X射线存储材料Si4 掺杂BaFBr:Eu2 中电子陷阱的研究

在BaFBr：Eu^2 中掺人Si^4 合成了一种新的X射线影像板材料，其主要光激励发光(PSL)性能，如射线敏感度和长波可激发性都优于低价阳离子掺杂的BaFBr：Eu^2 。用喇曼和顺磁共振(EPR)等手段表征了掺Si^4 后BaFBr：Eu^2 中电子陷阱的结构，并根据此结构解释了其激发波长的红移量比其它低价阳离子掺杂都高的原因。     

不同聚集态色心对BaFBr:Eu2+光激励发光的影响

BaFBr:Eu^2 作为一种优良的光激励发光材料,广泛应用于生物学、医学、同步辐射等领域。BaFBr:Eu^2 粉末材料涂覆在基片上做成X线影像板（简称IP板）,可以代替X线感光胶片记录X线影像。本文系统研究了在BaFBr:Eu^2 中掺杂不同的金属离子,促使BaFBr:Eu^2 的光激励波长峰值红移以及对其发光强度的影响,并在理论上探讨了不同金属离子的掺入所形成色心的类型。     

纳米蓝粉CaAl2O4:Eu2+的制备与研究

将超声波运用于沉淀法合成了彩色PDP用纳米级蓝粉CaAl2O4：Eu^2 用X射线粉晶衍射(XRD)、透射电镜(TEM)、荧光分光光度仪及PDP真空紫外荧光光谱测试系统对样品的性能进行了表征。XRD显示在1350℃煅烧就能得到单相的CaAl2O4基质，相对于高温固相反应法烧结温度降低了150℃；分别用高温固相法、传统的沉淀法和运用了超声波的沉淀法制备出了CaAl2O4：Eu^2 产物，结果表明运用了超声波的沉淀法制备出的纳米CaAl2O4：Eu^2 未发生团聚，粒度达70nm，相对发光强度大大提高；同时研究了Eu^2 对CaAl2O4：Eu^2 的发光性能的影响，确定了Eu^2 的最佳掺杂浓度；并研究了在真空紫外条件147nm激发下纳米CaAl2O4：Eu^2 的发光性能，结果表明其余辉时间为2．51ms，相对发光强度为商用PDP蓝粉BaMgAl10O17：Eu^2 的92％，色坐标y值为0．0426，比：BaMgAl10O17：Eu^2 的色坐标，值小，说明纳米CaAl2O4：Eu^2 的色彩重现域更广，在PDP应用中会具有较好的前景。     

Eu^2＋在KCaPO4中的发光及晶体学格位

采用高温固相法制备了KCaPO4：Eu^2＋蓝绿色荧光粉,研究了材料的发光特性。在400 nm近紫外光激发下,材料呈非对称的单峰发射,主峰位于487 nm。监测487 nm发射峰,对应的激发光谱覆盖300-450 nm,说明材料能够很好的吸收紫外-近紫外光,发射蓝绿色光。利用van Uitert公式计算了Eu^2＋取代...     

电子俘获材料KCl:Eu2+的光存储特性研究

采用高温固相反应法制备出了粉末态的 KCl:Eu2 样品 ,研究了 Eu掺杂浓度与光激励发光的关系。测试了样品的发光性能和存储性能 ,并分析了 KCl:Eu2 的光存储的机制。     

长余辉材料SrAl2O4：Eu^2＋，Dy^3＋的制备及发光性能研究

采用高温固相法，在碳粉还原条件下制备了发光亮度高、余辉时间长的SrAl2O4：Eu^2＋，Dy^3＋长余辉发光材料，对其发光性能进行了研究。发光粉体经碳粉还原后的发射光谱表明，其发射主峰位于509nm左右；余辉衰减曲线证明其余辉衰减过程存在快速衰减和慢衰减两个过程，该发光粉体的余辉时间能持续20h以上。此外还考察了烧结温度、稀土掺杂量和助熔剂含量对此发光粉体发光性能的影响。     

BaFBr:Eu2 中Al3 的最佳掺杂浓度研究

把Al^3 掺入BaFBr：Eu^2 中，取代了其中部分Ba^2 ，这些金属离子将影响到色心F(Br^-)，使其激发能变小。通过电子顺磁共振(EPR)谱研究了掺杂Al^3 的量值对光激励发光强度的影响，确定光激励发光强度最大时的最佳掺杂比例为0．015％。对这一结果从色心的形成机理上进行了讨论，指出掺杂量不是越多越好，过多的掺杂Al^3 能导致俘获电子的空位发生聚集，俘获电子的能力变弱，使光激励发光强度降低。     

燃烧法合成BaMgAl10O17:Eu2+荧光体及发光性能的研究

应用燃烧法在较低温度（600℃）下，于空气中快速合成BaMgAl10O17：Eu^2＋（BAM）荧光体。通过XRD和荧光光谱对荧光体进行表征和研究，考察了Eu^2＋的掺入浓度、尿素用量和Sr^2＋的掺杂等对荧光体发光性能的影响。结果表明BaMgAl10O17：Eu^2＋荧光粉在450nm处的荧光发射源于Eu^2＋的4f^65d^1-4f^7跃迁。荧光体的发射强度与Eu外浓度有很大关系，当Eu^2＋摩尔分数为10％时，发射强度最大。尿素用量对荧光体结晶性能和发光性能有很大影响，当尿素与硝酸盐之比为2．5：1时，荧光体发光强度最高。Dy^3＋、Er^3＋、Nd^3＋和Pr^3＋掺杂时，荧光体发光强度增加。Sr^2＋的掺杂对BAM荧光体的晶体结构和发光性能有很大影响。     

电子俘获光存储材料的最新研究进展

电子俘获材料是一类有着巨大应用潜力的光存储材料，它能将写入光照射材料后产生的电子(空穴)束缚在材料的某些稳定的高能级(陷阱)上。只有经过合适的读出光照射，被束缚住的电子(空穴)才能脱离陷阱复合发光。发光在空间的强度分布与写入光的分布一致，即再现了写入光的信息。电子俘获材料的种类很多，研究进展各不相同。其中，以作为X光影像存储材料的BaFBr：Eu为代表的碱土金属氟卤化物已经广泛应用于医疗诊断方面。本文分类介绍了近年来几种典型的电子俘获材料在发光机理和应用方面的最新进展，尤其重点介绍了新兴的玻璃陶瓷型电子俘获材料的研究工作情况。     

宽频谱红外上转换材料CaS:EU,Sm的快速合成及表征

分别以尿素、甘氨酸及二者一定比例混合体作为有机燃料，采用低温燃烧法快速合成了宽频谱红外上转换发光材料CaS：Eu，Sm，反应时间为2～3min，产物为红色疏松多孔的超细粉末。研究了燃料种类、燃料用量对于燃烧反应现象、燃烧产生的气体量及终产物表观状态的影响；研究了辅助氧化剂用量对于燃烧反应的影响。X射线衍射（XRD）物相分析表明样品为面心立方CaS晶格结构。光谱分析表明样品在800-1600nm之间具有宽频谱红外响应效应，上转换发光峰值波长位于655nm，对应于Eu^2＋离子的4f^65d→4f^7（^8S7/2）跃迁。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.