A new micro programmable blazed grating (μPBG) and its application to multispectral imaging

A new micro programmable blazed grating (μPBG) was designed, fabricated and characterized using the two-layer polysilicon surface micromachining process. The μPBG presented is simple in structure and has the capability of continuous spectral tuning for a wide wavelength range. To maximize the operational blazed angle, dimple structure was adopted as the key component for grating slats, and its height was close to the air gap. By the measurements, the developed μPBG sample can reach a maximum blazed angle of ~5.19° at a driving voltage of 112 V. Accordingly, the blazed wavelength can reach a mid-infrared wavelength of 4.88 μm. Then, a preliminary experiment to investigate the feasibility of multispectral imaging by using the developed μPBG as the core dispersing element was performed, and the results are encouraging. The advantages of the proposed method for multi- spectral imaging are discussed, and some suggestions for further research are also put forward.     

Rupture process of the Wenchuan <Emphasis Type="Italic">M</Emphasis>8.0 earthquake of Sichuan China: the segmentation feature

Moment tensor solution, rupture process and rupture characteristics of the great Wenchuan M8.0 earthquake are studied by using 39 long-period P and SH waveforms with evenly azimuth coverage of stations. Our results reveal that the Wenchuan M8.0 event consisted of 5 sub-events of Mw≥7.3 occurring succesively in time and space. Rupture started with a Mw7.3 introductory strike-slip faulting in the first 12 s, then within 12?40 s, two sub-events with Mw7.6 and Mw7.4 occurred within 80 km northeast from the init...     

Focal mechanism analysis and parameter estimation of Zhangbei-Shangyi earthquake from differential SAR interferometry

On 10 January, 1998 an earthquake of Ms=6.2occurred in the Zhangbei-Shangyi region of North China.The surface seismic deformation was measured in the previous study using the 3 pass ERS-1/2 SAR differential interferometric technology (D-INSAR). In this note the focal mechanism of Zhangbei-Shangyi earthquake is estimated from the D-INSAR measurement of surface deformation based on a standard elastic dislocation model for seismic displacement. The inversion procedure is an iterative, linear least-squares algorithm. Through the relation between the focal parameters and displacement in the line of sight direction measured in the radar interferogram, the optimum focal parameter set is derived. The results show that the seismic fault of Zhangbei-Shangyi earthquake is a thrust fault dipping SW with a large right-lateral displacement component.The strike and dip are 95° and 30° respectively on a fault patch of 12 km long by 14 km wide. Its hypocenter is located at N40°58', E114°21', and 7.5 km in depth. The estimated slip vector is 0.728 m with a rake of 105.95°, the trend of slip is NW13.26°, and M0is 2.69×1018 N @ m.     

油水乳化液在复合疏水网膜上破乳与分离实验研究

油水分离对于采油、炼油,以及含油废水的处理有着重要的意义.以不锈钢丝网为基底,采用喷涂-高温塑化的方法复合聚苯硫醚-聚四氟乙烯(PPS-PTFE)涂层,得到了表面形态不同的复合网膜.采用扫描电镜、接触角测量仪等设备对其表面形态与疏水性进行了表征.具有立体纤维网状结构的破乳网膜对乳化液具有良好的破乳效果,从而使乳化油转化为分散油和浮油,然后由超疏水油水分离网膜对油水混合物进行多级分离,达到油水分离的目的.实验过程对不同操作条件下的油水分离效果进行了研究,在优化的操作条件下,经五级分离,出口水中油含量可降至25mg/L,良好的分离效果为超疏水油水分离网膜今后的应用奠定了基础.对破乳分离机理进行了简要分析.     

Static slip model of the M w 9.0 Tohoku (Japan) earthquake: Results from joint inversion of terrestrial GPS data and seafloor GPS/acoustic data

Based on co-seismic displacements recorded by terrestrial GPS stations and seafloor GPS/acoustic stations, the static slip model of the 2011 Mw 9.0 Tohoku earthquake was determined by inverting the data using a layered earth model. According to a priori information, the rupture surface was modeled with a geometry that is close to the actual rupture, in which the fault dip angle increases with depth and the fault strike varies with the trend of the trench. As shown by the results inferred from the joint inversion, the "geodetic" moment is 3.68 × 10 22 Nm, corresponding to Mw 9.01, and the maximum slip is positioned at a depth of 13.5 km with a slip magnitude of 45.8 m. Rupture asperities with slip exceeding 10 m are mainly distributed from 39.6 to 36.97°N, over a length of almost 240 km along the trench. The slip was mostly concentrated at depths shallower than 40 km, up-dip of the hypocenter. "Checkerboard" tests reveal that a joint inversion of multiple datasets can resolve the slip distribution better than an inversion with terrestrial GPS data only-especially when aiming to resolve slip at shallow depths. Thus, the joint inversion results obtained by this work may provide a more reliable slip model than the results of other studies that are only derived from terrestrial GPS data or seismic waveform data.     

AlGaInAs multi-quantum wells ring laser with optical coupling waveguides

Based on InAIGaAs multi-quantum wells epitaxy structure for Fabry-Pero laser diode, a multi-quantum wells semiconductor ring laser is realized using ICP dry etching process and polyimide planarization process, The laser is generated in a semiconductor resonator ring and is output by two coupled integrated bus waveguides. The ring diameter is 700μm and the width of the waveguide is 3 μm. The output optical power-current （P-I） characteristic and the wavelength spectra of the ring laser are measured using a fiber coupled to the cleaved facet of the bus waveguide. The threshold current of the device is 120 mA and the wavelength is 1602 nm at an injected current of 160 mA. In addition, the operation mode for the laser in the resonator ring is roughly discussed based on the P- I characteristic plot.     

Slip model for the 2011 M_w 9.0 Sendai （Japan） earthquake and its M_w 7.9 aftershock derived from GPS data

Using GPS-measured coseismic and post-seismic displacements for the 8 h following the M w 9.0 Sendai earthquake of March 11, 2011, coseismic and post-seismic fault slip models were developed based on a layered crustal model. The geodetic moment magnitude of the main shock was measured as approximately M w 8.98. The slip exhibits clear reverse characteristics, with a maximum near the hypocenter, and a magnitude of about 23.3 m. Some strike-slip behavior may occur on the two sides of the peak rupture zone. Almost 90% of the seismic moments released by the main shock occurred at depths less than 40 km. The energy released by the fault slip in the 8 h following the main shock is approximately equal to an earthquake of M w 8.13. With a maximum of ~1.5 m, the post-seismic slip was concentrated in the southwestern part of the coseismic rupture fault, which agrees well with the location and behavior of the M w 7.9 aftershock. This implies that the post-seismic deformation in the 8 h after the main shock was mainly induced by the M w 7.9 aftershock. In addition, a post-seismic slip of 0.2-0.4 m was observed at the down-dip extension of the coseismic rupture, which may have been caused by the effect of after-slip during this period.     

利用蚕丝制作的微米光器件的研究

利用Na2CO3水溶液将蚕茧去除丝胶得到直径为5～15μm的生物纤维,采用扫描电镜(SEM)和透射电镜(TEM)观察了其形貌特征。通过倏逝波耦合的方法,利用SiO2微纳光锥将波长为671 nm的红光、532 nm的绿光、473 nm的蓝光分别耦合进入微米蚕丝生物光纤,分析了其导光特性,测量了光在蚕丝纤维中的传输损耗。制作了2×2、3×1、1×4、环形等光子结构。实验证明蚕丝微米生物光纤具有良好的柔韧性和表面光滑度,其中波长为532 nm的绿光在直径为9.0μm的蚕丝纤维中传输时的损耗为0.78 dB.mm-1。     

基于软印刷技术的竹材表面仿制荷叶超疏水结构

 利用软印刷技术,研究了在竹材表面仿制荷叶表面的超疏水性微纳结构。以新鲜荷叶为模板,以聚二甲基硅氧烷（PDMS）为印章,经过两次复形处理使竹材表面获得类似荷叶表面的超疏水结构。扫描电子显微镜（SEM）观测及接触角测试结果表明,制备的仿生荷叶竹材样品具有与荷叶类似的微纳乳突结构粗糙表面,其与水滴的接触角达到150.5°（平均值）,非常接近荷叶表面的接触角（154.5°）,表现出超疏水特性。仿生荷叶微纳结构竹材样品的成功制备,证实了纳米技术赋予竹材等亲水材料以超疏水性能的可行性。     

Source rupture process of Lushan M S7.0 earthquake, Sichuan, China and its tectonic implications

The source rupture process of the M _S7.0 Lushan earthquake was here evaluated using 40 long-period P waveforms with even azimuth coverage of stations. Results reveal that the rupture process of the Lushan M _S7.0 event to be simpler than that of the Wenchuan earthquake and also showed significant differences between the two rupture processes. The whole rupture process lasted 36 s and most of the moment was released within the first 13 s. The total released moment is 1.9×10¹⁹N m with M _W=6.8. Rupture propagated upwards and bilaterally to both sides from the initial point, resulting in a large slip region of 40 km×30 km, with the maximum slip of 1.8 m, located above the initial point. No surface displacement was estimated around the epicenter, but displacement was observed about 20 km NE and SW directions of the epicenter. Both showed slips of less than 40 cm. The rupture suddenly stopped at 20 km NE of the initial point. This was consistent with the aftershock activity. This phenomenon indicates the existence of significant variation of the medium or tectonic structure, which may prevent the propagation of the rupture and aftershock activity. The earthquake risk of the left segment of Qianshan fault is worthy of attention.     

Structural studies of membranes and surface layers up to 1,000 A thick using X-ray standing waves

The X-ray standing wave (XSW) method, developed in the 1960s, was used originally to determine heavy atom positions in and on silicon and germanium single crystals. An X-ray standing wave generated by the interference of coherent incident and reflected beams excites X-ray fluorescence from the heavy atom, the intensity of which as a function of incident angle provides an indication of the atom's distance from the X-ray reflecting surface. The availability of X-ray mirrors and the ability to prepare layered synthetic microstructures has made possible the study of biologically relevant structures using the XSW technique on length scales of typically tens to hundreds of ?ngstr?ms, allowing heavy atoms in such structures to be located with ?ngstr?m or sub?ngstr?m resolution. Many model biological systems (such as Langmuir-Blodgett films, which mimic membranes) require access to still larger scales, but it is not obvious that an XSW will remain coherent over such length scales. Here we report studies of a lipid multilayer system using the XSW method, in which we have been able to locate the metal atoms in a zinc arachidate bilayer with ?ngstr?m resolution at a distance of almost 1,000 A above the surface of a gold mirror. Our results indicate that the XSW technique should be useful for structural studies of supramolecular aggregates, receptor-ligand interactions and multi-membrane stacks, in which length scales of this order are encountered.     

主动区溶洞对桩锚支护基坑稳定性的影响

为了研究存在最危险滑移面时主动区溶洞对桩锚支护基坑稳定性的影响,首先运用FLAC3D软件模拟出没有溶洞时基坑最危险滑移面的位置,然后再分别模拟出主动区不同位置、不同大小的溶洞对桩体最大水平位移和弯矩、锚索最大轴力以及地表最大沉降位移的影响规律,最后提出主动区溶洞的处理方法.结果表明:最危险滑移面的剪出口出现在强风化石灰岩与中风化石灰岩的分界线处,最危险滑移面为与基坑内壁夹角约45.方向的弧形面;在同一溶洞中心埋深下,越靠近最危险滑移面的溶洞对基坑稳定性影响越大,当溶洞中心埋深不同但都在最危险滑移面上时,越靠近剪出口的溶洞对基坑稳定性影响越大;溶洞边长越大,对基坑稳定性影响越大,当边长大于等于2 m时,需要对溶洞进行处理,且利用增大锚索预应力的处理方法对主动区溶洞的处理效果比较明显.可见,考虑最危险滑移面的不利影响对研究主动区溶洞对桩锚支护基坑稳定性的影响是必要的.     

瞬态瑞利波法在秦峪滑坡勘查中的应用

秦峪滑坡是国道212线上最严重的滑坡之一,是在断裂带基础上发育的多层次、多期次大型滑坡群组合体.在探测覆盖层的厚度、基岩埋深、滑坡的滑动面等方面,瞬态瑞利波勘探是一种有效的地震勘探手段,为此利用瞬态瑞利波勘探方法对秦峪滑坡进行了勘探,基本查明了滑坡的剖面结构,为国道212线秦峪滑坡的治理以及拟建兰州一海口高速公路的选线和设计提供理论依据.     

基于倾斜变形的边坡临界滑动面确定方法研究

采用强度折减法寻找三维边坡临界滑动面是边坡稳定性分析工作中的重要问题。基于对边坡临界状态位移场的分析,提出一种三维边坡临界滑动面的确定方法,即认为当边坡处于临界状态时,滑动面上的点是空间倾斜角度最大的位置点。通过强度折减计算使边坡达到临界状态,沿边坡表面及坡体内部等距布置测线和离散点,并计算各离散点的空间倾斜角度,提取每条测线上离散点空间倾斜角度最大值的坐标点;然后利用局部加权回归散点平滑方法做平滑处理,并将曲面在边坡范围外的多余部分进行裁剪即可得到三维边坡的临界滑动面。最后,探讨了倾斜变形计算长度大小和离散点布置的疏密程度对滑动面的影响,结果表明,倾斜变形计算长度对滑动面形状影响较小,离散点间距对滑动面形状存在一定的影响。     

Yb3+-doped large-mode-area photonic crystal fiber laser with 210 W continuous-wave output power

An Yb^3＋-doped double-clad large-mode-area photonic crystal fiber （LMA PCF） laser with up to 210 W of continuous-wave output power centered at 1.05 lira is demonstrated. The length of the fiber used is 2 m and the produced laser power per meter can attain 105 W. The PCF is pumped by two diode lasers with central wavelength of 976 nm. The slope efficiency is 76%, and the beam quality factor M^2 at x and y axes are measured to be 1.06 and 1.08, respectively. No thermo-optical problems and other roll-over even are observed at the highest output power.     

The template preparation and characterization of three new shapes of titania nanometer-array systems

Nano-structure systems such as nano-structure de- vices and quantum devices have become a hot spot[1] in the materials science. Recently, the synthesis and the preliminary exploration of the properties of novel nano-structures or nanometer constitutional …     

不同假定对边坡安全系数计算的影响分析

基于滑面正应力假定,可以很方便地得到给定滑动面的安全系数,但不同的滑面正应力假定对结果的影响值得研究。本文通过随机模拟方法,给出了不同滑面正应力假定下安全系数的分布,并对给定的多个滑动面,经计算比较了该方法与不平衡推力法的误差大小。分析结果表明：给定滑动面愈接近临界滑动面,其结果误差愈小;对任意给定的滑动面,误差可高达900%以上。     

面波勘探和台阵地脉动观测相结合的地基调查法及其在松江古照壁保护中的应用

通过对高密度面波勘探和台阵地脉动勘探的频散分析算法的理论分析,推导出了2种勘探数据频散分析目标函数的统一表达式.根据该结果,用加权函数将2个目标函数结合起来,联合分析2种数据得到一条由高频到低频的完整的频散曲线;反演该频散曲线就可得到由地表到大深度的地下构造.将该方法应用于松江古照壁文物保护之地基勘查,为建立地震响应分析模型提供了由地表到40 m深处的横波速度构造.该方法是一种简便快速并兼顾浅层精度和勘探深度的工程地质调查方法.     

Influence of surface passivation on the minority carrier lifetime,Fe-B pair density and recombination center concentration

Three kinds of methods (0.08 mol/L iodine in ethanol, SiNx:H, and 40% HF) are used to passivate solar-grade Czochralski (Cz) silicon wafers. Thereafter, minority carrier lifetime and Fe-B pair density of the wafers are measured using the microwave pho-to-conductance decay (μ-PCD) technique. Based on the measured minority carrier lifetime, it is found that the passivation quality achieved by 0.08 mol/L iodine in ethanol is the best, while that by 40% HF solution is the worst. For the identical wafer, the density distribution of Fe-B pairs is different when different passivation methods are used. When the wafers are passivated by SiNx:H, there exists a close correlation between the distribution of minority carrier lifetime and the concentration distribution of Fe-B pairs. Furthermore, for wafers with high-quality passivation, there is a strong correlation between the recombination center concentration and the Fe-B pair density. All the analyses verify that the surface passivation quality of wafers influences the measurement results of minority carrier lifetime, Fe-B pair density and recombination center concentration.     

Research of high speed optical switch based on compound semiconductor

High-speed optical switch and its array are the crucial components of all-optical switching system. This paper presents the analytical model of a total-internal-reflection （TIR） optical switch. By employing the carrier injection effect in GaAs and the GaAs/AlGaAs double heterojunction structure, the X-junction TIR switch and the Mach-Zehnder interference （MZI） switch are demonstrated at 1.55 μm. The measured results show that the extinction ratio of both switches exceeds 20 dB. The switching speed reaches the scale of 10 ns.