Influence of purity of HfO2 on reflectance of ultraviolet multilayer

The impurities in two kinds of HfO2 materials and in their corresponding single layer thin films were determined through glow discharge mass spectrum technology and secondary ion mass spectrometry(SIMS) equipment respectively.It was found that ZrO2 was the main impurity in the two kinds of HfO2 either in the original HfO2 materials or in the electron beam deposited films.In addition,the difference of Zr content in the two kinds of HfO2 single laver films was much laxger than that of the other impurities such as Ti and Fe.which showed that it was just ZrO2 that made the difference between the optical performance of the film products including the two kinds of HfO2.With these two kinds of HfO2 and the same kind of SiO2.we deposited HfO2/SiO2 multilayer reflective coatings at the wavelength of 266 nm.Experimental results showed that the reflectances of these two mirrors were about 99.85% and 99.15% respectively,which agreed well with the designed results what were based on the optical constants obtained from the corresponding single layer thin films.     

Region of interest and pixel-by-pixel analysis of dynamic contrast enhanced magnetic resonance imaging parameters and time-intensity curve shapes: a comparison in chondroid tumors

Dynamic contrast enhanced (DCE) MRI is widely acknowledged to be a helpful tool in the diagnosis and differentiation of tumors. In common clinical settings, the dynamic changes described by the time-intensity curves (TICs) are evaluated to find patterns of atypical tissue behavior, i.e., areas characterized by rapid contrast wash-in and wash-out. Despite the ease of this approach, there is no consensus about the specificity of the TIC shapes in discriminating tumor grades. We explore a new way of looking at TICs, where these are not averaged over a selected region of interest (ROI), but rendered pixel-by-pixel. In this way, the characteristic of the tissue is not given as a single TIC classification but as a distribution of the different TIC patterns. We applied this method in a group of patients with chondroid tumors and compared its outcome with the outcome of the standard ROI-based averaged TIC analysis. Furthermore, we focused on the problem of ROI selection in these tumors and how this affects the outcome of the TIC analysis. Finally, we investigated what relationship exists between the "standard" DCE-MRI parameter maximum enhancement (ME) and the TIC shape. CONCLUSIONS: We demonstrate that, where the ROI approach fails to show the presence of areas of rapid contrast wash-in and wash-out, the pixel-by-pixel approach reveals the coexistence of a heterogeneous pattern of TIC shapes. Secondly, we point out the differences in the DCE MRI parameters and tumor volume that can result when selecting the tumor based on DCE parameter maps or post-contrast T1-weighted images. Finally, we show that ME maps and TIC shape maps highlight different tissue areas and, therefore, the use of the ME maps is not appropriate for the correct identification of areas of atypical TICs.     

Study on the radiation problem caused by electron beam loss in accelerator tubes

The beam dynamic code PARMELA was used to simulate the transportation process of accelerating electrons in S-band SW linacs with different energies of 2.5, 6 and 20 MeV. The results indicated that in the ideal condition, the percentage of electron beam loss was 50% in accelerator tubes. Also we calculated the spectrum, the location and angular distribution of the lost electrons. Calculation performed by Monte Carlo code MCNP demonstrated that the radiation distribution of lost electrons was nearly uniform along the tube axis, the angular distributions of the radiation dose rates of the three tubes were similar, and the highest leaking dose was at the angle of 160° with respect to the axis. The lower the energy of the accelerator, the higher the radiation relative leakage. For the 2.5 MeV accelerator, the maximum dose rate reached 5% of the main dose and the one on the head of the electron gun was 1%, both of which did not meet the eligible protection requirement for accelerators. We adopted different shielding designs for different accelerators. The simulated result showed that the shielded radiation leaking dose rates fulfilled the requirement.     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Quick single-photon detector with many avalanche photo diodes working on the time division

Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.     

Experimental study on SC RF cavities by using China large grain niobium for ILC

Large grain niobium has the potential of simplifying the production sequence and consequently reducing the cost of the superconducting RF cavities for ILC.To investigate the feasibility of fabrication and the possibility to achieve high gradient by large grain cavities,two 1.3 GHz cavities were made of China large grain niobium and a series of vertical tests were carried out following several different surfaces treatment procedures.Two cavities have both reached the high gradient of more than 43 MV/m repeatedly and the maximum accelerating field of 47.9 MV/m has been achieved by China large grain niobium.This paper introduces the features of the fabrication and surface treatments on the large grain cavities and presents the preliminary results of the research.     

Analysis of Laser-generated Rayleigh wave on viscoelastic materials

In order to understand the viscoelasticity of material, this research has been conducted to study the propagation characteristics of viscoelastic Rayleigh wave theoretically. A model is presented for the pulsed laser generation of ultrasound on viscoelastic medium surface. Referred to the Kelvin model, the frequency equation and the normal displacement of viscoelastic Rayleigh wave were derived, the influence of the viscoelastic modulus on dispersion and attenuation was discussed. From the theoretical calculation, it is shown that the effect of viscoelasticity on the attenuation of Rayleigh wave is more than that on its dispersion. In the case of a weak viscosity, the attenuation of viscoelastic Rayleigh wave is directly proportional to viscosity modulus; the effect of shear viscosity on the attenuation is much more than that of bulk viscosity. The transient response of viscoelastic Rayleigh wave was also simulated using Laplace and Hankel inversion transform, which are showed in good agreement with the theoretic predictions. The model provides a useful tool for the determination of viscoelastic parameters of medium.     

Autofluorescence of Plant Secreting Cells as a Biosensor and Bioindicator Reaction

Autofluorescence of intact secretory cell of plants is considered as a possible biosensor for the cellular biomonitoring. The fluorescence of secretory cells was due to the chemical composition of their secretions. This phenomenon could be recommended: 1. for the diagnostics of secretory cells among non-secretory ones; 2. for the express-analysis of the content of secretory cells at norm and under various factors; 3. for the analysis of cell-cell interactions. Identification of intact secretory cells filled with products of secondary metabolism is based on their fluorescence characteristics. The filling of the cells with a secretion and the removing of the secretions are easily observed under the luminescence microscope—from confocal microscope to various microspectrofluorimeters. The cellular fluorescence can serve as an indicator of the cell state in vivo. The following development of the earlier diagnostics based on the autofluorescence may be the area of the remote monitoring of agriculture crops and yields of medicinal plants as well as the remote sensing of the environmental stress.     

Synergistic effects on iodine release in potassium iodide solution by combination of ultrasound and visible light irradiations

Iodine release in potassium iodide solution has been investigated under the irradiations of ultrasound and visible light respectively and simultaneously. We have observed that the amount of iodine liberated under the combined irradiation of ultrasound and visible light is larger than the sum of that under the respective irradiations of ultrasound and visible light, indicating a synergistic effect of ultrasound and visible light irradiations. Based on the investigation of the reaction kinetics of iodine liberated, we have ascribed the synergistic effect to the perfect stirring of the photochemical reactor induced by the applying simultaneous ultrasound. The ideal stirring can result in the homogenization of the primary light effect in the whole reaction medium, which induces the acceleration of the photochemical reaction. On behavior of our knowledge, there are few reports on the investigations of utilizing the combination of ultrasonic energy and light energy to accelerate the reaction yield and rate as well as the kinetics of the reaction.     

Rotation of the light polarization plane by an ensemble of oriented linear associates: Model representations

In an “oriented gas” model expressions are obtained for the angle of nongyrotropic rotation of the polarization plane (NRPP) of transmitted light by an ensemble of oriented associates consisting of nongyrotropic molecules. The cluster character of the nongyrotropic rotation of the polarization plane and the dependence of its angle on the incident light polarization vector azimuth are noted, which distinguish linear and circular polarization effects. Measurement of linear dichroism by the angle of nongyrotropic rotation of the polarization plane with the use of commercial spectropolarimeters is theoretically justified. Institute of Molecular and Atomic Physics, National Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072 Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 1, pp. 95–101, January–February, 1998.     

A study on the best irradiation dose of X-ray for Hep-2 cells by Fourier transform infrared spectroscopy

Fourier transform infrared spectroscopy (FTIR) was employed to study the human epidermis larynx carcinoma cell lines (Hep-2) which were irradiated by different doses of X-ray.The results show that (1) the irradiation of X-ray damages the structure of the CH3 groups of the thymine in DNA,which restrains the reproduction of Hep-2 cells effectively,(2) the 8 Gy dose of X-ray irradiation changes the framework and the relative contents of some proteins,lipids and the nucleic acid molecules intercellular in the greatest degree,and (3) the 8 Gy dose of X-ray irradiation is the best irradiation dose for lowering the degree of the cancerization of Hep-2 cells according to the criteria for the degree of the cancerization reported recently.Meanwhile,the apoptosis of these cells were detected by using flow cytometry (FCM) primarily.It shows that the apoptotic ratio of the Hep-2 cells depends on the irradiation dose to some extent,but is not linearly.And the apoptotic ratio of the 12 Gy dose group is the maximum (20.36%),but the apoptotic ratios of the 2 to 8 Gy dose groups change little.     

LM and TEM study of the orthokeratinized and parakeratinized epithelium of the tongue in the domestic duck (Anas platyrhynchos f. domestica)

The previous histological studies of the lingual mucosa in birds characterized two types of keratinized epithelium, i.e. orthokeratinized and parakeratinized. These epithelia are composed of three layers: basal, intermediate and keratinized. The present study showed detailed ultrastructural features of cells in particular layers of two types of keratinized epithelia on the tongue in the domestic duck and defined structural differences.TEM observations showed a gradual reduction in cell organelles in the following layers, at increasing amounts of keratin fibers. The characteristic feature of the ortho- and parakeratinized epithelium is the presence of sub-layers in the intermediate layer, i.e. the upper and lower part, which results from the different shape of cell nuclei and dye affinity of the cytoplasm. The keratinized layer of ortho- and parakeratinized epithelium is built of two types of cells such as electron dark and light cells, which undergo exfoliation. The basic difference between the keratinized epithelia is the presence of flattened cell nuclei in the keratinized layer of the parakeratinized epithelium. The differentiating feature is also an arrangement of keratin fibers in the cell cytoplasm of the keratinized layer. The analysis of the thickness of the epithelium and the keratinized layer, indicated differences between keratinized epithelia, which result from two variants of performing protective functions, either through a thick keratinized layer or by a higher epithelium.Differences in the ultrastructure of the ortho- and parakeratinized epithelium are associated with mechanical functions of the epithelium resulting from different forces acting on the tongue during feeding activities.     

波源和接收者在介质体内的客观运动理论

建立介质体概念并指出介质体的内部独立性和外部相关性。建立双列车模型,对波在介质体内的多普勒效应进行量化分析。建立波源和接收者在介质体内的客观运动理论。把客观运动理论应用于天文学。指出天体介质体的边缘凸透镜特性。明确时间和物理介质空间的客观性。指出相对论的错误。明确波和粒子的区别。     

Formation and dynamics of Saturn and its disk simulated by using a new N-body model

The formation of Saturn and its disk is simulated using a new N-body self-gravitational model. It is demonstrated that the formation of the disk and the planet is the result of gravitational contraction of a slowly rotated particle cloud that have a shape of slightly deformed sphere. The sphere was flattened by a coefficient of 0.8 along the axis of rotation. During the gravitational contraction, the major part of the cloud transformed into a planet and a minor part transformed into a disk. The thin structured disk is a result of the electromagnetic interaction in which the magnetic forces acting on charged particles of the cloud originate in the core of the planet. The simulation program gives such parameters of Saturn as the escape velocity of about 35 km/s at the surface, density, rotational velocities of the rings and temperature distribution.     

FTIR，XPS和SEM研究聚羧酸盐分散剂在吡唑醚菌酯颗粒表面的吸附性能

采用傅里叶变换红外光谱、X射线光电子能谱和扫描电子显微镜相结合的方式，从微观角度研究梳状聚羧酸盐分散剂在吡唑醚菌酯颗粒表面的吸附性能，为聚羧酸盐分散剂在吡唑醚菌酯悬浮剂中的应用提供理论依据。研究结果表明：吡唑醚菌酯吸附聚羧酸盐分散剂后，红外谱图未出现新的吸收峰，聚羧酸盐分散剂与吡唑醚菌酯之间主要是物理吸附，范德华力是聚羧酸盐分散剂与吡唑醚菌酯颗粒表面结合的主要作用力。吡唑醚菌酯颗粒吸附聚羧酸盐分散剂后，吡唑醚菌酯颗粒界面的N和Cl电子峰强度减弱，C和O电子峰强度明显增强，还出现了Na的电子峰，这主要是聚羧酸盐分散剂中C，O和Na的贡献，说明聚羧酸盐分散剂在吡唑醚菌酯颗粒表面形成了良好的吸附。并以Cl元素为特征元素，计算出聚羧酸盐分散剂在吡唑醚菌酯颗粒表面的吸附层厚度约为1.22 nm。用扫描电子显微镜研究了样品的形貌，吸附聚羧酸盐分散剂后，原本光滑的吡唑醚菌酯颗粒表面吸附了很多细小的颗粒，且有序分布，这是由于分散剂疏水集团对吡唑醚菌酯颗粒形成了包覆，亲水基团充分外露，从而有效阻止吡唑醚菌酯颗粒间的团聚，提高了吡唑醚菌酯悬浮剂的物理稳定性。     

橄榄油的聚集荧光猝灭及吸收光谱特性的研究

素有“液体黄金”之称的橄榄油已成为健康食用油的代名词,不仅身价陡增,而且在非产地市场也已成为一种畅销油。在橄榄油检测技术中光谱法与其他技术相比具有快速、无损、无样品处理等优势而备受关注,而不同的光谱检测方法在检测的物质成分上各有侧重,例如红外光谱法侧重于脂肪酸含量的检测、拉曼光谱法侧重于分子的检测、荧光光谱法侧重于光敏物质的检测以及吸收光谱法侧重于光敏物质和不饱和脂肪酸的检测等。荧光及吸收光谱对光敏物质反应极其灵敏,而橄榄油富含叶绿素等光敏物质,因此荧光及吸收光谱成为一种鉴别橄榄油的有效技术手段。叶绿素是一种含有环卟啉结构的有机分子,该类分子结构具有吸光特性,且不同的叶绿素吸收光谱各异,其中绿色植物的叶绿素a含量最多。为深入研究叶绿素的吸收光谱及荧光特性在橄榄油鉴别中的应用,将特级初榨橄榄油中掺入不同比例的玉米油,已达到间接调控橄榄油中叶绿素含量的目的,测量不同掺伪比例橄榄油的荧光及吸收光谱并研究与叶绿素浓度的相关性,以此来研究叶绿素浓度与掺伪量对橄榄油吸收光谱及荧光特性的影响。取10份同批次的特级初榨橄榄油,将其中9份按照等比例稀释,并对10份样品按照掺伪量依次排序;依次采集这10份样品的荧光及吸收光谱,比较叶绿素浓度与掺伪量的相关性及对这两种光谱技术在橄榄油鉴别中的影响。随着叶绿素浓度的上升,荧光强度由弱变强,并在某一时刻后会出现荧光强度急剧减弱的现象,即聚集荧光猝灭。这种现象主要是由于叶绿素的环卟啉分子结构引起的分子间π-π作用,使未被激发的低能分子与高能分子堆叠在一起,能量的辐射跃迁（荧光）也转变为分子间的能量转移（热能交换）。对于吸收光谱,随着叶绿素浓度的上升,吸收光谱的强度也逐渐增强。橄榄油中叶绿素吸收的能量主要去向包括镁电子辐射跃迁产生荧光以及分子间热能交换两部分,而橄榄油的吸收光谱并未出现类似于聚集荧光猝灭的现象,且吸收光谱强度与掺伪浓度间存在近似线性相关的关系。结果表明：当聚集荧光猝灭出现时,叶绿素吸收的能量仍然与浓度呈线性相关,此时高、低能分子堆叠引起的热能交换效率提高。     

不同微波条件对蛋清蛋白糖基化产物不均匀性的影响

实验研究微波对蛋清蛋白粉与葡萄糖干样混合体系的影响,构建微波条件下蛋清蛋白-葡萄糖圆柱体反应模型。通过改变微波的功率,时间和位置,采用红外热像仪、荧光、紫外,高效液相色谱等方法研究微波场中蛋清蛋白糖基化产物不均匀性。将蛋清蛋白粉末与葡萄糖等质量混合,手工震荡和研钵充分研磨后在平皿表面铺一薄层粉末,放置于微波炉中心反应。将反应后的样品按左、中、右分成三个规则区域均匀采样。热像图表明微波功率越高,样品表面温度越高。凝胶电泳图表明240 W微波加热30 min样品边缘已经发生了反应,而且样品中间部分几乎还未反应;自由氨基含量测定表明高功率长时间微波作用才会观测到明显糖基化反应而低功率短时间条件下反应不明显,且边缘部分的样品反应总是比中间部分的样品剧烈;通过荧光光谱可知,蛋清蛋白和葡萄糖发生了反应,而样品边缘部分荧光强度降低得比样品中间部分多说明样品边缘反应更加剧烈;紫外光谱测定表明越剧烈的微波条件样品紫外吸收越多,边缘部分紫外吸收最高。液相结果也证实了这一点,糖基化样品边缘部分5-羟甲基糠醛(HMF)含量明显高于样品中间部分,且随时间和功率逐渐增加。