Three-dimensional morphology and crystallography of gold nanorods

We determine the three-dimensional shape, to within 1 nm resolution, of single-crystal gold nanorods grown in the presence of silver ions using electron tomography and thickness profile measurements. We find that, contrary to the current literature, the octagonal side-facets are sparsely packed atomic planes all belonging to the same symmetry-equivalent family, {0 5 12}. Furthermore, the rod ends terminate in a pyramid with slightly different facets, and each pyramid is connected to the sides by four small {0 5 12} "bridging" facets.     

The cathode strip chamber data acquisition electronics for CMS

Data Acquisition (DAQ) electronics for Cathode Strip Chambers (CSC) [CMS Collaboration, The Muon Project Technical Design Report, CERN/LHCC 97-32, CMS TDR3, 1997] in the Compact Muon Solenoid (CMS) [CMS Collaboration, The Compact Muon Solenoid Technical Proposal, CERN/LHCC 94-38, 1994] experiment at the Large Hadron Collider (LHC) [The LHC study group, The Large Hadron Collider: Conceptual Design, CERN/AC 1995-05, 1995] is described. The CSC DAQ system [B. Bylsma, et al., in: Proceedings of the Topical Workshop on Electronics for Particle Physics, Prague, Czech Republic, CERN-2007-007, 2007, pp. 195–198] includes on-detector and off-detector electronics, encompassing five different types of custom circuit boards designed to handle the high event rate at the LHC. The on-detector electronics includes Cathode Front End Boards (CFEB) [R. Breedon, et al., Nucl. Instr. and Meth. A 471 (2001) 340], which amplify, shape, store, and digitize chamber cathode signals; Anode Front End Boards (AFEB) [T. Ferguson, et al., Nucl. Instr. and Meth. A 539 (2005) 386], which amplify, shape and discriminate chamber anode signals; and Data Acquisition Motherboards (DAQMB), which controls the on-chamber electronics and the readout of the chamber. The off-detector electronics, located in the underground service cavern, includes Detector Dependent Unit (DDU) boards, which perform real time data error checking, electronics reset requests and data concentration; and Data Concentrator Card (DCC) boards, which further compact the data and send it to the CMS DAQ System [CMS Collaboration, The TriDAS Project Technical Design Report, Volume 2: Data Acquisition and High-level Trigger, CERN/LHCC 2002-26, 2002], and serve as an interface to the CMS Trigger Timing Control (TTC) [TTC system http://ttc.web.cern.ch/TTC/intro.html] system.Application Specific Integrated Circuits (ASIC) are utilized for analogous signal processing on front end boards. Field Programmable Gate Arrays (FPGA) are utilized on all boards in the system to provide programmability. The DAQ system has been installed and commissioned, and is ready for LHC data taking.     

Whole grains — impact of consuming whole grains on physiological effects of dietary fiber and starch

Much of the present research on the physiological effects of dietary fiber and starch has been done on sources isolated from the parent material, and it is not clear whether they have the same effects if fed in the intact or whole grain. For dietary fiber, physiological effect depends on extent of fermentation in the large intestine, and this is influenced by chemical composition, solubility, physical form, and presence of lignin or other compounds. All of these factors are altered by isolation of a fiber source from the whole grain, and hence effects of eating fiber vary. Similarly, physical form and presence in the whole grain will affect digestibility of starch in the small intestine, which in turn influences the glycemic response and colonic effects determined by the extent of malabsorption and entry into the colon. Starch that enters the colon is fermented and produces short‐chain fatty acids, particularly butyrate, which is necessary to maintain a healthy mucosa. Hence, their presence within the whole grain may have important implications for health for both dietary fiber and starch. Evidence indicates that such effects are beneficial and that whole‐grain consumption should be encouraged.     

Histogram approaches for lossy compression of digital holograms of three-dimensional objects.

We present a novel nonuniform quantization compression technique-histogram quantization-for digital holograms of 3-D real-world objects. We exploit a priori knowledge of the distribution of the values in our data. We compare this technique to another histogram based approach: a modified version of Max's algorithm that has been adapted in a straight-forward manner to complex-valued 2-D signals. We conclude the compression procedure by applying lossless techniques to our quantized data. We demonstrate improvements over previous results obtained by applying uniform and nonuniform quantization techniques to the hologram data.     

Electrochemical Synthesis of Magnetostrictive Fe–Ga/Cu Multilayered Nanowire Arrays with Tailored Magnetic Response

Arrays of nanowires are fabricated with alternating segments of the magnetostrictive alloy Fe_1–xGa_x and Cu using electrochemical deposition in nanoporous anodic aluminium oxide (AAO) templates. The difficult nature of Ga‐alloy electrochemistry is overcome by controlling mass‐transfer and hydrodynamic conditions using novel rotating disk electrode templates to obtain highly uniform segment lengths throughout the arrays. Extensive structural characterization by XRD, EBSD and TEM reveals a strong <110> textured Fe_1–xGa_x growth. Furthermore, using vibrating sample magnetometry (VSM), we demonstrate that control of magnetization reversal processes is possible once uniform aspect ratios are obtained for both the Fe–Ga and Cu segments.     

Correlation between chemical and electrical profiles in Si+, Se+ and S+ implanted bulk and epitaxial GaAs

We compare the chemical profiles of Cr, Mn, Si and Se with the electron concentration profiles in Si, Se and S implanted semi-insulating Cr-O doped bulk GaAs substrates and undoped VPE buffer layers annealed with and without a SiO₂ encapsulant in a H₂-As₄ atmosphere. A higher activation efficiency in the net electron concentration and the gateless saturated channel current is measured for SiO₂ encapsulated wafers annealed under arsine overpressure than for capless annealed ones using Cr-O doped bulk GaAs substrates. On the other hand, the net donor concentration peak is higher for implanted buffer epi layers capless annealed under arsine overpressure than for SiO₂ encapsulated ones. Secondary ion mass spectrometry (SIMS) studies of the Cr decoration of the implant damage indicate that the damage from the 100 keV Si implant anneals out at 840°C while a temperature of 900°C is required to anneal out the 260 keV Se implant damage. An explanation of these differences is provided using an impurity redistribution model and charge neutrality considerations. Excellent Hall electron mobilities at liquid nitrogen temperature of 5400–9200 cm²/V-sec are measured for Si-implanted buffer epi substrates.     

Why Audit a Web Server?: Auditing Web servers: IIS 4.0 — Part 2

The first of these articles, in Network Security’s July issue, described how Web servers work, and suggested that the security objectives for them might differ from those for standard applications. It also discussed some basic procedural controls. This article complements it with a more detailed look at the security features in Microsoft IIS, and then at how to apply those features together with operating system controls, to help secure the site.