An investigative ceporting （Rhizo-epiphyte） on the variety microorganisms of the roots of maize

对贵阳市花溪区不同玉米种植地中的玉米根际真菌进行分离,获得真菌117株。经显微形态观察鉴定,分别属于3个纲17个属。基于此结果,又进行了纤维素的降解实验,得到能降解纤维素的菌种11个属,对玉米根际真菌的研究做了一个初步探索。     

Marinamide, a novel alkaloid and its methyl ester produced by the application of mixed fermentation technique to two mangrove endophytic fungi from the South China Sea

For a long time, terrestrial microorganisms are abundant natural pharmaceutical resource for human, but it becomes more and more difficult to find new species and microorganisms with special functions from land as the research goes on. Consequently, the s…     

Study on the behaviors of poly（p-phenylene benzobisoxazole） in coagulation

Poly（p-phenylene benzobisoxazole）（PBO） is a candidate of high performance materials for many applications. PBO materials＇ properties are considered to be closely related to their fabrication process, especially coagulation. In this paper, the coagulation effect on the chemical and microstructure of PBO was investigated with the help of a PBO model compound, 2, 2＇-（ 1,4-phenylene） bis （5-amino-6-benzoxazolole）. During coagulation, the hetero-cyclic ring of the PBO structure was experienced cleavage and even being broken down completely under some extreme conditions. Wide-angle X-ray diffraction （WAXD） analysis showed that different coagulants could cause the microstructure difference in PBO materials. In a slow coagulation process, PBO molecular chains aligned more orderly in the side-by-side direction （200）.     

Study on the binding mode of Mg（Sal2trien） with DNA

Polyamide could not only combine with DNA out- side but also inhibit expressing of gene[1]. At the same time, polyamide could coordinate many molecules. Ren et al.[2] found that [MgⅡ(dien)(OH)] can cleave pBR322DNA effectively in 2004. Liu et al.[3,4] f…     

Experimental Study on the Hydrodynamics and Mass Transfer Characteristics of Airlift Loop Reactors（ALR）

1IntroductionWhen used in the reaction system,airlift loopreactors(ALRs)have the characteristics of highmass transfer coefficient,good mixingperformance,low flow sheer stress and energysaving,and thus enjoy a broad prospect ofapplication.In additionto tra…     

Experimental Study on the Hydrodynamics and Mass Transfer Characteristics of Airlift Loop Reactors（ALR）

The promoting effect of ultrasonic wave on the hydrodynamics and mass transfer characteristics of the airlift loop reactor was studied．The effect of the airlift reactor and ultrasonic wave on the reactor’s gas holdup,liquid circulation velocity,mixing time and overall volumetric mass transfer coefficient respectively with and without the presence of ultrasonic wave is empathetically examined and compared．The experiment has proven that the incorporation of ultrasonic wave has no effect on the gas holdup but has the tendency to gradually decrease the liquid circulation velocity and increase the overall volumetric mass transfer coefficient; the effect on the mixing time is relatively complex．At low gas velocity,low powered ultrasonic wave promotes the radial mixing of fluid;with the increase of ultrasonic power,ultrasonic vibration obstructs the radial mixing of fluid．Therefore,there exists an optimal ultrasonic power．Moreover,the effect of ultrasonic wave on the mixing time gradually decreases with the increase of the superficial gas velocity．Correlations were also proposed for the hydrodynamics and mass transfer characteristics of the reactor．     

Study on wavy distribution of rainfall associated with typhoon Matsa （2005）

An analysis is made to investigate the structure features of the extensive heavy rainfall left by typhoon Matsa, after its landfall in mainland China in August 2005, based on a range of observational results, including surface intensive observation data, TBB data from China's FY-2 satellite, and NCEP 1°×1° reanalysis data. The study tries to explore the interaction between atmospheric waves, 3-D atmospheric structures, and typhoon rainbands. Observational facts, diagnostic analysis, and atmospheric wave theory are used to look into the formation mechanism of distant typhoon rainbands. Results show that (1) Matsa rainbands have the features of noticeable wave train distribution and long distance propaga-tion; (2) the typhoon rainbands extend as far as 2000 km northwardly from the typhoon center, with a wavelength of 500―1000 km and a wave period of 12―24 h; (3) the wave structure of Matsa rainbands is closely associated with the corresponding wave variation of the ambient 3-D atmospheric structures, including disturbance vorticity, divergence field, vertical motion field, water vapor flux divergence field, etc. (4) both observational facts and theoretical analysis show that the northward extending typhoon rainbands are associated with the mixed effects of atmospheric inertia wave and internal gravity wave; (5) only under proper atmospheric stratification and vertical wavenumber of gravity wave, can a ty-phoon stimulate such a wave being able to reach such a distance, and result in extending wavy rain-bands.     

Study on temperature characteristics of organic light-emitting diodes based on tris-（8-hydroxylquinoline）-aluminum

Both single-layer and double-layer organic light-emitting devices based on tris-（8-hydroxylquino- line）-aluminum （AIq3） as emitter are fabricated by thermal vacuum deposition. The electroluminescent characteristica of these devices at various temperatures are measured, and the temperature characteristics of device performance are studied. The effect of temperature on device current conduction regime is analyzed in detail. The results show that the current-voltage （I-V） characteristics of devices are in good agreement with the theoretical prediction of trapped charge limited current （TCLC）. In addition, both the charge carrier mobility and charge carrier concentration in the organic layer increase with the rise of temperature, which results in the monotonous increase of AIq3 device current. The current conduction mechanisms of two devices at different temperatures are identical, but the exponent m in current-voltage equation changes randomly with temperature. The device luminance increases slightly and the efficiency decreases monotonously due to the aging of AIq3 luminescent properties caused by high temperature. A tiny blue shift can be observed in the electroluminescent （EL） spectra as the temperature increases, and the reduction of device monochromaticity is caused by the intrinsic characteristics of organic semiconductor energy levels.     

First-principles studies of the adsorption of O2 on Al （001）

Oxidationisaubiquitousphenomenonofnature.Theeconomiclossduetooxidationisverylargeeveryyear.Theinvestigationoftheadsorptionofoxygenonthesur-facesofmetalsisofgreatimportanceforbetterunder-standingoftheoxidationmechanismbecauseitistheverybeginningstageofoxidationofmetals.Itisgenerallybe-lievedthattheprocessofO2adsorptiononmetalsisinanorderofO2?O?O-?O2-,andthefollowingstagesareoxidenucleation,growthandtheoxidefilmformation.Astheprocessofadsorptionistooquicktobeobservedbyexperiments,atheoreticals…     

Study on Dyeing of a Novel,Pro-environment Polylactic Acid （PLA） Fiber Yarn

Seventeen disperse dyes including anthraquinone, azo, methine, nitro, and quinoline dyes were applied to dye the Polylactic Acid （PLA） yarns at different conditions, and the dyebath exhaustion was determined. The result shows that C.I. disperse red 167, C.I. disperse orange 30, and C.I. disperse blue 284 have dye-uptakes greater than 80%. Therefore, they can be used as the three principal dyes for PLA yams. The experiment discovered that the dyes, because of their Monoazo and ester group contents, have a higher dye-uptake for the PLA fiber. The research on the optimization of dyeing techniques suggests that PLA yarn can obtain a high level of dyeing effectiveness at the following conditions： pH 4- 5, dyeing temperture 110℃ for 30- 40 min. Color fastness to perspiration, and waterwashing fastness increased 1 - 1.5 by the addition of the abstergent FB during the reduction clearing.     

Study on the specific interaction between angiogenin and aptamer by atomic force microscopy （AFM）

The specific interaction between angiogenin and aptamer has been investigated by using AFM. The specificity of the interaction is revealed by comparing the binding probability of aptamer to other elements in a series of control experiments. The results have shown that there is specific interaction force between angiogenin and aptamer. Moreover, the single molecular pull-off force between angiogenin and aptamer has also been determined using the Poisson statistical method to be 133.7±11.7 pN. These findings obtained are helpful to the better revelation of recognition mechanism between angiogenin and aptamer, which provided basis for further understanding the inhibition of the aptamer to angiogenic activity.     

Study on the HPHT synthetic diamond crystal from Fe-C（H） system and its significance

Investigations of crystal habit, micro-topographic imaging, micro-composition and micro-structural analysis of HPHT synthetic diamonds from the Fe-C（H） system indicate that most of them have an octahedral habit. The crystals grow mainly layer-to-layer from center to periphery. HPHT synthetic diamond is smaller in size than natural diamond because it only goes through nucleation and growth in the early stage. In the middle and late stages, due to the coalescence of diamond grains related to differences of surface energy, the growth of HPHT synthetic diamond is limited. The active energy （E） of transforming single nitrogen into a nitrogen-pair is lowered and the time of transforming single nitrogen into a nitrOgen-pair is shortened because of the existence of hydrogen. Therefore, aggregate nitrogen （A-centers） may exist in synthetic diamond from HPHT and explosive detonation processes. It needs further discussion on a worldwide view that the time of natural diamond formation extracted from nitrogen aggregation is some hundred million years. Consideration of the way in which surface energy influences the growth of diamond can help to understand some of the remaining issues （e.g. growth mechanism, etc.） in the HPHT synthetic process and effectively explain the formation of natural diamond in terms of HPHT thermodynamic theory. Especially, it is important to pay more attention to the influence of hydrogen on surface energy in that hydrogen may be a ＂bridge＂ for explaining the formation of HPHT synthetic and natural diamond.     

Study on cellular internalization of poly（vinyldiaminotriazine）-based hydrogen bonding type non-viral transgene vector

Previously we successfully prepared poly（vinyldiaminotriazine）（PVDT）-based non-viral vectors which complexed piasmid DNA via hydrogen bonding with adenine-thymine base pairs, in this report, surface charges and complex sizes of this system were further examined. The results showed that PVDT-based polymer could cover surface charges of DNA resulting in slightly negative or neutral complexes. It was also found that the complex sizes were governed by two events： the aggregation induced by the instability of neutral particles, and more compact complexes produced by PVDT-based polymers. In the study of cellular uptake, chlorpromazine and filipin III were used to inhibit clathrin-and caveolae-mediated endocytosis, respectively. We found that PVDT-based systems were transported into cells via a non-clathrin, non-caveolae mediated endocytosis. This special process was studied by temperature inhibition and kinetics assays. It was revealed that such a pathway was characterized by （i） a more en- ergy dependent process and （ii） a much slow transfection-effective internalization.     

Theoretical study of NO adsorbed on the surface of TiO2（110） cluster model

The chemisorption properties of N18O adsorption on TiO2(110) surface were investigated by experimental and theoretical methods. The results of temperature programmed desorption (TPD) indicated that the temperatures of the three desorption peaks of the main N2 molecules were at (low) temperature of 230 K, 450 K, and (high) temperature of 980 K. This meant that N18O decomposed and recombined during the process of N2 desorption after N18O was exposed. Analysis of the stable combination and orbital theory calculation of the surface reaction of NO adsorption on the TiO2(110) cluster model showed that there was clear preference for the Ti-NO orientation.     

Study on the enzymatic activity of Caspase-3 in response to alginic acid decomposing bacteria in Laminaria japonica Aresch.（Phaeophyta）

Caspase-3 is the major factor in apoptosis triggered by various stimuli, and plays a critical role during the apoptosis process. By using CaspGLOWTM fluorescein active caspase-3 staining method, caspase-3 enzymatic activities were detected in response to alginic acid bacteria in Laminaria japonica sporophytic tissues. Results showed that caspase-3 enzymatic activities were observed at 5 min after the infection. Caspase-3 enzymatic activity increased with the infection time, and had a tendency of moving from the infection site to outside. By applying caspase-specific peptide inhibitor Z-VAD-FMK, caspase-3 activation could be effectively abolished in the infected tissues. Our results indicate that programmed cell death (PCD) may be involved in the infected Laminaria japonica sporophytic tissues, and provide the evidence that defense mechanisms in algae may have similar caspase cascade events in animals.     

Angular dependent NEXAFS study of the molecular orientation of PTCDA multilayers on Au （111） surface

The molecular orientation of perylene-3,4,9,10-tetracarboxylic acid dianhydride (PTCDA) multilayers adsorbed on Au (111) surface has been investigated using angular dependent O K-edge near edge X-ray absorption fine structure (NEXAFS) spectroscopy. The significant angular dependence of important resonant structures (π* and σ*) reveals that PTCDA molecules adopt an ordered geometry on the substrate surface. The average tilt angle of the PTCDA molecular planes is 27°±10° from the Au (111) surface.     

Influence of Mica Particles on the Rheological Properties and Thermal Stability of Poly（ lactic acid）

The influence of mica particles on the rheological and thermal properties of poly（ lactic acid）（ PLA） / mica composites were investigated by capillary rheometer and thermogravimetric（ TG）analysis. The results show that the PLA / mica blends are nonNewtonian pseudoplastic and display shear-thinning. The value of non-Newtonian index of the blends melt decreased obviously with the addition of mica particles but somehow even increased when shear rate exceeded 4 500 s- 1. In this work,it could be indicated that appropriate amount of mica particles could somehow enhance the resistance of PLA melt under high shear rate to deviate from Newtonian fluid. TG analysis shows that the thermal stability of PLA decreases a little after the incorporation of the mica particles.As mica particles decompose in a completely different way in contrast to PLA,this abnormal decrease of thermal stability of PLA / mica composite may be attributed to moisture stored between mica layers released at high temperature.     

pH-Compensation Effect of Lysine on the Acidic Degradation of Electrospun Poly（ lactide-co-glycolide） Fibers in PBS

Electrospun aligned ultrafine fibers of poly（ lactide-coglycolide）（ PLGA） can be used to construct biomimetic scaffolds for engineering those structurally anisotropic and dense tissues（ e. g.,tendon,ligament,etc.）. But the acidic degradation products of the PLGA could result in p H decrease in the vicinity of the scaffolds,which may give rise to biocompatibility concerns. To address the noted problem, this study was designed to evaluate the p Hcompensation capacity of using Lysine（ Lys） —a kind of basic amino acid on the acidic degradation products of PLGA. Ultrafine PLGA（ 50∶ 50） fibers with 0,10%,20%,and 30% by weight of Lys loadings were prepared by a stable jet electrospinning（ SJES）approach. The morphology,structure,and mechanical properties of the electrospun aligned fibrous mats of Lys-incorporated PLGA（ 50∶50） were characterized by scanning electron microscope（ SEM）,Fourier transform infrared spectroscopy（ FTIR）,and tensile testing,respectively. Thereafter,the fibrous PLGA（ 50 ∶50） scaffolds were subjected to degradation by being immersed in phosphate buffered saline（ PBS,p H 6. 86） solution at 37 ℃ for 5weeks. Our results show that the formed Lys / PLGA composite ultrafine fibers have a well-aligned and uniform morphology with a fineness of ca. 1 #m in diameter. Introduction of Lys led to increased mechanical performance; that is,when the Lys loading is less than 30%,tensile strength and Young＇s modulus of the aligned Lys / PLGA fibers reached up to the impressive values of 84. 5 MPa and 2. 4 GPa,respectively. Degradation results show that the p H of the PLGA group fell to 5. 6 in 5 weeks while the p H of the Lys /PLGA groups with 10%,20%, and 30% of Lys loadings was maintained at 6. 3, 6. 5 and 6. 7, respectively. This work demonstrated that incorporation of Lys into electrospun PLGA fibers could be an effective approach in mediating the p H decrease caused by the acidic degradation products of the PLGA.     

Effect of substrate miscut on the electron mobility in InSb（001） structures on Ge and Ge-on-insulator substrates

InSb epilayers and InSb/Al0.20In0.80Sb quantum wells were grown on Ge(001)substrates and Ge-on-insulator(GeOI)-on-Si(001)substrates by molecular beam epitaxy.Growth on both on-axis and 4°-off-axis substrate orientations was studied.Anti-phase domains were formed when InSb films were grown on on-axis substrates,but suppressed significantly by the use of 4°-off-axis substrates.Such off-axis substrates also reduced the densities of micro-twin defects and threading dislocations.The defect reduction resulted in an increase in the room-temperature electron mobility from 37,000 to 59,000 cm2/Vs in 4.0-lm-thick InSb epilayers and from 10,000 to20,000 cm2/Vs in 25-nm-thick InSb quantum wells on Ge(001)and GeOI-on-Si(001)substrates.