The maturity of 5G technology has enabled crowd-sensing services to collect multimedia data over wireless network,so it has promoted the applications of crowd-sensing services in different fields,but also brings more ...The maturity of 5G technology has enabled crowd-sensing services to collect multimedia data over wireless network,so it has promoted the applications of crowd-sensing services in different fields,but also brings more privacy security challenges,the most commom which is privacy leakage.As a privacy protection technology combining data integrity check and identity anonymity,ring signature is widely used in the field of privacy protection.However,introducing signature technology leads to additional signature verification overhead.In the scenario of crowd-sensing,the existing signature schemes have low efficiency in multi-signature verification.Therefore,it is necessary to design an efficient multi-signature verification scheme while ensuring security.In this paper,a batch-verifiable signature scheme is proposed based on the crowd-sensing background,which supports the sensing platform to verify the uploaded multiple signature data efficiently,so as to overcoming the defects of the traditional signature scheme in multi-signature verification.In our proposal,a method for linking homologous data was presented,which was valuable for incentive mechanism and data analysis.Simulation results showed that the proposed scheme has good performance in terms of security and efficiency in crowd-sensing applications with a large number of users and data.展开更多
The present note determines the structure of the K2-group and of its subgroup over a finite commutative ring R by considering relations between R andfinite commutative local ring Ri (1 < i < m), where R Ri and K...The present note determines the structure of the K2-group and of its subgroup over a finite commutative ring R by considering relations between R andfinite commutative local ring Ri (1 < i < m), where R Ri and K2(R) =K2(Ri). We show that if charKi= p (Ki denotes the residual field of Ri), then K2(Ri) and its subgroups must be p-groups.展开更多
Let G be a group, HG and R a G graded ring. We study the duality Theorem for G actions and smash products R#G/H of the G graded ring R and the G set G/H.
半导体光催化剂是一种极具前景的绿色催化剂,广泛用于污染物降解、水解制氢和有机合成等领域,有望利用太阳能来解决能源和环境问题,是当前的研究前沿和热点.然而,单组分半导体光催化剂的光生电子和空穴容易复合,导致量子效率差和光催化...半导体光催化剂是一种极具前景的绿色催化剂,广泛用于污染物降解、水解制氢和有机合成等领域,有望利用太阳能来解决能源和环境问题,是当前的研究前沿和热点.然而,单组分半导体光催化剂的光生电子和空穴容易复合,导致量子效率差和光催化效率低.近年人们发现,将两种或多种催化材料结合,构建异质结光催化体系可有效促进光生电子-空穴分离.但传统的异质结体系中光生电子的还原性和光生空穴的氧化性通常在电荷转移后变弱,因此,很难同时具备高电荷转移效率和强氧化还原能力.研究发现,构建Z型异质结光催化体系不仅可以减少本体电子-空穴的复合,使其在不同半导体材料上实现空间分离,具有光谱响应宽、电荷分离效率高和稳定性高等优势,而且能保持良好的氧化还原能力.在半导体材料领域,石墨相氮化碳(g-C_(3)N_(4))作为一种无金属聚合物半导体,具有良好的热化学稳定性、电学和光学特性,但存在量子效率低和适用范围窄等局限性.而五氧化二钒(V_(2)O_(5))是一种重要的过渡金属氧化物半导体,由于具有良好的电学和光学性能被广泛用于锂离子电池、气敏传感器和光电器件.V_(2)O_(5)能带间隙(~2.19 e V)窄,具有合适的能量频带边缘(ECB=0.81 e V,EVB=3.0 e V),可以与g-C_(3)N_(4)(ECB=1.14 e V,EVB=1.59 e V)很好地匹配,形成稳定状态的Z型光催化体系,并提高光催化有机合成反应的效率.本文以三聚氰胺和偏钒酸铵为原料,采用热处理法分别制备g-C_(3)N_(4)和V_(2)O_(5),采用水热法制备Z型V_(2)O_(5)/g-C_(3)N_(4)二元复合材料.X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)和紫外-可见光吸收光谱(UV-Vis)等结果表明,成功制备了Z型V_(2)O_(5)/g-C_(3)N_(4).UV-Vis结果表明,V_(2)O_(5)/g-C_(3)N_(4)具有较宽的光吸收范围,从而提高了复合半导体材料的光学性能.在温和条件下,以未活化烯烃修饰的喹唑啉酮和芳基氧膦为反应物,V_(2)O_(5)/g-C_(3)N_(4)为多相光催化剂,进行膦酰化自由基偶联反应,制得一系列环合的膦酰化喹唑啉酮,收率为63%-83%.该反应具有原料易得、条件温和、底物范围广、产品收率及区域选择性良好等优点,同时催化剂循环使用性能良好.值得注意的是,不同吸电子取代基、供电子取代基修饰的喹唑啉酮和非对称结构的芳基氧膦均能兼容于该反应体系,并以中等至良好的收率得到了各种膦酰化喹唑啉酮化合物.本文采用的合成策略同样适用于三氟甲基化、二氟烷基化和芳基磺酰化等自由基串联环化反应,且具有良好的催化性能.机理研究结果表明,V_(2)O_(5)/g-C_(3)N_(4)被光激发后,V_(2)O_(5)导带(CB)上的光生电子与g-C_(3)N_(4)价带(VB)上的光生空穴迅速复合,导致g-C_(3)N_(4)的导带上无法与本体空穴复合的电子发生单电子转移(SET)过程,且与分子氧(空气中)反应生成超氧阴离子自由基(O_(2)·^(-)).V_(2)O_(5)价带上的空穴氧化芳基氧膦产生自由基阳离子,去质子化产生氧膦自由基,随后加成到未活化烯烃生成新的自由基物种,最后发生分子内环化反应,得到目标产物.V_(2)O_(5)/g-C_(3)N_(4)成本较低,且该光催化反应策略可实现克级制备,循环使用5次后催化活性保持不变.综上,本文可为光催化自由基串联环化反应,杂环化合物合成研究和Z型异质结的光催化应用提供参考.展开更多
The ubiquitin-proteasome proteolysis pathway is responsible for the degradation of abnormal and short-lived proteins to regulate many important biochemical activities in eukaryotes. By employing affymetrix microarray ...The ubiquitin-proteasome proteolysis pathway is responsible for the degradation of abnormal and short-lived proteins to regulate many important biochemical activities in eukaryotes. By employing affymetrix microarray analysis, we have identified a novel ubiquitin ligase E3 gene GhRING2 that is differentially expressed between two Gossypium hirsutum lines-Texas Marker-1 (TM-1) and Chromosome Substitution Line CS-B25. The CS-B25 line has chromosome 25 from G. barbadense substituted into TM-1. The complete nucleotide sequences of GhRING2 along with its 5’-flanking region were obtained by genomic walking. GhRING2 was highly expressed in elongating fiber, and GUS expression directed by the GhRING2 promoter was found in hypocotyls and young stems of transgenic Arabidopsis plants. Using a yeast two-hybrid assay GhRING2 was found to interact with a PROTODERMAL FACTOR1 (GhPDF1) protein. GhPDF1 was expressed preferentially in immature ovules and fiber initials, and the GhPDF1 gene had been suggested to play a role in cell fate determination and fiber development. Pull down and plasmid swap assays further confirmed the interaction between GhRING2 and GhPDF1. The expression and protein interaction data indicate that GhRING2 may be involved in the turnover of GhPDF1 and participation in the transition from initiation to elongation stages during fiber development. Our data strongly suggest that the ubiquitin-proteasome pathway may regulate cotton fiber growth and development. The nucleotide sequence data of GhRING2 in this article have been submitted to the Gen Bank Nucleotide Sequence Data Bases under the accession number BankIt 1,742,008 SeqKM 108,000.展开更多
Let R be a ring and e,g in E(R),the set of idempotents of R.Then R is called(g,e)-symmetric if abc=0 implies gacbe=0 for any a,b,c∈R.Clearly,R is an e-symmetric ring if and only if R is a(1,e)-symmetric ring;in parti...Let R be a ring and e,g in E(R),the set of idempotents of R.Then R is called(g,e)-symmetric if abc=0 implies gacbe=0 for any a,b,c∈R.Clearly,R is an e-symmetric ring if and only if R is a(1,e)-symmetric ring;in particular,R is a symmetric ring if and only if R is a(1,1)-symmetric ring.We show that e∈E(R)is left semicentral if and only if R is a(1−e,e)-symmetric ring;in particular,R is an Abel ring if and only if R is a(1−e,e)-symmetric ring for each e∈E(R).We also show that R is(g,e)-symmetric if and only if ge∈E(R),geRge is symmetric,and gxye=gxeye=gxgye for any x,y∈R.Using e-symmetric rings,we construct some new classes of rings.展开更多
基金supported by National Natural Science Foundation of China under Grant No.61972360Shandong Provincial Natural Science Foundation of China under Grant Nos.ZR2020MF148,ZR2020QF108.
文摘The maturity of 5G technology has enabled crowd-sensing services to collect multimedia data over wireless network,so it has promoted the applications of crowd-sensing services in different fields,but also brings more privacy security challenges,the most commom which is privacy leakage.As a privacy protection technology combining data integrity check and identity anonymity,ring signature is widely used in the field of privacy protection.However,introducing signature technology leads to additional signature verification overhead.In the scenario of crowd-sensing,the existing signature schemes have low efficiency in multi-signature verification.Therefore,it is necessary to design an efficient multi-signature verification scheme while ensuring security.In this paper,a batch-verifiable signature scheme is proposed based on the crowd-sensing background,which supports the sensing platform to verify the uploaded multiple signature data efficiently,so as to overcoming the defects of the traditional signature scheme in multi-signature verification.In our proposal,a method for linking homologous data was presented,which was valuable for incentive mechanism and data analysis.Simulation results showed that the proposed scheme has good performance in terms of security and efficiency in crowd-sensing applications with a large number of users and data.
文摘The present note determines the structure of the K2-group and of its subgroup over a finite commutative ring R by considering relations between R andfinite commutative local ring Ri (1 < i < m), where R Ri and K2(R) =K2(Ri). We show that if charKi= p (Ki denotes the residual field of Ri), then K2(Ri) and its subgroups must be p-groups.
文摘Let G be a group, HG and R a G graded ring. We study the duality Theorem for G actions and smash products R#G/H of the G graded ring R and the G set G/H.
文摘半导体光催化剂是一种极具前景的绿色催化剂,广泛用于污染物降解、水解制氢和有机合成等领域,有望利用太阳能来解决能源和环境问题,是当前的研究前沿和热点.然而,单组分半导体光催化剂的光生电子和空穴容易复合,导致量子效率差和光催化效率低.近年人们发现,将两种或多种催化材料结合,构建异质结光催化体系可有效促进光生电子-空穴分离.但传统的异质结体系中光生电子的还原性和光生空穴的氧化性通常在电荷转移后变弱,因此,很难同时具备高电荷转移效率和强氧化还原能力.研究发现,构建Z型异质结光催化体系不仅可以减少本体电子-空穴的复合,使其在不同半导体材料上实现空间分离,具有光谱响应宽、电荷分离效率高和稳定性高等优势,而且能保持良好的氧化还原能力.在半导体材料领域,石墨相氮化碳(g-C_(3)N_(4))作为一种无金属聚合物半导体,具有良好的热化学稳定性、电学和光学特性,但存在量子效率低和适用范围窄等局限性.而五氧化二钒(V_(2)O_(5))是一种重要的过渡金属氧化物半导体,由于具有良好的电学和光学性能被广泛用于锂离子电池、气敏传感器和光电器件.V_(2)O_(5)能带间隙(~2.19 e V)窄,具有合适的能量频带边缘(ECB=0.81 e V,EVB=3.0 e V),可以与g-C_(3)N_(4)(ECB=1.14 e V,EVB=1.59 e V)很好地匹配,形成稳定状态的Z型光催化体系,并提高光催化有机合成反应的效率.本文以三聚氰胺和偏钒酸铵为原料,采用热处理法分别制备g-C_(3)N_(4)和V_(2)O_(5),采用水热法制备Z型V_(2)O_(5)/g-C_(3)N_(4)二元复合材料.X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)和紫外-可见光吸收光谱(UV-Vis)等结果表明,成功制备了Z型V_(2)O_(5)/g-C_(3)N_(4).UV-Vis结果表明,V_(2)O_(5)/g-C_(3)N_(4)具有较宽的光吸收范围,从而提高了复合半导体材料的光学性能.在温和条件下,以未活化烯烃修饰的喹唑啉酮和芳基氧膦为反应物,V_(2)O_(5)/g-C_(3)N_(4)为多相光催化剂,进行膦酰化自由基偶联反应,制得一系列环合的膦酰化喹唑啉酮,收率为63%-83%.该反应具有原料易得、条件温和、底物范围广、产品收率及区域选择性良好等优点,同时催化剂循环使用性能良好.值得注意的是,不同吸电子取代基、供电子取代基修饰的喹唑啉酮和非对称结构的芳基氧膦均能兼容于该反应体系,并以中等至良好的收率得到了各种膦酰化喹唑啉酮化合物.本文采用的合成策略同样适用于三氟甲基化、二氟烷基化和芳基磺酰化等自由基串联环化反应,且具有良好的催化性能.机理研究结果表明,V_(2)O_(5)/g-C_(3)N_(4)被光激发后,V_(2)O_(5)导带(CB)上的光生电子与g-C_(3)N_(4)价带(VB)上的光生空穴迅速复合,导致g-C_(3)N_(4)的导带上无法与本体空穴复合的电子发生单电子转移(SET)过程,且与分子氧(空气中)反应生成超氧阴离子自由基(O_(2)·^(-)).V_(2)O_(5)价带上的空穴氧化芳基氧膦产生自由基阳离子,去质子化产生氧膦自由基,随后加成到未活化烯烃生成新的自由基物种,最后发生分子内环化反应,得到目标产物.V_(2)O_(5)/g-C_(3)N_(4)成本较低,且该光催化反应策略可实现克级制备,循环使用5次后催化活性保持不变.综上,本文可为光催化自由基串联环化反应,杂环化合物合成研究和Z型异质结的光催化应用提供参考.
文摘The ubiquitin-proteasome proteolysis pathway is responsible for the degradation of abnormal and short-lived proteins to regulate many important biochemical activities in eukaryotes. By employing affymetrix microarray analysis, we have identified a novel ubiquitin ligase E3 gene GhRING2 that is differentially expressed between two Gossypium hirsutum lines-Texas Marker-1 (TM-1) and Chromosome Substitution Line CS-B25. The CS-B25 line has chromosome 25 from G. barbadense substituted into TM-1. The complete nucleotide sequences of GhRING2 along with its 5’-flanking region were obtained by genomic walking. GhRING2 was highly expressed in elongating fiber, and GUS expression directed by the GhRING2 promoter was found in hypocotyls and young stems of transgenic Arabidopsis plants. Using a yeast two-hybrid assay GhRING2 was found to interact with a PROTODERMAL FACTOR1 (GhPDF1) protein. GhPDF1 was expressed preferentially in immature ovules and fiber initials, and the GhPDF1 gene had been suggested to play a role in cell fate determination and fiber development. Pull down and plasmid swap assays further confirmed the interaction between GhRING2 and GhPDF1. The expression and protein interaction data indicate that GhRING2 may be involved in the turnover of GhPDF1 and participation in the transition from initiation to elongation stages during fiber development. Our data strongly suggest that the ubiquitin-proteasome pathway may regulate cotton fiber growth and development. The nucleotide sequence data of GhRING2 in this article have been submitted to the Gen Bank Nucleotide Sequence Data Bases under the accession number BankIt 1,742,008 SeqKM 108,000.
基金supported by the Foundation of Natural Science of China(12301029,11171291)Natural Science Fund for Colleges and Universities in Jiangsu Province(11KJB110019 and 15KJB110023).
文摘Let R be a ring and e,g in E(R),the set of idempotents of R.Then R is called(g,e)-symmetric if abc=0 implies gacbe=0 for any a,b,c∈R.Clearly,R is an e-symmetric ring if and only if R is a(1,e)-symmetric ring;in particular,R is a symmetric ring if and only if R is a(1,1)-symmetric ring.We show that e∈E(R)is left semicentral if and only if R is a(1−e,e)-symmetric ring;in particular,R is an Abel ring if and only if R is a(1−e,e)-symmetric ring for each e∈E(R).We also show that R is(g,e)-symmetric if and only if ge∈E(R),geRge is symmetric,and gxye=gxeye=gxgye for any x,y∈R.Using e-symmetric rings,we construct some new classes of rings.
