期刊文献+
共找到17,080篇文章
< 1 2 250 >
每页显示 20 50 100
Transition Metal Substitutions Induce Ferromagnetism in Bi2Te3
1
作者 鞠林 徐同帅 +3 位作者 胡丹 崔海涛 张雍家 时长民 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2015年第2期173-178,I0001,共7页
The possibilities of magnetism induced by transition-metal atoms substitution in Bi2Te3 system are investigated by ab initio calculations. The calculated results indicate that a transition-metal atom substitution for ... The possibilities of magnetism induced by transition-metal atoms substitution in Bi2Te3 system are investigated by ab initio calculations. The calculated results indicate that a transition-metal atom substitution for a Bi atom produces magnetic moments, which are due to the spin-polarization of transition-metal 3d electrons. The values of magnetic moments are 0.92, 1.97, 2.97, 4.04, and 4.98 μB for 4% Ti-, V-, Cr-, Mn- and Fe-doped Bi2Te3 re- spectively. When substituting two transition-metal atoms, the characteristics of exchanging couple depend upon the distributions of the Bi atoms substituted. When two transition- metal atoms substituting for Bi atoms locate at the sites of Bil and Bi5, with the distance of 11.52A, the Bi1.84TM0.16Te3 system is energetically most stable and exhibits ferromagnetic coupling. 展开更多
关键词 Transition-metal atom substitution Magnetic moment First-principles cal-culation
下载PDF
Real-world efficacy of daclatasvir and asunaprevir with respect to resistance-associated substitutions 被引量:3
2
作者 Hideki Fujii Atsushi Umemura +12 位作者 Taichiro Nishikawa Kanji Yamaguchi Michihisa Moriguchi Hideki Nakamura Kohichiroh Yasui Masahito Minami Saiyu Tanaka Hiroki Ishikawa Hiroyuki Kimura Shiro Takami Yasuyuki Nagao Toshihide Shima Yoshito Itoh 《World Journal of Hepatology》 CAS 2017年第25期1064-1072,共9页
AIM To investigate daclatasvir(DCV) and asunaprevir(ASV) efficacy in hepatitis C(HCV) patients, with respect to resistance-associated substitutions(RASs).METHODS A total of 392 HCV-infected patients from multiple cent... AIM To investigate daclatasvir(DCV) and asunaprevir(ASV) efficacy in hepatitis C(HCV) patients, with respect to resistance-associated substitutions(RASs).METHODS A total of 392 HCV-infected patients from multiple centers were included in this study. We evaluated their clinical courses and sustained virologic responses(SVR) according to pretreatment factors(gender, age, history of interferon-based regimens, platelet counts, level of viremia, pretreatment NA5A:L31, and Y93 substitutions). We also analyzed the pretreatment and post-treatment major RASs of NS3:D168, NS5A:L31 and Y93 substitutions using a direct-sequencing method in 17 patients who were unable to achieve SVR at 12 wk after treatment completion(SVR12).RESULTS The overall SVR12 rate was 88.3%. Thirty-one patients discontinued treatment before 24 wk because of adverse events, 23 of whom achieved SVR12. There were no significant differences in SVR12 rates with respect to gender, age, history of interferon-based regimens, and platelet counts. The SVR12 rate in patients with viral loads of ≥ 6.0 log IU/m L was significantly lower than those with viral loads of < 6.0 log IU/m L(P < 0.001). The SVR12 rate in patients with Y93 substitution-positive was significantly lower than those with Y93 substitution-negative(P < 0.001). The L31 substitution-positive group showed a lower SVR12 rate than the L31 substitution-negative group, but the difference was not statistically significant. Seventeen patients who did not achieve SVR12 and had available pretreatment and post-treatment sera had additional RASs in NS3:D168, NS5:L31, and Y93 substitution at treatment failure.CONCLUSION Combination of DCV and ASV is associated with a high SVR rate. Baseline RASs should be thoroughly assessed to avoid additional RASs after treatment failure. 展开更多
关键词 Hepatitis C Asunaprevir Combination therapy Resistance-associated substitutions Daclatasvir
下载PDF
Preliminary Studies on Base Substitutions and Repair of DNA Mismatch Damage Stimulated by Low Energy N^+ Ion Beam Implantation in Escherichia coli 被引量:4
3
作者 谢传晓 郭金华 +1 位作者 程备久 余增亮 《Plasma Science and Technology》 SCIE EI CAS CSCD 2003年第1期1677-1682,共6页
Ever since the low energy N+ ion beam has been accepted that the mutation effects of ionizing radiation are attributed mainly to direct or indirect damage to DNA. Evidences based on naked DNA irradiation in support of... Ever since the low energy N+ ion beam has been accepted that the mutation effects of ionizing radiation are attributed mainly to direct or indirect damage to DNA. Evidences based on naked DNA irradiation in support of a mutation spectrum appears to be consistent, but direct proof of such results in vivo are limited. Using mutS, dam and/or dcm defective Eschericha coli imitator strains, an preliminary experimental system on induction of in vivo mutation spectra of low energy N+ ion beam has been established in this study. It was observed that the mutation rates of rifampicin resistance induced by N+ implantation were quite high, ranging from 9.2 x 10~8 to 4.9× 10~5 at the dosage of 5.2×1014 ions/cm2. Strains all had more than 90-fold higher mutation rate than its spontaneous mutation rate determined by this method. It reveals that base substitutions involve in induction of mutation of low energy nitrogen ion beam implantation. The mutation rates of mutator strains were nearly 500-fold (GM2929), 400-fold (GM5864) and 6-fold larger than that of AB1157. The GM2929 and GM5864 both lose the ability of repair DNA mismatch damage by virtue of both dam and dcm pathways defective (GM2929) or failing to assemble the repair complex (GM5864) respectively. It may explain the both strains had a similar higher mutation rate than GM124 did. It indicated that DNA cytosine methylase might play an important role in mismatch repair of DNA damage induced by N+ implantation. The further related research were also discussed. 展开更多
关键词 low energy N^+ ion beam base substitutions dam(DNA adenine methylase) dcm(DNA cytosine methylase) MUTS MMR (mismatch repair) Escherichia coli mutator strain
下载PDF
Assessment of Genetic Relationship and Application of Computational Algorithm to Assess Functionality of Non-Synonymous Substitutions in DQA2 Gene of Cattle, Sheep and Goats 被引量:1
4
作者 Steven B. Ugbo Abdulmojeed Yakubu +4 位作者 Jude N. Omeje Bwaseh S. Bibinu Ibrahim S. Musa Joseph O. Egahi N. I. Dim 《Open Journal of Genetics》 2015年第4期145-158,共14页
The major histocompatibility complex (MHC) is a fundamental part of the immune system in nearly all vertebrates. DQA2 is a member of the MHC complex and an important candidate gene involved in susceptibility/resistanc... The major histocompatibility complex (MHC) is a fundamental part of the immune system in nearly all vertebrates. DQA2 is a member of the MHC complex and an important candidate gene involved in susceptibility/resistance to various diseases. Therefore, the present study aimed at investigating computationally molecular genetic variation of DQA2 gene of cattle, sheep and goats especially on its evolution and differentiation within and among species as well as the attendant effects of the polymorphism on the function of DQA2 gene. A total of thirty three DQA2 nucleotide sequences comprising cattle (10), sheep (12) and goats (11) were retrieved from the GenBank. Forty seven amino acid substitutions of the wild type alleles located in the putative peptide coding region of caprine DQA2 alleles were obtained from the alignment of deduced amino acid sequences of goats. Out of these, eleven amino acid substitutions (H14L, H14R, L34M, E35L, G56S, G56R, 161V, A62E, D69Q, T72N and T72G) were returned neutral;an indication that they did not impair protein function. The Expected Accuracy (EA) ranged from 53% - 87%. For sheep, sixteen amino acid substitutions (A11P, A11T, A11G, A11M, L14S, L14T, V27L, V27S, G35S, S46T, D55E, L57T, L57A, L57G, K65Q and V68I) appeared beneficial while the rest forty seven appeared harmful (EA ranged from 53% - 93%). Twenty four amino acid substitutions did not impair the function of protein while seventy seven substitutions appeared to have a negative effect on the function of protein of cattle (EA ranged from 53% - 94%). The phylogeny based on nucleotide and amino acid sequences of DQA2 gene revealed the close relatedness of the caprine, ovine and bovine species. The present knowledge would be relevant for performing further genotype-phenotype research as well as pharmacogenetics studies in order to show association between caprine, ovine and bovine DQA2 allelic variation and the clinical progression of infectious diseases especially in a developing country such as Nigeria. 展开更多
关键词 DQA2 Genetic Relationship AMINO Acid substitutION PHYLOGENY RUMINANTS
下载PDF
Physicochemical, Biochemical and Instrumental Attributes and Consumer Acceptability of Dry-Fermented Sausages Elaborated with Combined Partial Substitutions of Sodium Chloride and Pork Backfat 被引量:1
5
作者 Hassan Safa Philippe Gatellier +5 位作者 Jean-Louis Berdagué Nathalie Kondjoyan Frédéric Mercier Stéphane Portanguen Raphaël Favier Pierre-Sylvain Mirade 《Food and Nutrition Sciences》 2016年第14期1297-1314,共18页
We performed 6 fabrications of dry-fermented sausages to investigate, at laboratory scale, the effects of combined partial substitutions of sodium chloride by potassium chloride and pork backfat by sunflower oil on ke... We performed 6 fabrications of dry-fermented sausages to investigate, at laboratory scale, the effects of combined partial substitutions of sodium chloride by potassium chloride and pork backfat by sunflower oil on key physical-chemical and biochemical parameters, instrumental colour and texture measurements, and the consumer acceptability of the end-products. Regarding the physical-chemical parameters, statistical analysis of results showed that final product weight loss was impacted by fat content and use of sunflower oil;final mean water activity value was only affected by salt level;and animal fat content impacted pH values, only at the end of drying. Regarding the biochemical parameters investigated, we statistically found a marked impact of partial substitution of NaCl by KCl on the proteolysis evolution, of fat level and sodium content on the end-product lipolysis, and finally, a significant effect of animal fat level and incorporation of sunflower oil on both protein and lipid oxidations. However, the new product formulations combining salt and fat substitutions lead to globally acceptable water loss and water activity values and similar rates of proteolysis, lipolysis and lipid oxidation, but less protein oxidation. From a practical point of view, the results clearly showed that sodium and animal fat contents in dryfermented sausages can be drastically reduced with no too marked adverse effect on colour, final textural properties or consumer acceptability. On the basis of these laboratory results, new healthier dry-fermented products can be manufactured by an industrial company in the near future. 展开更多
关键词 Dry-Fermented Sausage Combined Partial substitutions KCL Sunflower Oil Oxidation
下载PDF
THE STRUCTURE OF INVERTIBLE SUBSTITUTIONS ON A THREE-LETTER ALPHABET
6
作者 Tan Bo Wen Zhixiong Zhang Yiping (Wuhan University,China) 《Analysis in Theory and Applications》 2003年第4期365-382,共18页
We study the structure of invertible substitutions on three-letter alphabet. We show that there exists a finite set S of invertible substitutions such that any invertible substitution can be written as I wσ 1σ ... We study the structure of invertible substitutions on three-letter alphabet. We show that there exists a finite set S of invertible substitutions such that any invertible substitution can be written as I wσ 1σ 2…σ k,where I w is the inner automorphism associated with w, and σ j∈ S for 1≤j≤k. As a consequence,M is the matrix of an invertible substitution if and only if it is a finite product of non-negative elementary matrices. 展开更多
关键词 invertible substitution indecomposable substitution combinatorics of words
下载PDF
Charting the course to solid-state dual-ion batteries 被引量:1
7
作者 Habtom D.Asfaw Antonia Kotronia +2 位作者 Nuria Garcia-Araez Kristina Edström Daniel Brandell 《Carbon Energy》 SCIE EI CAS CSCD 2024年第3期132-177,共46页
An electrolyte destined for use in a dual-ion battery(DIB)must be stable at the inherently high potential required for anion intercalation in the graphite electrode,while also protecting the Al current collector from ... An electrolyte destined for use in a dual-ion battery(DIB)must be stable at the inherently high potential required for anion intercalation in the graphite electrode,while also protecting the Al current collector from anodic dissolution.A higher salt concentration is needed in the electrolyte,in comparison to typical battery electrolytes,to maximize energy density,while ensuring acceptable ionic conductivity and operational safety.In recent years,studies have demonstrated that highly concentrated organic electrolytes,ionic liquids,gel polymer electrolytes(GPEs),ionogels,and water-in-salt electrolytes can potentially be used in DIBs.GPEs can help reduce the use of solvents and thus lead to a substantial change in the Coulombic efficiency,energy density,and long-term cycle life of DIBs.Furthermore,GPEs are suited to manufacture compact DIB designs without separators by virtue of their mechanical strength and electrical performance.In this review,we highlight the latest advances in the application of different electrolytes in DIBs,with particular emphasis on GPEs. 展开更多
关键词 anion intercalation concentrated electrolytes dual-ion battery graphite ionic liquids polymer electrolyte
下载PDF
Atom substitution of the solid-state electrolyte Li_(10)GeP_(2)S_(12)for stabilized all-solid-state lithium metal batteries 被引量:1
8
作者 Zijing Wan Xiaozhen Chen +3 位作者 Ziqi Zhou Xiaoliang Zhong Xiaobing Luo Dongwei Xu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第1期28-38,I0002,共12页
Solid-state electrolyte Li_(10)GeP_(2)S_(12)(LGPS)has a high lithium ion conductivity of 12 mS cm^(-1)at room temperature,but its inferior chemical stability against lithium metal anode impedes its practical applicati... Solid-state electrolyte Li_(10)GeP_(2)S_(12)(LGPS)has a high lithium ion conductivity of 12 mS cm^(-1)at room temperature,but its inferior chemical stability against lithium metal anode impedes its practical application.Among all solutions,Ge atom substitution of the solid-state electrolyte LGPS stands out as the most promising solution to this interface problem.A systematic screening framework for Ge atom substitution including ionic conductivity,thermodynamic stability,electronic and mechanical properties is utilized to solve it.For fast screening,an enhanced model Dop Net FC using chemical formulas for the dataset is adopted to predict ionic conductivity.Finally,Li_(10)SrP_(2)S_(12)(LSrPS)is screened out,which has high lithium ion conductivity(12.58 mS cm^(-1)).In addition,an enhanced migration of lithium ion across the LSr PS/Li interface is found.Meanwhile,compared to the LGPS/Li interface,LSrPS/Li interface exhibits a larger Schottky barrier(0.134 eV),smaller electron transfer region(3.103?),and enhanced ability to block additional electrons,all of which contribute to the stabilized interface.The applied theoretical atom substitution screening framework with the aid of machine learning can be extended to rapid determination of modified specific material schemes. 展开更多
关键词 Atom substitution Solid-state electrolyte Machine learning Stabilized interface
下载PDF
Manure substitution improves maize yield by promoting soil fertility and mediating the microbial community in lime concretion black soil 被引量:1
9
作者 Minghui Cao Yan Duan +6 位作者 Minghao Li Caiguo Tang Wenjie Kan Jiangye Li Huilan Zhang Wenling Zhong Lifang Wu 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第2期698-710,共13页
Synthetic nitrogen(N)fertilizer has made a great contribution to the improvement of soil fertility and productivity,but excessive application of synthetic N fertilizer may cause agroecosystem risks,such as soil acidif... Synthetic nitrogen(N)fertilizer has made a great contribution to the improvement of soil fertility and productivity,but excessive application of synthetic N fertilizer may cause agroecosystem risks,such as soil acidification,groundwater contamination and biodiversity reduction.Meanwhile,organic substitution has received increasing attention for its ecologically and environmentally friendly and productivity benefits.However,the linkages between manure substitution,crop yield and the underlying microbial mechanisms remain uncertain.To bridge this gap,a three-year field experiment was conducted with five fertilization regimes:i)Control,non-fertilization;CF,conventional synthetic fertilizer application;CF_(1/2)M_(1/2),1/2 N input via synthetic fertilizer and 1/2 N input via manure;CF_(1/4)M_(3/4),1/4 N input synthetic fertilizer and 3/4 N input via manure;M,manure application.All fertilization treatments were designed to have equal N input.Our results showed that all manure substituted treatments achieved high soil fertility indexes(SFI)and productivities by increasing the soil organic carbon(SOC),total N(TN)and available phosphorus(AP)concentrations,and by altering the bacterial community diversity and composition compared with CF.SOC,AP,and the soil C:N ratio were mainly responsible for microbial community variations.The co-occurrence network revealed that SOC and AP had strong positive associations with Rhodospirillales and Burkholderiales,while TN and C:N ratio had positive and negative associations with Micromonosporaceae,respectively.These specific taxa are implicated in soil macroelement turnover.Random Forest analysis predicted that both biotic(bacterial composition and Micromonosporaceae)and abiotic(AP,SOC,SFI,and TN)factors had significant effects on crop yield.The present work strengthens our understanding of the effects of manure substitution on crop yield and provides theoretical support for optimizing fertilization strategies. 展开更多
关键词 FERTILIZATION manure substitution soil fertility maize yield bacterial community
下载PDF
Synthesis and Modulation of Low-Dimensional Transition Metal Chalcogenide Materials via Atomic Substitution 被引量:1
10
作者 Xuan Wang Akang Chen +3 位作者 XinLei Wu Jiatao Zhang Jichen Dong Leining Zhang 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第9期49-94,共46页
In recent years,low-dimensional transition metal chalcogenide(TMC)materials have garnered growing research attention due to their superior electronic,optical,and catalytic properties compared to their bulk counterpart... In recent years,low-dimensional transition metal chalcogenide(TMC)materials have garnered growing research attention due to their superior electronic,optical,and catalytic properties compared to their bulk counterparts.The controllable synthesis and manipulation of these materials are crucial for tailoring their properties and unlocking their full potential in various applications.In this context,the atomic substitution method has emerged as a favorable approach.It involves the replacement of specific atoms within TMC structures with other elements and possesses the capability to regulate the compositions finely,crystal structures,and inherent properties of the resulting materials.In this review,we present a comprehensive overview on various strategies of atomic substitution employed in the synthesis of zero-dimensional,one-dimensional and two-dimensional TMC materials.The effects of substituting elements,substitution ratios,and substitution positions on the structures and morphologies of resulting material are discussed.The enhanced electrocatalytic performance and photovoltaic properties of the obtained materials are also provided,emphasizing the role of atomic substitution in achieving these advancements.Finally,challenges and future prospects in the field of atomic substitution for fabricating low-dimensional TMC materials are summarized. 展开更多
关键词 Transition metal chalcogenides Atomic substitution Ion exchange Low-dimensional materials Controllable synthesis
下载PDF
Design of low-alloying and high-performance solid solution-strengthened copper alloys with element substitution for sustainable development 被引量:1
11
作者 Jiaqiang Li Hongtao Zhang +2 位作者 Jingtai Sun Huadong Fu Jianxin Xie 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第5期826-832,共7页
Solid solution-strengthened copper alloys have the advantages of a simple composition and manufacturing process,high mechanical and electrical comprehensive performances,and low cost;thus,they are widely used in high-... Solid solution-strengthened copper alloys have the advantages of a simple composition and manufacturing process,high mechanical and electrical comprehensive performances,and low cost;thus,they are widely used in high-speed rail contact wires,electronic component connectors,and other devices.Overcoming the contradiction between low alloying and high performance is an important challenge in the development of solid solution-strengthened copper alloys.Taking the typical solid solution-strengthened alloy Cu-4Zn-1Sn as the research object,we proposed using the element In to replace Zn and Sn to achieve low alloying in this work.Two new alloys,Cu-1.5Zn-1Sn-0.4In and Cu-1.5Zn-0.9Sn-0.6In,were designed and prepared.The total weight percentage content of alloying elements decreased by 43%and 41%,respectively,while the product of ultimate tensile strength(UTS)and electrical conductivity(EC)of the annealed state increased by 14%and 15%.After cold rolling with a 90%reduction,the UTS of the two new alloys reached 576 and 627MPa,respectively,the EC was 44.9%IACS and 42.0%IACS,and the product of UTS and EC(UTS×EC)was 97%and 99%higher than that of the annealed state alloy.The dislocations proliferated greatly in cold-rolled alloys,and the strengthening effects of dislocations reached 332 and 356 MPa,respectively,which is the main reason for the considerable improvement in mechanical properties. 展开更多
关键词 element substitution copper alloy solid solution strengthening microstructure and performance
下载PDF
Substitutions of vertex configuration of Ammann–Beenker tiling in framework of Ammann lines
12
作者 Jia-Rong Ye Wei-Shen Huang Xiu-Jun Fu 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第8期500-504,共5页
The Ammann–Beenker tiling is a typical model for two-dimensional octagonal quasicrystals. The geometric properties of local configurations are the key to understanding its formation mechanism. We study the configurat... The Ammann–Beenker tiling is a typical model for two-dimensional octagonal quasicrystals. The geometric properties of local configurations are the key to understanding its formation mechanism. We study the configuration correlations in the framework of Ammann lines, giving an in-depth inspection of this eightfold symmetric structure. When both the vertex type and the orientation are taken into account, strict confinements of neighboring vertices are found. These correlations reveal the structural properties of the quasilattice and also provide substitution rules of vertex along an Ammann line. 展开更多
关键词 QUASICRYSTALS Ammann–Beenker tiling Ammann lines substitution rules
下载PDF
Mitigation of N_(2)O emissions in water-saving paddy fields:Evaluating organic fertilizer substitution and microbial mechanisms 被引量:1
13
作者 Delei Kong Xianduo Zhang +5 位作者 Qidong Yu Yaguo Jin Peikun Jiang Shuang Wu Shuwei Liu Jianwen Zou 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第9期3159-3173,共15页
Water-saving irrigation strategies can successfully alleviate methane emissions from rice fields,but significantly stimulate nitrous oxide(N_(2)O)emissions because of variations in soil oxygen level and redox potentia... Water-saving irrigation strategies can successfully alleviate methane emissions from rice fields,but significantly stimulate nitrous oxide(N_(2)O)emissions because of variations in soil oxygen level and redox potential.However,the relationship linking soil N_(2)O emissions to nitrogen functional genes during various fertilization treatments in water-saving paddy fields has rarely been investigated.Furthermore,the mitigation potential of organic fertilizer substitution on N_(2)O emissions and the microbial mechanism in rice fields must be further elucidated.Our study examined how soil N_(2)O emissions were affected by related functional microorganisms(ammonia-oxidizing archaea(AOA),ammonia-oxidizing bacteria(AOB),nirS,nirK and nosZ)to various fertilization treatments in a rice field in southeast China over two years.In this study,three fertilization regimes were applied to rice cultivation:a no nitrogen(N)(Control),an inorganic N(Ni),and an inorganic N with partial N substitution with organic manure(N_(i)+N_(o)).Over two rice-growing seasons,cumulative N_(2)O emissions averaged 0.47,4.62 and 4.08 kg ha^(−1)for the Control,Ni and N_(i)+N_(o)treatments,respectively.In comparison to the Ni treatment,the N_(i)+N_(o)fertilization regime considerably reduced soil N_(2)O emissions by 11.6%while maintaining rice yield,with a lower N_(2)O emission factor(EF)from fertilizer N of 0.95%.Nitrogen fertilization considerably raised the AOB,nirS,nirK and nosZ gene abundances,in comparison to the Control treatment.Moreover,the substitution of organic manure for inorganic N fertilizer significantly decreased AOB and nirS gene abundances and increased nosZ gene abundance.The AOB responded to N fertilization more sensitively than the AOA.Total N_(2)O emissions significantly correlated positively with AOB and nirS gene abundances while having a negative correlation with nosZ gene abundance and the nosZ/nirS ratio across N-fertilized plots.In summary,we conclude that organic manure substitution for inorganic N fertilizer decreased soil N_(2)O emissions primarily by changing the soil NO_(3)^(−)-N,pH and DOC levels,thus inhibiting the activities of ammonia oxidation in nitrification and nitrite reduction in denitrification,and strengthening N_(2)O reduction in denitrification from water-saving rice paddies. 展开更多
关键词 organic manure substitution inorganic fertilizer N_(2)O functional microbe rice paddy
下载PDF
Structure and Magnetic Properties of Nd-Fe-B/α-Fe Nanocomposite Magnets by Co, Nb, Dy Substitutions
14
作者 Jian ZHANG Xaokai SUN +2 位作者 Wei LIU Baozhi CUI Xinguo ZHAO and Zhidong ZHANG(Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110015, China) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1999年第3期198-202,共5页
Structure and magnetic properties of the nanocomposite magnets prepared by mechanical al loying procedure with composition 55 wt pct Nd (Fe0.92B0.08)5.5+45 wt pct α-Fe,55 wt pct Nd(Fe0.8-.Co0.12Nbx B0.08)5.5+45 wt p... Structure and magnetic properties of the nanocomposite magnets prepared by mechanical al loying procedure with composition 55 wt pct Nd (Fe0.92B0.08)5.5+45 wt pct α-Fe,55 wt pct Nd(Fe0.8-.Co0.12Nbx B0.08)5.5+45 wt pct α-Fe (x=0.00, 0.01- 0.03) and 55 wt pct (Nd0.9Dy0.1) (Fe0.77Co0.12Nb0.03B0.08)5.5+45 wt pct α-Fe were studied. It was found that substitution of Co for Fe could significantly improve the permanent magnetic properties of the nanocomposite magnets and typically, the maximum magnetic energy product was increased from 104.8 kJ/m3 (13.1 MGOe) to 141.6 kJ/m3 (17.7 MGOe). In contrast to the case of conventional nominally single-phase magnets, the addition of Nb results in promoting the growth of α-Fe grain and is thus unfavorable for the improvement of permanent magnetic properties of the nanocomposites. Although the addition of Dy can increase the coercivity of the magnets, the increase of magnetic anisotropy of hard phase leads to decrease of the critical grain size of soft phase. Additionally it causes the difficulty of preparing the nanocomposites because it is more difficult to control the grain size of soft phase to meet the requirement of appropriate exchange coupling between hard and soft grains 展开更多
关键词 Fe Nanocomposite Magnets by Co Dy substitutions NB Structure and Magnetic Properties of Nd-Fe-B Nd
下载PDF
Effects of long-term partial substitution of inorganic fertilizer with pig manure and/or straw on nitrogen fractions and microbiological properties in greenhouse vegetable soils 被引量:1
15
作者 Shuo Yuan Ruonan Li +5 位作者 Yinjie Zhang Hao'an Luan Jiwei Tang Liying Wang Hongjie Ji Shaowen Huang 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第6期2083-2098,共16页
Partial substitution of inorganic fertilizers with organic amendments is an important agricultural management practice.An 11-year field experiment(22 cropping periods)was carried out to analyze the impacts of differen... Partial substitution of inorganic fertilizers with organic amendments is an important agricultural management practice.An 11-year field experiment(22 cropping periods)was carried out to analyze the impacts of different partial substitution treatments on crop yields and the transformation of nitrogen fractions in greenhouse vegetable soil.Four treatments with equal N,P_(2)O_(5),and K_(2)O inputs were selected,including complete inorganic fertilizer N(CN),50%inorganic fertilizer N plus 50%pig manure N(CPN),50%inorganic fertilizer N plus 25%pig manure N and 25%corn straw N(CPSN),and 50%inorganic fertilizer N plus 50%corn straw N(CSN).Organic substitution treatments tended to increase crop yields since the 6th cropping period compared to the CN treatment.From the 8th to the 22nd cropping periods,the highest yields were observed in the CPSN treatment where yields were 7.5-11.1%greater than in CN treatment.After 11-year fertilization,compared to CN,organic substitution treatments significantly increased the concentrations of NO_(3)^(-)-N,NH_(4)^(+)-N,acid hydrolysis ammonium-N(AHAN),amino acid-N(AAN),amino sugar-N(ASN),and acid hydrolysis unknown-N(AHUN)in soil by 45.0-69.4,32.8-58.1,49.3-66.6,62.0-69.5,34.5-100.3,and 109.2-172.9%,respectively.Redundancy analysis indicated that soil C/N and OC concentration significantly affected the distribution of N fractions.The highest concentrations of NO_(3)^(-)-N,AHAN,AAN,AHUN were found in the CPSN treatment.Organic substitution treatments increased the activities ofβ-glucosidase,β-cellobiosidase,N-acetyl-glucosamidase,L-aminopeptidase,and phosphatase in the soil.Organic substitution treatments reduced vector length and increased vector angle,indicating alleviation of constraints of C and N on soil microorganisms.Organic substitution treatments increased the total concentrations of phospholipid fatty acids(PLFAs)in the soil by 109.9-205.3%,and increased the relative abundance of G^(+)bacteria and fungi taxa,but decreased the relative abundance of G-bacteria,total bacteria,and actinomycetes.Overall,long-term organic substitution management increased soil OC concentration,C/N,and the microbial population,the latter in turn positively influenced soil enzyme activity.Enhanced microorganism numbers and enzyme activity enhanced soil N sequestration by transforming inorganic N to acid hydrolysis-N(AHN),and enhanced soil N supply capacity by activating non-acid hydrolysis-N(NAHN)to AHN,thus improving vegetable yield.Application of inorganic fertilizer,manure,and straw was a more effective fertilization model for achieving sustainable greenhouse vegetable production than application of inorganic fertilizer alone. 展开更多
关键词 organic substitution management greenhouse vegetable production N fractions microbial community composition extracellular enzyme activity enzyme stoichiometry coefficients
下载PDF
Mechanism of Na and K Substitutions in Bioapatite Within Salty Area
16
作者 LI Zhen 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2014年第S1期86-86,共1页
Introduction Na and K are two most important cations in salty water,and also are two typical ions in animals’body fluids.The mineral,bioapatite,is a form of carbonated hydroxylapatite,which makes up over 50 wt.%of bones
关键词 bone NA Mechanism of Na and K substitutions in Bioapatite Within Salty Area
下载PDF
Evidence for Base Substitutions and Repair of DNA Mismatch Damage Induced by Low Energy N^+ Ion Beam Implantation in E. coli
17
作者 谢传晓 Guo +6 位作者 Jinhua Yao Jianmin Wu Lijun Yu Zengliang 《High Technology Letters》 EI CAS 2003年第2期1-6,共6页
Ever since the low energy N + ion beam has been accepted, the mutations of ionizing radiation are attributable mainly to avoidance of DNA damages repair. Evidences based on in vivo proof results are limited. Using the... Ever since the low energy N + ion beam has been accepted, the mutations of ionizing radiation are attributable mainly to avoidance of DNA damages repair. Evidences based on in vivo proof results are limited. Using the E.coli wild type and mutator strains, the mutant frequencies suggest that base substitutions in rpoB gene are induced by the N + implantation. A highly conserved region is selected to get the direct evidence for base substitutions by sequence of the high fidelity PCR amplification products in mutants. Most of the mutants (90.9%, 40/44) have at least one base substitution in the amplification region. The evidences for CG to TA (55%, 22/40), AT to GC (20%, 8/40) and TA to CG (5%, 2/40) transitions are identified. The transversions are AT to TA (15%, 6/40) and GC to CG (5%, 2/40). It is suggested that DNA cytosine methylase might play an important role in mismatch repair of DNA damage induced by N + implantation by analysis of the mutant frequencies of mutator strains. 展开更多
关键词 low energy N + ion beam base substitutions mismatch repair mutator strains
下载PDF
Effect of Rare-Earth Element Substitution in Superconducting R_(3)Ni_(2)O_(7) under Pressure
18
作者 Zhiming Pan Chen Lu +1 位作者 Fan Yang Congjun Wu 《Chinese Physics Letters》 SCIE EI CAS CSCD 2024年第8期77-81,共5页
Recently,high temperature(T_(c)≈80 K)superconductivity(SC)has been discovered in La_(3)Ni_(2)O_(7)(LNO)under pressure.This raises the question of whether the superconducting transition temperature T_(c) could be furt... Recently,high temperature(T_(c)≈80 K)superconductivity(SC)has been discovered in La_(3)Ni_(2)O_(7)(LNO)under pressure.This raises the question of whether the superconducting transition temperature T_(c) could be further enhanced under suitable conditions.One possible route for achieving higher T_(c) is element substitution.Similar SC could appear in the Fmmm phase of rare-earth(RE)R_(3)Ni_(2)O_(7)(RNO,R=RE element)material series under suitable pressure.The electronic properties in the RNO materials are dominated by the Ni 3d orbitals in the bilayer NiO_(2) plane.In the strong coupling limit,the SC could be fully characterized by a bilayer single 3d_(x^(2)−y^(2))-orbital t–J‖–J⊥ model.With RE element substitution from La to other RE element,the lattice constant of the Fmmm RNO material decreases,and the resultant electronic hopping integral increases,leading to stronger superexchanges between the 3d_(x^(2)−y^(2)) orbitals.Based on the slave-boson mean-field theory,we explore the pairing nature and the evolution of T_(c) in RNO materials under pressure.Consequently,it is found that the element substitution does not alter the pairing nature,i.e.,the inter-layer s-wave pairing is always favored in the superconducting RNO under pressure.However,the T_(c) increases from La to Sm,and a nearly doubled T_(c) could be realized in SmNO under pressure.This work provides evidence for possible higher T_(c) R_(3)Ni_(2)O_(7) materials,which may be realized in further experiments. 展开更多
关键词 ELEMENT substitutION RARE
下载PDF
Upcycling the spent graphite/LiCoO_(2) batteries for high-voltage graphite/LiCoPO_(4)-co-workable dual-ion batteries
19
作者 Miao Du Hongyan Lü +5 位作者 Kaidi Du Shuohang Zheng Xiaotong Wang Xiaotong Deng Ronghua Zeng Xinglong Wu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第7期1745-1751,共7页
The worldwide proliferation of portable electronics has resulted in a dramatic increase in the number of spent lithium-ion batteries(LIBs).However,traditional recycling methods still have limitations because of such h... The worldwide proliferation of portable electronics has resulted in a dramatic increase in the number of spent lithium-ion batteries(LIBs).However,traditional recycling methods still have limitations because of such huge amounts of spent LIBs.Therefore,we proposed an ecofriendly and sustainable double recycling strategy to concurrently reuse the cathode(LiCoO_(2))and anode(graphite)materials of spent LIBs and recycled LiCoPO_(4)/graphite(RLCPG)in Li^(+)/PF^(-)_(6) co-de/intercalation dual-ion batteries.The recycle-derived dualion batteries of Li/RLCPG show impressive electrochemical performance,with an appropriate discharge capacity of 86.2 mAh·g^(-1) at25 mA·g^(-1) and 69%capacity retention after 400 cycles.Dual recycling of the cathode and anode from spent LIBs avoids wastage of resources and yields cathode materials with excellent performance,thereby offering an ecofriendly and sustainable way to design novel secondary batteries. 展开更多
关键词 RECYCLE lithium cobalt oxide lithium cobalt phosphate GRAPHITE dual-ion batteries spent lithium-ion batteries
下载PDF
Impact of Co^(2+)substitution on structure and magnetic properties of M-type strontium ferrite with different Fe/Sr ratios
20
作者 Yang Sun Ruoshui Liu +1 位作者 Huayang Gong Baogen Shen 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第10期427-433,共7页
Ion substitution has significantly improved the performance of ferrite magnets,and cobalt remains a key area of research.Studies on the mechanism of Co^(2+)in strontium ferrite,especially SrFe_(2n-x)Co_(x)O_(19-d)(n=6... Ion substitution has significantly improved the performance of ferrite magnets,and cobalt remains a key area of research.Studies on the mechanism of Co^(2+)in strontium ferrite,especially SrFe_(2n-x)Co_(x)O_(19-d)(n=6.1-5.4;x=0.05-0.20)synthesized using the ceramic method,showed that Co^(2+)preferentially enters the lattice as the Fe/Sr ratio decreases.This results in a decrease in the lattice constants a and c due to oxygen vacancies and iron ion deficiency.The impact of Co substitution on morphology is minor compared to the effect of the Fe/Sr ratio.As the Fe/Sr ratio decreases and the Co content increases,the saturation magnetization decreases.The magnetic anisotropy field exhibits a nonlinear change,generally increasing with higher Fe/Sr ratios and Co content.These changes in the performance of permanent magnets are attributed to the absence of Fe^(3+)ions at the 12k+2a and 2b sites and the substitution of Co^(2+)at the 2b site.This suggests that by adjusting the Fe/Sr ratio and appropriate Co substitution,the magnetic anisotropy field of M-type strontium ferrite can be effectively optimized. 展开更多
关键词 HEXAFERRITE Co substitution Raman spectra magnetic properties
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部