The present article is the first part in a two-part series in which crystallographic texture developed during friction stir processing of AA5182-O and AA6111-T4 is characterized and its impact on tensile properties explored. For the texture measurements, coupons were cut from the friction stir processed zone at selected orientations relative to the direction of tool translation. Texture was characterized with electron backscatter diffraction (EBSD) in a scanning electron microscope. Measurements were made at key positions along the coupon surfaces and texture differences between the two friction stir processed Al alloys are discussed in detail. Grain size variations were also measured in both the base and friction stir processed materials and subsequently compared. In part 2, a state-of-art digital image correlation technique is used to investigate tensile properties of both friction stir processed Al alloys. The impact of crystallographic texture on mechanical properties is also explored in this latter part.
Statistical circuit simulation is exhibiting increasing importance for circuit design under process variations. Existing approaches cannot efficiently analyze the failure probability for circuits with a large number of variation, nor handle problems with multiple disjoint failure regions. The proposed rare event microscope (REscope) first reduces the problem dimension by pruning the parameters with little contribution to circuit failure. Furthermore, we applied a nonlinear classifier which is capable of identifying multiple disjoint failure regions. In REscope, only likely-to-fail samples are simulated then matched to a generalized pareto distribution. On a 108-dimension charge pump circuit in PLL design, REscope outperforms the importance sampling and achieves more than 2 orders of magnitude speedup compared to Monte Carlo. Moreover, it accurately estimates failure rate, while the importance sampling totally fails because failure regions are not correctly captured.
Study ObjectiveTo explore the profile of patients who visit a sleep center with symptoms that fulfill the four essential criteria for restless legs syndrome (RLS).DesignA prospective study.SettingOutpatients from one sleep disorders clinic in Taiwan.Participants1,200 consecutive patients visit sleep disorders clinic with any sleep complaints.InterventionsAfter completing a history and physical examination, all participants answered the RLS questionnaire. Subjects who fulfilled the four essential criteria for RLS were referred to a special clinic. A work-up including blood tests, polysomnography, and specialized neurological tests etc. was performed to make the final diagnosis.Measurements and ResultsA total of 1,185 participants were enrolled, and, of these, 131(11.1%) fulfilled the four essential criteria for RLS, and 121 completed the supplemental work-up. Their mean age was 47.6±13.3 and 52.9% were male. Insomnia and snoring were the most common chief complaints. Obstructive sleep apnea syndrome and other diseases were found in 103 patients. Only 18 (14.9%) patients had no comorbid condition and were diagnosed with primary RLS.ConclusionsSymptoms of RLS are common in patients with sleep complaints. Even in a sleep clinic, using a questionnaire approach for identification of RLS has a low positive predictive value. Clinicians should pay attention to the limitations of the 4-item questionnaire in diagnosis of RLS and also the importance of a careful differential diagnosis to identify possible secondary causes of RLS.
Epitaxial α-Fe films have been grown on HF cleaned Si(111) substrates at 30 °C by electron beam evaporation in an ultrahigh vacuum environment to a thickness of several thousands of Angstroms. Conventional θ−2θ x-ray diffraction shows that only the Fe(222) peak is present, indicating that the films are oriented with the Fe(111) plane parallel to the Si(111) plane. Transmission electron microscopy shows that the Fe[11̄0] direction is parallel to the Si[11̄0] direction in the plane of the substrate.
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