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81.
The translocation dynamics of a single biopolymer chain through a nanopore in a membrane is investigated by taking the coil-helix transition into account. Based on the changing of the free energy due to the coil-helix transition, the mean first passage time T is obtained, and then the corresponding numerical simulations are presented under different conditions. It is shown that the coil--helix transition can significantly shorten the translocation time of the biopolymer chain. In addition, we also discuss the scaling behaviour for T with the chain length N and some related problems. 相似文献
82.
83.
Using translation formulas for Slater type orbitals (STO’s) the infinite series through the overlap integrals are derived
for the magnetic multipole moment integrals. By the use of the derived expressions the magnetic multipole moment integrals,
therefore, the magnetic properties of molecules can be evaluated most efficiently and accurately. The convergence of the series
is tested by calculating concrete cases. An accuracy of 10−5 for the computer results is obtained in the case 2
p
-pole magnetic moment integrals for 1 ≤ v ≤ 5, and for the arbitrary values of internuclear distances and screening constants of atomic orbitals. 相似文献
84.
To improve the students' autonomous learning ability and learning enthusiasm in practice course,we introduce micro video,which is short,fast,precise,easy,and fun,into inorganic chemistry laboratory teaching.As an important supplementary means of teaching,micro videos will solve the repeated problems,help students promote study efficiency,provide students with a good way for communication,and improve the students' study enthusiasm. 相似文献
85.
Chaos in an Ar+ Composite Resonator Laser Using KNSBN;Cu Crystal Self-Pumped Phase-Conjugator 下载免费PDF全文
Observation of the dynamics in a single-mode Ar+ composite resonator laser using KNSBN;Cu crystal self-pumped phase-conjugator is reported. The sequence of instabilities occurring on gain change corresponds to the transition the chaos of the logistic equation. Period-doubling route to chaos, and period-5, -3,-3×2, and -2 together with -3 windows in the chaotic range were observed. The strange attractor which is similar to that of the forced Duffing equation is obtained by reconstructing phase-space pictures of the system. 相似文献
86.
87.
Electron and hole transfer from indium phosphide quantum dots 总被引:1,自引:0,他引:1
Blackburn JL Selmarten DC Ellingson RJ Jones M Micic O Nozik AJ 《The journal of physical chemistry. B》2005,109(7):2625-2631
Electron- and hole-transfer reactions are studied in colloidal InP quantum dots (QDs). Photoluminescence quenching and time-resolved transient absorption (TA) measurements are utilized to examine hole transfer from photoexcited InP QDs to the hole acceptor N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) and electron transfer to nanocrystalline titanium dioxide (TiO2) films. Core-confined holes are effectively quenched by TMPD, resulting in a new approximately 4-ps component in the TA decay. It is found that electron transfer to TiO2 is primarily mediated through surface-localized states on the InP QDs. 相似文献
88.
To raise the room temperature ionic conductivity and improve the mechanical strength of a PEO-based polymer electrolyte, a noncrystalline two-component epoxy electrolyte system has been prepared. The diglycidyl ether of polyethylene glycols as precursors of the system were synthesized by a two-step process. The presumed structure of the product was characterized, by ~(13)C, ~1H NMR and IR spectroscopy. It was found that a side-reaction occurred between the secondary hydroxyl group of PEG-chlorohydrin and epichlorohydrin in some degree, resulting in a by- product containing—CH_2Cl side group. By selecting a characteristic signal, which is undistorted by the increase in the length of CH_2 CH_2—O segment, a ~1H NMR approach of determining the equivalent epoxy weight (EEW) was proposed. The method is valid to specimens even though the EEW is as high as 2,000. The examination of the specimens by DSC showed that epoxidation greatly depressed the crystallinity of the PEG's, whereas the T_g was raised. 相似文献
89.
Polymeric solid electrolyte system composed of triglycidyl ether of glycerol (TGEG), diglycidyl ether of polyethylene glycol (DGEPEG)and LiClO_4 salt were synthesized. In this" system the electrolyte has a pecularity that not merely can the LiClO_4 provide ionic carriers, but also catalyze the crosslinking reaction without adding an usual curing agent. The effect of salt content and degree of crosslinking on the viscoelasticity and ionic conductivity were studied. Both WLF and VTF equations were used to treat the experimental data in order to elucidate the mechanism of ionic conduction. It was found that the ionic conductivity of the system is carded out through the segmental motion mechanism. However, the data must be treated with care. For example, in evaluating WLF parameters, the contribution concerned with ionic carrier generation with temperature to the conductivity must be differentiated from that concerned with segmental motion. Besides, the temperature range suitable to WLF equation must also be considered. For VTF equation, it might be inapplicable ff the temperature is too low and close to the glass transition temperature of the specimen. Further study is needed in order to have a quantitative information on the limitation of these equations. 相似文献
90.