A PREDATOR-PREY SYSTEM WITH STAGE STRUCTURE AND HARVESTING FOR PREDATOR

In this paper, we consider a predator-prey system with stage structure and harvesting (where the predator population has two stages, an immature stage and a mature stage with harvesting, and the growth of the prey population is of Lotka-Volterra nature). We obtain the conditions of the globally asymptotic stability for three nonne-gative equilibria of this system.     

ISOLATION AND CHARACTERIZATION OF THE PRESUMED PHOTORECEPTOR PROTEIN OF Blepharisma japonicum

Abstract— Photosensory responses in the ciliated protozoan Blepharisma japonicum are mediated by a hypericin-like chromophore, blepharismin, localized in granules distributed under the cell membrane. A blepharismin-binding protein, with an apparcnt molecular weight ranging between 35 and 38 kDa, has been isolated by means of column separations and preparative isoelectric focusing and characterized by means of gel electrophoresis, analytic isoelectric focusing as well as absorption and fluorescence spectroscopy.     

TBP萃淋树脂吸附钪的性能研究及应用

本文采用静动态两种方法较系统地研究了TBP草淋树脂在高氟酸介质中吸附钪的性能，并用自己设计的减压微色谱柱考察了共存离子的萃取色谱行为，选择了分离微量钪的最佳条件，获得了良好的分离效果，用于标准矿样中微量机的测定，分析结果与标准值相近。     

瞬态功率光限幅实验

应用单脉冲时间分辨技术测量了富勒烯溶液瞬态功率光限幅特性。在激发波长为532nm,脉冲宽度为8ns,峰值功率密度达到180MW/cm²的条件下,其瞬态功率光限幅的开关速度约为5ns.     

测量液体粘滞系数实验的研究

本文利用液体的绝对速度理论得到液体的粘滞系数随温度变化的关系式，在不同的温度下测得液体的粘滞系数，找出液体的粘滞系数随温度变化的数学表达式。     

The nature of the lowest triplet configuration of flavins

Abstract— The phosphorescence spectrum of riboflavin has been reexamined at 77°K in an ethylene glycol: water matrix. The phosphorescence occurs at approximately the 605 nm (ca. 2-·05 eV) region, in reasonable agreement with the theoretical calculations of 1·6–1·8 eV [21]. The emission was found to be negatively polarized, and to have a relatively long lifetime (0·56 sec). On the basis of this data and additional theoretical results, it is concluded that the lowest triplet of riboflavin is of ³(τ,τ*) type. Upon addition of potassium iodide, the phosphorescence emission is enhanced through spin-orbit perturbation. The presence of oxygen (atmospheric pressure) in the frozen glass apparently has no effect on the emission. The phosphorescence spectra of alloxazine are also presented. Results of the present work have been applied to the photodephosphorylation of menadiol diphosphate in elucidating its mechan ism involving the riboflavin triplet and singlet oxygen.     

Crystal structure and properties of FeSr2NdCu2O7+δ

The compound FeSr₂NdCu₂O₇₊ (Fe1212) was successfully synthesized by solid-state reaction. X-ray diffraction data indicate that the sample is of single phase. Rietveld whole-pattern-fitting method was used to refine the crystal structure of samples prepared under different annealing conditions using the tetragonal system with space group P4/mmm. Magnetization measurements indicate that magnetic susceptibility changes with temperature in a Curie-type manner. Resistance measurements indicate that these samples have a semiconductor-like behavior. PACS 61.10.Nz; 74.72.Jt     

Barium ferrite (BaFe12O19) thin films prepared by pulsed laser deposition on MgO buffered Si substrates

Barium ferrite (BaFe₁₂O₁₉) thin films have been deposited by pulsed laser deposition (PLD) on Si substrates with MgO underlayers. The films were deposited in oxygen atmosphere by excimer laser (=248 nm, pulse duration=23 ns) in the temperature range 750–900 °C. The experiments showed that the substrate temperature has remarkable effect on the films magnetic and structural properties. The BaFe₁₂O₁₉ films deposited at 900 °C in 200 mTorr oxygen showed some perpendicular orientation, with a perpendicular squareness of 0.5 and an in-plane squareness of 0.3. Such thin BaFe₁₂O₁₉ films have platelet grains with a size of about 300 nm. The perpendicular saturation magnetization and coercivity are 185 emu/cm³ and 1.4 kOe, respectively. PACS 81.15.Fg.; 75.70.Ak; 75.50.Pp; 68.55.j     

Room temperature diluted magnetic semiconductor synthesized by dual beam laser deposition

Diluted magnetic semiconductor Co-doped ZnO film has been synthesized by a dual beam pulsed laser deposition method. The magnetic, electrical, and optical properties of the Zn_0.985Co_0.015O_0.67 film are studied in this paper. The film shows ferromagnetic behavior with a coercivity of about 300 Oe at room temperature, and semiconductor behavior with carrier concentration of 2.2×10¹⁸ cm^-3, and a resistivity of 102 mcm. Structural investigations indicated that the film has similar lattice constants to that of ZnO. It is shown that the film exhibits excellent optical properties with a band gap energy of 3.31 eV, which is close to that of ZnO. The origins of the magnetism are also discussed. PACS 81.15.Fg; 75.50 Pp; 61.72.Vv