A comment on “Using locally estimated geodesic distance to optimize neighborhood graph for isometric data embedding”

A geodesic distance-based approach to build the neighborhood graph for isometric embedding is proposed to deal with the highly twisted and folded manifold by Wen et al. [Using locally estimated geodesic distance to optimize neighborhood graph for isometric data embedding, Pattern Recognition 41 (2008) 2226-2236]. This comment is to identify the error in their example and the ineffectiveness of their algorithm.     

Externalizing cognitive maps via map reconstruction and verbal description

Universal Access in the Information Society - Helping blind people to build cognitive maps of an environment is one of the aims of several assistive systems. In order to evaluate such assistive...     

车载移动测量系统前方交会中的误差分析

车载移动测量系统是由多个传感器集成的系统,定位精度受到很多因素的影响.首先简要介绍了车载摄影测量中内外方位元素的计算方法;其次,针对线性法前方交会求解中符号矩阵的直接求逆内存占用大的问题,提出利用杜利特尔分解(LU分解)的方法,推导出了前方交会的解算公式;最后,针对短基线小交会角的情况利用误差传播定律分析了各误差源对最终定位结果的影响,对于进一步研究车载移动测量系统具有一定的参考意义.     

Synthesis of Single-Crystalline Silicon Nitride Nanobelts Via Catalyst-Assisted Pyrolysis of a Polysilazane

Recently, one-dimensional nanostructures have attracted extensive attention since they are potentially important for both applications and fundamental research. In this paper, we report the synthesis of ultra-long single crystal Si₃N₄ nanobelts via catalyst-assisted pyrolysis of polymeric precursors. The obtained products contain both α- and β-Si₃N₄ nanobelts, which are 50–100 nm in thickness, 400–1000 nm in width, and a few hundreds of micrometers to several millimeters in length. Different from previous techniques for synthesizing one-dimensional structures, the current nanobelts are synthesized through confined crystallization of an amorphous phase. A solid–liquid–gas–solid reaction/crystallization growth mechanism is proposed. The formation of nanobelts instead of nanowires is attributed to the anisotropy growth at an earlier stage.     

数字多用表的比例功能在电阻箱检测中的应用

本文提出了检测电阻箱的一种新方法--比例法.文章除介绍其原理和方法外,还对装置的不确定度进行了分析,并对比例法检测数据和数表法直接测量的检定结果进行比对.比例法检测电阻箱的特点是对标准器和辅助设备的要求低、工作效率高并可实现半自动检定.拥有数字多用表和标准电阻的检测部门可利用本方法.     

Fabrication of thick BOX SOI by Smart-cut technology

A SOI material with thick BOX (2.2 μm) was successfully fabricated using the Smart-cut technology. The thick BOX SOI microstructures were investigated by high resolution cross-sectional transmission electron mi-croscopy (XTEM), while the electrical properties were studied by the spreading resistance profile (SRP). Experimen-tal results demonstrate that both structural and electrical properties of the SOI structure are very good.     

Investigation of elastic modulus of nanoporous alumina membrane

Nanoporous alumina membranes containing parallel regular pores of uniform size and normal to substrate surface were fabricated by anodically oxidizing high purity aluminum foils in acid solutions and their elastic modulus was investigated. The continuous out-of-plane displacement and current load of the porous membranes were obtained through bulge test combining real-time ESPI (electronic speckle pattern interferometry) observation system. Then the elastic modulus was calculated through an analytical model and the pore distortion after load was characterized by HRSEM (high resolution scan electron microscope). Measurement of mechanical properties indicates unusual mechanical behavior of these anodic alumina films compared with bulk alumina materials. This observation may help shed light on fracture mechanism of these films with nanopore arrays and bring further understanding on connecting of micro-meso structure and mechanical properties.     

水产品加工废水深度处理的试验

进行了用"生物接触氧化-微滤膜"组合工艺对水产品加工废水深度处理的试验研究.试验结果表明:在进水COD约900~1 200 ms/L,水力停留时间>16 h的情况下,平均出水COD<50 ms/t,达到再生水杂用水质标准.同时,研究探讨了处理过程中膜组件的污染及清洗问题,为实际工程中膜的运行提供了必要的参考.     

k分Cantor集的Hausdorff测度的一种计算

以比较初等的方法重新证明了著名的Ｃａｎｔｏｒ三分集的Ｈａｓｄｏｒｒｆｆ维数为ｓ＝ｌｏｇ２／ｌｏｇ３，Ｈａｕｓｄｏｒｆｆｃ测度为１，并对直线上类似的一类构造集推广了此方法。     

Rapid growth of angle-confined large-domain graphene bicrystals

In the chemical vapor deposition growth of large-area graphene polycrystalline thin films,the coalescence of randomly oriented graphene domains results in a high density of uncertain grain boundaries (GBs).The structures and properties of various GBs are highly dependent on the misorientation angles between the graphene domains,which can significantly affect the performance of the graphene films and impede their industrial applications.Graphene bicrystals with a specific type of GB can be synthesized via the controllable growth of graphene domains with a predefined lattice orientation.Although the bicrystal has been widely investigated for traditional bulk materials,no successful synthesis strategy has been presented for growing two-dimensional graphene bicrystals.In this study, we demonstrate a simple approach for growing well-aligned large-domain graphene bicrystals with a confined tilt angle of 30° on a facilely recrystallized single-crystal Cu (100) substrate.Control of the density of the GBs with a misorientation angle of 30° was realized via the controllable rapid growth of subcentimeter graphene domains with the assistance of a cooperative catalytic surface-passivation treatment.The large-area production of graphene bicrystals consisting of the sole specific GBs with a tunable density provides a new material platform for fundamental studies and practical applications.