用球形、倒锥形或其他磨成圆角的测头(统称 R 形测头)测量阿基米德蜗杆与延长渐开线蜗杆(分别简称为 ZA、ZN 型蜗杆)的齿形误差时,会产生测量误差。本文从实用出发,介绍一种应用简便,计算结果足够准确的误差算式,供读者参考。并对资料...用球形、倒锥形或其他磨成圆角的测头(统称 R 形测头)测量阿基米德蜗杆与延长渐开线蜗杆(分别简称为 ZA、ZN 型蜗杆)的齿形误差时,会产生测量误差。本文从实用出发,介绍一种应用简便,计算结果足够准确的误差算式,供读者参考。并对资料上见到的一些不妥或疑误的论述提出商榷。展开更多
The effect of R-styrene-maleic anhydride copolymer （R- SMA） compatibilzation on Nylon 6 （ PA6 ）/polypropylene （ PP ） blends has been investigated experimentally through Molan test, microscopic morphology, and ch...The effect of R-styrene-maleic anhydride copolymer （R- SMA） compatibilzation on Nylon 6 （ PA6 ）/polypropylene （ PP ） blends has been investigated experimentally through Molan test, microscopic morphology, and chemical structure. Results show that the moderate R-SMA addition can promote reaction between anhydride in R-SMA and amino in PA6, and lead to a new PA6-g- R-SMA copolymer in the blends. Such PA6-g-R-SMA eopolymer in the blends can effectively reduce the interfaeial tension and PP particle size, and improve the compatibility of two immiscible phases in the blends. The crystallinity of PA6 in PA6/PP blends has greatly decreased by PP blends. The blends have the best comprehensive mechanical and thermal properties when the mass ratio of PA6/PP/ R-SMA is 90：10：2 to 90：10：4. The impact strength of the PA6/PP blends with the eompatibilizer is increased by more than 150 %.展开更多
Given a graph G and a positive integer d, an L( d, 1) -labeling of G is afunction / that assigns to each vertex of G a non-negative integer such that |f(u)-f (v) | >=d ifd_c(u, v) =1;|f(u)-f(v) | >=1 if d_c(u, v...Given a graph G and a positive integer d, an L( d, 1) -labeling of G is afunction / that assigns to each vertex of G a non-negative integer such that |f(u)-f (v) | >=d ifd_c(u, v) =1;|f(u)-f(v) | >=1 if d_c(u, v) =2. The L(d, 1)-labeling number of G, lambda_d(G) is theminimum range span of labels over all such labelings, which is motivated by the channel assignmentproblem. We consider the question of finding the minimum edge span beta_d( G) of this labeling.Several classes of graphs such as cycles, trees, complete k-partite graphs, chordal graphs includingtriangular lattice and square lattice which are important to a telecommunication problem arestudied, and exact values are given.展开更多
Studies on susceptibility to debris flows at regional scale （ioo-looo km2） are important for the protection and management of mountain areas. To reach this objective, routing models, mainly based on land topography,...Studies on susceptibility to debris flows at regional scale （ioo-looo km2） are important for the protection and management of mountain areas. To reach this objective, routing models, mainly based on land topography, can be used to predict susceptible areas rapidly while necessitating few input data. In this research, Flow-R model is implemented to create the susceptibility map for the debris flow of the Vizze Valley （BZ, North-Eastern Italy; 134 km^2）. The analysis considers the model application at local scale for three sub-catchments and then it explores the model upsealing at the regional scale by verifying two methods to generate the source areas of debris-flow initiation. Using data of an extreme event occurred in the Vizze Valley （4 August 2012） and historical information, the modeling verification highlights that the propagation parameters are relatively simple to set in order to obtain correct runout distances. A double DTM filtering - using a threshold for the upslope contributing area （0.1 km^2） and a threshold for the terrain-slope angle （15°） provides a satisfactory prediction of source areas and susceptibility map within the geological conditions of the Vizze Valley.展开更多
The multiple antibiotic resistance regulatory protein(MarR) binds to two promoter sites on the marO operator in Escherichia coli.Our study showed that more than one MarR dimer proteins bound to either of its two promo...The multiple antibiotic resistance regulatory protein(MarR) binds to two promoter sites on the marO operator in Escherichia coli.Our study showed that more than one MarR dimer proteins bound to either of its two promoter sites(Site I and Site II),suggesting that MarR might form higher complexes than homodimers when bound to DNA inside E.coli cells.To further verify this hypothesis,we site-specifically incorporated a photocrosslinking probe at the interface between two MarR dimer proteins.Photolysis in living E.coli cells revealed a covalent linkage between the two interdimer subunits of MarR,suggesting that MarR forms dimer of dimers in vivo.展开更多
We study the concept of module twistor for a module over an algebra. This concept provides a unifying framework for various deformed constructions of modules over algebras, such as module R-matrices,(n-factor iterated...We study the concept of module twistor for a module over an algebra. This concept provides a unifying framework for various deformed constructions of modules over algebras, such as module R-matrices,(n-factor iterated) twisted tensor products and L-R-twisted tensor products of algebras. Among the main results,we find the relations among these constructions. Furthermore, we study some properties of module twistors.展开更多
基金Science and Technology Program from Jiangxi Provincial Department of Education,China (No. CJJ10377)
文摘The effect of R-styrene-maleic anhydride copolymer （R- SMA） compatibilzation on Nylon 6 （ PA6 ）/polypropylene （ PP ） blends has been investigated experimentally through Molan test, microscopic morphology, and chemical structure. Results show that the moderate R-SMA addition can promote reaction between anhydride in R-SMA and amino in PA6, and lead to a new PA6-g- R-SMA copolymer in the blends. Such PA6-g-R-SMA eopolymer in the blends can effectively reduce the interfaeial tension and PP particle size, and improve the compatibility of two immiscible phases in the blends. The crystallinity of PA6 in PA6/PP blends has greatly decreased by PP blends. The blends have the best comprehensive mechanical and thermal properties when the mass ratio of PA6/PP/ R-SMA is 90：10：2 to 90：10：4. The impact strength of the PA6/PP blends with the eompatibilizer is increased by more than 150 %.
文摘Given a graph G and a positive integer d, an L( d, 1) -labeling of G is afunction / that assigns to each vertex of G a non-negative integer such that |f(u)-f (v) | >=d ifd_c(u, v) =1;|f(u)-f(v) | >=1 if d_c(u, v) =2. The L(d, 1)-labeling number of G, lambda_d(G) is theminimum range span of labels over all such labelings, which is motivated by the channel assignmentproblem. We consider the question of finding the minimum edge span beta_d( G) of this labeling.Several classes of graphs such as cycles, trees, complete k-partite graphs, chordal graphs includingtriangular lattice and square lattice which are important to a telecommunication problem arestudied, and exact values are given.
基金granted by the Junior Research Grant Universitàdegli Studi di Padova,year 2013,prot.CPDR138494(“Criticitàidrauliche nel reticolo montano nei riguardi del movimento di detrito legnoso e di colate detritiche”Prof.Vincenzo D’Agostino)
文摘Studies on susceptibility to debris flows at regional scale （ioo-looo km2） are important for the protection and management of mountain areas. To reach this objective, routing models, mainly based on land topography, can be used to predict susceptible areas rapidly while necessitating few input data. In this research, Flow-R model is implemented to create the susceptibility map for the debris flow of the Vizze Valley （BZ, North-Eastern Italy; 134 km^2）. The analysis considers the model application at local scale for three sub-catchments and then it explores the model upsealing at the regional scale by verifying two methods to generate the source areas of debris-flow initiation. Using data of an extreme event occurred in the Vizze Valley （4 August 2012） and historical information, the modeling verification highlights that the propagation parameters are relatively simple to set in order to obtain correct runout distances. A double DTM filtering - using a threshold for the upslope contributing area （0.1 km^2） and a threshold for the terrain-slope angle （15°） provides a satisfactory prediction of source areas and susceptibility map within the geological conditions of the Vizze Valley.
基金supported by research grants from the National Natural Science Foundation of China(91013005, 21001010 and 20932006 to P.R.C.)National Key Basic Research Foundation of China(2010CB912300 to P.R.C.)
文摘The multiple antibiotic resistance regulatory protein(MarR) binds to two promoter sites on the marO operator in Escherichia coli.Our study showed that more than one MarR dimer proteins bound to either of its two promoter sites(Site I and Site II),suggesting that MarR might form higher complexes than homodimers when bound to DNA inside E.coli cells.To further verify this hypothesis,we site-specifically incorporated a photocrosslinking probe at the interface between two MarR dimer proteins.Photolysis in living E.coli cells revealed a covalent linkage between the two interdimer subunits of MarR,suggesting that MarR forms dimer of dimers in vivo.
基金supported by National Natural Science Foundation of China (Grant Nos. 11201285 and 11371238)the First-class Discipline of Universities in Shanghai
文摘We study the concept of module twistor for a module over an algebra. This concept provides a unifying framework for various deformed constructions of modules over algebras, such as module R-matrices,(n-factor iterated) twisted tensor products and L-R-twisted tensor products of algebras. Among the main results,we find the relations among these constructions. Furthermore, we study some properties of module twistors.
