Synthesis, structure and magnetic properties of two new coordination polymers with carboxylate-substituted benzoimidazole ligands

This paper reports two new coordination polymers formed by carboxylate-substituted benzoimidazole and formate ligands: [Mn(L)·(HCO2)]n (1) and [Co(L)·(HCO2)]n (2) (L = benzoimidazol-1-yl-acetate). Com-plexes 1 and 2 are isomorphous and adopt a new 3,6-connected three-nodal topology showing inter-esting magnetic properties: spin canted antiferromagnetism for MnⅡ complex 1, but simple antiferro-magnetic coupling for CoⅡ complex 2.     

New results on the geometry of the moduli space of Riemann surfaces

We briefly survey our recent results about the Mumford goodness of several canonical metrics on the moduli spaces of Riemann surfaces,including the Weil-Petersson metric,the Ricci metric, the Perturbed Ricci metric and the Kahler-Einstein metric.We prove the dual Nakano negativity of the Weil-Petersson metric.As applications of these results we deduce certain important results about the L~2-cohomology groups of the logarithmic tangent bundle over the compactifled moduli spaces.     

Investigation of changes in properties of water under the action of a magnetic field

The properties of water and their changes under the action of a magnetic field were gathered by the spectrum techniques of infrared, Raman, visible, ultraviolet and X-ray lights, which may give an insight into molecular and atomic structures of water. It was found that some properties of water were changed, and a lot of new and strange phenomena were discovered after magnetization. Magnetized water really has magnetism, which has been verified by a peak shift of X-ray diffraction of magnetized water + Fe₃O₄ hybrid relative to that of pure water + Fe₃O₄ hybrid, that is a saturation and memory effect. The properties of infrared and ultraviolet absorptions, Raman scattering and X-ray diffraction of magnetized water were greatly changed relative to those of pure water; their strengths of peaks were all increased, the frequencies of some peaks did also shift, and some new peaks, for example, at 5198, 8050 and 9340 cm⁻¹, occurred at 25°C after water was magnetized. In the meanwhile, the magnetized effects of water are related to the magnetized time, the intensity of an externally applied magnetic field, and the temperature of water, but they are not a linear relationship. The study also showed a lot of new and unusual properties of magnetized water, for example, the six peaks in 3000–3800 cm⁻¹ in infrared absorption, the exponential increase of ultraviolet absorption of wave with the decreasing wavelength of light of 200–300 nm, the frequency-shifts of peaks, a strange irreversible effect in the increasing and decreasing processes, as well as a stronger peak of absorption occurring at 50°C, 70°C and 80°C, the existence of many models of motion from 85°C to 95°C in 8000–10000 cm⁻¹, and so on. These results show that the molecular structure of water is very complicated, which needs further study. Furthermore, the macroscopic feature of mechanics, for instance, surface tension force of magnetized water, was also measured. Experiments discovered that the size in contact angles of magnetized water on the surface of hydrophobic materials decreases, thus the surface tension force of magnetized water decreases relative to that of pure water. It is seen from the above results that the clustering structure of hydrogen-bonded chains and polarization effects of water molecules are enhanced after magnetization. These results are helpful in revealing the mechanism of magnetization of water. Supported by the National Basic Research Program of China (Grant No. 2007CB936103)     

超分子抗癌药物双环铂的结构研究

铂类抗癌药物在水中的溶解度和稳定性直接与药物的活性和毒性有关.几十年来,为了改进药物的效能和降低药物的毒性,做了大量的研究.超分子铂类化合物可能具有与众不同的物理化学性质,我们成功设计和合成了一个新型的超分子抗癌药物-双环铂,己证实双环铂对人类的恶性肿瘤有好的治疗效果.用X射线单晶衍射法测定了双环铂的晶体结构,又用电喷雾离子化质谱研究了它在水溶液中的状态.根据实验结果提出了双环铂在水溶液中的结构模型,解释了双环铂在水中好的稳定性和溶解度.     

Properties of nonadiabatic quantum fluctuations of the strongly coupled electron-phonon systems

A new variational-ansatz of states of electrons and phonons was proposed on the basis of the Holstein model in strongly coupled electron-phonon systems for studying the influence of nonadiabatic phonon fluctuation, arising from the motion and density fluctuation of electrons, on the properties of ground state, uncertainty relation, stability of polarons, charge density wave (CDW) and phonon staggered ordering. The new ansatz represents the correlation among the displacement and squeezing states of phonons and polaron’s state of electrons as well as the squeezing-antisqueezing effect. The correlation and squeezing-antisqueezing effect result in the decrease of ground state energy, enhancement of stability of the systems, increase of binding energy of the polarons, weakening of the growing speed of polaron narrowing of the electron band, increase of the charge density wave order and suppression of the increased tendency of anomalous quantum fluctuation of the phonons in such a case, when compared with the uncorrelated case in the systems. The results obtained show that the ground state determined by the new state ansatz is most stable, thus the new ansatz describing the properties of the coupled electron phonon systems is very relevant and available, especially in strongly coupled and largely squeezed cases. Supported by the National “973” Project of China (Grant No. 2007CB6103)     

Global spherically symmetric classical solution to the Navier-Stokes-Maxwell system with large initial data and vacuum

We study the initial boundary value problem to the system of the compressible Navier-Stokes equations coupled with the Maxwell equations through the Lorentz force in a bounded annulus Ω of R3. And a result on the existence and uniqueness of global spherically symmetric classical solutions is obtained. Here the initial data could be large and initial vacuum is allowed.     

Synthesis and biological evaluation of peptide-siRNA conjugates with phosphodiester unit as linker

In this paper, a series of peptide-siRNA conjugates with phosphodiester unit as the linker targeting to Cdc2 gene were synthesized by solid phase stepwise strategy. The conjugation of peptides at either 3′-terminus of siCdc2 bring no change to the classical A-form of RNA duplex, but slightly compromise the thermodynamic stability. Peptide conjugation at the 3′-terminus of sense strand could improve the serum stability obviously, however, the opposite peptide conjugation at the 3′-terminus of antisense strand shows no such influence. According to the results of artificial silencing activity assay system, peptide conjugation at 3′-terminus of antisense strand slightly weakens the silencing activity of siCdc2. But sense strand peptide conjugation exhibits similar silencing activity as native siCdc2, meanwhile, it could mitigate the unwanted off-target effect of sense strand targeting to its own mRNA.     

Electrical characteristics of Pt-ZnO Schottky nano-contact

The electrical characteristics of Pt-ZnO Schottky nano-contact have been studied. Well aligned ZnO nanorod arrays were synthesized by two-step wet-chemical method. A Pt-coated conducting probe of atomic force microscope was placed on the head face of the ZnO nanorod, thereby forming a Pt-ZnO nano-contact. The I-V characteristic curve shows that the Pt-ZnO nano-contact exhibits rectifying effect, like a Schottky diode with an ideality factor of 3.2 and a reverse-bias breakdown voltage more than -10 V. The st...     

Curvature measurement of optical surface using digital holography

In this paper, an optical surface curvature measurement technique based on digital holography is proposed. Unlike the previous digital holographic methods, which only involve a small part of the measured data for parameter estimation, the proposed method adopts more of them using least square method. Hence, the analyzed result is not affected by data extraction direction and less sensitive to imperfect phase compensation. The proposed method is demonstrated with a sample of reflection mirror in laser resonator, and verified by comparing the measurement result with that of the white light interferometer.     

Stability of bifurcating periodic solutions for a single delayed inertial neuron model under periodic excitation

Using the averaged method, we investigate the dynamical characteristics of a single inertial neuron model with time delay under periodic external stimuli. It is shown that the system will lose its stability when the time delay is increased and will give rise to a quasi-periodic motion and chaos under the interaction of the periodic excitation. Numerical simulations show that the results of the analytical method are correct by a comparison with those of direct numerical integration.