林木种子X射线片的数字图象处理

<正>用X射线,特别是软X射线拍摄林木种子,判渎并分析所摄图象以鉴定林木种子质量,三十年来这一方法在国外发展相当迅速。可望成为林木种子检验的常规手段之一。近年来我国林业工作者就这一方法进行了试验研究,取得不少经验。 对X射线片的分析研究,目前是把与原物等大的黑白透明X射线片衬在灯箱上,借助透身十光线用肉眼观察胚和胚乳的发育状况,并判断胚孔同种腔和胚同胚腔的比例关系,据以鉴定种子质量。对具有机械伤害或生理伤害的种子,则利用各种衬比剂使伤害部分在图象上显现,仍用肉眼判断受害部分同整个胚或胚乳面积的比例关系。在这一过程中,有时由于X射线片上各组织间轮廓不清,或是种子粒太小,肉眼不易分辨,往往带有一定程度的主观随意性,不能得到准确的数据,因此,改善X射线片图象的判读性能,取得种子内部各组织发育程度及相互间比例的精确数据,进而把检验工作从定性提高到定量化水平,将是林木种子X射线影摄检验法更趋完善的一项有意义的研究课题。     

响叶杨(Populus adenopoda)种子的形成及其寿命

<正>用显微技术及软X射线摄影,定位观察响叶杨种子发育过程中的形态变化与胚胎发育的对应关系。根据观察、试验的结果,讨论了环境条件与种子寿命的关系;还测定了响叶杨种子寿命的变化规律及其影响因素,探索延长这种子寿命的方法。     

手工焊熔滴过渡X射线高速摄影方法的研究

本文对X射线高速摄影技术进行了研究。试验表明;X光管电压、透射物与X光管及图象增强器之间的几何关系、拍摄光路参数的选择与匹配,以及图象增强器性能的优劣是影响拍摄效果的主要因素。在此基础上确定了最佳透视规范和拍摄规范,进行了手工焊熔滴过渡过程X射线高速摄影,获得了良好的拍摄结果。     

用X射线摄影术测定马尾松种子发芽能力的研究

应用直接射线摄影术研究了马尾松种子的发育状况与发芽能力之间的关系。得出了各发育等级种子的归约系数,利用归约系数可以估测新鲜种子的发芽能力。同时用射线衬比法测定马尾松种子发芽能力的方法及其标准化,为马尾松种子选择了合适的衬比条件,确定了判断种子发芽能力的标准。结果表明,用射线衬比法估测的发芽能力与发芽测定法得到的发芽率相当一致。     

封闭式出现电势谱仪及其应用

一、引言七十年代期间,由于表面科学迅速发展的需要,研究固体表面组分、表面结构或表面原子的电子结构的各种谱仪不断出现.软X射线出现电势谱(SXAPS)就是其中之一.在出现电势谱仪中,用一定能量的电子轰击固体(靶)表面,然后用光电法测定所产生的软X射线强度与轰击电子能量之间的关系.大家知道,在这种软X射线中包含着     

非织造布纤维网的取向度研究

本文引入了一种软X射线示踪纤维摄影法来检测非织造布纤维网的取向度。这种方法基于传统的示踪纤维方法。文中还讨论了一种计算机处理图片及计算取向度的方法。随着计算机图像处理技术的发展和广泛应用,这种方法可以发展为一种在线、无损检测纤维或纱线在纺织品中分布和取向的方法。     

基于CCD的软X射线成像系统研究

随着空间科学技术的发展,空间科学试验对样品的检测技术提出了新的要求,不但要求能在线检测样品,而且还能实时分析实验进程与样品变化。通过对软X射线实时成像技术的研究,从软X射线源、软X射线转换装置、CCD驱动电路、信号采集电路等方面提出在空间开展软X射线成像实验的技术途径和实现方法,为空间科学实验的在线无损检测创造技术条件。     

飞灰成砖

1895年德国物理学家WilhelmRontgen正在进行电子撞击金属物体后产生射线的研究实验时,发现自己的手骨被投影到一面墙壁上,于是发现了这种穿透力极强的射线。之后,Rontgen将这种来历不明的射线称为X射线。     

2013-16 科技要闻

三维相干衍射成像领域取得新进展山东大学晶体材料国家重点实验室江怀东等利用三维相干X射线衍射成像技术和软X射线显微技术,实现了原位定量研究地幔橄榄石矿在纳米尺度上的微观结构,在高压材料研究方面取得重要进展。相干X射线衍射成像作为新兴的高分辨显微成像方法,利用     

杉木种子X射线衬比检验方法的研究

本研究发现,碘化钾是杉木种子衬比射线检验的最佳衬比剂;衬比过程是:杉木种子在自来水中浸泡16h;吸干种子表面水分,在40％的碘化钾溶液中处理2 h;在流水中冲洗5～6min后在70℃下干燥4h。研究结果表明,胚和胚乳(雌配子体)发育良好且未被碘化钾浸渗的种子都有生活力。用X射线衬比法测定的34份杉木种子发芽能力(X),同它们的实际发芽率(Y)相当一致。它们的关系是Y=-1.5+0.998X,r=0.97。     

A high-intensity highly coherent soft X-ray femtosecond laser seeded by a high harmonic beam

Synchrotrons have for decades provided invaluable sources of soft X-rays, the application of which has led to significant progress in many areas of science and technology. But future applications of soft X-rays--in structural biology, for example--anticipate the need for pulses with much shorter duration (femtoseconds) and much higher energy (millijoules) than those delivered by synchrotrons. Soft X-ray free-electron lasers should fulfil these requirements but will be limited in number; the pressure on beamtime is therefore likely to be considerable. Laser-driven soft X-ray sources offer a comparatively inexpensive and widely available alternative, but have encountered practical bottlenecks in the quest for high intensities. Here we establish and characterize a soft X-ray laser chain that shows how these bottlenecks can in principle be overcome. By combining the high optical quality available from high-harmonic laser sources (as a seed beam) with a highly energetic soft X-ray laser plasma amplifier, we produce a tabletop soft X-ray femtosecond laser operating at 10 Hz and exhibiting full saturation, high energy, high coherence and full polarization. This technique should be readily applicable on all existing laser-driven soft X-ray facilities.     

Fabrication of the beam splitters for soft X-ray laser application

The electron densities of a laser-produced plasma near the critical surface can be measured by using soft X-ray laser interferometry because the soft X-ray laser has shorter wavelength, higher brightness and better coher-ence and so on. It has obvious dominance in the experi-mental research of diagnosing the distribution of electron densities in a laser-produced plasma. The experimental results can not only give the information correlated with plasmas, which cannot be described accurately in t…     

Soft X-ray in-line holographic experiment

“Water window” soft X-ray has some advantages in the microimaging of biological specimens. Soft X-ray holography can give us three-dimensional images of biological cells in their natural condition. Quasi-monochromatic soft X-ray from the pdymonochromatic synchrotron radiation is obtained by a zone plate-pinhole linear monochromator at National Synchrotron Radiation Laboratory (NSRI,) at Hcfei. The pinhole is used to increase the temporal coherence of the soft X-ray. and also to increase the spatial coherence of it. An in-line holographic experiment has been finished with soft X-ray of main wavelength 4.5 nm and pinhole of diameter 0.03 mm. The magnified hologram is recowtructed with He-Ne laser. A smaller pinhole is wanted to be used to improve the cuherence of the soft X-ray so as to improve the quality of the hologram.     

Optical pulsations from the anomalous X-ray pulsar 4U0142+61

Anomalous X-ray pulsars (AXPs) differ from ordinary radio pulsars in that their X-ray luminosity is orders of magnitude greater than their rate of rotational energy loss, and so they require an additional energy source. One possibility is that AXPs are highly magnetized neuron stars or 'magnetars' having surface magnetic fields greater than 10(14) G. This would make them similar to the soft gamma-ray repeaters (SGRs), but alternative models that do not require extreme magnetic fields also exist. An optical counterpart to the AXP 4U0142+61 was recently discovered, consistent with emission from a magnetar, but also from a magnetized hot white dwarf, or an accreting isolated neutron star. Here we report the detection of optical pulsations from 4U0142+61. The pulsed fraction of optical light (27 per cent) is five to ten times greater than that of soft X-rays, from which we conclude that 4U0142+61 is a magnetar. Although this establishes a direct relationship between AXPs and the soft gamma-ray repeaters, the evolutionary connection between AXPs, SGRs and radio pulsars remains controversial.     

极紫外和软X射线多层膜光学

综述了极紫外和软X射线多层膜光学及其应用，指出了极紫外和软X射线光学的优点和难点。在软X射线激光诊断高温高密度等离子体的干涉实验中，迫切需要既有一定反射率、又有一定透过率，同时具有很高面形精度的半反半透多层膜和高反射率多层膜组成的X射线激光干涉仪，以实现对高温等离子体临界面附近电子密度的诊断。在分析软X射线多层膜偏振特性基础上，设计了类镍银软X射线激光干涉仪用半反半透多层膜，并用离子束溅射方法制备了这样的元件，同步辐射反向率和透过率测试表明已制备的半反半透多层膜达到了进行软X射线干涉实验的要求。     

Correlative ionospheric disturbances in the sunlit hemisphere during the flare on July 14, 2000

Using GPS data obtained from GPS sites located on the sunlit hemisphere during the flare on July 14, 2000, the ionospheric response to the flare was analyzed. A kind of tiny correlative ionospheric fluctuations were revealed from the temporal total electron content (TEC) curves derived from GPS measurements, and the values of this kind of disturbances are about 1015 m-2. A comparative analysis of these disturbances and soft X-ray flux detected at GOES satellite during the flare is done. It is found that this kind of disturbances revealed in the temporal TEC curves did occur in a very large area of sunlit ionosphere and its behavior is mainly controlled by the characteristics of the flare's extra radiation. Because the similar fluctuations are not found in the curve of soft X-ray flux, it is concluded that the flare extra radiation in EUV band should have corresponding fluctuations and it is the fluctuations that cause the TEC disturbances. The height, where the disturbances occur, should be in the F region.     

高白填料氢氧化铝的微观结构

不同分解工艺生产的高白填料,其氢氧化铝晶体生长形态不同.采用扫描电镜、X射线衍射和拉曼光谱等分析手段研究了碳分和种分氢氧化铝高白填料产品的微观结构,揭示了它们晶体发育的变化.结果表明,高白填料氢氧化铝晶体属单斜晶系,空间群P21/n,择优生长晶面均为(002)晶面;种分氢氧化铝晶体比碳分氢氧化铝晶体的(002)晶面择优取向因子值小,为多晶面生长;种分氢氧化铝晶体晶格参数比碳分氢氧化铝晶体晶格参数和拉曼光谱特征峰半高宽数值小,因此,种分高白填料氢氧化铝晶体中杂质和晶格缺陷比较少,晶体结晶度明显好于碳分高白填料产品.     

嵌段聚酯脲氨酯弹性体的结晶形态

用宽角X-ray衍射(WAXD)研究了嵌段聚酯脲氨酯(PUU)弹性体在不同退火条件下的结晶行为,用扫描电子显微镜(SEM)研究了这些材料断面上的结晶形态。结果表明:PUU中存在着软、硬段结晶,软段结晶对退火温度较敏感,升高退火温度可以增加软段结晶,改善软、硬段两相分离的程度。从SEM照片上看到;在PUU的断面上存在着球晶、棒晶和无定形的连续相,晶体的尺寸和分布依赖于硬段含量和软段分子量的变化。我们认为晶相和硬段无定形相起着物理交联作用,使材料表现出橡胶状的弹性性质。     

溅射与水热混合法制备ZnO纳米结构薄膜的异常光致发光特性(英文)

用一种混合方法用来制备ZnO纳米结构薄膜,首先利用射频磁控溅射法在玻璃衬底上沉积ZnO薄膜作为种子层,然后用水热方法合成ZnO纳米结构薄膜.为研究ZnO纳米结构薄膜的特性,利用X——射线衍射(XRD)及扫描电子显微镜(SEM)对薄膜的结构和形貌进行分析,并用X——光电子能谱技术(XPS)对薄膜的化学组份进行分析,最后利用光致发光方法(PL)对ZnO薄膜的发光性能进行了研究.从XRD谱图中可以看出,无论溅射的ZnO种子层还是水热合成ZnO纳米结构薄膜均为良好c轴(002)结晶状态的六角纤锌矿结构.从SEM图像看出,磁控溅射ZnO种子层为连续平整的膜状结构;而经过水热处理后则得到垂直于衬底的六角纳米棒和纳米片两种不同形貌的结构.XPS分析现示,在ZnO种子层中,锌和氧的比例基本上为1,说明磁控溅射ZnO晶体质量较好;而ZnO纳米结构薄膜中存在明显的氧空位缺陷.值得提出的是ZnO纳米薄膜光致发光谱存在异常的特性,采用波长为325 nm的He-Cd激光激发出可见光范围(500~700 nm)内的发光带,强度最强的是橙——红色的光(~600 nm),且肉眼可直接观察到.随着激发光波长在280~380 nm范围内变化,橙...