Particle emission characteristics of office printers

In modern society, printers are widely used in the office environment. This study investigated particle number and PM2.5 emissions from printers using the TSI SMPS, TSI CPC 3022, and 3025A TSI P-Trak and DustTrak. The monitoring of particle characteristics in a large open-plan office showed that particles generated by printers can significantly (p = 0.01) affect the submicrometer particle number concentration levels in the office. An investigation of the submicrometer particle emissions produced by each of the 62 printers used in the office building was also conducted and based on the particle concentrations in the immediate vicinity of the printers, after a short printing job, the printers were divided into four classes: non-emitters, and low, medium, and high emitters. It was found that approximately 60% of the investigated printers did not emit submicrometer particles and of the 40% that did emit particles, 27% were high particle emitters. Particle emission characteristics from three different laser printers were also studied in an experimental chamber, which showed that particle emission rates are printer-type specific and are affected by toner coverage and cartridge age. While a more comprehensive study is still required, to provide a better database of printer emission rates, as well as their chemical characteristics, the results from this study imply that submicrometer particle concentration levels in an office can be reduced by a proper choice of the printers.     

Preliminary investigations of the production of MgAlON bonded refractories

The aim of the work was to find an appropriate composition for the formation of MgAlON bonding phase for Al₂O₃ and MgO based refractories. The first step was the preparation of pure MgAlON. AlN and Al₂O₃ were used as starting powders and either MgO or MgAl₂O₄ was added as a source of magnesium. The results verified the possibility to produce MgAlON under the prevailing conditions. Afterwards, MgAlON bonded alumina and magnesia refractories were investigated. The obtained results confirmed the possibility of the production of MgAlON bonded alumina refractories. However, in the case of magnesia-based samples MgAlON was not formed and instead stoichiometric spinel, AlN and alumina rich spinel were detected in the bonding phase. Additionally, the joining between the MgO grains and the matrix was poor with wide gaps on the interface.     

澳洲西花蓟马及番茄病毒性萎蔫病

西花蓟马（Franklienella occidentalis）是传播番茄、马铃薯、芦笋及辣椒病毒性萎蔫病的最主要的害虫之一。西花蓟马喜食辣椒、黄瓜和豆类作物的果实。其嚼食叶片和果实后,留下疤痕或使其畸形,尤其是幼苗和鲜嫩的组织更容易受其侵害。     

Inhibition of HSP90 with Pochoximes: SAR and Structure‐Based Insights

The pochoximes, based on the radicicol pharmacophore, are potent inhibitors of heat shock protein 90 (HSP90) that retain their activity in vivo. Herein we report an extended library that broadly explores the structure–activity relationship (SAR) of the pochoximes with four points of diversity. Several modifications were identified that afford improved cellular efficacy, new opportunities for conjugation, and further diversifications. Cocrystal structures of pochoximes A and B with HSP90 show that pochoximes bind to a different conformation of HSP90 than radicicol and provide a rationale for the enhanced affinity of the pochoximes relative to radicicol and the pochonins.     

信息技术的下一个浪潮

多年来我一直关注和期待着厂商宣布磁盘存储退出。最近,这件事终于发生了。做出这一个大胆声明的厂商是Sun公司,具体讲是Sun公司的CEO和总裁Jonathan Schwartz。     

Broadband beamforming of dense aperture array (DAA) and focal plane array (FPA) signals using 3D spatio-temporal filters for applications in aperture synthesis radio astronomy

It is shown that 3D spatio-temporal filters have potential applications in aperture synthesis radio astronomy for the broadband-beamforming of the array of signals that is received from dense aperture arrays (DAAs) and also from focal plane arrays (FPAs). In particular, we consider possible applications for the planned Square Kilometer Array (SKA) project where broadband beamforming is required at the front-end of the signal processing system for some experiments such as pulsar timing. In the case of a synthesized aperture that is composed of DAAs, the required 3D magnitude frequency response has a non-separable narrow-cone-shaped (or narrow-frustum-shaped) passband whereas, for FPAs, the required 3D magnitude frequency response has a non-separable wide-cone-shaped (or wide-frustum-shaped) passband. The corresponding 3D passbands are designed to faithfully transmit the celestial signals of interest (SOIs), whereas the 3D stopbands are designed to significantly attenuate such undesired signal components such as natural and artificial sources of radio frequency interference (RFI) and the dominant part of the 3D electronic broadband noise that is contributed by millions of low noise amplifiers (LNAs), each of which amplifies the signal received in each elemental antenna of the DAAs or FPAs. The criteria for designing both narrow- and wide-cone/frustal filters, in order to achieve optimal sensitivity, are presented in terms of the power of the recovered signal and the power of the contaminating noise.     

Characterization of germanium implanted Si1−xGex layer

Characterization of a Si_1−xGe_x layer formed by high-dose germanium implantation and subsequent solid phase epitaxy is reported. Properties of this layer are obtained from electrical measurements on diodes and transistors fabricated in this layer. Results are compared with those of the silicon control devices. It was observed that the germanium implantation created considerable defects that are difficult to eliminate with annealing. These defects result in boron deactivation in the p-type regions of the devices, giving rise to larger resistance. Optimization of the device structure and fabrication process is discussed.     

The electron beam evaporation and deposition process

The electron beam evaporation and deposition (EBED) process produces virtually defect-free ingots, disks and cylindrical shapes. When produced by EBED, high-temperature alloys have virtually no inclusions and titanium alloys have essentially no low-density inclusions (Type I defects). Most alloys produced by the process have grain sizes of less than 10 μm and are superplastic. Envisioned applications of EBED include the production of: complex, cylindrical shapes; high-purity sputtering targets; higher-fabricability alloys; and hot-section disks and compressor for aircraft engines.     

Structural Fault Based Specification Reduction for Testing Analog Circuits

Specification reduction can reduce test time, consequently, test cost. In this paper, a methodology to reduce specifications during specification testing for analog circuit is proposed and demonstrated. It starts with first deriving relationships between specifications and parameter variations of the circuit-under-test (CUT) and then reduces specifications by considering bounds of parameter variations. A statistical approach by taking into account of circuit fabrication process fluctuation is also employed and the result shows that the specification reduction depends on the testing confidence. A continuous-time state-variable benchmark filter circuit is applied with this methodology to demonstrate the effectiveness of the approach.