High－Power Blue Light Generation by External Frequency Doubling of an Optical Parametric Oscillator ＊

We report on an all-solid-state high-power quasi-continuous blue light source by the frequency doubling of asignal wave from an optical parametric oscillator (OPO). A 50-mm-long LiB305 (LBO) crystal is used for theOPO, which is pumped by a diode-pumped Nd:YAG green laser (1OkHz, 50ns). Tunable blue emission in a newnonlinear crystal BiB306 (BiBO) is obtained with a wavelength range from 450 to 495 nm. The average power ofthe signal output is as high as 9.3 W from 924 to 970nm. The maximum output of the blue laser with the secondharmonic walk-off compensation is 1.3W average power at 470nm for 6.2W of OPO signal light at 940nm.     

双抗转基因烟草纯合系的选育及田间试验

为了将双抗转基因烟草推向实用,进行了双抗转基因烟草纯合系的选育。在试验田中利用人工攻毒进行了T1代植物的抗病毒特性的分离试验;在抗性良好的T1植株的后代T2代植物上进行了田间的病毒接种试验和转基因表达的分析,从中选育出双抗转基因烟草纯合系。又于试验田中,在这些纯合系后代T3代上验证了抗病毒特性的遗传稳定性。在转基因表达分析中,发现CMV外壳蛋白基因的表达在翻译水平上受到抑制。     

VIRUS RESISTANCE OF TRANSGENIC TOBACCO PLANTS EXPRESSING TOBACCO MOSAIC VIRUS COAT PROTEIN GENE

An intermediate expressing vector carrying the tobacco mosaic virus (TMV, Chinese common strain) coat protein (CP) gene was constructed by recombinant DNA techniques. The TMV-CP gene was transferred into the tobacco genome via Ti plasmid and a large number of regenerated plants, including both systemic and local lesion hosts for TMV, were obtained. Southern blot analysis revealed that 1-5 copies of the CP gene were integrated into the tobacco genome. RNA and protein analysis demonstrated that the TMV-CP gene was correctly expressed in the transgenic plants. The abundance of TMV-CP mRNA in total leaf RNA accounted for 0.005-0.01%, while the amount of coat proteins reached 0.05-0.2% of the total leaf soluble proteins. Virus challenge experiments showed that the symptom development of virus infection was markedly delayed and the replication as well as the spread of the virus was significantly inhibited in the transgenic plants expressing the TMV-CP gene. Three of these plants were completely protected afte     

V型腔腔内和频产生3 W连续波589 nm黄光激光器

报道了双Nd：YAG棒串接V型折叠腔腔内KTP和频全固态黄光激光器，得到了3 W连续波589 nm黄光输出.为了提高黄光输出功率，采用了两种手段：一是通过优化腔型设计使得两束基频在腔内达到了最佳的空间重合，二是通过选择合适大小的二极管激光器的抽运功率使得两束基频在腔内达到了最佳的功率配比. 关键词： 全固态激光器 Nd：YAG激光器 黄光 腔内和频     

La2CaB10O19晶体三倍频特性表征

本文研究了LCB晶体主平面内有效非线性光学系数最大的相位匹配方向上的三倍频特性,所用LCB晶体切割方向为:θ=48.7°,φ=90°,晶体尺寸:4×4×10 mm3.测量了它的角度带宽:θ角的角度带宽△θ×1为1.15mrad-cm;φ角的角度带宽△φ×1为86.15 mrad-em.还对其温度带宽进行了测定,结果为7.6℃-cm.利用这块晶体,得到了最高为31.8％的三倍频转换效率,而在相同实验条件下用LBO晶体(尺寸与LCB相同)得到的转换效率最高为38.4％.     

超级电容器用MnO2基复合电极材料研究现状与展望

超级电容器因其功率密度高、环保性能优异等特点引起人们的兴趣.二氧化锰具有天然含量丰富、绿色环保、高比容量和晶体结构多样性等优点,是一种优良的电极材料.但二氧化锰的导电性能差,工作过程中结构不稳定等缺点严重影响了其电化学性能.本文对本课题组和国内外学者多年来对MnO2应用金属掺杂、硫化物、碳材料、导电聚合物复合、微观结构改性构建核壳结构等研究成果进行总结概括,并展望今后的工作研究方向和重点.     

6MeV/u 12C6+离子对四种作物种子的生物学效应研究

在中科院近代物理研究所兰州重离子研究装置(HIRFL)上,采用46.6MeV/u~(12)C~(6+)离子对四种不同作物种子进行了生物学效应研究,结果表明:重离子的轰击和贯穿,不仅会在种子表面外貌而且也对种子内部细胞造成严重损伤,重离子对种子萌发能力和生长发育均有明显的抑制作用,对生物功能也有影响;在种子的根尖细胞中出现的染色体畸变具有多种类型,而且畸变频率明显高于对照组。重离子对多种细胞器也产生了严重损伤,受损DNA具有一定的修复能力,测定了四种作物种子的半致死剂量及失活截面,找到了四种作物之间辐射敏感性的差异,讨论了细胞器损伤与生理过程异常的关系和受损DNA的修复过程。 The biological effects of 46.6MeV/u ~(12)C~(6+) ions on four kinds of plant seeds were studiedat HIRFL of Institute of Modern Physics (IMP), Academia Sinica. The results indicate that seriousinjuries were presented on not only external features of the seeds but also internal cells due to the bombardment and penetration of the ions. The heavy ions can significantly inhibitgermination and growth of the seeds and can affect physiological functions. In root tip cells ofirradiated seeds...     

表达烟草花叶病毒外壳蛋白的转基因烟草及其对TMV的抗性

利用体外重组DNA技术构建携带烟草花叶病毒(TMV,国内流行的普通株)外壳蛋白基因(CP)的中间表达载体,通过土壤农杆菌(Agrobacterium tumefaciens)Ti质粒,重组TMV-CP基因被转移至烟草细胞,并获得大量再生的转基因烟草。工程烟草的基因组经Southern印迹法分析证明,CP基因在再生工程株染色体中有1—5个拷贝的插入。分子杂交分析确证TMV-CP基因在转基因株中获得正确表达,其mRNA和蛋白产物的丰度分别达0.005—0.01％及0.05—0.2％。攻毒实验表明90％以上的能表达TMV—CP基因的工程烟草能不同程度地抑制病毒的复制、扩散,并显著延缓,减轻系统病状的发生。有3株工程植株直至花期无病状表现,生长正常。这一抗性作用机制在于转化细胞中的外壳蛋白在病毒侵染早期有效地抑制了入侵病毒颗粒的脱壳,从而阻断病毒的复制。     

信息技术与物理课程整合的几点思考

自2001年教育部明确提出信息技术与课程整合的思想和要求以来,多媒体技术广泛应用于教育教学,并以它的文字、图像、动画、视频、音频等数字资源融为一体的特点,改变着传统课堂教学的单一教学模式,极大地满足了学生视、听感官的需求,教学质量有了显著提高,但与此同时,也暴露出一些问题,发人深省.下面笔者就近年来信息技术与物理课程整合问题谈谈自己的看法,供大家分享与讨论.