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21.
A novel oxamide-bridged trimeric tetranuclear complex 1 incorporating a macro- cyclic oxamide of formula {[(CuL)3Mn](ClO4)2}3 (macrocyclic oxamide L = 2,3-dioxo-5,6,14,15- dibenzo-1,4,8,12-tetraazacyclopentadeca-7,12-diene) was prepared and structurally characterized. The compound [(CuL)3Mn](ClO4)2 crystallizes in the trigonal system, space group with a = 22.434(17), b = 22.434(17), c = 18.82(2) (A), α = β = 90, γ = 120o, V = 8203(13) (A)3, Z = 6, Dc = 1.751g/cm3, μ(MoKα) = 1.557, F(000) = 4392, the final R = 0.083 and wR = 0.1727 for 9604 obser- ved reflections with I > 2σ(I). The single-crystal X-ray analysis shows that 1 is a trimeric complex. There are three similar constitutes, dissimilar conformations and asymmetrically independent 'building-block' [(CuL)3Mn] in one crystal cell of the title complex 1. 相似文献
22.
基于金纳米棒构成的三聚体微元结构模型,详细地研究了等离激元诱导透明(plasmon induced transparency,PIT)现象产生的物理过程.研究发现,三聚体的吸收谱线随着其耦合距离以及尺寸的变化,竖直金纳米棒所对应的偶极明模在平行双长条金纳米棒对应的暗模作用下会产生分裂.依据这一结果提出了一个新的物理解释,PIT现象的产生主要来自于竖直金纳米棒中偶极振荡的模式分裂后的相干叠加.同时,考虑到两个振子之间的耦合会伴随着一定的相位关联性,进而引入了耦合相位因子修正了洛伦兹振子耦合模型,解析地研究了耦合相位因子对吸收谱的调控作用和分裂明模之间的相干叠加效应对PIT效应的影响.这为在纳米尺寸范围设计人造原子、光开关、慢光效应等方面的应用提供了理论参考. 相似文献
23.
The Bose-Hubbard model with an effective off-site three-body tunneling,characterized by jumps towards one another,between one atom on a site and a pair atoms on the neighborhood site,is studied systematically on a one-dimensional(1D) lattice,by using the density matrix renormalization group method.The off-site trimer superfluid,condensing at momentum k = 0,emerges in the softcore Bose-Hubbard model but it disappears in the hardcore Bose-Hubbard model.Our results numerically verify that the off-site trimer superfluid phase derived in the momentum space from[Phys.Rev.A81,011601(R)(2010)]is stable in the thermodynamic limit.The off-site trimer superfluid phase,the partially off-site trimer superfluid phase and the Mott insulator phase are found,as well as interesting phase transitions,such as the continuous or first-order phase transition from the trimer superfluid phase to the Mott insulator phase.Our results are helpful in realizing this novel off-site trimer superfluid phase by cold atom experiments. 相似文献
24.
通过六氟丙烯三聚体(全氟壬烯)氧基苯磺酸钠(C9F17OC6H4SO3Na,OBS)与阳离子碳氢表面活性剂CnNR[CnH2n+1N(CH3)3Br,CnNM,n=8,10和CnH2n+1N(CH2CH3)3Br,CnNE,n=8,10,12]复配,研究了OBS与CnNR的摩尔比、CnNR疏水链长及CnNR亲水基团大小对此类阴、阳离子碳氟-碳氢表面活性剂混合体系的临界胶束浓度(cmc)、最低表面张力(γcmc)、总饱和吸附量((Γ)tm)及极限分子面积(Amin)的影响.结果表明,通过与CnNR复配,OBS的cmc和γcmc均大幅下降,达到了全面增效的结果.不同摩尔比的OBS-C8NE混合体系中,摩尔比为1∶1时表面活性最好,cmc和γcmc均最小;偏离等摩尔比时,OBS过量时混合体系的cmc小于C8 NE过量时混合体系的cmc,但γcmc相差不大.与单体系相比,OBS-C8 NE混合体系的(Γ)tm明显增大、Amin明显变小.OBS与不同疏水链长的CnNE复配时,cmc的变化规律为C8NE>C10NE>C12NE,表明CnNE疏水链长的增加能降低混合体系的cmc.通过比较CnNM和CnNE(n=8,10)的表面活性发现,改变混合体系中CnNR的亲水基团大小对混合体系的表面活性无明显影响. 相似文献
25.
取代基对木质素三聚体模型化合物醚键均裂反应影响的密度泛函理论研究 《燃料化学学报》2016,44(3):335-341
利用密度泛函理论M062X/6-31++G(d,p)方法,对27种具有不同取代基(甲基、羟甲基和甲氧基)的木质素三聚体模型化合物的Cα-O和Cβ-O键均裂解离能进行了理论计算,探究了不同位置取代基对醚键解离能的影响规律。结果表明,当R2或R3位氢原子仅有一个被甲氧基取代时,Cβ-O键解离能变化很小;当R2、R3位氢原子均被甲氧基取代时,Cβ-O键解离能明显降低;且R4、R5位甲氧基能强化R2、R3位甲氧基对Cβ-O键解离能的降低程度,而不受R1位取代基的影响。当R4、R5位氢原子相继被甲氧基取代时,Cα-O键解离能逐渐降低,且R2、R3位甲氧基也能强化R4、R5位甲氧基对Cα-O键解离能的降低程度。当R1位氢原子相继被甲基、羟甲基取代时,Cα-O键解离能逐渐升高,然而R2、R3位甲氧基会弱化R1位甲基、羟甲基对Cα-O键解离能的升高程度;R1位甲基不会影响Cβ-O键解离能,羟甲基却能明显提高Cβ-O键解离能。 相似文献
26.
In this paper, we study quantum dynamics of entanglement and single excitation transfer (SET) in an LH1-RC-type trimer which can describe a basic unit cell in the LH1-RC complex in the photosynthetic process. It is shown that there exists a sudden change of entanglement at the critic point of quantum phase transition (QPT) of the system at low temperatures, the entanglement sudden change caused by the QPT is suppressed at higher temperatures. We investigate the influence of environment on entanglement and SET. We show the generation of the dephasing-assisted entanglement between a donor and an acceptor and the existence of the steady-state entanglement, and demonstrate the entanglement transfer from donor-donor entanglement to donor-acceptor entanglement in the dynamic evolution. We reveal the close relation between the SET probability and donor-acceptor entanglement. Especially, we find that the SET probability is proportional to the amount of donor-acceptor entanglement under certain conditions. 相似文献
27.
The effects of magnetic exchange, double exchange and vibronic coupling on magnetic properties of the d1–d1–d2 trimer with C2V symmetry are discussed in the generalized vibronic model. The magnetic moments are calculated with the semiclassical adiabatic approach. The results show that the PKS vibronic coupling and the P vibronic coupling favor the localization and the delocalization of the ‘extra’ electron, respectively. The magnetic properties are determined by the interplay among magnetic exchange, double exchange and vibronic coupling. 相似文献
28.
We have reported previously the ultrafast energy transfer process with a time constant of 0.8 ps from a monomeric to a dimeric subunit within a perylenetetracarboxylic diimide trimer, which was derived indirectly from a model fitting into the transient absorption ex-perimental data. Here we present a direct ultrafast fluorescence quenching measurement by employing fs time-resolved transient fluorescence spectroscopy based on noncollinear optical parametric amplification technique. The rapid decay of the monomer's emission due to en-ergy transfer was observed directly with a time constant of about 0.82 ps, in good agreement with the previous result. 相似文献
29.
We study exciton transfer dynamics in a trimer system by investigating excitation transfer probability (ETP). We calculate ETP in the zero-temperature limit and theoretically predict the environment-assisted quantum critical effect, in which ETP exhibits a sudden change at the critical point of quantum phase transition for the trimer. In particular, we find that the steady-state ETP can be observed in the presence of the environment interaction. 相似文献
30.
SHIYing-yan WANGXing-qiao LIXiang-qing ZHENGWen-qi DINGHong ZHUGuang-shan LIUGuo-fa 《高等学校化学研究》2004,20(3):262-265
ω-Bromopropylporphyrin ether synthesized from the raction of 1,3-dibromopropane as the bridge-linkedreagent and 5- (4-hydroxyphenyl)-10,15,20-triphenylporphyrin (H2MHTPP) as the matrix reacts with 5, 15-di(4- hydroxyphenyl)-10, 20-diphenyl porphyrin(trans-H2DHDPP) to give the title nanometer porphyrintrimer. The characterization was carried out by means of elemental analyses, UV-Vis, IR, ^1H NMR andXRD. 相似文献