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991.
JIN Xiang-qun ZHANG Jing-min XU Hui ZHOU Yan WANG Guang-shu ZHAO Yan-qiu ZHANG Han-qi 《高等学校化学研究》2006,22(2):185-188
Introduction Malignantdiseasesarecharacterizedbytheunreg ulatedgrowthoftransformedcells.Inrecentyears,dramaticinsightsintothemolecularmechanismsofthis phenomenonhavebeenachievedfrombasiccancerre search.Manycellularfunctionsareregulatedbychan gesingeneexpr… 相似文献
992.
Strong pulse sequences can be used to control the position and width of the molecular wave packet. In this paper we propose a new scheme to maximally compress the wave packet in a quasistatic way by freezing it at a peculiar adiabatic potential shaped by two laser pulses. The dynamic principles of the scheme and the characteristic effect of the different control parameters are presented and analyzed. We use two different molecular models, electronic potentials modeled by harmonic oscillators, with the same force constants, and the Na(2) dimer, to show the typical yield that can be obtained in compressing the initial (minimum width) molecular wave function. 相似文献
993.
在甲烷氧化偶联制C2烃的研究中,人们发现碱土金属与稀土金属组成的复合氧化物催化剂具有高的催化活性[1,2].稀土化合物作为有希望的工业催化剂之一,已受到广泛的关注.一般认为,它们含有的氧空位对活化甲烷的有效氧物种有利.Debey等在1%Sr/La2O... 相似文献
994.
Hexa-Coordinate phosphorus Chemistry and Life Chemistry 总被引:1,自引:0,他引:1
ZHAO Yu-Fen YIN Yin-Wu LI Yan-Mei TAM Bo Department of Chemistry Tsinghua University Beijing 《有机化学》1993,(2)
The amino acids' side chains were acting as the relay device to regulate the chemical reactivi-ties of the N-phosphoryl amino acids. These modulation effects were performed through the partici-pation of the phosphoryl group. 相似文献
995.
A pressurized gradient capillary electrochromatography (pCEC) instrument was developed to separate 18 amino acid derivatives. A reversed-phase C18 column (3 microm, 130 mm x 75 microm I.D.) and an acetate buffer (50 mmol/l NaAc, pH 6.4) with an ion-pair reagent (1% N,N-dimethylformamide) were used to separate derivatized amino acids from a standard solution (2 microg/ml), and the wavelength of the UV-Vis detector was 360 nm. The pressure on the capillary column was kept at approx. 70 Pa and 3 kV positive voltage was added on the outlet end of column. The effect of voltage on the eluting order of amino acids and the resolution of separation were studied, and it was found that when the voltage was higher than 3 kV, the adsorption of amino acids in the porous C18 column occurred. The effect of salt concentration, injection volume, and column length on the separation of amino acids was determined. The amino acid sample was separated by pCEC, and RSDs of the migration times of each amino acid were all less than 2.5%. 相似文献
996.
New 2D graphical representation of DNA sequences 总被引:5,自引:0,他引:5
We consider a 2D graphical representations of DNA sequences, which avoids loss of information associated with crossing and overlapping of the corresponding curve. We outline an approach, which is based on the construction of a three-component vector whose components are the normalized leading eigenvalues of the L/L matrices associated with DNA. The examination of similarities/dissimilarities among the coding sequences of the first exon of beta-globin gene of different species illustrates the utility of the approach. 相似文献
997.
Rong Long Li Cheng You Kan Ze Ping Li Yi Du Yan Nan Cui Department of Chemical Engineering Key Laboratory of Advanced Materials of Ministry of Education Tsinghua University Beijing China 《中国化学快报》2007,18(6):741-743
The effects of ionic emulsifier, sodium dodecylbenzene sulfate (SDBS), on the formation of the multihollow structures in sub-micron sized polymer particles produced by alkali/acid posttreatment were investigated. The original latex particles with narrow size distribution were synthesized by a new sequence emulsifier-free/emulsifier emulsion copolymerization of styrene (St) and methacrylic acid (MAA). Results indicated that the pore size decreased and the pore number increased with the increase of SDBS amount, and the morphology of the posttreated latex particles was also significantly influenced by the introducing time of SDBS in the preparation of the original latex particles, and a suitable introducing time was 3 h of polymerization. 相似文献
998.
Roman Boča 《Theoretical chemistry accounts》1982,61(2):179-192
The perturbative configuration interaction using localized orbitals (the PCILO method) was extended in the way that current limitations to the two-centre bond approach were overcome. The localized molecular orbitals contain an arbitrary number of the basis set components; this follows from the a priori stated localized bonding model of a molecule. The extended PCILO method was formulated for the CNDO, INDO and NDDO Hamiltonian approximations. The configuration interaction was performed using the Rayleigh-Schrödinger many-body perturbation theory with the Møller-Plesset type of Hamiltonian partitioning, similar to that used in the so-called modified PCILO method. Applications to molecules with semi-localized and/or semi-delocalized bonds, as benzene or diborane, are presented. 相似文献
999.
Yan Shaozong 《数学年刊B辑(英文版)》1980,1(34):485-499
Let H be a Hilbert space, and let A be a linear bounded operator on H. For
\(\lambda \in \rho (A)\), the \({U_\lambda } = {(A - \lambda )^{ * - 1}}(A - \lambda )\) is called polar.Produot operator.
In this paper, we discuss the properties of \({U_\lambda }\) and the relation between \({U_\lambda }\) and A. We obtain tbe following results.
Definition. Let B be a linear bounded operator on H, suppose \(0 \in \rho (B)\). For every
\(x,y \in H\), we definite \([x,y] = (Bx,y)(H,B)\)(or (H, [·,·]) is called a non-
degenerate bilinear space (it is obvious that if B=B*,then (H,B)is a space with an
indefinite metric; and that if B>0, then (H,B) is a Hilbert Space. If an operator
U(A) satisfies
\[[Ux,Uy] = [x,y]([Ax,y] = [x,Ay]),x,y \in H\]
then the operator U(A) is called a wvitary (self adjoint) on (H,B).
Theorem I . Suppose A is a linear bounded operator on H,
(1) If \(0 \in \rho (A)\), then \(U = {A^{ * - 1}}A\) is a unitary operator on (H,A) or (H, A*), and \(\sigma (U) = \frac{1}{{\sigma (U)}}\).
(2) If there is a complex number \(\alpha \), such that \({\mathop{\rm Im}\nolimits} A \ge \alpha > 0\) then a)\(0 \in \rho (A)\), and
the operator \(U = {A^{ * - 1}}A\) is a unitary on Hilbert space \((H,{\mathop{\rm Im}\nolimits} A) and 1 \in \rho (U)\);b) there exist two Hilbert spaces \((H,{v_1}),(H,{v_2})\), such that A, A* are all the unitary operator
from (H,v1) onto (H,v2), and there are two spectral measures \(\{ E_\lambda ^i,\lambda \in [\alpha ,\chi ] \subset (0,2\pi )\} ,i = 1,2,\), such that \(AE_\Delta ^1H \subset E_\Delta ^2H,{A^ * }E_\Delta ^1H \subset E_\Delta ^2H\) for any \(\Delta = (\lambda ,u] \subset (0,2\pi ]\).
(3) If \(0 \in \rho (A) \cap \rho ({\mathop{\rm Im}\nolimits} A)\) then the operator \(U = {A^{ * - 1}}A\) is a unitary on \((H,{\mathop{\rm Im}\nolimits} A)\).
with an indefinite met He, and \(1 \in \rho (U)\).
(4) For any complex number \(\lambda = r{e^{i\theta }},\left| \lambda \right| > \left\| A \right\|\), then \({U_\lambda }\) must be a unitary operator on the Hilbert space \(\left( {H,{\mathop{\rm Im}\nolimits} (\frac{1}{{i\lambda }}A + iI)} \right),and - {e^{i2\theta }} \in \rho ({U_\lambda })\)
Theorem 2. (1) A is a normal operator iff there exists a complex number \(\lambda \),
\(\lambda \in \rho (A)\), such that \(\frac{{\partial {U_\lambda }}}{{\partial \lambda }}{U_\lambda } = {U_\lambda }\frac{{\partial {U_\lambda }}}{{\partial \lambda }}\),where \(\frac{\partial }{{\partial \lambda }}\) is the directional derivative.
(2) If there exists a complex number \(\alpha ,{\mathop{\rm Im}\nolimits} A \ge \alpha > 0\) then A is a normal operator
iff \(U = {A^{ * - 1}}A\) is also.
(3) If A is a hyperiwrmal or a subnormal, then for every \(\lambda \in \rho (A),\sigma ({U_\lambda })\) lies on the circle.
3, 4期
关于极?积算子炉一U
499
Theorem 3? Let A be a linear bounded operator on Hm Suppose 0£p(J.)?
(1) If U=А*~гА is a unitary operator in a certain non-degenerate bilinear space
(H} 1 J |Л|>1 入 J Ш=1
solmble iff (l)cr(ü) =-=i=-, (2) the operotor Ui= f XdE\ is unitarity equivalent to
cr(C7) J |л|>1
the operator ül_1 == ШЕ1, 、
J 1Л|>1
If the conditions (1),(2) are satified, then we have
(3) the subspace JJi?^2 of H reduces any solution of the equation A*"1 A — U, and
1
AI (Ягея*)1 = ^Uo where Ъ is any in vertible self-adjoint on (i?i?J?2) L, and bv Uo
(Uo = Jiai i ЫЕ1 )}⑷41Я1фя, = , Ла = A1ü2, if the operator V is to
realize TJt and Ut^unitary equivalence^ then Ai = VSf where S is any invertible on Нг
and SvUi. "
Corollary. Swpp)se operator U is a normal on a certain Hilbert space(Hy v) (^the
U is similar to a certain normal operator on IT), if U satisfies the conditions (1)、(2) of
Theorem^ on ?S,v) ? Then the general form of the solution of А*~гА = U is A = vA'y
where A' is same as A in Theorem^.
Theorem 5. Let U be a linear bounded operator on H. Suppose O?p(J.)and p(ü)
is a simply connected region, then the equation А*~гЛ = U is a solvable iff there
exists a certain space {H,v) with a indefinite metric, such that U is a unitary operator
on (Hf 丨).
If is a unitary operator on ?H,v),then there exists a particular solution of
I X+$
А*~гА = U: Ar = 2e v [ (?7 —X)_1+X], where eie ? p (JJ), and the general form of the
solution is Аж АУ, wliere V is any in vertible self-adjoint on (H, -u)and VvU, 相似文献
1000.
8-羟基喹啉衍生物及其金属配合物的合成与光致发光特性 总被引:6,自引:0,他引:6
设计合成了三种新型的8-羟基喹啉衍生物配体: 5-[(4-E-苯乙烯基)-苯甲亚胺基]-8-羟基喹啉(1), 5-[(4-溴-2-氟)-苯甲亚胺基]-8-羟基喹啉(2)和N-乙基-3-[2-(8-羟基喹啉基)-乙烯基]咔唑(3), 以及它们相应的金属配合物, 产物经质谱(MS)、元素分析(EA)、红外光谱(IR)、紫外光谱(UV)、核磁共振氢谱(1H NMR)进行表征, 并测定了它们的荧光性质. 结果与8-羟基喹啉比较表明, 5位和2位取代8-羟基喹啉衍生物的荧光发生了明显的红移. 同时测定了配合物(3)2Zn的荧光寿命, 结果表明, N-乙基-3-[2-(8-羟基喹啉基)-乙烯基]咔唑锌配合物表现出较长的荧光寿命. 相似文献