昆明附近的森林植物锈菌

云南銹菌的調查研究,雖然早在十九世紀末期Delavay就在云南採集过13种銹菌,后來到二十世紀初期又有Handel-Mazzetti在我國西南部采集了24种銹菌;但比较全面的調查研究,实际上是从我国真菌学家戴芳(?)教授的工作开始,戴先生在1947年所發表的「中國西部的锈菌」中共记載了分布在云南、四川、湖南、貴州、甘肃等省的銹菌213种,其中分布在云南各类植物上的銹菌就有164种。 1954—1955年间,我們為了适应教学上的需要和為进一步研究昆明附近森林植物病害准备條件,會在昆明附近各林區內進行初步的森林植物病害毒调查,採集了一些森林植物病害标本,现将其中有关銹菌的部     

Two localized CO2 laser treatment methods for mitigation of UV damage growth in fused silica

Two methods：high-power,short-time,single-shot irradiation（Method A） and low-power,long-time,multi-shot irradiation（Method B） are investigated to mitigate the UV damage growth in fused silica by using a 10.6-μm CO2 laser.To verify the mitigation effect of the two methods,the laser induced damage thresholds（LIDTs） of the mitigated sites are tested with a 355-nm,6.4-ns Nd：YAG laser,and the light modulation of the mitigation sites are tested with a 351-nm continuous Nd：YLF laser.The mitigated damaged sites treated with the two methods have almost the same LIDTs,which can recover to the level of pristine material.Compared with Method A,Method B produces mitigated sites with low crater depth and weak light modulation.In addition,there is no raised rim or re-deposited debris formed around the crater edge for Method B.Theoretical calculation is utilized to evaluate the central temperature of the CO2 laser beam irradiated zone and the radius of the crater.It is indicated that the calculated results are consistent with the experimental results.     

电子文件载体的保护

电子文件是数字化信息技术的产物，它是指能被计算机系统识别、处理，按一定格式存储于磁盘或光盘等介质上，并可在网上传送的数字代码序列。当前有一种观点认为，由于电子文件、电子档案的栽体可以方便的更换，方便地进行逻辑归档或非实体归档，因此，传统意义上的实体保护已失去意义。但人们不能回避这样一个现实，即我们的计算机系统受到病毒、黑客的破坏而造成文件被修改，甚至造成系统崩溃的情况时有发生，这说明现阶段的软件保护技术还难以完全保证电子文件、电子档案的真实性和可靠性，难以保证计算机系统的绝对安全。而将需要归档的…     

高功率脉冲电子束辐照SiO$lt;sub$gt;2$lt;/sub$gt;的光学和激光损伤性能

研究了不同剂量的60 kW高功率脉冲电子束辐照对高纯熔石英玻璃的微观结构、光学性能和激光损伤特性的影响规律. 光学显微图像表明, 辐照后熔石英样品由于热效应导致表面破裂, 裂纹密度和尺寸随辐照剂量增加而增大, 采用原子力显微镜分析表面裂纹的微观形貌, 裂纹宽度约1 um, 同时样品表面分布着大量尺寸约0.1–1μm的碎片颗粒. 吸收光谱测试表明, 所有样品均在394 nm处出现微弱的吸收峰, 吸收强度随着电子束辐照剂量增大呈现先增加后减小的趋势. 荧光光谱测试发现辐照前后样品均有3个荧光带, 分别位于460, 494和520 nm, 荧光强度随辐照剂量的变化趋势与吸收光谱一致. 利用355 nm激光研究了不同剂量电子束辐照对熔石英激光损伤阈值的影响, 结果表明熔石英的损伤阈值随着辐照剂量的增加而降低. 在剂量较低时, 导致熔石英激光损伤阈值下降的原因主要是色心缺陷; 剂量较高时, 导致损伤阈值降低的原因主要是样品表面产生的大量微裂纹和碎片颗粒对激光的调制和吸收. 关键词： 熔石英 电子束辐照 色心 激光损伤阈值     

Two localized CO₂ laser treatment methods for mitigation of UV damage growth in fused silica

Two methods:high-power,short-time,single-shot irradiation(Method A) and low-power,long-time,multi-shot irradiation(Method B) are investigated to mitigate the UV damage growth in fused silica by using a 10.6-μm CO2 laser.To verify the mitigation effect of the two methods,the laser induced damage thresholds(LIDTs) of the mitigated sites are tested with a 355-nm,6.4-ns Nd:YAG laser,and the light modulation of the mitigation sites are tested with a 351-nm continuous Nd:YLF laser.The mitigated damaged sites treated with the two methods have almost the same LIDTs,which can recover to the level of pristine material.Compared with Method A,Method B produces mitigated sites with low crater depth and weak light modulation.In addition,there is no raised rim or re-deposited debris formed around the crater edge for Method B.Theoretical calculation is utilized to evaluate the central temperature of the CO2 laser beam irradiated zone and the radius of the crater.It is indicated that the calculated results are consistent with the experimental results.     

Mitigation of laser damage growth in fused silica by using a non-evaporative technique

A non-evaporative technique is used to mitigate damage sites with lateral sizes in a range from 50 μm to 400 μm and depths smaller than 100 μm.The influence of the pulse frequency of a CO 2 laser on the mitigation effect is studied.It is found that a more symmetrical and smooth mitigation crater can be obtained by increasing the laser pulse frequency form 0.1 to 20 kHz.Furthermore,the sizes of laser-affected and distorted zones decrease with the increase of the laser pulse frequency,leading to less degradation of the wave-front quality of the conditioned sample.The energy density of the CO 2 laser beam is introduced for selecting the mitigation parameters.The damage sites can be successfully mitigated by increasing the energy density in a ramped way.Finally,the laser-induced damage threshold(LIDT) of the mitigated site is tested using 355 nm laser beam with a small spot(0.23 mm 2) and a large spot(3.14 mm 2),separately.It is shown that the non-evaporative mitigation technique is a successful method to stop damage re-initiation since the average LIDTs of mitigated sites tested with small or large laser spots are higher than that of pristine material.     

基于随机Petri网的个人碳交易机制下电动汽车采纳行为演化研究

环境问题的日益紧迫与企业碳交易试点的快速推进预示着个人碳交易机制(Personal Carbon Trading,PCT)有望在未来落地,这将极大地影响消费者的绿色意识与行为决策.本研究构建随机Petri网(SPN)模型,以分析PCT机制下居民电动汽车采纳行为的演化过程,并定量地探讨环境意识和PCT机制对电动车采纳行为...     

基于SPI的1960—2018年山东省冬小麦生长期干旱时空特征分析

根据山东省1960—2018年的逐月降水量观测数据,采用标准化降水指数(SPI)作为干旱衡量指标,分析近59年来山东省冬小麦生长期的干旱时空分布特征,研究冬小麦各生长阶段干旱强度及影响范围,为山东省冬小麦的干旱防御及稳定增收提供参考.研究表明:(1)冬小麦生长期内干旱频率多集中在15％～20％之间,相对高值区集中于山东...     

唐代河南地区人口问题管窥

据史料的记载,汉晋隋以来,河南地区的人口在历朝居于全国的第一位。而自唐以后到清朝,河南地区的人口数量再也没有出现过全国最高值,使得唐代成为一个明显的转折点。唐初到天宝年间,河南地区人口数量呈现由低到高的发展趋势。而此后至唐末,人口数量则明显地下降,部分州郡甚至十几倍地减少。而且,唐代河南地区人口地理配置不同,中部、东部稠密,西南部相对稀疏。从人口的数量变化和地理配置可以看出,人口问题与自然和社会历史因素是息息相关的。     

两税合并的探讨

内外有别的税制、税率导致了税收负担差别很大,外资企业所得税享有诸多"超国民待遇"。两税合并,实现4个统一,是中国税制改革同世界接轨的一个重要标志,有其必要性和重要意义。各类企业站在同一条起跑线上竞争,不仅使国内企业得到实惠,而且有利于提升外资质量和优化外资结构。