RFID印刷电路板跟踪技术探析

高级印刷电路板(PCB)的封装工作已经受到条形码标签的限制。尽管条形码与RFID标签仍将共存,但条形码尺寸相对较大,难以满足高密度板上极为有限的空间要求。此外,灵活的制造工艺可基于基准设计产生数十种乃至数百种不同模式,如果采用条形码,就必须在生产最后阶段逐一贴上标签,有鉴于此,制造商必须考虑条形码跟踪与RFID跟踪到底孰优孰劣。     

Design of next-generation cdma using orthogonal complementary codes and offset stacked spreading

This article presents an innovative code-division multiple access system architecture that is based on orthogonal complementary spreading codes and time-frequency domain spreading. The architecture has several advantages compared to conventional CDMA systems. Specifically, it offers multiple-access-interference-free operation in AWGN channels, reduces co-channel interference significantly, and has the potential for higher capacity and spectral efficiency than conventional CDMA systems. This is accomplished by using an "offset stacked" spreading modulation technique followed by quadrature amplitude modulation, which optimizes performance in a fading environment. This new spreading modulation scheme also simplifies the rate matching algorithms relevant for multimedia services and IP-based applications.     

Conditioned vocalization in rats.

Examined 2 crucial variables which might explain inconsistent results of attempts to condition vocalization in the rat: mobility of the S during conditioning and variability of the intertrial interval (ITI). 12 male Long-Evans rats were tested in 4 conditions of mobility-immobility, and fixed and variable ITI. Results support the importance of immobilizing the S, but not of varying the ITI during conditioning. It is suggested that vocal behavior in the rat may be conditioned only when no competing species-specific defense reaction (e.g., freezing) is available to the S. (31 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nystagmus, turning sensations, and illusory movement in motion sickness susceptibility

The relationships of motion sickness susceptibility to nystagmic eye movements, sensations of turning, and duration of the spiral aftereffect were determined with 48 subjects separated into groups on the basis of sex and extremes of motion sickness susceptibility. When subjective alertness levels were controlled, there was no enhancement of elicited nystagmus nor turning sensations in susceptible individuals. However, spiral aftereffect durations were significantly longer in susceptible individuals than in nonsusceptible individuals. The results are interpreted as favoring Graybiel's model of the structural elements in motion sickness.     

The Inpatient Scale of Minimal Functioning: a revision of the Social Breakdown Syndrome Gradient Index

The Inpatient Scale of Minimal Functioning (ISMF)--based on revised scoring of the Social Breakdown Syndrome Gradient Index (SBSGI) item pool--is described as a means of overcoming inherent problems in the SBSGI scoring procedure. The ISMF was found to possess greater reliability, with a general increment in concurrent validity as compared to the SBSGI. The ISMF is recommended to replace the SBSGI in a battery previously recommended by Lentz, Paul, and Calhoun, combining interview-based and higher level rating-scale measures for assessing global level of functioning in severely debilitated institutionalized patients. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Some psychological correlates of motion sickness susceptibility

Four groups of 37 subjects each (highly susceptible men, highly susceptible women, nonsusceptible men, and nonsusceptible women) were obtained from a population of 2,432 college students ranging in age from 18 to 39 years. Susceptibility to motion sickness was determined by scores on a motion sickness questionnaire (MSQ); only individuals with extreme scores were considered for inclusion in the experimental groups. The following tests were administered: Floor Ataxia Test Battery, State-Trait Anxiety Inventory, Menstrual Distress Questionnaire, Cornell Medical Index, Cornell Work Form, Eysenck Personality Inventory, Rotter Internal-External Locus of Control Scale, and the 16 Personality Factors test. Each subject was tested on at least three, but not more than six, of the eight tests. Significant sex differences were obtained on the ataxia battery and the Cornell Medical Index. Susceptible subjects did not differ significantly from nonsusceptibles on the ataxia battery but did differ significantly on all personality tests except the Menstrual Distress Questionnaire (administered only to women) and the Rotter Scale. The generally consistent and significant patterns of results from the psychological tests probably reflect the selection factors used in defining the subject groups; certain personality characteristics are associated with a high degree of susceptibility to motion sickness.     

Optically transmissive window on ITER port cell door

In the ITER Thomson Scattering Core LIDAR system there are currently three concepts for collecting scattered light from the plasma and delivering it to the diagnostic room. An option to use a broadband mirror in Cassegrain configuration has been explored. In this concept a large optical window, 1.5 m in diameter, is required in the port cell door. This could be manufactured in a number of ways, including using a single thick window or mosaic arrangement with a supporting structure. Challenges associated with this design include maintaining the secondary confinement barrier, withstanding a pressure differential of 0.5 bar across the window in foreseeable fault conditions, and maintaining the optical properties of the window. It must also be possible to protect the window when work is being carried out in the area. Fracture analysis for brittle material was carried out, for a flaw size with a length to depth ratio of 80/20, which gave a safety reserve factor of 4. The flaw size was based on a standard optical transmissive lens for collection light. A static analysis was carried out on both options of having a single thick glass window or a mosaic arrangement. The principal stress for a single window arrangement is 12 MPa and for a proposed mosaic arrangement is 12.5 MPa. The analyses have demonstrated that a single glass window with a thickness of 42 mm would be mechanically acceptable but expensive to manufacture and it would be difficult to polish glass of that size to lens quality. By comparison in the proposed mosaic window arrangement, the glass thickness is reduced by 50% with the aid of the supporting structure. As a result of the supporting structure the geometrical optical losses are 4%, which are mechanically and optically acceptable, whilst significantly reducing the cost of manufacturing.     

Enhancing exterior performance of clear coatings through photostabilization of wooden surfaces. Part 1: Treatment and characterization

The aim of this work was to produce a less photodegradation-prone substrate for clear coating by partially delignifying the surface cells of Pinus radiata boards to a depth of 2–3 mm while maintaining the integrity of the wood surface tissues in the delignified zone. To achieve this, several surface oxidative delignification treatments were trialled in the method development process and peracetic acid was chosen as the method for refinement and deployment. The treatment method was optimized to yield a significant degree of delignification compatible with the aim of producing a photostabilized yet intact wooden surface. A preweathering technique was also used as a second delignification method for producing photostabilized boards. Microscopic and chemical techniques were used to characterize the effects of chemical and preweathering treatments, which produced delignified surface envelopes 2–3 mm and 100 μm deep, respectively. Acetyl bromide lignin analyses, infrared spectroscopic analyses, and density changes of 30-μm-thick sections of peracetic-acid-treated samples, as a function of depth from the wood surface, suggested that a partial delignification had occurred that diminished with depth. Light and transmission electron microscopy provided evidence of delignification at the cellular level. In the surface layers of peracetic-acid-treated boards, all cell wall regions were delignified, with the middle lamella being the most severely affected. Lignin appeared to be completely removed from the cell corner middle lamella regions, but tracheids were still joined in other parts of the middle lamella. The S₁, S₂, and S₃ walls were also delignified. In subsurface layers, cell walls were only partially delignified and the tissues held their integrity. In contrast, in the preweathered boards, cell walls in the outermost layers were completely separated at the middle lamella from photodegradation. Preferential lignin removal over that of hemicelluloses was achieved via oxidative treatment of solid wood. The outcome of this was the successful fulfillment of our aim to produce partially delignified wooden surfaces that retained sufficient strength and aesthetic appearance and were suitable for application in wooden structures, provided that the necessary protection measures were carried out. Due to the narrow surface zone produced, machining of such surfaces would not be recommended as the most delignified zone would be removed first. In Part 2 of this series, the photostability of treated boards, which had been clear coated and weathered, will be considered.