Nd∶YAP的偏振光谱性质的研究

提出一种简单的偏振光谱分析法,并考虑在各向异性激光晶体的色散关系情况下,测量并标定了a轴切割Nd∶YAP激光晶体在3个主要跃迁波段4F3/2→4I9/2,4F3/2→4I11/2和4F3/2→4I13/2的偏振受激发射截面光谱.该偏振光谱法简单易行,且精度高,所标定的结果可为激光器件的设计和理论分析提供重要的光谱数据.     

Tm:YAP激光晶体的生长

采用提拉法生长了b轴TmYAP晶体,晶体尺寸为○(20～25)mm×(60～70)mm.针对部分晶体中存在的开裂、散射颗粒等宏观缺陷,分析讨论了其成因并提出了改进措施.对晶体吸收光谱和荧光光谱的测定结果表明,晶体的吸收峰位于694和795 nm,荧光谱峰值在2.01 μm附近.     

Nd:YAP激光晶体偏振光谱的测量与分析

从分析NdYAP和NdYAG两种激光晶体的优缺点入手,指出前者的各向异性能够提供许多特殊的用途,讨论了它的能级和光谱特性,详细介绍了该晶体偏振吸收谱、偏振受激发射截面谱和荧光寿命的测量方法,并给出了两块沿a轴切割的NdYAP晶体的测量结果和分析.这些分析与测量反映了NdYAP晶体各向异性的特性优势,将使其在固体激光器应用领域可以成为传统NdYAG晶体很有潜力的替代者.     

BBO晶体对皮秒YAP和YAG激光的腔内倍频

以ＢＢＯ晶体作为腔内倍频元件，研究带抗共振环对撞脉冲锁模Ｎｄ；ＹＡＰ和Ｎｄ：ＹＡＧ激光器的腔内倍频效应，在两种激光器中分别获得基波脉宽８ｐｓ和１０ｐｓ，倍频能量转换继７０．０％和６３．６％。理论分析和实验结果相吻合。     

闪光灯泵浦1300 nm波段Nd3+:YAG和Nd3+:YAP脉冲激光器的比较研究

描述了闪光灯泵浦1300 nm Nd3+YAG和Nd3+YAP脉冲激光器的比较研究,并给出和分析了这二种脉冲激光器的输出能量、效率等实验结果.     

Role of the HTLV-III/LAV envelope in syncytium formation and cytopathicity

Acquired immune deficiency syndrome (AIDS) is characterized by marked depletion of the T4+ helper subset of T cells. The aetiological agent of the disease, the human T-lymphotropic virus type III (HTLV-III)/lymphadenopathy-associated virus (LAV), specifically kills T4+ cells in vitro. Part of this specificity for the T4+ population residues in the relative efficiency with which HTLV-III infects these cells, as a result of a specific interaction between the T4 molecule and the virus envelope glycoprotein. In addition, the cytotoxic consequences of HTLV-III replication are dependent on cell type, as certain lymphoid and myeloid cells can be productively infected without notable cytopathic effect. Here we investigate the basis for the specific cytotoxicity of the virus, and report that high-level expression of the HTLV-III envelope gene induces syncytia and concomitant cell death in T4+ cell lines but not in a B-lymphocyte line. Syncytium formation depends on the interaction of envelope-expressing cells with neighbouring cells bearing surface T4 molecules. These results explain, at least in part, the specific cytopathic effect of HTLV-III infections.     

标记主位在诗歌文本中的文体功能及英汉翻译对策

作为一种信息重组的重要手段，标记主住通过对语言常规的偏离，在诗歌文本中可以产生特殊的文体效果，如促成语义前景化、实现篇章音乐美等。英汉诗歌翻译中既要正确理解标记主位展示的文体效果，把握诗歌神韵，力争做到形神兼顾，实现文体功能对等，又要灵活处理，注意英汉表这习惯的差异，对原语信息的传递以不超出译语读者能够接受的限度为准。     

（RE）BaCuO／Ag Composites： The Role of Silver in Bulk Materials and Joints

We have investigated the phase equilibria in (RE)BaCuO/Ag systems, the influence of Ag on the processing of (RE)BaCuO/Ag composites and the resulting properties. YBaCuO/Ag composites have been grown by the modified melt crystallization process with YBa2Cu3O7, Y2O3, Pt and Ag2O in the precursor. The improved strength of the YBaCuO/Ag composites compared with the conventional YBaCuO bulk material permitted us to magnetize these materials to achieve trapped fields up to 16 T (at 24 K) in the gap of a mini-magnet. The investigation of the microstructure revealed a remarkable increase of the spacing between micro-cracks especially of those perpendicular to a/b-planes when 12wt% Ag was added. In the case of SmBaCuO/Ag composites, Ag has a strong influence on processing and causes interactions between RE123 seeds and the sample. We show the growth of single-grain SmBaCuO/Ag composites in air and discuss the influence of post-annealing on increasing Tc and Jc. Furthermore, YBaCuO/Ag composites have been shown to be appropriate materials used as a solder to join large single grains to large arrays or to “repair” grain boundaries in arrays grown by a multiseeding technique.     

上海企业成为"知识产权经济"主角

知识产权是指对智力劳动成果所享有的权利。上海企业是怎样不断提高科技原创力,形成一批具有自主知识产权核心技术的?他们是怎样在企业界形成“靠知识产权打天下”,视知识产权工作为“一把手工程”的?其中有哪些好的经验和做法值得各地借鉴?本期聚焦推出——     

DNA甲基化在肿瘤形成中的作用(综述)

DNA甲基化改变是肿瘤细胞中常见的现象,DNA甲基化与肿瘤的发生有密切关系。从以下几方面对此做一综述。（1）简介哺乳动物细胞的DNA甲基化;（2）DNA甲基化与肿瘤基因突变;（3）肿瘤DNA甲基化的基因外作用,其中包括：原癌基因的低甲基化和抑癌基因的高甲基化。     

多巴胺能神经递质系统在癫痫发生与发展过程中的作用

在癫痫的发生与发展过程中,多巴胺（DA）受体密度及PDA可以发生改变,其变化情况因癫痫类型及不同脑区而异。不同的DA受体在癫痫发生与发展过程中发挥不同的作用,其作用也与癫痫类型等因素有关。     

论企业信息化在企业管理中的作用

通过实施企业信息化可以优化企业的各项管理流程,提高企业竞争力。而要让这种竞争优势发挥作用,还需要人的主观能动性和创造性的配合,这种配合要从人们观念的更新、企业制度的创新、组织机构的重新设计和业务流程的重组等方面去进行。     

Role of gamma-interferon in antibody-producing responses

Interferon preparations, especially those containing gamma-interferon (IFN-gamma), have long been known to modulate immune responses. However, because many studies used only partially purified interferons, it has been difficult to separate the immunoregulatory effects of the interferons from those of other biologically active molecules contaminating the preparations. Recently, with the cloning of the interferon genes in mouse and man, it has become possible to use these cloned interferons directly to test their effects in assays other than those involving the protection of cells from viruses. For example, cloned IFN-gamma has been shown to be a potent inducer of Ia antigen expression on macrophages. Similarly, cloned IFN-gamma has been reported to act as a macrophage activation factors, as judged by the ability of activated macrophages to kill tumour cells in vitro. We demonstrate here that cloned murine IFN-gamma can also substitute for a late-acting helper factor which acts synergistically with other helper factors in the stimulation of B-cell antibody responses in vitro.     

Role of Information Technology in Manufacturing

Manufacturing of a product is constituted of the va ri ous attributes such as quality, cost, performance, and time to market. Manufactu ring can also be understood as the entire product realization process, from spec ification through design and production to marketing and distribution. The induc tion of Information Technology (IT) in manufacturing includes the hardware that computes and communicates, the software that provides data, knowledge, and infor mation while at the same time controlling the hardwa...     

The Role of Context in Interpretation

In this paper, we＇ll explore the role of context in the interpretation of a piece of discourse. We＇ll present three context models put forward respectively by Firth, Hymes and Lewis. We＇ll also take into consideration the features of co-text and expanding context. At last, we＇ll throw some light on the problem of what aspects of the apparently illimitable features of context are relevant to a particular communicative act.     

氧自由基和牛磺酸在家兔休克再灌注损伤中的作用

探讨氧自由基 (OFR)在失血性休克再灌注损伤中的作用及牛磺酸的保护效应。健康家兔 2 4只随机分为 3组(n =8) :对照组、单纯休克组、牛磺酸治疗组 ;采用失血性休克再灌注损伤模型。连续观察休克前 ,休克 1.5h ,再灌注 1h、2h、3h时血浆超氧化物歧化酶 (SOD)活性、丙二醛 (MDA)含量、乳酸脱氢酶 (LDH)活性的动态变化 ;并测定再灌注 3h时心、肺组织MDA含量和SOD活性。结果显示 ,1)单纯休克组再灌注各时限MDA含量、LDH活性显著升高 ;SOD活性显著下降。 2 )再灌注 3h时心、肺组织MDA含量显著升高 ;SOD活性显著下降。 3)牛磺酸 (40mg·kg-1,iv)可减轻再灌注各时限上述指标的变化 (均P <0 .0 1)。提示OFR介导了休克再灌注损伤 ,牛磺酸对休克再灌注损伤的保护作用可能与减少OFR的生成和促进自由基的清除有关。