha and Awana [18] reported the effect of Ag addition on the superconducting performance of Y123 superconductor prepared by solid-state reaction. The powder of Y2O3, BaCO3, CuO and Ag2O was used as the starting materials. The calcination at 870 °C, 890 °C, and 910 °C with sintering temperature at 920 °C were done. Ag-added Y123 superconductor showed the optimum intergranular coupling that the grain size is found to increase with Ag doping until the maximum value then decrease. Azambuja et al. [19] prepared the Y123 dope Ag by conventional solid-state reaction with Y2O3, BaCO3, CuO, Ag2O and metallic Ag as beginning materials. They were calcinated in air at 870 °C, 900 °C, 920 °C and the sintered temperature at 920 °C. The sample were heated in flowing oxygen at 420 °C. Their results revealed that Ag doping does not modify expressively the value of critical temperature. Ag is incorporated in the intergrain regions providing a better grain coupling. Another way to higher performance parameters of High-Tc superconductor are to find the new formula that can achieve our aim. The new formula of this group are Y5-6-11, Y7-9-16, Y358, Y5-8-13, Y7-11-18, Y156, Y3-8-11, and Y13-20-23, where the numbers indicate Y, Ba, and Cu atoms respectively [20, 21]. Chainok et.al [22] studied the YBaCuO superconductors having one Yttrium atom that Y123 (YBa2Cu3O7-y), Y134 (YBa3Cu4O9-y), Y145 (YBa4Cu5O 11-y) and Y156 (YBa5Cu6O13-y). The sintering temperature at 950 °C and 980 °C were used for synthesized their samples. The critical temperature in range 88 – 94 °C were found.
In this paper, we interested in Y134 superconductor that proposed by Chainok et.al [22] because this formula having the amount of element nearby the Y123. We synthesized Y134 superconductor doped Ag2O by solid state reaction and investigated the effect of Ag2O addition on the critical temperature.
Experimental Details
Series samples of YBa3Cu4AgxO9-δ (where x = 0, 0.05, 0.10, 0.15), the precursor powders were mixed according to chemical formula that pure sample Y: Ba: Cu as 1:3:4 and for doping samples Y: Ba: Cu: Ag as 1:3:4:0.05, 1:3:4:0.10, 1:3:4:0.15. Samples were synthesized by standard solid state reaction method. The appropriate ratio of the constituent oxides and carbonate i.e. Y2O3, CuO, Ag2O and BaCO3 were mixed and ground by mortar and pestle. After regrinding and mixing, the powder was kept in an alumina crucible and heated at 950 0C for the calcination process. After calcinations the material was ground to enhance chemical homogeneity. The homogeneous powder was pressed to form of pellets before sintering. These pellets sintered in air at 950 °C and the final annealing at 500 0C was done. The surface morphology of as synthesized materials has been carried out by a Joel scanning electron microscope (JSM-5600). The electrical resistivity have been measured by standard four point probe method. Results and Discussions After preparation process was done, we took all samples for SEM, resistance, and. In Fig. 1, the SEM images of Y134 superconductor were shown. We found that the large pores of Y134 without Ag2O doping were eliminated from the composites by the addition of Ag2O. Y134 doped Ag2O has rather smooth and small pores feature,
Fig. 1 Shown results from SEM observation on given samples.
The resistance measurement by four-point-probe technique of sample obtained were shown in
Fig. 2. The critical temperature onset and offset were read out from these data that were shown in
Table 1
Fig. 2 Shown the resistivity of pure Y134 and Y134 with Ag2O doping.
Table 1 The critical temperature of Y134 and Y134 doped Ag superconductor.
| sample | Tcoffset (K) | Tconset (K) | ΔTc |
| Y134 | 90 | 95 | 5 |
| Y134 +0.05Ag | 88 | 92 | 4 |
| Y134 +0.10Ag | 95 | 97 | 2 |
| Y134 +0.15Ag | 90 | 92 | 2 |
According to Table 1. We found that the highest critical temperature was in Y134+0.1 Ag sample with Tc onset at 97 K the lowest was found in Y134+0.15Ag and Y134+0.05Ag at 92 K. This result was present the maximum critical temperature found at an optimal doping, 0.1 Ag, with Tc onset =97 K. This result was consistent with the research of Li et al [12] and Plesch et al [15] that studied Ag doped superconductor, found that fills the intergranular space and improves the electrical properties of samples. So not only, adding Ag2O contributes to strengthening this Ag2O doping in appropriate volume will higher critical temperature.
Conclusions
We have prepared YBa3Cu4AgxO9-δ (Y134+xAg) where x = 0, 0.05, 0.10, 0.15 by solid state reaction and investigated the effect of Ag2O addition on the critical temperature 950 oC. The critical temperature onset of all sample were equal 95K, 92K, 97K, and 92K with x = 0, 0.05, 0.10, 0.15,respectively. The maximum critical temperature found at an optimal doping, 0.1 Ag, with Tc onset =97 K. SEM images of Y134 superconductor shown that the pores of Y134 without Ag2O doping were fill up by admix Ag2O in Y134. Additional, Ag2O doping in appropriate volume will higher critical temperature.
Acknowledgements
The author would like to express my sincere thank the Promotion of Science and Mathematics Talented Teacher (PSMT), the Institute for the Promotion of Teaching Science and Technology (IPST), Faculty of science Srinakharinwirot University.
Reference
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[2] M. K. Wu, J. R. Ashbum, C. J. Torng, P. H. Hor, R. L. Meng, L. Gao, Z. J. Huang, Y. Q. Wang, C. W. Chu, Superconductivity at 93 K in a New Mixed-Phase Y-Ba-Cu-O Compound System at Ambient Pressure, Phys. Rev. Lett. 58(9) (1987) 908-910.
[3] M. Karppinen, H. Yamauchi, Hole-doping routes for understanding the relationship between atomic arrangements and superconductivity properties in multi-layered copper oxides, J. Inorg. Mater. 2(6) (2000) 589-599.
[4] K. Salama, V. Selvamanickam, L. Gao, K. Sun, High current density in bulk YBa2Cu3Ox superconductor, Appl. Phys. Lett. 54 (1989) 2352-2354.
[5] S. Ravi, V. Seshu Bai, Ac-susceptibility study of the 110-K superconducting phase of Bi-Sr-Ca-Cu-O, Phys. Rev. B. 49(18) (1994) 13082-13088.
[6] D. X. Chen, R. B. Goldfarb, J. Nogues, K. V. Rao, Magnetic susceptibility of sintered and powdered Y-Ba-Cu-O, J. Appl. Phys. 63(3) (1988) 980-983.
[7] T. Nishio, Y. Itoh, F. Ogasawara, M. Suganuma, Y. Yamada, U. Mizutani, Superconducting and mechanical properties of YBCO/Ag composite superconductors, J. Mater. Sci. 24(9) (1989) 3228.
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[12] A. P. Li, Q. H. Ni, Q. P. Kong, Mechanical properties of Ag-doped YBa2Cu3O7−y superconductors, Phys. Status Solidi (a) 127(1) (1991) 187-193.
[13] Y. Zhao, C. H. Cheng, J. S. Wang, Roles of silver doping on joins and grain boundaries of melt-textured YBCO superconductor, Supercond. Sci. Technol. 18(2) (2005) S34.
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[16] B. Shao, A. Liu, Y. Z. Hou, J. Zhang, J. Wang, Effect of Ag-doping on critical current densities in high Tc superconducting materials of YBa2Cu3O7-x, Mat. Res. Bull. 24(11) (1989) 1369-1373.
[17] X. G. Zheng, H. Matsui, S. Tanaka, M. Suzuki, C. N. Xu, K. Shobu, Superconducting properties of silver-doped YBa2Cu4O8 and Y0.9Ca0.1Ba2Cu4O8, Mater. Res. Bull. 33(8) (1998) 1213- 1219.
[18] P. Rani, R. Jha, V. P. S. Awana, AC Susceptibility Study of Superconducting YBa2Cu3O7: Agx Bulk Composites (x = 0.0–0.20): The Role of Intra and Intergranular Coupling, J. Supercond. Nov. Magn. 26 (2013) 2347-2352.
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