发酵液中L-苹果酸和残糖的扫描光度法测定

通过对纸层析斑点面积法、DNS法和紫外—可见扫描光度法的比较研究,建立后一种可同时测定发酵液中L-苹果酸和残糖含量的新方法,在本测定条件下,扫描峰值(或OD)与L-苹果酸浓度在40～200μg/ml、和残糖浓度在150～400μg/ml内均呈线性关系,其标准误差分别为0.53和0.64;变异系数分别为4.23％和0.24％;平均回收率分别为93.33％和91.42％。

分散液液微萃取-数码扫描光度法快速测定水中铜离子

研究了分散液液微萃取-数码扫描光度法测定水中的铜离子。萃取液点样在薄层硅胶板上进行数码扫描成像,成像斑点灰度值与铜离子浓度成正比,据此建立了测定水中铜离子新方法。对影响萃取富集效率和扫描成像效果的因素进行了优化。铜离子浓度在0～100μg/mL范围内有良好的线性关系(r=0.9953).方法具有仪器成本低、方便快速等特点,可满足野外现场检测的要求。

人参和西洋参中磷脂组分的薄层扫描快速定量分析

采用薄层色谱扫描一吸光度比例系数校正法对生晒参、兴京白参、新开河红参和西洋参中的磷脂组分进行了研究。磷脂薄层单向展开后,以专属显色剂Vashovsky试剂显色,薄层扫描定量,数据采用吸光度比例系数校正。结果表明,人参和西洋参均含8种磷脂组分,其中生晒参和新开河红参以磷脂酰胆碱为主,兴京白参以磷脂酸为主,西洋参以双磷脂酰甘油为主。

胶体金/DNA体系法快速测定不同水质中银离子

目的：建立简单、快速检测银离子的新方法。方法：建立简单、快速检测银离子胶体金/DNA体系方法,利用分光光度计扫描加入银离子前、后胶体金/DNA体系光谱,通过比较加入银离子前、后A660/A530大小来快速定量银离子。加入银离子后,体系A660/A530变化较其他离子大,颜色由红色变成蓝色。结果：该方法的线性范围为0.1~2.0μg/mL,检出限为0.05μg/mL,线性相关系数r=0.999。结论：该法应用于不同水质中银的测定,简单、快速、准确,结果满意。

Reconstructing DEM using TLS point cloud data and NURBS surface

Underground coal mining inevitably results in land surface subsidence.Acquiring information on land surface subsidence is important in the detection of surface change.However,conventional data acquisition techniques cannot always retrieve information on whole subsidence area.This study focuses on the reconstruction of a digital elevation model（DEM） with terrestrial laser scanning（TLS） point cloud data.Firstly,the methodology of the DEM with terrestrial 3-dimensional laser scanning is introduced.Then,a DEM modeling approach that involves the application of curved non-uniform rational B-splines（NURBS） surface is put forward.Finally,the performance of the DEM modeling approach with different surface inverse methods is demonstrated.The results indicate that the DEM based on the point cloud data and curved NURBS surface can achieve satisfactory accuracy.In addition,the performance of the hyperbolic paraboloid appears to be better than that of the elliptic paraboloid.The reconstructed DEM is continuous and can easily be integrated into other programs.Such features are of great importance in monitoring dynamic ground surface subsidence.

大肠癌细胞DNA含量与形态学定量分析

目的探讨大肠癌的生物学行为及其临床诊治价值。 方法应用流式细胞仪 (flowcytometry ,FCM)和扫描显微分光光度计 (microspectrophotometry ,MSP)对 88例大肠癌和腺瘤以及 83例正常结肠粘膜的细胞核进行DNA含量测定、倍体分析和细胞周期研究 ,所获数据与临床病理指标和血清癌胚抗原 (carcinoembryonicantigen ,CEA)作比较。 结果正常结肠粘膜的细胞核DNA含量均为二倍体 ,DNA指数 (DI)为 1.0 0± 0 .10 ,MSP直方图为I型。大肠腺瘤的细胞核DNA含量明显低于大肠癌组 (P <0 .0 1) ,而与正常结肠粘膜相比无显著差异 (P >0 .0 5 ) ,其细胞核面积与大肠癌组无显著差异 (P >0 .0 5 )。 83例大肠癌细胞中异倍体检出率为 6 8.6 8% ,DI >1.10或 <0 .90 ,癌细胞核DNA含量与细胞核面积显著相关 (r =0 .71,P <0 .0 1)。随着Dukes分期的升高 ,异倍体检出率上升 ,二者呈正相关。细胞周期分析表明二倍体癌DNA合成期分数 (SPF)介于正常结肠粘膜和异倍体癌之间。异倍体癌病人的术前CEA水平显著高于二倍体癌 (P <0 .0 5 )。FCM的DI值与MSP的模态均值 (MV)有很好的相关性 (r=0 .73,P <0 .0 1) ,异倍体癌符合率达 95 % ,然而二倍体癌符合率仅 5 0 %。 结论DNA含量的检测有利于大肠癌的早期发现 ;倍体分析与CEA在评估大肠癌?

脑水解物制备

脑活素是营养脑组织的药物,提高智力的保健品,是具有脑组织活性的多肽和脑组织氨基酸的脑水解物。我们以动物脑组织用同种动物的胰酶水解,获得的脑水解物中多呔含量为10％,氨基酸含量90％。

午后极光强度与行星际磁场的相关

利用 1 997年和 1 998年南极中山站多通道扫描光度计的地面观测数据和WIND卫星在弓激波上游对行星际磁场 (IMF)的观测数据 ,对午后高纬极光强度与IMF各分量、以及时钟角之间的相关进行了定量研究 .统计表明 ,630nm的强度Ir 随IMFBx 的增大而减小 ,其线性相关系数为 - 0 .83 ;而 557.7nm的变化趋势与此相反 ,其相关系数要低得多 .630nm的强度随IMFBy 的变化曲线为一“V”形结构 ,其谷底在By=- 3nT附近 ;557.7nm的强度也有相似的变化趋势 ,其谷底的位置在By=- 2nT附近 .极光强度随IMFBz 的变化曲线为一倒着的“Z”字形结构 .630nm的强度随IMF的模B的增大而增强 ,其线性相关系数达到 0 .89,而557.7nm与B之间的相关性要差得多 .极光强度随IMF时钟角的变化曲线为一倒“V”结构 ,其反转点在θ =1 30°附近 .

Preparation and infrared emissivities of alkali metal doped ZnO powders

Alkali metal(Li, Na, K) doped ZnO powders were synthesized by solid-state reaction at different calcination temperatures and holding time. Effects of holding time and K sources on the infrared emissivity of ZnO were investigated. The structure and surface morphologies of samples were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM). The UV-Vis absorption and infrared emissivities were investigated by a UV-Vis spectrophotometer and an infrared emissometer, respectively. XRD patterns confirm the wurtzite structure of the as prepared samples with single phase. Smooth grain surfaces are detected in all doped ZnO samples, while ZnO:Li and ZnO:Na present the aggregation of grains. The redshifts in the optical band-gap are observed in K-, Na-, and Li-doped ZnO with the values 3.150, 3.144, and 3.142 eV. Due to better crystalline quality, ZnO:K shows a lower emissivity than others. The emissivity of K-doped ZnO decreases to the minimum value(0.804), at 1200 °C and holding 2 h. Compared with KNO3 as K source, K2CO3 doped ZnO has lower emissivities.

Effect of laser heating on the microstructure and hardness of TRIP590advanced high strength steel used for roll forming

TRIP590 advanced high strength steel sheets were heated by laser with different powers.Changes of the microstructure and the hardness of TRIP590 steel under laser heating with different powers were investigated by metallographic microscope,scanning electron microscope,and hardness tester.The purpose was to study the effect of laser power on microstructure and hardness of TRIP590 steel.It is shown that the power of laser plays an important role on the microstructure and hardness of heated steel sheets.The results are helpful to determine suitable power for the laser auxiliary forming of Trip590 steel in order to obtain uniform microstructure and high hardness.

Green synthesis of nickel nanoparticles using Ocimum sanctum and their application in dye and pollutant adsorption

Nickel nanoparticles as an eco-friendly adsorbent was biosynthesized using Ocimum sanctum leaf extract. The physiochemical properties of green synthesized nickel nanoparticles(Ni Gs) were characterized by UV–Vis spectroscopy(UV–Vis), Fourier Transform Infrared Spectroscopy(FTIR), X-ray diffraction(XRD), Scanning Electron Microscope(SEM) and Transmission Electron Microscope(TEM). Ni Gs were used as adsorbent for the removal of dyes such as crystal violet(CV), eosin Y(EY), orange II(OR) and anionic pollutant nitrate(NO3-), sulfate(SO42-) from aqueous solution. Adsorption capacity of Ni Gs was examined in batch modes at different p H, contact time, Ni G dosage, initial dye and pollutant concentration. The adsorption process was p H dependent and the adsorption capacity increased with increase in contact time and with that of Ni G dosage, whereas the adsorption capacity decreased at higher concentrations of dyes and pollutants. Maximum percentage removal of dyes and pollutants were observed at 40, 20,30, 10 and 10 mg·L-1initial concentration of CV, EY, OR, NO3-and SO42-respectively. The maximum adsorption capacities in Langmuir isotherm were found to be 0.454, 0.615, 0.273, 0.795 and 0.645 mg·g-1at p H 8, 3, 3, 7and 7 for CV, EY, OR, NO3-and SO42-respectively. The higher coef ficients of correlation in Langmuir isotherm suggested monolayer adsorption. The mean energies(E), 2.23, 3.53, 2.50, 5.00 and 3.16 k J·mol-1for CV, EY, OR, NO3-and SO42-respectively, calculated from the Dubinin–Radushkevich isotherm showed physical adsorption of adsorbate onto Ni Gs. Adsorption kinetics data was better fitted to pseudo-second-order kinetics with R2 N 0.870 for all dyes and pollutants. Ni Gs were found to be an effective adsorbent for the removal of dyes and pollutants from aqueous solution and can be applied to treat textile and tannery ef fluents.

Effect of current density on corrosion resistance of micro-arc oxide coatings on magnesium alloy

Oxide coatings were prepared on magnesium alloys in electrolyte solution of Na2SiO3 at different current densities(3,4 and 5 A/cm 2 )with micro-arc oxidation process.X-ray diffractometry(XRD)results show that the oxide coatings formed on magnesium alloys are mainly composed of MgO and MgAl2O4 phases;in addition,the content of MgO increases with increasing the current density.The morphology and surface roughness of the coatings were characterized by confocal laser scanning microscopy (CLSM).The results show that the surface roughness(Ra)decreases with increasing the current density.Moreover,the electrochemical corrosion results prove that the MgO coating produced in the electrolyte Na2SiO3 at current density of 5 A/cm 2 shows the best corrosion resistance.

Detection of coal dust in a mine using optical tomography

A dust concentration imaging system based on optical tomography is proposed to monitor concentration variations of coal dust in a mine.Concentration profiles,rather than just a point value,of coal dust concentrations are the goal of this method.An optical sensor array is employed to realize an optical sensing field of the coal dust concentration during on-line monitoring.A novel image reconstruction algorithm,called the simultaneous iterative reconstruction technique(SIRT),is compared to the well known linear,back projection algorithm(LBP).The SIRT was applied to the present problem and tested by modeling.The disadvantage of the SIRT is a slow speed but some improvements have been made by adding a weighting function that reduces the relative error to 1.7% from 3.1% for 50 iterations.The results of image reconstruction are presented for both simulated and real objects.They prove that the optical tomography technique,based on a multi-source fan projection scheme,can be an effective approach for estimating coal dust distribution.This system can be applied in real time for continuous measurements in a mine.

Effect of Powder Particle Size on the Fabrication of Ti-6Al-4V Using Direct Laser Metal Deposition from Elemental Powder Mixture

Direct LMD （laser metal deposition） was used to fabricate thin-wall Ti-6Al-4V using the powder mixture of Ti-6 wt.%Al-4 wt.%V. SEM （scanning electron microscopy）, OM （optical microscopy） and EDS （energy dispersive spectroscopy） were employed to examine the chemical composition and microstructure of the as-deposited sections. Vickers hardness tests were then applied to characterize the mechanical properties of the deposit samples which were fabricated using pre-mixed elemental powders. The EDS line scans indicated that the chemical composition of the samples was homogenous across the deposit. After significant analysis, some differences were observed among two sets of deposit samples which varied in the particle size of the mixing Ti-6wt.%Al-4wt.%V powder. It could be found that the set with similar particle number for Ti, Al and V powder made composition much more stable and could easily get industry qualified Ti-6Al-4V components.

Influence of surface finish and annealing treatment on oxidation behavior of Ti-48Al-8Cr-2Ag alloy

The effect of surface finish and annealing treatment on the oxidation behavior of Ti-48Al-8Cr-2Ag (molar fraction, %) alloy was investigated at 900 and 1 000 ℃, respectively in air. Thermal gravimetric analysis (TGA) was conducted for the characterization of oxidation kinetics. The microstructures of oxide scales were studied by scanning electron microscopy (SEM) and transmission election microscopy (TEM) techniques. Unfavorable effect of the annealing treatment on the oxidation behavior of the coating was also investigated. The results indicate that the oxidation behavior of the alloy is influenced by surface finish and annealing treatment. The oxidation rate of ground sample is lower than that of the polished alloy at 1 000 ℃ in air. The former forms a scale of merely Al2O3, and the latter forms a scale of the mixture of Al2O3 and TiO2. Annealing can improve the formation of TiO2.

Hydrophobic Ti_xO_y-C_mH_n Nanoparticle Film Prepared by Plasma Enhanced Chemical Vapor Deposition

The hydrophobic films of TixOy-CmHn. deposited from mixture gases of titanium isopropoxide （TTIP） and oxygen by plasma enhanced chemical vapor deposition （PECVD） were investigated. The films were investigated by scanning electron microscope （ SEM ）, transmission electron microscope （ TEM ）, Fourier transform infrared spectrometer （ FTIR）, X-Ray diffraction （ XRD ）, element analysis （ EA ）, ultraviolet visible spectrometer （ UV-Vis）, and water contact angle （WCA）. The results reveal that the surface of the films is formed by mierosized papillaes aggregated by inorganic and organic phases of complex nanoparticles with size from 50 nm to 200 nm when the discharge power is increased from 40 W to 150 W. All fdms demonstrate the strong broad of Ti-O-Ti stretching vibration at 400 -800cm-1, -CH bending vibration at 1 388 cm -1, and broadening -OH stretching vibration at 3 000-3500 cm-1 With the increase of the discharge power, the asdeposited film changes from amorphous to crystallization. The WCA of the film can be as high as 160°, indicating the hydrophobicity. The films show a similar ultraviolet absorption property as the bulk TiO2 film. The composition of the composition of film deposited at 150 W can be formulated as Tio.302-C1.5H3. Therefore, the composition formula of this hydrophobic film could be expressed as TiO2-C5H10O4.7. It is believed that the complex micro/nano structures of TiO2 and C5H10O4.7 residues are responsible for the observed hydrophobicity and the ultraviolet absorption property of the film.

Thermal behavior and mass spectrometry analysis of N-methyl-N-nitroso-p-toluenesulfonamide

The effect of temperature on the functional groups transition of N-methyl-N-nitroso-p-toluenesulfonamide （Diazald） and thermal decomposition were investigated by Fourier Transform Infrared Spectroscopy （FT-IR） and Differential Scanning Calorimeter （DSC）. The results showed that the functional groups transition of Diazald was temperature dependent, and thermal decomposition of Diazald was accelerated above 47.7℃. The HPLC-ESI-MS method was used for Diazald analysis, which indicated the strong hydrogen bonding between Diazald and water and instability of the NO group.

Photocatalytic activity of bauxite-tailings supported nano-TiO_2

TiO2/bauxite-tailings （TiO2/BTs） composites were prepared via a chemical liquid deposition method and characterized by X-ray diffractometry （XRD）, scanning electronic microscopy （SEM） and N2 adsorption analysis. The photocatalytic performance of TiO2/BTs composites was evaluated with UV-Vis spectrophotometer following the changes of phenol concentration under different illumination time. Effects of the calcination temperature, the pH and the cycles on the photocatalytic activity of TiO2/BTs composites were investigated. The composites calcined at 500 and 600 ℃ exhibit the best photocatalytic performance, and the phenol degradation ratios reacting for 40 and 160 rain reach 35% and 78% respectively under the same conditions, higher than those of 29% and 76% of the Degussa P25（TiO2）. The ability of TiO2/BTs500 （BTs500 represents bauxite-tailings calcined at 500 ℃） composites to degrade phenol increases with decreasing pH.