Probabilistic evaluation of lateral extent of soil liquefaction under earthquake loading

A Monte Carlo simulation method for calculating the probability of soil liquefaction of a finite area in which the ground motion is propagated upward from the bedrock through the soil layers is presented. The vertical propagation of the ground motion through the soil layers is analyzed using random vibration analysis. To account for the variability of soil properties with depth, the soil deposit is divided into layers. Within each layer the horizontal statistical correlation of the undrained cyclic shearing strength against liquefaction is taken into consideration by describing it as a two-dimensional homogeneous random field. The method computes the probability of liquefaction spreading over a specified area under a given earthquake loading considering the effects of spatial correlation of soil properties.     

X射线聚束透镜原理及其应用

本文阐述了一种新型的Ｘ射线聚束装置─—Ｘ射线透镜的聚束原理。给出了透镜的基本设计方法，并对它应用于Ｘ射线光刻研究领域的前景作了展望。     

Synthesis and characterization of tungsten disulphide films grown by pulsed-laser deposition

The synthesis and characterization of tungsten disulphide (WS₂) films grown on 440C stainless steel substrates using the 248 nm line from a KrF excimer laser are reported. Film properties could be adjusted by controlling substrate temperature and by laser or thermal anneals. X-ray photoelectron spectroscopy, glancing angle XRD, Raman spectroscopy and high-resolution scanning electron microscopy were used to evaluate film chemistry, crystallinity and morphology. Films grown at room temperature were amorphous, near stoichiometric, and had a multiplicity of chemical states. Local order and bonding were improved most dramatically through post-deposition laser anneals. Crystallite size could be increased by raising the substrate temperature during deposition and, to a lesser degree, by post-deposition thermal anneals. Local disorder was observed within the larger crystallites compared to those that were laser annealed. Crystallinity was induced in amorphous films by mechanical rubbing at room temperature under conditions where frictional heating was negligible. The degree of control over film properties provided by PLD demonstrates its value for growing/designing tribological coatings.     

高纯锗探测器的快定时性能及其应用

为了将高纯锗（ＨＰＧｅ）探测器用于快定时的物理实验中，本实验研究厂影响高纯锗探测器定时谱仪时间性能的各种因素，找出了获得谱仪最小时间分辨的各种最佳参数。并建立了分辨时间为４．１９ｎｓ，能量分辨率为２０ｋｅＶ，微分非线性好于±２．０％，计效率可承受１２０×１０￣３ｓ￣（－１）的时间微分扰动角关联谱仪。利用此谱仪，以￣（２０４）Ｂｉ为探针核，研究了Ｂｉ系高温超导的微观机理，取得了较好的结果。     

EFFECT OF THE RATIO Th/U ON TL DATING ACCURACY

ＥＦＦＥＣＴＯＦＴＨＥＲＡＴＩＯＴｈ／ＵＯＮＴＬＤＡＴＩＮＧＡＣＣＵＲＡＣＹ￥Ｐ．Ｌ．Ｌｅｕｎｇ（梁宝鎏）；ＭｉｃｈａｅｌＪ．Ｓｔｏｋｅｓ（ＤｅｐａｒｔｍｅｎｔｏｆＰｈｙｓｉｃｓａｎｄＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅ，ＣｉｔｙＰｏｌｙｔｅｃｈｎｉｃｏ...     

Multitemporal passive microwave mapping in MACHYDRO'90

MACHYDR0'90 was an experiment conducted in Pennsylvania in 1990 to study the synergistic use of remote sensors in multitemporal hydrologic studies. As part of this mission the pushbroom microwave radiometer was flown and used to produce brightness temperature maps. Verification studies and vegetation algorithms for mixed land cover areas are described     

Optoelectronic integration of a GaAs/AlGaAs bistable field effecttransistor (BISFET) and LED

The bistable field effect transistor (BISFET) is a novel inversion-channel switching device exhibiting abrupt current transitions and hysteresis in its output characteristics. The semiconductor structure of the BISFET is compatible with a range of electronic and optoelectronic devices. In this work, integration of a BISFET with an LED is reported. Both devices have been implemented on a single semiconductor substrate using a single fabrication sequence. The BISFET is used to current drive the LED. Abrupt transitions and hysteresis are seen in the optical output from the circuit in the range of gate voltage from 1.75 V to 1.9 V     

Modeling the I-V characteristics of fully depleted submicrometerSOI MOSFET's

In this paper, an analytic current-voltage model for submicrometer fully-depleted (FD) silicon-on-insulator (SOI) MOSFET's is presented. This model takes into account the source/drain series resistances which can be especially high in thin film SOI devices. The effect of drain induced conductivity enhancement is also included, which is important for submicrometer channels. The model is verified by comparison to measured SOI I-V characteristics. Good agreement is obtained for SOI film thicknesses ranging from 40 to 220 nm and effective channel lengths down to 0.25 μm