Particle track identification: application of a new technique to apollo helmets

The Apollo helmets are being used to record the dose of heavy particles to which astronauts are exposed on space missions. An improved method for examining and identifying the etched tracks of heavy charged particles consists of replicating tracks and measuring the etching rate as a function of position along the track. Tracks have been observed in Apollo helmets that correspond to ionized atoms heavier than iron.     

Olivines: revelation of tracks of charged particles

A one-step, three-component aqueous etchant was developed for revealing the tracks of charged particles in olivine. The etchant reveals tracks of small cone angle, which are equally well developed in all the crystallographic directions. The scope of fossil cosmic-ray track studies in extraterrestrial samples has thus been increased, because olivine is often an abundant constituent and because it has a higher threshold ionization for track registration and has lower uranium, thorium, and trace element concentrations as compared with pyroxenes and feldspars. The etchant does not attack any of the principal rock-forming minerals in normal etching time, which allows a nondestructive study of fossil tracks in thin-section mounts. The study of fossil cosmic-ray tracks in olivine is particularly valuable for investigations of very, very heavy cosmic-ray nuclei and for highly irradiated samples such as those found in the lunar regolith.     

Direct and remote sensing observations of the effects of ships on clouds

Under certain conditions ships can affect the structure of shallow layer clouds. Simultaneous observations of two ship track signatures in stratus clouds from a satellite and in situ from an aircraft show that in the ship tracks the droplet sizes were reduced and total concentrations of both droplets and particles were substantially increased from those in adjacent clouds. In situ measurements of the upwelling radiance within the ship tracks was significantly enhanced at visible wavelengths, whereas radiance at 2.2 micrometers was significantly reduced. Cloud reflectivity along the tracks was enhanced at 0.63 and 3.7 micrometers. These observations support the contention that ship track signatures in clouds are produced primarily by particles emitted from ships.     

Heavy-particle radiography

Energetic heavy particles from an accelerator mnay be used to produce radiographs with high contrast and high depth resolution. Small differences in the stopping power of objects can be detected and permnanently recorded by using stacks of plastic track detectors. This method should aid in the diagnosis of soft-tissue abnormalities, including some tumnors, and make possible quantitative reconstruction of the internal density structure of objects.     

基于链表的出栈序列生成算法

目的:向栈中依次输入若干字符,输出所有不同的出栈序列.方法:根据栈后进先出的特征,采用链表确定字符进栈的所有时刻序列,输出字符的所有出栈序列.结果:抛开烦琐的组合数学证明,充分利用数据结构中链表、栈来解决出栈序列问题,并用c 程序描述了该算法.结论:从进栈出栈具有时刻先后关系出发,解决出栈序列问题,算法理解更为简单直观.     

Solar particle tracks in glass from the surveyor 3 spacecraft

A glass filter from Surveyor 3 has a surface density of approximately 1 x 10(6) tracks per square centimeter from heavy solar flare particles. The variation with depth is best fitted with a solar particle spectrum dN/dE = 2.42 x 10(6) E(-2) [in particles per square centimeter per year per steradian per (million electron volts per nucleon)], where E is the energy and N is the number of particles, from 2 million electron volts per nucleon to approximately 7 million electron volts per nucleon and dN/dE = 1.17 x 10(7) E(-3) at higher energies. Not much difference is observed between 0.5 and 5 micrometers, an indication that there is a lack of track-registering particles below 0.5 million electron volts per nucleon. The Surveyor data are compatible with track results in lunar rocks, provided an erosion rate of approximately 10(-7) centimeter per year is assumed for the latter. The results also suggest a small-scale erosion process in lunar rocks.     

Discovery of nucler tracks in interplanetary dust

Nuclear tracks have been identified in interplanetary dust particles (IDP's) collected from the stratosphere. The presence of tracks unambiguously confirms the extraterrestrial nature of IDP's, and the high track densities (10(10) to 10(11) per square centimeter) suggest an exposure age of approximately 10(4) years within the inner solar system. Tracks also provide an upper temperature limit for the heating of IDP's during atmospheric entry, thereby making it possible to distinguish between pristine and thermally modified micrometeorites.     

基于以太网交换机的Linux协议栈虚拟化技术

网络协议栈虚拟化的目标是在一台网络设备上虚拟出多个协议栈以实现网络设备的一虚多功能。由于Linux操作系统的网络协议栈本身是不支持这种网络协议栈虚拟化技术的，因此本文通过对Linux操作系统3.11.10版本IPV4网络协议栈进行改造以实现Linux网络协议栈的虚拟化，并在设备平台上验证了经过网络协议栈虚拟化改造后的以太网交换机对业务流的隔离功能。     

烟叶单层厚度与层积厚度测定方法的对比分析

[目的]对比分析烟叶单层厚度和层积厚度测定方法,为卷烟工业合理选用烟叶原料并进行适宜的工艺处理提供依据。[方法]对单层厚度和层积厚度作了定义,按照定义的试验方法,对云南烟叶K326品种的中部叶作了单层厚度和层积厚度的测定,并对2个处理的数据进行了分析。[结果]层积厚度处理的变异系数比单层厚度处理的小,说明用层积厚度的方法来测定烟叶的厚度比/单层厚度测定方法更加稳定和可靠;对单层厚度法和层积厚度法的测定结果作配对样本t检验,结果显示P〉0.05,表明2个方法差异不显著,因此用层积厚度来表征烟叶的厚度指标更加稳定。[结论]该研究可为以后烟叶厚度的测定提供新的可靠的方法。     

股权激励与公司绩效：基于调整成本

利用商业软件ANSYS从结构动力学角度模拟分析了回热器结构的改变对热声热机的影响.在之前研究的基础上，改造了普通板叠回热器的结构，建立针束、肋片板、微坑板异形回热器模型，对包含各回热器的热声整机模型进行了结构动力学分析.分析得出，普通板叠回热器热声热机在150 Hz附近谐振，而异型板叠回热器热机由于结构的改变，共振频率发生变化，在高阶模态应变到达峰值，说明了回热器的结构优化是提高热声热机性能的有效手段.     

图书馆书库管理新革命——图书馆机器人管理书库的应用研究与启示

分析了图书馆书库管理的弊端以及机器人系统进书库所引发的书库管理新革命,并对我国图书馆书库引入机器人管理做了可行性研究。     

Particle Track, X-ray, Thermal, and Mass Spectrometric Studies of Lunar Material

Particle tracks in Apollo 11 samples are dominantly of cosmic ray and solar origin: primary galactic and solar flare particles, likely spallation recoil tracks, and possible solar-wind heavy particles. The energy spectrum of irongroup nuclei is inferred from track density gradients in surface layers, and a limit of < 10(-7) centimeter per year is deduced for the surface erosion rate. From cosmic ray tracks in rock and core samples it is clear that the lunar soil is stirred often during each few million years. X-rays reveal augite, anorthite, olivine, ilmenite, troilite, nonmeteoritic iron, and assorted glasses, but no major structural damage. Hydrogen, helium, and other gases in the fines are compatible with expected solar wind ratios.     

Solid state studies of the radiation history of lunar samples

Particle track densities up to > 3 x 10(9) per square centimeter have been measured in different samples. Rocks 17, 47, 57, and 58 have VH (Z >22) galactic cosmic ray ages of 11, 14, 28, and 13 x 10(6) years, respectively. Rock 57 has a calculated erosion rate of 10(-7) centimeter per year. Near-surface track versus depth data in rock 17 can be fit with solar flare particles that have a differential energy spectrum aE(-3); lunar samples can be used to study the history of solar activity. The uranium in the crystalline rocks occurs principally in small regions <10 to approximately 100 micrometers in size. The (low) thermoluminescence of the fines increases with depth in core 10004. With one possible exception, x-ray studies have not shown pronounced radiation damage effects. The total energy release upon heating is small up to 900 degrees C and occurs in three broad regions.     

秸秆生物反应技术在烤烟漂浮育苗上的应用效果

通过设置秸秆生物反应堆漂浮育苗与常规漂浮育苗对比试验,研究秸秆生物反应堆对苗床增温效果、种子出苗率、烤烟苗床生育期及烟苗素质的影响.结果表明:采用秸秆生物反应堆进行漂浮育苗较常规漂浮育苗提高苗床温度1～6℃,提早种子出苗和提高出苗速度,缩短苗床期7 d,降低了低温烟苗死苗率.成苗期对烟苗农艺性状调查还表明,采用秸秆生物反应堆进行漂浮育苗,对提高烟苗茎高、茎粗、增加侧根数、促进叶长、叶宽、增加根冠重均有较好的作用.秸秆生物反应技术在烤烟漂浮育苗方面可进行推广应用.     

北五味子生态特性与栽培技术

综述了北五味子栽培方面近10a的有关研究工作，同时着重论述了野生五味子生态特性及在制定栽培技术时应采取的相应措施，五味子具有喜湿喜肥喜光的生态特性，在栽培生产中，通过人工支架，挖定植沟，定植沟回填粪土混合物和在苗期、移栽后，开花结果期加强水肥管理等技术措施，满足其生长需要，可使五味子人工园持续高产稳产，五味子种子具有休眠特性，经层积处理后，才能用于生产中，层积的温度及层积需要的时间，生产上应根据开始层积日距播期的时间间隔估算和确定。     

贮存高度和锯末覆盖厚度对猪粪NH3和温室气体排放量及其增温潜势的影响

为研究贮存高度和锯末覆盖厚度对猪粪NH3和温室气体排放量及其增温潜势的影响,以猪粪为贮存材料,锯末为覆盖材料,试验设2种猪粪贮存高度(20 cm和40 cm)和3种锯末覆盖高度(0、10 cm和20 cm),共6个处理,每个处理3个重复。通过动态箱技术对猪粪贮存过程中NH3和温室气体排放进行不间断测试,每小时测量一次进气口和排气口NH3、N2O、CH4和CO2的质量浓度,进而计算增温潜势,共测量42 d。结果表明:猪粪便的贮存高度对各种气体排放量均有显著影响,与20 cm贮存高度的猪粪相比,40 cm贮存高度猪粪的NH3、N2O和CO2排放量显著降低,而CH4排放量显著增加。锯末覆盖降低了猪粪贮存过程中NH3和CO2的排放量,但是增加了CH4的排放量;锯末覆盖对不同贮存高度猪粪N2O排放量影响不同,锯末覆盖增加了20 cm贮存高度猪粪N2O排放量,却降低了40 cm贮存高度猪粪N2O排放量。各处理组单位质量猪粪排放的总温室气体增温潜势为36.62～62.83 g·kg-1(CO2基础)。覆盖可以减少猪粪贮存过程中总温室气体增温潜势11.59%～23.61%,但差异不显著。与20 cm贮存高度的猪粪相比,40 cm贮存高度显著降低了猪粪总温室气体增温潜势达36.26%～41.48%。研究表明,增加猪粪贮存高度可以减少猪粪贮存过程中总温室气体的增温潜势。     

Fossil alpha-particle recoil tracks: a new method of age determination

The discovery of a new type of fossil nuclear track in mica is reported. This track is produced by the recoil nucleus accompanying the alpha-particle decay of uranium and thorium impurities. The tracks are very short and can be seen with phase contrast microscopy. Measurement of fossil alpha-recoil track densities, coupled with determinations of the thorium and uranium contents, provides a new dating technique analogous to the previously discovered "fission-track method." The primary advantage of the alpha-recoil method is a several-thousand-fold increase in sensitivity over the fission-track technique. The alpha-recoil method should also prove useful in studying the problem of extinct isotopes in meteorites.     

论高校图书馆样本书库的管理与利用

结合图书馆对样本书库管理与利用的实际操作,论述了加强高校图书馆样本书库管理,充分利用样本书库资源的有效措施。     

葡萄酒灌装线自动码垛机的技术改造

介绍了自动码垛机的概念、分类,重点阐述了葡萄酒灌装线码垛机的结构、工作过程及原理,分析了葡萄酒灌装过程中自动码垛机在对小箱(1×6瓶)进行码垛后出现的掉箱现象的原因,并进行了技术改造。改造后在不增加托盘尺寸的条件下,每垛箱子数量由120箱增加到145箱,提高了箱垛的稳定性,大大降低了掉箱的概率,同时减少了仓库存储的占地面积。     

蚯蚓堆肥处理剩余污泥混合有机垃圾的效率研究

为了研究基质堆料高度和高密度接种条件对蚯蚓堆肥处理有机垃圾混合剩余污泥时蚯蚓生物量及其堆肥效率的影响,共设6个处理进行试验,按接种密度-堆料高度表示,分别为:1/10-10cm组、1/10-15cm组、1/15-10cm组、1/15-15cm组、1/20-10cm组、1/20-15cm组。试验结果表明,在堆料高度相同时,蚯蚓生物量与其接种密度呈显著的负相关关系,但接种密度对蚯蚓堆肥效率的影响有限,只有在1/10组同1/15组或1/20组比较时表现出显著差异,而后两个组别之间差异不显著;在接种密度相同时,堆料高度对蚯蚓堆肥效率的影响不显著,而对蚯蚓生物量的影响可能存在一个密度临界点(1/15),在此密度附近,堆料高度对蚯蚓生物量的影响较显著,呈显著正相关关系,而在此密度以上或以下,堆料高度的影响不显著。从产业应用的角度,综合考虑蚯蚓维持种群繁衍的再生产能力以及混合污泥的堆肥效率这两个因素,赤子爱胜蚓(Eisenia foetida)处理有机垃圾混合剩余污泥的最佳接种密度为1/15,堆料高度为15cm。