He-Ne激光选育高木质素降解率的白腐真菌Lx

用He-Ne激光对一株木质素降解活性较高的白腐真菌L₁进行选育.将该菌的菌丝体和原生质体多次照射诱变,结果得出:在波长632.5nm,用功率为6mW和7mW照射该菌的菌丝体,选育出的菌株L₆和L₇木质素降解率可达38.1%和39.88%,比出发菌株L₁提高了33%和39%.用功率9mW的He-Ne激光辐照原生质体,照射20min时,原生质体致死率已达100%.在照射时间为10min时,选育出一株木质素降解率达43.03%的菌株L_x,比出发菌株L₁提高了50%.同工酶分析显示该菌株发生了稳定的遗传突变.     

He-Ne激光诱变黑曲霉Sx的原生质体

对生淀粉糖化菌黑曲霉Sx用混和酶制取原生质体进行了探索.在GM培养基中加入一定量的Cu²⁺、Mn²⁺,原生质体产量较高;采用pH4～5的蜗牛酶、纤维素酶、溶菌酶的混合酶,最佳浓度比为:1.5:3.5:1.5(mg/mL).取在GM培养基中培养17～18h的菌丝,在32℃酶解3h,原生质体产量最高,达到2.4×10⁵个/mL;在加入β-巯基乙醇及二硫苏糖醇处理菌丝时,原生质体产量提高近3倍.在再生培养基中,加入终浓度为30mmol/LMgSO₄时,原生质体再生率由16.7%提高到25.6%.用He-Ne激光照射原生质体时,功率9mW照射30min时致死率为50%,随着时间的延长,原生质体存活率降低.采用波长632.5nm、功率9mW、光斑直径5mm的He-Ne激光多次照射诱变,筛选出一株酶活力最高菌株黑曲霉Sy,活力提高51%,经连续传代5次,酶活力稳定.     

紫外、氦氖激光等复合诱变产果胶酶细菌ZH1的研究

ZH₁菌株是从自然界分离筛选而来的,该菌株产果胶酶的最适pH为7.0;最适温度33℃;培养36h达产酶高峰,酶活力为73.5μ/mL,将ZH₁作为出发菌株,经紫外线诱变、硫酸二乙酯诱变,亚硝基胍和紫外线复合诱变及氦氖激光等多次反复诱变,选育得到一株产果胶酶性稳定且酶活明显提高的突变株ZHg,其酶活为301m/mL,比出发菌株ZH₁产果胶酶能力提高3.1倍.     

紫外激光等选育生淀粉糖化酶高产菌株及其应用

以紫外线、LiCl、5氟尿嘧啶、HNO₂为诱变剂,黑曲霉Sx为出发菌株,选育出生淀粉糖化酶酶活力提高12%的突变株黑曲霉S’x制取黑曲霉S’x的原生质体,用HeNe激光照射,经反复筛选得到突变株黑曲霉Sy,其酶活力较出发菌株提高51%,而酸性蛋白酶活力降低45%并对其在农作物秸杆的应用进行了研究.     

He-Ne激光诱变选育高产白藜芦醇细胞系

以葡萄皮脱分化组织为最初材料,用根癌农杆菌702菌株感染,通过纸电泳证明胭脂碱合成醇基因的存在,并在无激素培养基上培养5～6代以上,将此组织(MS)作为本次实验的研究对象.用He-Ne激光辐照,对MS进行诱变处理,通过继代选育,得到优良细胞系T₁₂,其特点是:生长迅速,生长周期比对照组(CK)缩短10～15天;生长曲线的稳定期明显延长,白藜芦醇平均产量比MS组提高40%.通过稳定性实验证明T₁₂组遗传性状是可靠的.     

He-Ne激光、紫外线诱变氧化亚铁硫杆菌及耐砷菌株的选育

对适合氧化亚铁硫杆菌(Thiobacilus ferrooxidans)特点的诱变方法进行了研究:把菌体制成无铁细胞悬液进行小剂量、多次数的诱变.氧化亚铁硫杆菌菌株S₁经多次紫外线和激光照射,并结合逐级驯化处理,最终选育出了优良耐砷菌株S_x,它能在含11g/LA_s2O₃的环境中生长,比出发菌株的0.7g/L提高了近14.7倍.在用该菌株进行浸矿的实验结果表明:浸矿能力良好,在同样是10%接种量时,浸出时间比出发菌缩短了一天,并且砷元素的浸出率由原先的76%提高至85.7%.     

钒酸铟分级结构微米花和纳米线的水热合成和可见光催化性能

采用水热法合成InVO₄分级结构微米花和InVO₄纳米线．FESEM结果表明, 通过控制水热反应参数可以获得不同形貌InVO₄晶体．利用可见光(λ>420 nm)照射下的罗丹明B降解实验评价了InVO₄样品的光催化性能．结果表明,InVO₄的光催化活性比商用P25 TiO₂高得多,其中花状InVO₄纳米结构光催化效率最高,经可见光照射40 min,罗丹明     

半导体激光对钝顶螺旋藻形态和生长的影响

采用半导体激光(波长650nm,功率40mW,功率密度13mW/cm²)辐照钝顶螺旋藻,辐照时间为30min、15min、8min.通过测定藻丝形态参量、叶绿素a、β胡萝卜素,研究半导体激光对藻生长的影响.结果表明:三个辐照时间都对藻丝形态产生影响,使藻丝长、螺旋数、螺旋长发生变化;30min辐照组抑制藻体叶绿素a、β胡萝卜素的合成,8min和15min辐照组促进藻体叶绿素a和β胡萝卜素的合成,β胡萝卜素增幅最高达17.9%.8min促长作用最明显,使比生长速率提高10.9%,15min略有促长作用,而30min则起抑制生长作用.     

用于低动量高精度测量的漂移室氦基混合气体性能的研究

报道了用小型均匀场漂移室对不同比例的氦基混合气体He/CH₄(80/20,70/30)和He/iC₄H₁₀(85/15,80/20,70/30)的电子漂移速度和用正比计数管对上述气体的电子放大系数测量的结果,实验结果同用Garfield程序包计算的结果进行了比较,符合得很好. 对He/CH₄(80/20)混合气体得到漂移速度ud≈2.7cm/μs,其放大系数M在适当工作电压下能控制在10⁴—10⁵之间,这种混合气体可以作为低动量高精度测量的漂移室工作气体较为理想的候选者.     

硅基二氧化硅厚膜材料的快速生长

采用火焰水解法在Si片上快速淀积SiO₂厚膜材料,材料膜厚达到40μm以上,生长速率达8μm/min.然后将该材料分别在真空中/空气气氛中高温致密化处理,获得了各种形态的二氧化硅厚膜材料,包括平整度好、光滑透明的玻璃态SiO₂厚膜材料.并利用XRD、电子显微镜等仪器对SiO₂膜的表面和膜厚进行了测试分析.     

提高拮抗菌WB3对番茄灰霉病菌拮抗能力的He-Ne激光与氯化锂复合诱变技术

利用He-Ne激光(波长632.8 nm,功率12 mW)与氯化锂复合诱变一株番茄灰霉病菌拮抗菌WB3,获得14株拮抗效果突出的菌株,其最大抑菌带宽为15.7 mm.综合单一诱变组里菌株致死率以及拮抗能力的大小,其中辐照时间为30 min,氯化锂浓度为1.2%时为复合诱变最佳条件.经过复合诱变,L8拮抗菌最高抑菌带宽可提高14%以上,而单一He-Ne激光诱变后抑菌带宽提高8.8%,单一氯化锂诱变后抑菌带宽提高9%.L8菌株生长迅速,经传代培养证明其抑菌性能具有稳定遗传性.该实验研究He-Ne激光与氯化锂复合诱变枯草芽孢杆菌WB3的方法可应用于番茄灰霉病的生物防治领域.     

Annealing of gold nanoparticles on GaP(111)B: initial stage of GaP nanowire growth

GaP(111)B substrate was strewn with 30 nm colloidal Au nanoparticles. Organic residues were removed by: A) boiling in acetone and isopropylalcohol followed by a DI water rinse, B) treatment A + HF:H₂O, C) treatment A + O₂ plasma for 10 min, 20 min, and 40 min, and D) treatment A combined with O₂ plasma (10 min) and HF:H₂O. The substrate thus had original ‘epi‐ready' oxides (A), or fresh native oxides (B and D), or new added oxides (C). The samples were annealed at T_a = 650 °C for 10 min under PH₃ and H₂ in an MOVPE chamber. This resulted in the growth of GaP stumps along [111]B on each sample. Their length was <3 nm (B and D), ～20 nm (A), and ～220 nm (C 40 min). Elemental Ga is left as P₂O₅/Ga₂O₃ oxides form on etched GaP(111)B at room temperature. We believe that as the oxides disintegrated during annealing, they released the elemental Ga that combined with phosphorus from PH₃, and this led to the growth of the GaP stumps. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Effect of simultaneous helium implantation on the microstructure evolution of Inconel X-750 superalloy during dual-beam irradiation

This study focuses on investigation into the effect of helium implantation on microstructure evolution in Inconel X-750 superalloy during dual-beam (Ni⁺/He⁺) irradiation. The 1 MeV Ni⁺ ions with the damage rate of 10^?3 dpa/s as well as 15 keV He⁺ ions using rate of 200 appm/dpa were simultaneously employed to irradiate specimens at 400 °C to different doses. Microstructure characterization has been conducted using high-resolution analytical transmission electron microscopy (TEM). The TEM results show that simultaneous helium injection has significant influence on irradiation-induced microstructural changes. The disordering of γ′ (Ni₃ (Al, Ti)) precipitates shows noticeable delay in dose level compared to mono heavy ion irradiation, which is attributed to the effect of helium on promoting the dynamic reordering process. In contrast to previous studies on single-beam ion irradiation, in which no cavities were reported even at high doses, very small (2–5 nm) cavities were detected after irradiation to 5 dpa, which proved that helium plays crucial role in cavity formation. TEM characterization also indicates that the helium implantation affects the development of dislocation loops during irradiation. Large 1/3 〈1?1?1〉 Frank loops in the size of 10–20 nm developed during irradiation at 400 °C, whereas similar big loops detected at higher irradiation temperature (500 °C) during sole ion irradiation. This implies that the effect of helium on trapping the vacancies can help to develop the interstitial Frank loops at lower irradiation temperatures.     

Effect of laser irradiation on the structure and properties of dielectric column clusters in the YBaCuO superconducting films

The effect of laser irradiation on the structure and properties of the YBa₂Cu₃O_{7 ? δ} epitaxial super-conducting films (T _c = 90–91 K) that are grown on the SrTiO₃ and LaAlO₃ substrates is studied. The films exhibit a system of pyramidal peaks that are incorporated in the single-crystal structure of the film whose system of the (00l) planes is parallel to the surface of the substrate. It is demonstrated that the peaks represent growth defects that result from the relaxation of the accumulating strain due to the mismatch of the crystallographic parameters of the growing layers of the film and substrate. The island structures that are formed owing to the relaxation of strains acquire the (11l) or (10l) orientation and penetrate through the film layers in the course of growth. It is demonstrated that the irradiation using relatively short laser pulses makes it possible to modify the structure of the dielectric clusters and allows the smoothing of the film surface at an insignificant (5–10%) decrease in the concentration of the superconducting phase. An increase in the energy density to a level of greater than 100 mJ/cm² when the number of pulses is greater than five causes an increase in the volume of dielectric phases and the worsening of parameters.     

On the effect of SHI irradiation on dielectric properties of Y3+xFe5−xO12 (x=0.0–0.6) system

The present work aims to investigate the pre- and post-effect of 50 MeV Li³⁺ ion irradiation at a fluence of 5×10¹³ ions/cm² on the dielectric properties of Y_3+xFe_5?xO₁₂, x=0.0, 0.2, 0.4 and 0.6, garnet system over broad temperature, 300–673 K, and frequency, 100 Hz–13 MHz, ranges. Thermal variation of ac resistivity measurements suggests that the mechanism responsible for conduction in the system is polaron hopping. The observed modifications in dielectric properties after swift heavy ion irradiation are mainly due to the modifications of the metal–insulator contacts due to radiation damage-induced disorder and irradiation-induced point/cluster of defects in the material and also compressive strain generated in the lattice structure. The electric modulus presentation and the complex impedance spectral analysis have been employed to study the relaxation process. The YFeO₃ phase is found to be irradiation hard phase as compared with the garnet phase.     

Theoretical optimization of metalp–n silicon Schottky barrier solar cell

The theoretical optimization of the design parametersN _A ,N _D andW _P has been done for efficient operation of Au-p-n Si solar cell including thermionic field emission, dependence of lifetime and mobility on impurity concentrations, dependence of absorption coefficient on wavelength, variation of barrier height and hence the optimum thickness ofp region with illumination. The optimized design parametersN _D =5×10²⁰ m⁻³,N _A =3×10²⁴ m⁻³ andW _P =11.8 nm yield efficiencyη=17.1% (AM0) andη=19.6% (AM1). These are reduced to 14.9% and 17.1% respectively if the metal layer series resistance and transmittance with ZnS antireflection coating are included. A practical value ofW _P =97.0 nm gives an efficiency of 12.2% (AM1).     

The effects of Xe irradiation on He and H co-implanted Si

A combination of X-ray diffraction, cross-sectional transmission electron microscopy (XTEM), and Raman spectroscopy was used to study the effects of irradiation with swift heavy ions on helium and hydrogen co-implanted silicon.<100>-oriented silicon wafers were co-implanted with 30 keV helium to a dose of 3×10¹⁶He⁺/cm² and 24 keV protons to a dose of 2×10¹⁶ H⁺/cm². Moreover, selected helium and hydrogen co-implanted Si wafers were irradiated with 94 MeV xenon. After He and H co-implantation and Xe-irradiation, the wafers were annealed at a temperature of 673 K for 30 min. The damage region of the wafers was examined by the XTEM analysis. The results reveal that most of the platelets are aligned parallel to the (100) plane in the He and H co-implanted Si. However, majority of the platelets lie in<texlscub>111</texlscub>planes after Xe irradiation. Blisters do not occur on the sample surface after Xe irradiation. Raman results reveal that the intensities of both SiH₂ and V₂H₆ modes increase with the increase in the dose of Xe. A possible explanation is that strong electronic excitation during Xe irradiation produces annealing effect, which reduces both lattice damage and the out-of-plane tensile strain.     

Nanocarbon hybrids of graphene‐based materials and ultradispersed diamond: investigating structure and hierarchical defects evolution with electron‐beam irradiation

We report the influence of electron‐beam (E‐beam) irradiation on the structural and physical properties modification of monolayer graphene (Gr), reduced graphene oxide (rGO) and graphene oxide (GO) with ultradispersed diamond (UDD) forming novel hybrid composite ensembles. The films were subjected to a constant energy of 200 keV (40 nA over 100 nm region or electron flux of 3.9 × 10¹⁹ cm⁻²s⁻¹) from a transmission electron microscope gun for 0 (pristine) to 20 min with an interval of 2.5 min continuously – such conditions resemble increased temperature and/or pressure regime, enabling a degree of structural fluidity. To assess the modifications induced by E‐beam, the films were analyzed prior to and post‐irradiation. We focus on the characterization of hierarchical defects evolution using in situ transmission electron microscopy combined with selected area electron diffraction, Raman spectroscopy (RS) and Raman mapping techniques. The experiments showed that the E‐beam irradiation generates microscopic defects (most likely, interstitials and vacancies) in a hierarchical manner much below the amorphization threshold and hybrids stabilized with UDD becomes radiation resilient, elucidated through the intensity, bandwidth, and position variation in prominent RS signatures and mapping, revealing the defects density distribution. The graphene sheet edges start bending, shrinking, and generating gaps (holes) at ~10–12.5 min owing to E‐beam surface sputtering and primary knock‐on damage mechanisms that suffer catastrophic destruction at ~20 min. The microscopic point defects are stabilized by UDD for hybrids in the order of GO > rGO ≥ Gr besides geometric influence, i.e. the int erplay of curvature‐induced (planar vs curved) energy dispersion/absorption effects. Furthermore, an attempt was made to identify the nature of defects (charged vs residual) through inter‐defect distance (i.e. L_D). The trends of L_D for graphene‐based hybrids with E‐beam irradiation implies charged defects described in terms of dangling bonds in contrast to passivated residual or neutral defects. More importantly, they provided a contrasting comparison among variants of graphene and their hybrids with UDD. Copyright © 2015 John Wiley & Sons, Ltd.     

Effect of laser irradiation on the electrical properties of dysprosium doped LiCo-Ferrite

The effect of laser irradiation on the electrical properties of Li_0.5+z Co _z Dy _x Fe_2.5?2z?x O₄ ferrite (0.0 ≤ x ≤ 0.2, z = 0.1) has been studied in the temperature range 300 K ≤ T ≤ 750 K at frequencies of 10 kHz?5 MHz, using a LIMO-IR laser diode, at a wavelength of 808 nm. It was found that laser irradiation increases the polarization, the resistivity and the paramagnetic region. As the result of electronic rearrangement and lattice defects, small polorons and clusters were created. The doping of LiCo-Ferrite by Dy³⁺ increases both the AC and DC resistance of the investigated material. The variation of the AC and DC resistance with the Dy-content (x) obeys the following correlations R _ac/100 = 50x ²+4x+0.005 and R _dc/1000 = 31x ²+0.099x+0.09, respectively. A peculiar behaviour was obtained for the sample with Dy-content x = 0.075, as the resistance notably decreases. The applicable result is that laser irradiation increases the resistance of LiCo-ferrite by about 17% while its doping by dysprosium at x = 0.15 increases the resistance by about 23%. Its value is nearly stable for the temperature range from 340 to 480 K.