上三角矩阵代数上的保不变子空间格映射

设Tn是数域F上的n×n阶上三角矩阵代数,其中F是实数域R或复数域C.利用矩阵的可加性,证明了Tn上的每一个保不变子空间格的可加映射Φ为:Φ(A)=αA+φ(A)I ((A)A∈Tn),其中α是非零常数,φ∶Tn←F是可加映射,I∈Tn是单位算子.     

域上2×2矩阵代数保立方幂等的映射

设F为元素个数大于3的域,M2(F)为F上的2×2矩阵代数,T2(F)≡{T| T3=T,T∈M2(F)}.所有满足φ:M2(F)→M2(F),A+λB∈T2(F)＝>φ(A)+λφ(B)∈T2(F),∨A,B∈T2(F),λ∈F的单映射构成的集合用Φ表示.利用保立方幂等映射和原象之间的关系刻画了集合Φ中元素的形式.     

广义特征值的稳定性及刻画

设A是复Hilbert空间X上的有界线性算子,任意λ∈C,如果存在X上的非零有界线性算子B使得AB=λBA,那么就称λ是A的一个广义特征值．记A的全体广义特征值所构成的集合为∑（A）．利用算子分块的技巧,讨论了上三角算子矩阵的广义特征值的稳定性问题．此外,对X上的正可逆算子A,证得∑（A^n/m）=（∑（A））n/m,其中n,m∈Z,并且m≠0．     

Mn上保持矩阵自Jordan积的线性映射

设Mn是复数域上n×n矩阵代数,Φ是Mn上的非零线性映射,则Φ保持自Jordan积,即(V)A∈Mn,都有Φ(A*(.)A)=Φ(A)*(.)Φ(A)当且仅当存在Mn中的酉矩阵U,使得Φ(X)=UXU*,(V)X∈Mn,或者Φ(X)=UXTU*,(V) X∈un,其中XT表示矩阵X的转置.     

M2（R）上保持积AB-BAT的映射

设M2(R)是二阶实矩阵代数,A,B∈M2(R),定义新积[A B]T=AB-BAT,其中AT表示矩阵A的转置.φ是M2(R)→M2(R)上的非线性齐次双射且满足([A B]T)=[φ(A)φ(B)]T,则存在正交矩阵Q∈M2(R),对任意矩阵A∈M2(R),都有φ(A)=QAQT.     

因子von Neumann代数上的正交可导映射

设M是作用在维数大于2的复可分Hilbert空间(A)上的因子von Neumann代数如果(V)A,B∈M且A*B ＝AB*＝0,有φ(A)*B+A*φ(B)＝φ(A)B*+Aφ(B)*＝0,则称φ是M上的正交可导线性映射.证明了M上有界的正交可导线性映射是广义内导子.     

中心自共轭矩阵的一些性质

引入中心自共轭矩阵的定义,给出了中心自共轭矩阵的代数和、转置、积(幂及张量积)以及伴随矩阵也是中心自共轭矩阵的结论.得出当δ(A)＝δ(A-),以及当V是n阶翻矩阵,λ0∈δ(A),0≠X0=(a1,a2,…,an)Y∈Cn,AX0=λX0时,有A-VX0=λX0等论断.     

k-free数与其逆的差

运用Kloosterman和、特征和以及三角和的一些基本性质和估计得到了k-free数与其逆的差的一个渐近公式.并且证明了:当k≥2,m≥2,n2,n∈N,k∈N,m∈N,ε0时,M(n,m;k)=2φ(n)nm/ζ2(k)(m+1)(m+2)+O(2mnm+1/2+2/(k+1)+2εd(n)σ-1/2(n)σ(n)).特别是当k=2时,有无平方因子数与其逆的差:M(n,m;2)=72φ(n)nm/π4(m+1)(m+2)+O(2mnm+1/2+2/(k+1)+2εd(n)σ-1/2(n)σ(n).此处的d(n)表示因数函数,(n)表示欧拉函数.     

三角代数上的n阶导子系

设U=Tri(A,M,B)是三角代数,Dn={δ0,δ1,…,δn}为U上的一组可加映射且δ0=I.若A,B∈U有δm(AB)=∑mk=0Cmkδk(A)δm-k(B)(m=0,1,2,…,n),则称Dn为U上的一个n阶导子系,若A∈U有δm(A2)=∑mk=0Cmkδk(A)δm-k(A)(m=0,1,2,…,n),则称Dn为U上的一个n阶Jordan导子系.利用算子论的方法讨论了三角代数上的n阶导子系,证明了三角代数上的每个n阶Jordan导子系都是n阶导子系.     

两组谱数据之间势函数的关系

研究由谱数据等相关信息所建立的Sturm-Liouville逆问题.根据谱数据相关信息,建立积分方程K(x,s)+F(x,s)+∫0xK(x,t)F(t,s)dt=0,通过此方程得出2个势函数差距的具体表达式,即(x)-q(x)=2d/dx∑n=0 N 1/cn[φ(x,n)φ~(x,n)-φ(x,λn)φ~(x,λn)].     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press