光谱法研究α-萘乙酸与核酸的相互作用

利用荧光光谱法研究了α-萘乙酸（NAA）与DNA之间的相互作用。结果表明,DNA能使NAA的荧光强度猝灭,根据荧光强度变化和荧光猝灭公式求得NAA与DNA的荧光猝灭常数。荧光寿命实验结果表明,荧光猝灭是由形成复合物的静态猝灭过程所致。黏度实验、离子强度实验等多种实验结果表明,NAA与DNA间的结合作用为部分插入式和沟槽式相结合。     

高效液相色谱法测定普卢利沙星胶囊的含量

建立高效液相色谱法测定普卢利沙星胶囊含量的方法。采用高效液相色谱法,以0.01mol.L-1盐酸溶液为溶剂,测定波长为280nm。在10—100μg.mL-1浓度范围内,主峰面积与相应的浓度呈良好的线性关系（r=0.9998）。重复测定峰面积平均值为1215.9（n=6）,相对标准偏差为0.7%。平均回收率为99.77%（n=9）,相对标准偏差为0.26%。该方法准确简便、重复性好,可作为普卢利沙星胶囊含量测定的有效方法。     

Solid-state dye lasers based on polymethyl methacrylate modified with methanol

Solid-state dye samples based on modified polymethyl methacrylate with methanol (MPMMA) doped with pyrromethene 567 (PM567) were first prepared. The effects of volume percentage of methanol on the laser performances of the samples, including spectra properties, slope efficiency and photostability were studied. The highest slope efficiency 66.39% was obtained in the sample (MMA:methanol = 16:4). Pumping the samples at a repetition rate of 5 Hz with a pulse energy as high as 100 mJ (the fluence was 0.26 J/cm²), the output energy dropped to half of its initial value after approximate 156720 shots and the corresponding normalized photostability reached 101.86 GJ/mol in the sample (MMA:methanol = 17:3). Our results indicate that it can obtain a high slope efficiency and good photostability for a solid-state dye laser using MPMMA as solid hosts.     

Diode-pumped Nd<Superscript>3+</Superscript>:YAl<Subscript>3</Subscript>(BO<Subscript>3</Subscript>)<Subscript>4</Subscript> laser at 1338 nm

A high-power diode -pumped Nd³⁺:YAl₃(BO₃)₄ (Nd:YAB) laser emitting at 1338 nm is described. At the incident pump power of 9.8 W, as high as 734 mW of continuous-wave (CW) output power at 1338 nm is achieved. The slope efficiency with respect to the incident pump power was 9.0%. To the best of our knowledge, this is the first demonstration of such a laser system. The output power stability over 60 min is better than 2.6%. The laser beam quality M ² factor is 1.21.     

Synthesis and luminescence properties of novel 4-(N-carbazole methyl) benzoyl hydrazone Schiff bases

4-(N-carbazole methyl) benzoyl hydrazine was synthesized on the basis of carbazole, and then nine novel carbazolyl acylhydrazone Schiff bases were synthesized by the condensation reaction between 4-(N-carbazole methyl) benzoyl hydrazine and the substituted benzaldehydes. The relationships between the substituted group types and the UV fluorescence spectral properties, as well as the fluorescence quantum yields of the title Schiff bases were also investigated. The results show that the introduction of both the donating and accepting electron groups causes various grade redshifts of the fluorescence characteristic emission peak of the title Schiff bases to occur.The fluorescence quantum yields of the title Schiff bases with the donating group are increased, and the highest fluorescence quantum yield is up to 0.703.     

Mn, Cr-co-doped MgAl2O4 phosphors for white LEDs

The Mn-, Cr-doped and Mn, Cr-co-doped MgAl₂O₄ powders have been synthesized via a gel-solid reaction method. Energy transfer from Mn²⁺ to Cr³⁺ has been observed for the first time in the co-doped MgAl₂O₄ phosphors. When excited with blue light with a wavelength of 450 nm at room temperature, both green emission from Mn²⁺ around 520 nm and red emission from Cr³⁺ around 675and 693 nm were generated. Moreover, the color of the emission can be modified by controlling the doping concentrations of Mn²⁺ and Cr³⁺. Therefore, MgAl₂O₄: Mn²⁺, Cr³⁺ could be used as a single-phased phosphor for white LED with a blue LED chip. The energy transfer in terms of Mn²⁺ to Cr³⁺ is determined by means of radiation and reabsorption.     

Surface plasmon resonance sensors based on Ag-metalized nanolayer in microstructured optical fibers

Surface plasmon resonance sensors based on Ag-metalized nanolayer in microstructured optical fibers are theoretically analyzed by using finite element method (FEM). In our simulations we use Drude-Lorentz model to describe the metal dielectric constant. The numerical results show that the sensitivity of Ag-metalized SPR sensor could reach 1167 nm/RIU and corresponding resolution is 8.57×10⁻⁵ RIU. Compared to conventional Au-metalized SPR sensors the performance of our device is obviously better.     

Direct mass measurements of short-lived A=2Z-1 nuclides (63)Ge, (65)As, (67)Se, and (71)Kr and their impact on nucleosynthesis in the rp process

Mass excesses of short-lived A=2Z-1 nuclei (63)Ge, (65)As, (67)Se, and (71)Kr have been directly measured to be -46,921(37), -46,937(85), -46,580(67), and -46,320(141) keV, respectively. The deduced proton separation energy of -90(85) keV for (65)As shows that this nucleus is only slightly proton unbound. X-ray burst model calculations with the new mass excess of (65)As suggest that the majority of the reaction flow passes through (64)Ge via proton capture, indicating that (64)Ge is not a significant rp-process waiting point.     

Laser induced electronic acceleration process in nano dot

A physical model of the laser induced electron transport in dielectric with small size is discussed. The model assumes that free electrons are originally existent or produced by impact detrapping. The free electrons transporting in low dimensional dielectrics interact with phonons and surface. When the laser electric field strength is high enough, the inelastic electron scattering such as impact ionization and cascade processes will play important roles. A small size effect has been found in electron absorbing laser energy under the conditions that the laser wavelength is in near infrared zone and the material has size in nanometer level. This is a very significative effect to enlighten us on preparing ultrahigh threshold laser films with new nano-structure.     

Controlling of symmetric and asymmetric mode coupling in long-period fiber gratings singe-side induced by long-pulse CO2 laser

We report a simple fabricating approach to control the mode couplings in long-period fiber gratings (LPFGs) through side exposing fiber to long-pulse-10.6-μm laser from a cheap, internally modulated CO₂ tube. By tuning focused-spot size on fibers, not only circularly symmetric mode coupling but also asymmetric mode couplings can be effectively achieved. Simulation of mode profiles in grating cross-section with Finite Element Method (FEM), and LPFG-cladding etching experiment with hydrofluoric acid (HF), support our explanation that asymmetric mode coupling in LPFGs depends on local refractive-index (RI) change within an azimuthally thin cladding layer, resulted from large-spot method induced deep melt flow on fiber surface during CO₂ laser irradiation.