3004合金热轧带材显微组织和制耳的控制（1）

为了成功地生产出铝饮料罐体用板,控制铝合金带材热轧阶段的制耳是关键性的必要条件。本研究以工业规模试验和试验室研究相结合,探讨了合金组元和工艺参数对制品显微组织、织构和制耳的影响。结果表明,最佳的制品基本上取决于:合金含铁量,铸锭均匀化温度,热轧终了温度,热轧带材退火时的加热速度。退火后的制耳水平取决于立方(+Goss)织构强度和材料几乎随机分布取向体积之间的平衡。优势的0°/90°制耳倾向通常与粗大并拉长的晶粒组织相关。描述显微组织-织构的演变模式是立方/Goss晶粒(在过渡带内规律地成核)和随机取向晶粒(在粗大第二相质点周围成核)之间的竞争。     

印染助剂进展

本文概述了1988年间投入纺织加工各工序应用的大量新助剂。 前处理工序中开发了低温活性更好的煮练剂和更有效的氧漂稳定剂。染色助剂主要包括各种纤维染色用匀染剂以及改进活性和硫化染料染色织物耐洗牢度和汽车用装饰织物耐光牢度的化学助剂。     

Can default ICRP f1 values be applied to determine radiation dose from the intake of diet-incorporated thorium?

Data on the daily urinary excretion of thorium (Th) was obtained from 15 non-exposed adult German subjects. A radiochemical neutron activation analysis method was developed and standardised especially for this purpose. The daily urinary excretion of 232Th was found to be in the range 1.9-14.9 microBq d(-1) with a mean (+/-SD) value of 6.5 (+/-4.3) microBq d(-1). Using this excretion value and reported data on dietary intake of Th for a similar German population, the gastrointestinal absorption factor (f1 value) proposed by the International Commission on Radiological Protection (ICRP) was tested. Although the daily excretion of 232Th observed in the present study was comparable to some of the currently reported values in certain other countries, it was higher than the excretion value calculated by applying the biokinetic model of Th proposed by ICRP for the dietary intake values. The study showed that the default ICRP values of the f1 factor for diet-incorporated Th may not be applicable.     

Comparing endoscopic systems on two simulated tasks

Endoscopes are slender instruments for performing medical procedures through small incisions or natural body orifices. Three experiments examined the performance effects of various endoscope systems when naive participants executed tasks in a bladder-like environment. The systems involved a direct endoscope, requiring the user to look through a lens at the outer part of the endoscope, and a video endoscope that picks up the image via a camera attached to the endoscope and displays it on a video monitor. The results indicate that the participants performed the tasks better with video than with direct endoscopes, and showed more transfer of practice with video endoscopic surgery from a small to a large task environment than vice versa. The optimal position of the monitor with video endoscopic surgery appeared to involve a reasonable angle relative to the operating area (45 degrees was used). Performance was less at a greater angle (90 degrees), but also at a small angle (10 degrees). It did not matter whether the monitor was located left, right or above the operating area. As performance did not fully transfer to differently sized task environments, endoscopists should initially train with task environments of different, and especially small, sizes.     

Generating Bessel beams by use of localized modes

We propose a novel method for generating both propagating and evanescent Bessel beams. To generate propagating Bessel beams we propose using a pair of distributed Bragg reflectors (DBRs) with a resonant point source on one side of the system. Those modes that couple with the localized modes supported by the DBR system will be selectively transmitted. This is used to produce a single narrow band of transmission in kappa space that, combined with the circular symmetry of the system, yields a propagating Bessel beam. We present numerical simulations showing that a propagating Bessel beam with central spot size of approximately 0.5lambda0 can be maintained for a distance in excess of 3000lambda0. To generate evanescent Bessel beams we propose using transmission of a resonant point source through a thin film. A transmission resonance is produced as a result of the multiple scattering occurring between the interfaces. This narrow resonance combined with the circular symmetry of the system corresponds to an evanescent Bessel beam. Because propagating modes are also transmitted, although the evanescent transmission resonance is many orders of magnitude greater than the transmission for the propagating modes, within a certain distance the propagating modes swamp the exponentially decaying evanescent ones. Thus there is only a certain regime in which evanescent Bessel beams dominate. However, within this regime the central spot size of the beam can be made significantly smaller than the wavelength of light used. Thus evanescent Bessel beams may have technical application, in high-density recording for example. We present numerical simulations showing that with a simple glass thin film an evanescent Bessel beam with central spot size of approximately 0.34lambda0 can be maintained for a distance of 0.14lambda0. By choice of different material parameters, the central spot size can be made smaller still.     

浅析华为上下行不平衡故障

文章通过对无线网络华为设备中所存在的上下行不平衡故障进行原理分析,针对目前在用的边缘覆盖算法和上下行损耗差异算法进行分析,以及不平衡状态的定位,并列举了导致不平衡的几种原因和故障案例。     

基于PLC的流量比值控制系统设计

本文主要介绍了一种用于化工领域的流量比值控制系统。以三菱PLC为控制中心,结合传感器、流量计等设备,组成流量比值控制系统,以氯化钾和硫酸制造硫酸钾工艺为例介绍此控制系统在化工领域的应用。控制系统根据氯化钾流量控制硫酸的流量,满足了工艺要求,实际应用表明该系统具有较高的控制精度和稳定性。     

Real-time PCR detection and quantification of nine potential sources of fecal contamination by analysis of mitochondrial cytochrome b targets

We designed and tested real-time PCR probe/primer sets to detect and quantify Cytochrome b sequences of mitochondrial DNA (mtDNA) from nine vertebrate species of pet (dog), farm (cow, chicken, sheep, horse, pig), wildlife (Canada goose, white-tailed deer), and human. Linear ranges of the assays were from 10(1) to 10(8) copies/microl. To formally test the performance of the assays, twenty blinded fecal suspension samples were analyzed by real-time PCR to identify the source of the feces. Sixteen of the twenty samples were correctly and unambiguously identified. Average sensitivity was calculated to be 0.850, while average specificity was found to be 0.994. One beef cow sample was not detected, but mtDNA from 11 other beef cattle of both sexes and varying physiological states was found in concentrations similar (3.45 x 10(7) copies/g) to thatfound in human feces (1.1 x 10(7) copies/g). Thus, environmental conditions and sample handling are probably important factors for successful detection of fecal mtDNA. When sewage samples were analyzed, only human mtDNA (7.2 x 10(4) copies/ 100 mL) was detected. With a detection threshold of 250 copies/reaction, an efficient concentration and purification method resulted in a final detection limit for human feces of 1.8 mg/ 100 mL water.