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The primary contribution of this paper is the extension of the gm/ID design methodology to two-stage operational amplifiers with class-AB output stages. First, the circuit is analyzed from the perspective of the gm/ID methodology, with a focus on its performance metrics and constraints. Second, to handle optimization targets and constraints automatically, the circuit sizing task is formulated as a single-objective optimization problem, and an optimizer is employed to obtain the temporary solution automatically. Benefiting from the gm/ID methodology, the gap between analytical equations and circuit simulation is highly reduced. Third, following the temporary solution, a guided fine-tuning method is introduced to further optimize the temporary solution. To demonstrate the effectiveness of this approach, we compared the equation-based method using the square-law model, two simulation-based methods and a commercial tool, Cadence ADE GXL, employing SMIC 55 nm and SMIC 180 nm CMOS technologies. The simulation results confirm the success of the proposed approach, showing that it not only reduces the gap between analytical equations and simulations, but also achieves the best performance metrics. [ABSTRACT FROM AUTHOR]

BackgroundTritium is one of the radionuclides released during the operation of nuclear facilities. The radiation hazard of tritium to human body is internal exposure, which is not only related to the activity of tritium, but also closely related to the chemical form and intake route of tritium. In view of the current standards involving tritium, there is an inconsistency in the control limit of tritiated water (HTO), as well as elemental tritium (HT).PurposeThis study aims to derive and standardize the concentration limits of HTO and HT, as well as the discharge activity concentration limits of HTO.MethodsThe development of tritium concentration control limits and the basis for the formulation of relevant standards were analyzed. According to the current radiation protection standards of China, combined with the latest biodosimetry parameters of tritium in publications of International Atomic Energy Agency (IAEA) and International Commission on Radiological Protection (ICRP), the control limits of derived air concentration (DAC) and water activity concentration for tritium were recalculated. When calculating the recommended limit of air concentration derived from HTO, the skin absorption was converted into the inhalation, and the complete skin absorption was set to half of the inhalation.ResultsSince the dose conversion coefficient used in the current standard is close to that in the new international publications, the recommended limits of HTO are slightly smaller than that specified in the standard, and the corresponding values are basically in the same order of magnitude.ConclusionsThe derived results can provide reference for the standard formulation of radiation protection management. The applicable objects of control limits are also clearly exhibited and distinguished. These objects are only available for people, not for facilities or equipment.

This paper describes a software framework for the development of a ubiquitous computing environment for distributed engineering information services. Two fundamental issues are addressed: universal accessibility of devices to information services, and collaboration among the parties accessing the information services. The first calls for the development of device-independent information services that have the flexibility to support a wide range of client devices. We introduce a mediation-based framework that enables information clients to calibrate the source information services to the clients' characteristics. The second requires effective integration of information services, which we address in two ways: (1) we sketch an ontology standard and describe how such a standard can be effectively applied for exchanging project scheduling and resource information; and (2) we illustrate an infrastructure that is particularly suitable for the integration of engineering services. A prototype for the ubiquitous computing environment has been developed that incorporates a variety of project management software as well as different devices ranging from PDAs to Web browsers, desktop computers, and servers. CE Database subject headings: Computation; Information management; Information centers; Computer software.