The crystallization and properties of alloys with Fe partly substituted by Cr and Cu fully substituted by Au in Finemet

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Title: The crystallization and properties of alloys with Fe partly substituted by Cr and Cu fully substituted by Au in Finemet
Authors: N.Q. Hoa
N. Chau
S.-C. Yu
Keywords: nanocrystalline alloy
soft magnetic amorphous system
magnetocaloric effect
Issue Date: 2007
Publisher: ELSEVIER SCIENCE SA, PO BOX 564, 1001 LAUSANNE, SWITZERLAND
Citation: ISIKNOWLEDGE
Abstract: The structure, crystallization and magnetic properties of ribbons obtained by first making amorphous ribbons and then objecting them to a crystallization annealing have been published elsewhere by us previously. In the present work the soft magnetic ribbons Fe73.5-xCrxSi13.5B9Nb3Au1 (numbers indicate at.%, x = 1-5) are prepared by fast quenching on a single copper wheel. X-ray diffraction patterns show that the as-cast samples are amorphous. Differential scanning calorimetry analysis indicates that the crystallization temperature of the alpha-Fe(Si) phase is a little higher than that of pure Finemet. With the same annealing conditions, the crystallization volume fraction decreases with increasing Cr content substituted for Fe. Hysteresis loops of as-cast samples measured by Permagraph show that domain walls are pinned. After appropriate annealing, the ultrasoft magnetic properties of nanocomposite materials are established. The magnetic entropy change, vertical bar Delta S-m vertical bar, of studied samples has been determined, and a giant magnetocaloric effect is found. Our materials could be considered as promising magnetic refrigerants working at high temperatures (several hundreds degrees C). (c) 2006 Elsevier B.V. All rights reserved.
Description: MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING Volume: 449 Pages: 364-367 Published: MAR 25 2007 ; TNS07635
URI: http://repository.vnu.edu.vn/handle/VNU_123/31437
ISSN: 0921-5093
Appears in Collections: Bài báo của ĐHQGHN trong Web of Science

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The discovery of the colossal magnetocaloric effect in a series of amorphous ribbons based on Finemet

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Title: The discovery of the colossal magnetocaloric effect in a series of amorphous ribbons based on Finemet
Authors: N. Chau
N.D. The
N.Q. Hoa
Keywords: amorphous magnetic materials
magnetocaloric effect
nanocrystalline materials
Issue Date: 2007
Publisher: ELSEVIER SCIENCE SA, PO BOX 564, 1001 LAUSANNE, SWITZERLAND
Citation: ISIKNOWLEDGE
Abstract: A large number of amorphous ribbons based on Finemet have been prepared by rapid quenching on a single copper wheel with linear speed of v = 25-30 m/s. The ribbons are 20-25 mu m thick and 6-8 mm wide. All as-cast samples are amorphous. Two criteria producing the colossal magnetocaloric effect (CMCE) in magnetic materials working as magnetic refrigerants are high saturation magnetization and sharp ferromagnetic-paramagnetic phase transition. The Fe-based amorphous ribbons fit these cretia. Thermomagnetic curves as well as isothermal magnetization curves around the Curie temperature of all the studied samples have been determined. The results show that the magnetic entropy change, vertical bar Delta S-m vertical bar, belongs to a class of materials with CMCE and the vertical bar Delta S-m vertical bar(max) values have been obtained at a moderately low magnetic field change of 1.35 T, moreover vertical bar Delta S-m vertical bar(max) occurred at quite high temperature. (c) 2006 Elsevier B.V. All rights reserved.
Description: MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING Volume: 449 Pages: 360-363 Published: MAR 25 2007 ; TNS07634
URI: http://repository.vnu.edu.vn/handle/VNU_123/31436
ISSN: 0921-5093
Appears in Collections: Bài báo của ĐHQGHN trong Web of Science

Magnetic properties of half-metallic semi Heusler Co1-xCuxMnSb compounds

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Title: Magnetic properties of half-metallic semi Heusler Co1-xCuxMnSb compounds
Authors: N.P. Duong
L.T. Hung
T.D. Hien
Keywords: Co1-xCuxMnSb
Heusler alloys
half-metals
ferromagnets
localized electrons
itinerant electrons
Issue Date: 2007
Publisher: ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS
Citation: ISIKNOWLEDGE
Abstract: A study of the half-metallic character of the semi Hensler alloys Co1-xCuxMnSb (0 <= x <= 0.9) is presented. We investigated the saturation magnetization M-S at temperatures from 5 K to room temperature and the temperature dependence of the DC magnetic susceptibility y above Curie temperature T-C. The magnetic moments at 5 K, for most compositions are very close to the quantized value of 4 mu(B) for Mn3+ ion, the compound with 90% Co substituted by Cu is still ferromagnetic with M-S (5K) = 3.78 mu(B)/f.u. These results emphasize the role of Co atoms in maintaining the ferromagnetic order in the material. The Curie temperature is decreased from 476 K to about 300 K as the Cu content increases from 0% to 90%. Above T-C, the chi(-1) vs T curves follow very well the Curie-Weiss law. The effective moment mu(eff) and paramagnetic Curie temperature theta are derived. A comparison between the values of M-S at 5 K and mu(eff) shows a transition from localized to itinerant spin system in these compounds. (C) 2006 Elsevier B.V. All rights reserved.
Description: JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS Volume: 311 Issue: 2 Pages: 605-608 Published: APR 2007 ; TNS07633
URI: http://repository.vnu.edu.vn/handle/VNU_123/31435
ISSN: 1873-4766
0304-8853
Appears in Collections: Bài báo của ĐHQGHN trong Web of Science

Sulfurospirillum cavolei sp nov, a facultatively anaerobic sulfur-reducing bacterium isolated from an underground crude oil storage cavity

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Title: Sulfurospirillum cavolei sp nov, a facultatively anaerobic sulfur-reducing bacterium isolated from an underground crude oil storage cavity
Authors: Yumiko Kodama
Le Thu Ha
Kazuya Watanabe
Keywords: DEHALOSPIRILLUM-MULTIVORANS
GEN-NOV
STRAINS
Issue Date: 2007
Publisher: SOC GENERAL MICROBIOLOGY, MARLBOROUGH HOUSE, BASINGSTOKE RD, SPENCERS WOODS, READING RG7 1AG, BERKS, ENGLAND
Citation: ISIKNOWLEDGE
Abstract: A novel facultatively anaerobic sulfur-reducing bacterium, designated strain Phe91(T), was isolated from petroleum-contaminated groundwater in an underground crude oil storage cavity at Kuji in Iwate, Japan. Cells of strain Phe91(T) were slightly curved rods with single polar flagella. Optimum growth was observed at pH 7.0 and 30 degrees C, The novel strain utilized elemental sulfur, thiosulfate, sulfite, dithionite, arsenate, nitrate and DMSO as electron acceptors with lactate as an energy and carbon source, but nitrite was not utilized. Microaerophilic growth was also observed. Fumarate, pyruvate, lactate, malate, succinate, hydrogen (with acetate as a carbon source) and formate (with acetate) could serve as electron donors. Fumarate, pyruvate and malate were fermented. The DNA G + C content was 42.7 mol%. On the basis of 16S rRNA gene sequence phylogeny, strain Phe91(T) was affiliated with the genus Sulfurospirillum in the class Epsilonproteobacteria and was most closely related to Sulfurospirillum deleyianum (sequence similarity 97%). However, the DNA-DNA hybridization value between strain Phe91(T) and S. deleyianum was only 14 %. Based on the physiological and phylogenetic data, Phe91(T) should be classified as a representative of a novel species in the genus Suffurospirillum; the name Sulfurospirillum cavolei sp. nov. is proposed, with Phe91(T) (=JCM 13918(T) = DSM 18149(T)) as the type strain.
Description: INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY Volume: 57 Pages: 827-831 Part: 4 Published: APR 2007 ; TNS07632
URI: http://repository.vnu.edu.vn/handle/VNU_123/31434
ISSN: 1466-5026
Appears in Collections: Bài báo của ĐHQGHN trong Web of Science

Pollution sources and occurrences of selected persistent organic pollutants (POPs) in sediments of the Mekong River delta, South Vietnam

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Title: Pollution sources and occurrences of selected persistent organic pollutants (POPs) in sediments of the Mekong River delta, South Vietnam
Authors: Nguyen Hung Minh
Tu Binh Minh
Pham Hung Viet
Kajiwara, Natsuko
Nguyen Phuc Cam Tu
Keywords: Vietnam
Mekong River
POPs
sediment
pollution source
Issue Date: 2007
Publisher: PERGAMON-ELSEVIER SCIENCE LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND
Citation: ISIKNOWLEDGE
Abstract: The Mekong River delta is one of the largest agricultural land in the Southeast Asia. It plays a very important role for agriculture and fisheries in South Vietnam. However, comprehensive studies on the environmental pollution of persistent organic pollutants (POPs) in Mekong River delta have not been carried out in recent years. In this study, we collected sediment samples from the Mekong River to evaluate the contamination and ecological risks caused by several POP’s. The contamination pattern of POPs was DDT > PCBs > CHLs > HCHs > HCB. DDTs are the most abundant pollutants, their concentration ranging from 0.01 to 110 ng/g dry wt, followed by PCBs (0.039-9.2 ng/g dry wt). DDTs and PCBs concentrations were higher in sediment from adjacent to urban areas than those from rural and agricultural sites, suggesting urban areas as important point sources of DDTs and PCBs to the river. Ratio of pp’-DDT/p,p’-DDE was lower compared to those previously reported. However, some samples still had the ratio higher than 0.5, indicating recent input of DDT into the aquatic environments. This result shows that although the magnitude of contamination decreased over time, recent inputs of DDTs to the river still occur. Some sediment samples had concentrations of DDT compounds higher than the standards from the Canadian Environmental Quality Guideline, suggesting continuous monitoring for POPs contamination in the Mekong River is necessary. (c) 2006 Elsevier Ltd. All rights reserved.
Description: CHEMOSPHERE Volume: 67 Issue: 9 Special Issue: SI Pages: 1794-1801 Published: APR 2007 ; TNS07630
URI: http://www.sciencedirect.com/science/article/pii/S0045653506015761
http://repository.vnu.edu.vn/handle/VNU_123/31433
ISSN: 0045-6535
0045-6535

Thịt chó trong văn hóa ẩm thực của người Việt (nghiên cứu trường hợp phường Dương Nội, quận Hà Đông, Hà Nội)

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Title: Thịt chó trong văn hóa ẩm thực của người Việt (nghiên cứu trường hợp phường Dương Nội, quận Hà Đông, Hà Nội) : Luận văn ThS. Dân tộc học: 60 22 70
Authors: Nguyễn, Văn Chính , người hướng dẫn
Phạm, Thị Thu Hiền
Keywords: Dân tộc học
Văn hóa ẩm thực
Người Việt
Issue Date: 2013
Publisher: ĐHKHXH&NV
Abstract: Electronic Resources
153 tr. + CD-ROM + tóm tắt
Luận văn ThS. Dân tộc học — Trường Đại học Khoa học Xã hội và Nhân văn. Đại học Quốc gia Hà Nội, 2013
Khái quát quá trình chuyển đổi kinh tế tại phường Dương Nội và sự hình thành dịch vụ chế biến thịt chó ở đây: tập trung giới thiệu khái quát về phường Dương Nội, các đặc điểm lịch sử, kinh tế, xã hội, văn hóa tự nhiên của phường Dương Nội; Đặc biệt nhấn mạ (…)
URI: http://repository.vnu.edu.vn/handle/VNU_123/35861
Appears in Collections: USSH – Master Theses

Recognizing postures in Vietnamese sign language with MEMS accelerometers

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Title: Recognizing postures in Vietnamese sign language with MEMS accelerometers
Authors: Bui, The Duy
Nguyen, Long Thang
Keywords: human computer interaction
microelectronic mechanical system (MEMS) sensors
sign language recognition
Vietnamese sign language (VSL)
Issue Date: 2007
Publisher: IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA
Citation: ISIKNOWLEDGE
Abstract: In this paper, we discuss the application of microelectronic mechanical system (MEMS) accelerometers for recognizing postures in Vietnamese Sign Language (VSL). We develop a similar device to the Accele Glove [6] for the recognition of VSL. In addition to the five sensors as in the Accele Glove, we placed one more sensor on the back of the hand to improve the recognition process. In addition, we use a completely different method for the classification process leading to very promising results. This paper concentrates on signing with postures, in which the user spells each word with finger signs corresponding to the letters of the alphabet. Therefore, we focus on the recognition of postures that represent the 23 Vietnamese-based letters together with two postures for “space” and “punctuation.” The data obtained from the sensing device is transformed to relative angles between fingers and the palm. Each character is recognized by a fuzzy rule-based classification system, which allows the concept of vagueness in recognition. In addition, a set of Vietnamese spelling rules has been applied to improve the classification results. The recognition rate is high even when the postures are not performed perfectly, e.g., the finger is not bended completely or the palm is not straight.
Description: TNS07628 ; IEEE SENSORS JOURNAL Volume: 7 Issue: 5-6 Pages: 707-712 Published: MAY-JUN 2007
URI: http://repository.vnu.edu.vn/handle/VNU_123/31356
ISSN: 1530-437X
1558-1748
Appears in Collections: Bài báo của ĐHQGHN trong Web of Science