芝麻生化相克及麻秆还田的效应研究

早在1832年德·坎得尔(De Candolle)便报道了植物根系分泌物及其残体分解物质能影响或毒害附近生物的事例。笔者自60年代初以来,曾注意到并观察发现这一事实,并在从生产实践和实地调查得以证实。如:在桂花树冠下杂草却较少,芝麻(Pedaliaceae Sesamum)地中香附子杂草(Cyperus rotundus)

PCR结合生理生化鉴定对冷藏带鱼主要细菌菌相组成分析

将传统的微生物生理生化鉴定技术与16S rDNA分子生物学方法相结合,并通过系统发育树分析,对冷藏带鱼贮藏期间的主要细菌组成比例进行研究。样品在(4±1)℃贮藏,分别于不同贮藏时间取样,对各个阶段的微生物菌落进行分离纯化、形态观察和部分生理生化鉴定,对最终得到的细菌纯培养物直接提取DNA,作16SrDNA PCR扩增,产物经测序后于NCBI与已知序列进行相似性比对,最终得到13株具有典型特征的纯菌株。结果得出,冷藏带鱼在货架期终点时,其主要微生物的种类与所占比例依次为:腐败希瓦氏菌(Shewanella putrefaciens 34.7%)、荧光假单胞菌(Pseudomonas fluorescens 14.5%)、松鼠葡萄球菌(Staphylococcus sciuri 10.2%)、嗜水气单胞菌(Aeromonas hydrophila 8.2%)、弧菌(Vibrio rumoiensis 6.1%)、恶臭假单胞菌(Pseudomonas putida6.1%)、绿色气球菌(Aerococcus viridans 4.1%)、金黄色葡萄球菌(Staphyloccocus aureus 4.1%)、蜡样芽孢杆菌(Bacillus cereus 4.0%)、铜绿假单胞菌(Pseudomonas aeruginosa 2.0%)、嗜冷杆菌(Psychrobacter sp.2.0%)、成团肠杆菌(Enterobacter agglomerans 2.0%)、约氏不动杆菌(Acinetobacter johnsonii 2.0%),其中腐败希瓦氏菌为带鱼冷藏期间的主要优势腐败菌,假单胞菌在带鱼冷藏过程中的所占比例大小依次为荧光假单胞菌>恶臭假单胞菌>铜绿假单胞菌。

新型靛红衍生化β-环糊精键合SBA-15液相色谱固定相的制备与表征

利用靛红的羰基与β-环糊精单取代乙二胺的缩合反应,合成得到种靛红衍生化β-环糊精Schiff碱类化合物。以3-异氰酸丙基三乙氧基硅烷为偶联剂,将其键合到自制的有序介孔二氧化硅材料SBA-15表面,制得种新型的靛红衍生化β-环糊精键合SBA-15液相色谱固定相(ISCDP)。分别对β-环糊精衍生物、SBA-15及固定相进行必要的结构表征。在反相色谱条件下,以卤代尿嘧啶类极性化合物和二取代苯位置异构体为探针,评价新固定相的基本色谱性能。在极性有机溶剂和反相模式下,将新固定相分别用于β-受体阻滞剂药物和丹磺酰化氨基酸对映体的拆分,探讨了相关色谱分离机理。实验表明,靛红吲哚环的引入,增强了环糊精类固定相对卤代尿嘧啶的反相色谱分离能力,分析时间小于7 min。固定相分离硝基苯胺、氨基苯酚和苯二酚的位置异构体时也表现出较高的立体选择性,其中对位异构体均后被洗脱,这与包结作用相关;靛红衍生化β-环糊精配体也提高了固定相的手性分离能力,除疏水作用外,靛红衍生化β-环糊精配体还能提供偶极、氢键、π-π和包结等作用,多种协同作用力有利于提高新固定相的手性和非手性分离的选择性。SBA-15作为键合基质,其有序的孔结构有利于保持色谱柱的良好渗透性和小的传质阻力,在快速高效分离分析中具有应用潜能。

生化相克物质对小麦、水稻幼苗中淀粉酶、过氧化物酶、过氧化氢酶及其同工酶的影响

本文研究了经腐烂的小麦残株及土壤提取液(内含酚类物质)处理后的小麦、水稻幼苗中淀粉酶、过氧化物酶、过氧化氢酶的活性及其同工酶的变化。结果表明:经处理后的幼苗中,过氧化物酶的活性显著高于对照,而过氧化氢酶的活性变化呈相反的趋势,淀粉酶的活性严重的受抑制。同工酶的酶带着色时间、染色深浅及数目、宽窄与对照相比发生十分明显的变化。此变化与生化相克物质对种子萌发、幼苗生长的抑制有密切的联系。

农林业生产中的植物生化相克作用

农林业生产中的植物生化相克作用蔡灿星（广西农业大学南宁５３０００５）在农林业生产中，普遍存在一些现象，如花生、烟草、番茄等不能连作，芝麻不能与棉花间种，新开荒地种芝麻可抑制杂草生长；林地里铁芒箕群落地上种松、杉，幼树生长不良等等。这些现象与植物之间、...

Laser processing effects on Ti−45Nb alloy surface,corrosive and biocompatible properties

The Ti−45Nb(wt.%)alloy properties were investigated in relation to its potential biomedical use.Laser surface modification was utilized to improve its performance in biological systems.As a result of the laser treatment,(Ti,Nb)O scale was formed and various morphological features appeared on the alloy surface.The electrochemical behavior of Ti−45Nb alloy in simulated body conditions was evaluated and showed that the alloy was highly resistant to corrosion deterioration regardless of additional laser surface modification treatment.Nevertheless,the improved corrosion resistance after laser treatment was evident(the corrosion current density of the alloy before laser irradiation was 2.84×10^(−8)A/cm^(2),while that after laser treatment with 5 mJ was 0.65×10^(−8)A/cm^(2))and ascribed to the rapid formation of a complex and passivating bi-modal surface oxide layer.Alloy cytotoxicity and effects of the Ti−45Nb alloy laser surface modification on the MRC-5 cell viability,morphology,and proliferation were also investigated.The Ti−45Nb alloy showed no cytotoxic effect.Moreover,cells showed improved viability and adherence to the alloy surface after the laser irradiation treatment.The highest average cell viability of 115.37%was attained for the alloy laser-irradiated with 15 mJ.Results showed that the laser surface modification can be successfully utilized to significantly improve alloy performance in a biological environment.

Twinning behaviors of Mg-Sn alloy with basal or prismatic Mg_(2)Sn

The Mg-Sn alloys,with basal or prismatic Mg_(2)Sn laths,were employed to reveal the effect of precipitate orientation on twinning behavior quantitatively.The Mg-5wt.%Sn alloys with basal or prismatic Mg_(2)Sn were compressed to study the twinning behaviors.Subsequently,an Orowan strengthening model was developed to quantitatively investigate the critical resolved shear stress(CRSS)increment of precipitates on twinning.The results revealed that the prismatic precipitates hindered the transfer and growth of tensile twins more effectively compared with the basal precipitates.The decreased proportion of tensile twins containing prismatic Mg_(2)Sn might be attributed to a larger CRSS increment for tensile twins compared with that for basal precipitates.The obvious decreased twinning transfer in the alloy with prismatic Mg_(2)Sn could be due to its higher geometrically necessary dislocation and enhanced CRSS of tensile twins.Notably,the prismatic precipitates have a better hindering effect on tensile twins during compression.

森林植物间的他感作用

本文通过介绍森林植物间他感作用的表达方式和运行机制、他感物质的种类及其传播途径,论证了他感作用是森林植物相互关系的重要表现形式,并评介了该领域的研究现状和今后的发展方向.

化感作用对林木种苗的影响机理及应用

介绍了森林植物间化感作用的运行机制、表达方式和化感对林木种苗的影响及其传播途径,展望了其在种苗发展中的应用前景。

Growth of Cubic GaN by MOCVD at High Temperature

High quality cubic GaN (c GaN) is grown by metalorganic vapor deposition (MOCVD) at an increased growth temperature of 900℃,with the growth rate of 1 6μm/h.The full width at half maximum (FWHM) of room temperature photoluminescence (PL) for the high temperature grown GaN film is 48meV.It is smaller than that of the sample grown at 830℃.In X ray diffraction (XRD) measurement,the high temperature grown GaN shows a (002) peak at 20° with a FWHM of 21′.It can be concluded that,although c GaN is of metastable phase,high growth temperature is still beneficial to the improvement in its crystal quality.The relationship between the growth rate and growth temperature is also discussed.

Characterization of SiC nanowires prepared on C/C composite without catalyst by CVD

SiC nanowires were prepared on C/C composite surface without catalyst by chemical vapor deposition（CVD） using CH3 SiCl3 as precursor.SEM images of the CVD-product reveal that some long nanowires have grown to tens of micrometers with some gathered as a ball.Some short nanowires agglomerate like chestnut shell with many thorns accompanied by some deposited nano-particles.XRD,Raman-spectrum and FTIR patterns indicate that the product is a typical β-SiC.TEM images show that the nanowires have a wide diameter range from 10 to 100 nm,and some thin nanowires are bonded to the thick one by amorphous CVD-SiC.A SiC branch generates from an amorphous section of a thick one with an angle of 70° between them,which is consistent with the [111] axis stacking angle of the crystal.SAED and fast Fourier transform（FFT） patterns reveal that the nanowires can grow along with different axes,and the bamboo-nodes section is full of stacking faults and twin crystal.The twisted SiC lattice planes reveal that the screw dislocation growth is the main mechanism for the CVD-SiC nanowires.

Determination of Sulphonylurea Glimepiride in Dog Serum by RP-HPLC with Pre-column Derivatization

Aim A simple, sensitive and rapid RP HPLC method with pre column derivatization has been developed for the determination of sulphonylurea glimepiride in dog serum. Methods The sulphonylurea glimepiride was extracted from the dog serum using dichlromethane followed by derivatization with DNBF for 20 min at 100℃. The solvent was then evaporated at 60℃ under nitrogen, and the residue was taken up in 100 μL of mobile phase consisting of acetonitrile water (75∶30, v/v). The separation was performed on a Hypersil BDS C18 column with a flow rate of 0 8 mL·min -1 , and the ultraviolet detector wavelength was set at 350 nm. Results Extraction recovery ranged from 75.9% to 83.2%, and methodological recovery was between 96.5% and 109.3%. Within day RSD ranged from 1.5% to 6.3%, and inter day RSD was between 2 9% and 14.8%. The method showed good linearity (R=0.9998). Conclusion The method was simple, convenient and sensitive. The reaction of derivatization was reproducible.

Improved Epitaxy of 3C-SiC Layers on Si(100) by New CVD/LPCVD System

Single crystalline 3C-SiC epitaxial layers are grown on φ 50mm Si wafers by a new resistively heated CVD/LPCVD system,using SiH_4,C_2H_4 and H_2 as gas precursors.X-ray diffraction and Raman scattering measurements are used to investigate the crystallinity of the grown films.Electrical properties of the epitaxial 3C-SiC layers with thickness of 1～3μm are measured by Van der Pauw method.The improved Hall mobility reaches the highest value of 470cm 2/(V·s) at the carrier concentration of 7.7×10 17 cm -3 .

Anisotropic and temperature-dependent growth mechanism of S-phase precipitates in Al-Cu-Mg alloy in relation with GPB zones

By employing atomic-resolution imaging and first principles energy calculations, the growth behavior of S-phase precipitates in a high strength A1-Cu-Mg alloy was investigated. It is demonstrated that the nucleation and growth of the S-phase precipitate are rather anisotropic and temperature-dependent companying with low dimensional phase transformation. There are actually two types of Guinier-Preston （GP） zones that determine the formation mechanism of S-phase at high aging temperatures higher than 180 ℃. One is the precursors of the S-phase itself, the other is the structural units or the precursors of the well-known Guinier-Preston-Bagaryatsky （GPB） zones. At high temperatures the later GPB zone units may form around S-phase precipitate and cease its growth in the width direction, leading to the formation of rod-like S-phase crystals; whereas at low temperatures the S-phase precipitates develop without the interference with GPB zones, resulting in S-phase orecioitates with lath-like momhology.

瓦楞废水深度处理实验研究

为使某瓦楞废水经处理后达到《制浆造纸工业水污染物排放标准》水污染物特别排放限值(COD≤50mg/L),分别采用不同组合工艺对该废水进行深度处理。结果表明:当采用混凝-非均相联合技术时,系统在运行40min后,出水COD稳定降至50 mg/L以下,成本为2.21元/吨;当采用混凝-生化技术时,系统运行53h后,出水COD达标,成本为1.514元/吨。

A Pre-column Derivatization HPLC Method for the De-termination of Peimine and Peiminine in Bulbus Fritillar-iae

A pre-column derivatization HPLC method for the determination of peimine(P)and peiminine(PE)in Bulbus Fritillariae has been developed. Under the derivatization conditions optimized,the calibration curve is Y1=-3.83×103+1.33 ×105X1,r=0.998 for P and Y2=-7.86 × 102+6.33 × 104X2,r=0995 for PE,where Y is the peak area and X is the weight of the alkaloid; the average recovery is 98.0%(n=5, RSD=2.1%) for P and 101.0%(n=5,RSD=4.1%)for PE,the linear range is from 0.504 μg to 3.126μg for P and from 0.520μgto 3.328μgfor PE,respectively. Results of the determination of the two alkaloids in several samples of different Fritillaria species from various parts ofthe country are presented.The results suggest that P and PE are two major chemical constituents in bulbs of different Fritillaria species,and that the method developed is generally appli-cable to the determination of the hydroxy group on aliphatic fused ring systems without steric hin-drance.

AFM Observation of GaN Grown on Different Substrates at Low Temperatures

Aim To study the relationship between the substrate temperature and the morphology and properties of GaN. Methods\ Applying the hydride chemical vapor deposition method, GaN films were deposited on different kinds of substrates, including sapphire, Si(111),Si(100),GaAs and GaP(111) both on the P face and the Ga face. The growth was performed at low temperatures of below 700℃. XRD, Hall measurement, cathodoluminescence (CL) and atomic force microscopy (AFM) were used to characterise the film properties. Results\ It was found that the temperature and the nature of substrate materials influence the layer morphology. Conclusion\ The analysis shows that no apparent relationship exists between the optical properties and layer morphology.

Analysis on the Essential Characters and Biological Yield Change of Purple-fleshed Sweetpotato Xuzishu 3

Objective] This study was performed to investigate the trait changes and their correlations as wel as the dynamic changes of biological yield of Xuzishu 3, which wil help to enhance the yield and anthocyanin content of sweetpotato by cul-tivation. [Method] We systematical y measured the agronomic traits, qualitative char-acters and biological yield of Xuzishu 3 during six growing periods to investigate the dynamic changes of its essential characters and yield accumulation. [Result] The characters of Xuzishu 3 appeared most prosperous after the 90th d except for an-thocyanin content. Extremely significant positive correlations were found between ev-ery two of the dry matter rates of above-ground parts （including leaf petioles, leaves and stems）, reducing sugar content and potato weight per plant. Assimilated product distributed more in stems and leaves than in storage roots before the 90th d in growing period. Photosynthetic capacity and net assimilation rate gradual y de-creased after the 90th d, but the assimilated product distributing to storage roots in-creased quickly and maximized in the 135th d. [Conclusion] Xuzishu 3 is a late ma-turing variety requiring more fertilizer, and the accumulation of anthocyanin fluctuates during the growth period of Xuzishu 3. So yield of Xuzishu 3 can be increased by applying more fertilizer and extending the growth period reasonably, meanwhile the anthocyanin content can be increased by means of control ing temperature, light, water and phytohormone within 60 d after planting.

Measurement of Refractive Indices of (Al_xGa_(1-x))_(0.51)In_(0.49)P Grown by Low Pressure Organometallic Vapor Phase Epitaxy

The refractive indices of disordered (Al xGa 1-x ) 0 51 In 0 49 P,which is grown by low-pressure organometallic vapor phase epitaxy and lattice-matched to GaAs substrate,have been determined by measuring their reflectance spectra when the wavelength ranges between 0 5 to 2 5 micrometer.A single-oscillator dispersion model is used to verify the experiment data and calculate the reflectance spectrum.The refractive indices are used to analyze the waveguide of strain quantum well GaInP/AlGaInP visible laser diode.The simulated far field pattern is consistent with the experimental results very well.

A New Model on Origin and Evolution of Biology

Modified classical Boltzmann entropy as generalized entropy, then proposed Maximum Generalized Entropy Principle fusing physics and biology, and established a new model for biological origin and evolutions based on this principle, finally took protein evolution for an example to analyze. The model provided some reference for biological complexity research.