基于偏振度检测的光纤电流传感方案

本文提出了一种将光学谐振腔中多次来回反射所产生的法拉第旋转积累效应转化为光学信号偏振度变化的光纤电流传感方案。这种方案的主要优点是可以克服环境等因素的扰动带来偏振态变化所产生的影响。文中对所提出方案的特性进行了简单的理论分析和模拟计算，并给出了相应的实验结果验证。

Enlarging the depth of focus by filtering in the phase-space domain

The ambiguity function was employed as a merit function to design an optical system with a high depth of focus. The ambiguity function with the desired enlarged-depth-of-focus characteristics was obtained by using a properly designed joint filter to modify the ambiguity function of the original pupil in the phase-space domain. From the viewpoint of the filter theory, we roughly propose that the constraints of the spatial filters that are used to enlarge the focal depth must be satisfied. These constraints coincide with those that appeared in the previous literature on this topic. Following our design procedure, several sets of apodizers were synthesized, and their performances in the defocused imagery were compared with each other and with other previous designs. (c) 2005 Optical Society of America.

Analysis on a new type magneto-optical disk for blue lasers

The conventional TbFeCo magneto-optical (MO) medium has a relatively smaller Kerr rotation angle in the blue region than in the red. With the recording wavelength gradually moving to the short wavelength, if TbFeCo is still used as recording medium, the conventional MO disk structure must be optimized to get a larger carrier to noise ratio (CNR). Sabi et al. have found that adding a metal layer attached to the TbFeCo film as thermal control layer is a useful way to get a high CNR. In this paper, we proved this through calculation, and carried out optimization of the new type of disk. Calculation results showed that the new structure is useful in preventing an excessive temperature increase, and has a better thermal response. (c) 2005 Elsevier B.V. All rights reserved.

Investigation of the spectroscopic properties of (Y0.92-xLa0.08Ndx)(2)O-3 transparent ceramics

The spectroscopic properties of (Y0.92-xLa0.08Ndx)(2)O-3 transparent ceramics were investigated. According to three intensity parameters (Omega(2),Omega(4),Omega(6)) fitted by the Judd-Ofelt theory, the spectroscopic quality parameter (X-Nd), branching ratio (beta(J,J')), and quantum efficiency (eta) of Nd3+ were determined. It was found that X-Nd of the host, owing to the additive La2O3, was decreased from 1.6 to 0.46; thus beta(J,11/2) was increased from 46% to 56.82%. A figure of merit of the specimens was discussed and compared with Nd:YAG transparent ceramic. (c) 2007 Optical Society of America.

Optimization of near-field optical field of multi-layer dielectric gratings for pulse compressor

Multi-layer dielectric (MLD) gratings for pulse compressors in high-energy laser systems should provide high diffraction efficiency as well as high laser induced damage thresholds (LIDT). Nonuniform optical near-field distribution is one of the important factors to limit their damage resistant capabilities. Electric field distributions in the gratings and multi-layer film region are analyzed by using Fourier modal method. Optimization of peak electric field in the gratings ridge is performed with a merit function, including both diffraction efficiency and electric field enhancement when the top layer material is HfO2 and SiO2, respectively. A set of optimized gratings parameters is obtained for each structure, which reduce the peak electric field within the gratings ridge to being respective 1.39 and 1.84 times the value of incident light respectively. Finally, we also discuss the effects of gratings refractive index, gratings sidewall angle and incident angle on peak electric field in the gratings ridge. (c) 2006 Elsevier B.V. All rights reserved.

Characteristics of high reflection mirror with an SiO2 top layer for multilayer dielectric grating

The high reflection (HR) mirror composed of dielectric stacks with excellent spectrum characteristics and high damage resistant ability is critical for fabricating multilayer dielectric (MLD) grating for pulse compressor. The selection of the SiO2 material as the top layer of the HR mirror for grating fabrication is beneficial for improving the laser-induced damage threshold of MLD grating as well as minimizing the standing-wave effect in the photoresist during the exposure process. Based on an (HLL) H-9 design comprising quarter-waves of HfO2 ( H) and half-waves of SiO2 ( L), we obtain an optimal design of the HR mirror for MLD grating, the SiO2 top layer of which is optimized with a merit function including both the diffraction efficiency of the MLD grating and the electric field enhancement in the grating. Dependence of the performance of the MLD grating on the fabrication error of the dielectric mirror is analysed in detail. The HR mirror is also fabricated by E-beam evaporation, which shows good spectral characteristics at the exposure wavelength of 413 nm and at the operation wavelength of 1053 nm and an average damage threshold of 10 J cm(-2) for a 12 ns pulse.

基于严格耦合波理论的多层介质膜光栅衍射特性分析

基于严格耦合波理论建立了多层介质膜光栅的衍射机理模型,给出了TE波自准直条件下多层介质膜光栅衍射效率的表达式.以-1级衍射效率为评价函数,分析了表面浮雕结构分别为HfO2和SiO2材料的介质膜光栅获得衍射效率优于96%的结构参数.数值计算表明,顶层材料为HfO2的介质膜光栅具有更宽的结构选择范围.最后分析了介质膜光栅的制备容差和允许的入射角度范围.

新疆三种盐生植物种子萌发和幼苗早期生长对环境的适应对策

肉质小半灌木盐节木（Halocnemum strobilaceum）、里海盐爪爪（Kalidium capsicum）和盐爪爪（Kalidium foliatum）是中国西北盐生荒漠中分布的重要优势种植物。本文对生长在新疆盐漠环境中的三种植物种子的萌发生态学进行了研究。研究内容包括：（1）光照、温度对种子萌发的影响;（2）NaCl盐度对种子萌发和恢复、幼苗生长和恢复的影响;以及（3）低温层积处理对三种盐生植物种子休眠打破和耐盐性影响。 新成熟的盐节木、里海盐爪爪和盐爪爪种子都具有非深度生理休眠，它们分别需要经过4，4和8周的低温层积处理打破休眠。打破休眠的种子萌发的最适光温条件分别是25-30°C和光照（盐节木）;15-30°C，光照或黑暗（里海盐爪爪）;25°C和黑暗（盐爪爪）。 三种盐生植物的种子萌发对NaCl盐度胁迫有相似的响应，即低浓度不抑制萌发，高于一定浓度后，种子萌发随盐度的升高而逐渐降低，直至种子萌发被完全抑制。但是，开始抑制和完全抑制三种植物种子萌发的NaCl盐度是不同的。三种植物种子萌发受到抑制的起始浓度和种子萌发完全被抑制的盐度分别是：0.4和2.0 M（盐节木），0.2和0.6 M（里海盐爪爪），0.2和1.0 M（盐爪爪）。将未萌发的种子转入用蒸馏水饱和的滤纸上继续萌发，三种盐生植物的种子均有可恢复萌发的能力，经4.0 M NaCl处理后的种子，萌发恢复率都高于80%。三种植物的种子在蒸馏水中的总萌发率（在初始盐溶液中萌发的种子数与在蒸馏水中恢复萌发的种子数之和占所有供试种子数的百分率）高于各盐度条件下的种子总萌发率（在初始盐溶液中萌发的种子数与在蒸馏水中恢复萌发的种子数之和占所有供试种子数的百分率）。 盐节木和里海盐爪爪的种子萌发出的幼苗的早期生长对NaCl盐度胁迫有相似的响应，即随着盐度的升高，胚根的伸长逐渐降低;但是低盐度（≤0.4 M）不影响、甚至促进盐节木胚根的伸长，而各个盐度的NaCl均抑制里海盐爪爪的胚根伸长。盐节木的胚根生长较慢，在蒸馏水中培养24 h 后的根长< 1mm。低盐（0.2 M）促进胚根的伸长，但随盐度的继续升高（≥ 0.6 M），胚根伸长逐渐受到抑制，当盐度 ≥ 2.0 M NaCl时，盐节木胚根伸长完全停止。里海盐爪爪的胚根伸长快速，在蒸馏水中培养12 h后的平均根长为5 cm。低盐并不促进里海盐爪爪胚根的伸长，随盐度升高，胚根伸长逐渐受抑制。当盐度 ≥ 1.0 M NaCl时，里海盐爪爪的胚根伸长完全停止。但当转入蒸馏水中时，两种植物的胚根都可以继续伸长，伸长的能力随预处理盐溶液浓度的升高而降低，经 ≥ 4.0 M NaCl 预处理的盐节木胚根完全丧失继续伸长的能力;经0.6 M NaCl 预处理的里海盐爪爪胚根无法继续伸长。 低温层积处理对三种盐生植物的种子在NaCl溶液中的萌发均有显著促进作用。低温层积后，种子萌发可以发生的盐度范围提高;相同浓度NaCl溶液中，低温层积后的种子的萌发率和萌发速率都显著高于未经低温层积处理的种子。 实验结果表明三种盐生植物在种子萌发和早期幼苗生长阶段对盐生生境具有适应性。种子和幼苗早期在高盐分胁迫下保持的萌发恢复能力和胚根伸长生长的恢复能力是对盐生环境的特殊适应对策。这种适应对策有助于这三种植物在新疆的盐漠环境中得以成功的生存和繁衍。

毛乌素沙地两种固沙禾草种子萌发和幼苗生长与环境的关系

干旱区和半干旱区生长的植物具有复杂的生存机制，以确保其能够在特定的环境中生存和发展。植物在干旱的荒漠条件下的生存，与其特殊的种子萌发机制密切相关，这种机制能够确保植物在合适的时间与地点进行种子萌发与幼苗生长发育。在植物的生活史中，种子对极端环境具有最大的忍耐力，而萌发的幼苗对环境胁迫的忍耐程度最小。在干旱区生长的植物往往具有特殊的萌发机制使萌发出的幼苗能够度过对外界的敏感期，对于植物的生存具有重要意义。 毛乌素沙地是我国的四大沙地之一，该地区具有水分短缺，蒸发强烈，风沙剧烈和生境异质性高的特征。本文假设生长在这种极端环境中的植物也发展出了“适时适地”的种子萌发和幼苗生长的适应对策。为了验证以上的假设，本文选取毛乌素沙地不同生境中生长的两种优势固沙禾草——流动沙丘上生长的沙鞭(Psammochloa villosa)和固定沙丘上生长的赖草(Leymus secalinus)为研究材料，通过野外调查、温室控制实验和实验室控制实验的方法，从生理生态学的角度探讨这两种植物的种子萌发和幼苗生长过程对沙丘环境的适应对策，主要对比它们在种子休眠、萌发和幼苗早期生长过程中对沙丘生境适应性的异同点。研究结果表明： （1）新成熟的沙鞭和赖草的种子为适应冬季低温而发展出生理性的内生休眠——非深度生理休眠。沙鞭和赖草的种子分别需要经过4周和8周的低温层积处理(3－5ºC)来完全打破休眠。另外，划破种皮或者部分切除胚乳也能够促进种子的萌发，这进一步证明两种植物的种子具有非深度生理休眠。然而，切除胚乳在不同程度上影响它们的幼苗生长。由非深度生理休眠、温度和损伤种皮/胚乳调节的部分萌发机制能够确保两种植物的种子即使在条件适宜的情况下只有部分种子萌发，从而分散植物生存的风险性。 （2）毛乌素沙地的小量降水（无法触发萌发）使种子经常遭受湿润－干燥的交替胁迫过程。种子先在湿润条件下吸涨1d或者2d，然后在室温下干燥0-8天。尽管在经历反复吸涨和自然干燥脱水后仍能够保持萌发能力，沙鞭和赖草种子的萌发特性却发生了不同的变化：和各自的对照相比，沙鞭种子萌发率相同而萌发速率降低;赖草种子的萌发率和萌发速率都降低，部分种子进入休眠状态。沙鞭和赖草萌发出的幼苗可能由于没有后续降雨或者因沙蚀而遭受干燥胁迫，但是其幼苗在生长早期能够忍耐一定程度的干燥，再次湿润后部分幼苗能够恢复生长。沙鞭和赖草幼苗的耐干燥的“极限点”不同：当幼根长度为1 mm时，它们的幼苗忍耐干燥的时间分别是60d和30d;当幼根长度为4 mm时，它们的幼苗忍耐干燥的时间分别是14d和7d。沙鞭和赖草的种子和生长早期的幼苗的耐干燥性特性可能是它们对降雨量和降雨时间都不可预测的沙地生境的生存策略之一。 （3）不同的沙埋深度影响沙鞭和赖草的种子萌发和出苗。这两种植物的种子萌发和出苗都需1－2 cm的浅层沙埋。随着沙埋深度的增加，两种植物的种子萌发率和出苗率逐渐降低，强迫休眠率逐渐升高;萌发率与出苗率和沙埋深度呈负相关关系而休眠率和沙埋深度呈正相关关系。但是，沙鞭种子出苗的最大沙埋深度是8 cm，而赖草的则为4 cm。因强迫休眠而没有萌发的种子对维持一个长期的土壤种子库来说具有生态学优势，这些种子暴露在合适的萌发土壤深度时具有生长出幼苗的潜能。 （4）沙鞭和赖草的种子都具有大小的差异性，种子大小对沙鞭和赖草的种子在不同沙埋深度的出苗具有不同的影响。沙鞭的三种不同大小种子的平均质量分别为小，4.489 ± 0.012 mg (4 – 4.9 mg);中，5.457 ± 0.012 mg (5 – 5.9 mg)和大，6.415 ± 0.011 mg (6 – 6.9 mg)。赖草的两种不同大小种子的平均质量分别为小，3.083 ± 0.026 mg (3 – 3.5 mg)和大3.955 ± 0.028 mg (3.6 – 4.0 mg)。在相同的沙埋深度下，两种植物的大种子的出苗率都显著高于小种子。和小种子相比，两种植物的大种子由于贮藏更多的能量，所以在相同深度的沙埋中具有出苗率更高的生态优势，而大量小种子在沙埋中不能萌发，可以作为种子库保存在沙层中，这样就分散了一次性大量萌发给植物带来的冒险性。 （5）沙鞭和赖草的幼苗在生长过程中会遭受沙埋，其幼苗忍耐沙埋的能力与沙埋的相对深度（沙埋比例）和幼苗年龄有关。沙鞭和赖草幼苗的耐沙埋能力不同：沙鞭的2周龄幼苗可以忍耐达到株高100%的沙埋，而其1周龄幼苗只能忍耐75%的沙埋。赖草的1周龄和2周龄幼苗都只能忍耐75%的沙埋。沙埋之后，沙鞭和赖草幼苗的生物量，根/茎比以及根和茎的长度都受到不同程度的影响。赖草幼苗不能忍耐完全沙埋可能是限制它在流动沙丘上分布的一个原因。 （6）降雨量和降雨频率能够不同程度地影响沙鞭和赖草在不同沙层的萌发和出苗。这两种植物的种子萌发和出苗需要的最小降雨量不同：在一次浇水相当于5 mm降雨量后，沙鞭和赖草种子的萌发率都超过50%;但是使沙鞭和赖草的出苗率能够达到50%的降雨量分别为10 mm和15 mm。沙埋中的沙鞭和赖草种子的出苗对降雨的响应具有以下特征：两种植物种子的出苗随降雨量或者降雨频率的增加而增加;沙鞭的出苗率受到降雨量和降雨频率的显著影响，但是二者交互作用的影响不显著;赖草的出苗率受到降雨量、降雨频率以及二者交互作用的显著影响。 由非深度生理休眠，种子大小，干燥－湿润循环，沙埋和降雨调节的种子萌发和出苗机制确保了自然条件下沙鞭和赖草每次只有少量种子萌发和出苗，从而分散了两种植物在沙丘上的生存风险。 根据沙鞭和赖草在沙丘上的种子萌发和幼苗生长特性，本文为毛乌素沙地通过植物固沙恢复受损的沙地生态系统的种子飞播实践提出了几点建议。

濒危植物大花黄牡丹种子休眠与萌发特性研究

本文以中国极危种大花黄牡丹种子为研究材料，对其种子生物学、休眠与萌发特性进行研究，采用变温层积和激素处理解除种子休眠，并通过生物抑制物测试、胚培养、激素含量动态变化的测定，研究种子休眠的原因，从根本上解决了大花黄牡丹迁地保护过程中种子繁殖的技术难题，并初步探讨了大花黄牡丹致濒因素与种子休眠及萌发特性的关系，结果表明： 1.大花黄牡丹种子饱实度高，活力强，种皮较坚硬，但不存在吸水障碍，干燥条件下易因失水而丧失活力。迁地保护冷室中盆播18个月方可出苗，出苗率约4%;变温层积实验表明该种具有典型的下胚轴休眠和上胚轴生长抑制。 2.胚组织培养表明：带胚乳和种皮的胚不能萌发，剥除种皮和胚乳后，胚根可萌发，胚芽不生长，GA3处理上胚轴可促进生长，说明种皮和胚乳是导致大花黄牡丹种子下胚轴休眠的关键因素，而上胚轴生长抑制与胚本身关系更密切。 3.抑制物质提取实验表明：大花黄牡丹种子胚乳、种皮、胚等各部位的浸提液均存在抑制小白菜种子萌发的物质，且抑制作用依次增强，说明胚乳和胚是其下胚轴休眠的主要原因。经过暖层积（15 ℃/90 d）种子（未解除上胚轴生长抑制）的胚根、子叶、胚轴浸提液对小白菜和已解除休眠的大花黄牡丹种子的萌发均有不同程度的抑制作用，并依次减弱，说明种胚本身的抑制物质是导致生理休眠的主要原因。 4.变温层积处理和外源激素实验表明：新鲜种子采收后15 ℃暖层积3个月生根率可达85%，下胚轴休眠解除对温度要求严格，高于或低于15 ℃及变温条件均不利于下胚轴萌发;暖层积90d、根长大于6 cm种子再经过60～80 d/ 5 ℃冷层积，即可有效解除大花黄牡丹种子上胚轴的生长抑制，出芽率达80%，最终出苗率68%。不同浓度GA3及不同处理时间促进上胚轴伸长实验结果显示，GA3　400 mg/L浸种根长大于1.5 cm的种子2 h，出芽率可达100%，可以完全解除上胚轴的生长抑制作用。 5.休眠萌发过程中种子各部位内源激素含量动态变化分析结果说明，初始状态脱落酸含量高是导致大花黄牡丹种子下胚轴休眠、上胚轴生长抑制的主要原因之一，且上胚轴抑制与子叶、下胚轴和根的脱落酸含量密切相关;同时认为种子各部位初始生长素含量水平低是导致其休眠的另一个主要原因;变温层积过程中胚各部位脱落酸含量的急剧下降和生长素的迅速升高是解除休眠的关键;同时发现赤霉素在解除休眠和促进萌发过程中起着重要的促进作用，外源GA3能够有效地打破上胚轴的深度休眠。玉米素核苷在休眠与萌发进程中变化趋势与生长素和赤霉素相似，说明其对种子胚根和上胚轴的萌发和生长具有一定的促进作用。

Application of the phylogenetic analysis in mitochondrial disease study

Mitochondrial disease currently received an increasing concern. However, the case-control design commonly adopted in this field is vulnerable to genetic background, population stratification and poor data quality. Although the phylogenetic analysis could

IN-VITRO IMMUNOTOXICITY AND CYTOTOXICITY OF TRICHOSANTHIN AGAINST HUMAN NORMAL IMMUNOCYTES AND LEUKEMIA-LYMPHOMA CELLS

Trichosanthin (TCS) is a ribosome-inactivating protein from root tubers of Trichosanthes kirilowii Maxim. In this paper, the effects of TCS on the viability of human peripheral blood immunocytess, on the proliferation of lymphocytes, and its cytotoxicity to twelve cell lines of lymphoma or leukemia had been observed. TCS at high concentration (>12.5 mu g/ml) affected the viability of human B lymphocytes, but not that of human peripheral blood mononuclear cells (PBMCs), T lymphocytes and granulocytes. Human peripheral blood-derived monocytes/macrophages were highly sensitive to TCS (ID50 at 1.70 mu g/ml). TCS suppressed lymphocyte proliferation stimulated by Concanavalin A (Con A) or lipopolysaccharide (LPS). Human T cell lines and macrophage cell lines were more sensitive (ID50 < 0.9 mu g/ml) to TCS than B cell lines and myeloid lines. These results suggest that selective cytotoxicity of TCS to human macrophages/monocytes may be implicated in anti-HIV activity, and that selectively killing some leukemia-lymphoma cells by TCS merit further evaluation in treatment of some lymphoma and leukemia.

KARYOTYPE EVOLUTION OF SHREW MOLES (SORICOMORPHA: TALPIDAE)

The Chinese long-tailed mole (Scaptonyx fusicaudus) closely resembles American (Neurotrichus gibbsii) and Japanese (Dymecodon pilirostris and Urotrichus talpoides) shrew moles in size, appearance, and ecological habits, yet it has traditionally been classified either together with (viz subfamily Urotrichinae) or separately (tribe Scaptonychini) from the latter genera (tribe Urotrichini sensu lato). We explored the merit of these competing hypotheses by comparing the differentially stained karyotypes of S.fusicaudus and N. gibbsii with those previously reported for both Japanese taxa. With few exceptions, diploid chromosome number (2n = 34), fundamental autosomal number (FNa = 64), relative size, and G-banding pattern of S. fusicaudus were indistinguishable from those of D. pilirostris and U. talpoides. In fact, only chromosome 15 differed significantly between these species, being acrocentric in D. pilirostris, subtelocentric in U. talpoides, and metacentric in S. fusicaudus. This striking similarity is difficult to envisage except in light of a shared common ancestry, and is indicative of an exceptionally low rate of chromosomal evolution among these genera. Conversely, the karyotype of N. gibbsii deviates markedly in diploid chromosome and fundamental autosomal number (2n = 38 and FNa = 72, respectively), morphology, and G-banding pattern from those of Scaptonyx and the Japanese shrew moles. These differences cannot be explained by simple chromosomal rearrangements, and Suggest that rapid chromosomal reorganization Occurred ill the karyotype evolution of this species, possibly due to founder or bottleneck events.

A TAXONOMIC REVIEW OF TYLOTOTRITON VERRUCOSUS ANDERSON (AMPHIBIA, CAUDATA, SALAMANDRIDAE)

Generally it has not been recognized that salamanders of two distinctive color morphs currently are assigned to Tylototriton verrucosus Anderson. One form is uniformly dark brown dorsally, with bright orange coloration confined to the ventral edge of the tail; the other has a dark brown to black dorsal ground color with orange dorsolateral warts, an orange vertebral crest, and orange lateral and medial crests on the head. In addition, the limbs and ventrolateral surfaces of the second form have a variable pattern of orange coloration. The brown form occurs in northeastern India, Nepal, northern Burma, Bhutan, northern Thailand, the type locality in extreme western Yunnan, and perhaps in northern Vietnam. The orange-patterned form occurs only in western Yunnan Province, People's Republic of China. The two forms appear to be allopatric but occur close together in the area of the type locality near the Burma border in western Yunnan. There is no evidence of color intergradation in specimens from this region. Analyses of morphometric and meristic characters, however, suggest the possibility of limited genetic exchange between adjacent populations of brown and orange-patterned forms in western Yunnan. The genetic and taxonomic relationships between the two forms is not fully resolved. However, these two highly distinctive forms obviously have evolved along independent trajectories and merit taxonomic recognition. We therefore propose to restrict the concept of Tylototriton verrucosus to the brown form and designate a neotype for that purpose, and we describe a new species to receive the orange-patterned form.

Neutron irradiation effect in two-dimensional electron gas of AlGaN/GaN heterostructures

AlGaN/GaN heterostructures have been irradiated by neutrons with different influences and characterized by means of temperature-dependent Hall measurements and Micro-Raman scattering techniques. It is found that the carrier mobility of two-dimensional electron gas (2DEG) is very sensitive to neutrons. At a low influence of 6.13 x 10(15) cm(-2), the carrier mobility drops sharply, while the sheet carrier density remains the same as that of an unirradiated sample. Moreover, even for a fluence of up to 3.66 x 10(16) cm(-2), the sheet carrier density shows only a slight drop. We attribute the degradation of the figure-of-merit (product of n(s) x mu) of 2DEG to the defects induced by neutron irradiation. Raman measurements show that neutron irradiation does not yield obvious change to the strain state of AlGaN/GaN heterostructures, which proves that degradation of sheet carrier density has no relation to strain relaxation in the present study. The increase of the product of n(s) x mu of 2DEG during rapid thermal annealing processes at relatively high temperature has been attributed to the activation of Ge-Ga transmuted from Ga and the recovery of displaced defects.