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1.
激光诱变选育果胶酶高产菌株   总被引:2,自引:1,他引:1  
采用Ar+、He-Ne、LD、YAP等激光辐照果胶酶产生菌,不同波长激光辐照均获高酶活菌株,其中从LD激光与He-Ne激光辐照组中选育出酶活达6×104单位/g的高产菌株(比对照组提高122%),并稳定地应用于生产.文中从黑曲霉抱子与DNA的吸收光谱以及电镜观察黑曲霉抱子的结果出发,对激光诱变机制进行了初步探讨.  相似文献   

2.
陈荣  温彩霞 《光子学报》1998,27(1):56-59
分别采用功率密度为1.7W/cm2、照射剂量为2000J/cm2的Ar+激光与LD激光辐照高耐药性的志贺氏福氏痢疾杆菌,波长较短的Ar+激光(488nm)所引起细菌的致死率与药敏实变率明显高于波长较长的LD激光(808nm),即波长较短的Ar+激光的辐照导致细菌耐药性显著降低.  相似文献   

3.
He-Ne激光对小麦幼苗增强UV-B辐射损伤修复的影响   总被引:15,自引:4,他引:11  
韩榕  王勋陵  岳明  齐智 《光子学报》2001,30(10):1182-1187
采用He-Ne激光(5mW/mm2)来辐照处理经增强UV-B(10.8kJ·m-2·d-1)辐射损伤的小麦幼苗,通过荧光光谱测定其中双链DNA(dsDNA)的含量,分析研究了He-Ne激光对小麦DNAUV-B损伤的切除修复的影响和机制,以探明激光对UV-B损伤的修复途径及机制.结果表明:He-Ne激光能明显增强UV-B辐射处理后小麦种子的萌发力;小麦对UV-B辐射损伤具有一定的切除修复能力,切除修复的高峰期发生在UV-B辐射后4~6h内;He-Ne激光主要通过促进小麦的切除修复途径影响小麦对UV-B损伤的修复,而且能增强小麦的切除修复能力,其促进作用在修复高峰期(5h)表现尤为明显.  相似文献   

4.
He-Ne激光诱变黑曲霉Sx的原生质体   总被引:4,自引:1,他引:3  
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.  相似文献   

5.
He-Ne激光选育高木质素降解率的白腐真菌Lx   总被引:6,自引:1,他引:5  
郭爱莲  徐金贵  杨琳 《光子学报》2001,30(6):684-687
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Lx,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.  相似文献   

6.
研究了He-Ne激光对红霉素链霉菌(streptomyc eserythreus简称SE)和龟裂链霉菌(Streptomyces rimosus简称SR)灭活原生质体和种间融合频率的影响.正交实验结果表明:在温度40℃,融合时间5min,聚乙二醇(PEG)浓度为40%的条件下,灭活原生质体融合频率为1.03×10-5,在He-Ne激光与PEG双重促融作用下,双亲灭活原生质体的种间融合频率可达7.86×10-5.证实了He-Ne激光对原生质体融合有明显的促进作用.  相似文献   

7.
郭爱莲  郭廷巍 《光子学报》1999,28(9):780-784
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.  相似文献   

8.
吴学健  尉昊赟  朱敏昊  张继涛  李岩 《物理学报》2012,61(18):180601-180601
利用光纤飞秒光频梳和外腔可调谐半导体激光器, 建立了一套双频He-Ne激光器频率测量系统. 选用铷钟作为系统的频率基准, 通过将外腔半导体激光锁定至光频梳使得其频率溯源至铷钟, 再利用外腔可调谐半导体激光与双频He-Ne激光器输出的正交偏振激光拍频, 同时测量两路正交偏振激光频率. 将可调谐半导体激光器锁定至光频梳第1894449个梳齿, 其绝对频率为473612190000.0±2.7 kHz, 相对不确定度为5.7×10-12. 对商品双频He-Ne激光器进行频率测量实验, 双频He-Ne激光器水平方向偏振激光频率均值为473612229934 kHz, 竖直方向偏振激光频率均值为473612232111 kHz, 平均时间为1024 s的相对Allan标准差为5.2×10-11, 频差均值为2.177 MHz, 标准偏差为2 kHz.  相似文献   

9.
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He-Ne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.  相似文献   

10.
 在激光硬杀伤防护体系研究中,制备了鳞片石墨改性环氧树脂涂层,分析了它与辐照激光能量耦合作用规律,研究了其热烧蚀性能、隔热性能等抗激光辐照性能,并对不同参数激光辐照后该材料的损伤形貌进行宏观、微观分析,确定了损伤阈值与损伤形式。实验结果表明:石墨改性环氧树脂具有优良的抗强激光辐照性能,连续激光辐照下功率密度损伤阈值高于2 kW/cm2;高温下与激光能量耦合系数仅为10%左右,稳定热烧蚀率低至μg/J量级;具备优良的纵向隔热性能,高温下热导率在10 W·K-1·m-1以下;低功率密度激光辐照下损伤形式为轻微氧化,高功率密度激光辐照下则以汽化烧蚀为主;材料制备工艺简单,成本低廉,与被加固材料界面结合良好。  相似文献   

11.
比较了半导体激光器(LD)与He-Ne激光器的特点及区别,将半导体激光器应用于阿贝成像原理和空间滤波实验、迈克尔逊干涉仪的调整和使用实验中。通过对实验数据分析指出:半导体激光器可以替代He-Ne激光器在大学物理实验中使用。  相似文献   

12.
全内腔绿光He-Ne激光器   总被引:4,自引:0,他引:4  
龙兴武  杨开勇  黄云  袁杰  赵洪常  王飞 《光学学报》2005,25(12):639-1643
采用Needle法,对全内腔绿光He-Ne激光器膜系进行设计,并给出了所设计膜系的光谱性能。利用离子溅射镀膜技术镀制了所设计的膜片并且给出了测量结果。制备了多种规格的全内腔绿光He-Ne激光器并且讨论了相关工艺。其中腔长420mm的全内腔绿光He-Ne激光器的典型输出光功率为3mW(单模),腔长360mm的典型输出光功率为2mW(单模),腔长240mm的典型输出光功率为1mW(单模),腔长100mm的小短管子也能有0.1mw的出光功率。  相似文献   

13.
In this paper we used thermal lens spectrometry to determine the thermal diffusivity of cheese fats. We have used equal concentrations of cheese fats from oaxaca, chihuahua, gouda, manchego and mozzarella cheeses at 42°C temperature. The two lasers mismatched mode experimental configuration was used with a He-Ne laser, as a probe beam and an Ar+ laser as the excitation one. The characteristic time constant of the transient thermal lens was obtained by fitting the theoretical expression to the experimental data in order to obtain the thermal diffusivity of the cheese fat samples. This measured thermal property may contribute to a better understanding of the cheese fats quality, which is very important in food industry.  相似文献   

14.
A comprehensive control system has been developed for the stabilization of internalmirror He-Ne lasers to their power envelopes. It is designed particularly for use with lasers emitting at 552, 505, or 490 THz (543, 594, 612 nm). The aim has been to combine convenience in routine operation with good day-to-day resettability and minimal frequency drift during a day. The lasers are observed to emit in up to four modes simultaneously and their tuning behaviour is highly alignment-sensitive. They also tend to flip between modes having orthogonal linear planes of polarization. Reliable control of polarization and mode frequency are possible using permanent magnets and active length control through thermal expansion. The stabilized single-frequency outputs have frequency drifts of about 2×10–8 per year, and powers of between 150 W and 850 W.  相似文献   

15.
讨论了自启动被动锁模掺Yb3+光纤环形激光器产生短脉冲的机理,并研制出全光纤结构超短脉冲掺Yb3+光纤环形激光器.采用两个976nm半导体激光器级联抽运作为抽运源,高掺杂浓度掺Yb3+光纤作为增益介质,利用光纤的非线性偏振旋转效应,得到自启动、十分稳定的ps量级锁模光脉冲.激光器锁模阈值功率260mW,输出功率25mW,锁模光脉冲中心波长1056nm,3dB带宽11.7nm,重复频率20MHz.与其他结构光纤激光器相比,这种全光纤结构具有更高的效率和更好的稳定性. 关键词: 环形光纤激光器 3+光纤')" href="#">高掺杂浓度掺Yb3+光纤 自启动 被动锁模  相似文献   

16.
The possibility of creating direct nuclear-pumped lasers on Ne 3p-3s transitions has been investigated. Spectroscopic investigations of radiation from a nuclear-induced He-Ne plasma and calculations of the kinetics of various physical-chemical processes have been carried out.  相似文献   

17.
陈五岭  姚胜利 《光子学报》1998,27(7):651-655
通过比较He-Ne激光和聚乙二醇(PEG)对红霉素链霉菌(s.erythreus简称SE)和龟裂链霉菌(S.rimosus简称SR)灭活原生质体的诱导融合,筛选得到几株红霉素产量与亲本相比有明显差异的融合子,通过对融合子酯酶同工酶谱、产抗能力及遗传稳定性分析,结果表明:融合子酯酶同工酶谱与亲本相比,酶带条纹数、迁移率等特征发生了显著的改变,表明其遗传物质发生了杂交重组,融合子产抗能力与亲本的相比,最多提高了28.04%,融合子具有良好的遗传稳定性.  相似文献   

18.
InGaAsP/InGaP/GaAs separate confinement heterostructure (SCH) single quantum well (SQW) laser structures have been obtained by an improved liquid-phase epitaxy (LPE) process. Wide-contact stripe lasers have been fabricated with threshold current density below 300 A/cm2 and cavity length of 800 μm. Finally, with the same grown wafers, 1-cm bar laser diode (LD) arrays are made with 150 μm wide stripes and a maximum fill factor of 30%. Continuous Wave (CW) power output of 20 W has been reached.  相似文献   

19.
Efficiencies improvement of LD (laser diode) pumped multimode large mode area (LMA) Tm3+ doped double cladding silica fiber lasers with different in-line biconial tapers were reported. Two types of multimode Tm3+ doped fiber were used in this experiment. Each type of fiber was made into three fiber lasers, a uniform geometry fiber laser and two tapered fiber lasers with different taper parameters. Biconical tapers located several centimeters from the output end of the multimode fiber lasers were made by heating and stretching method. Although the threshold of the best tapered fiber laser was added 200 mW, the slope efficiency (25.3%) and the maximum output power (1.31 W) of the fiber laser increased by 10.3% and 350 mW respectively, in comparison with the un-tapered one. Pre and post output laser power ratio was 6.3–15.6. Simultaneously, the laser spectrum moved to shorter wavelengths. The same trends of these characteristics were also observed in the other three tapered fiber lasers.  相似文献   

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