A novel voice coil motor-driven compliant micropositioning stage based on flexure mechanism

This paper presents a 2-degrees of freedom flexure-based micropositioning stage with a flexible decoupling mechanism. The stage is composed of an upper planar stage and four vertical support links to improve the out-of-plane stiffness. The moving platform is driven by two voice coil motors, and thus it has the capability of large working stroke. The upper stage is connected with the base through six double parallel four-bar linkages mechanisms, which are orthogonally arranged to implement the motion decoupling in the x and y directions. The vertical support links with serially connected hook joints are utilized to guarantee good planar motion with heavy-loads. The static stiffness and the dynamic resonant frequencies are obtained based on the theoretical analyses. Finite element analysis is used to investigate the characteristics of the developed stage. Experiments are carried out to validate the established models and the performance of the developed stage. It is noted that the developed stage has the capability of translational motion stroke of 1.8 mm and 1.78 mm in working axes. The maximum coupling errors in the x and y directions are 0.65% and 0.82%, respectively, and the motion resolution is less than 200 nm. The experimental results show that the developed stage has good capability for trajectory tracking

A web-based appointment system to reduce waiting for outpatients: A retrospective study

<p>Abstract</p> <p>Background</p> <p>Long waiting times for registration to see a doctor is problematic in China, especially in tertiary hospitals. To address this issue, a web-based appointment system was developed for the Xijing hospital. The aim of this study was to investigate the efficacy of the web-based appointment system in the registration service for outpatients.</p> <p>Methods</p> <p>Data from the web-based appointment system in Xijing hospital from January to December 2010 were collected using a stratified random sampling method, from which participants were randomly selected for a telephone interview asking for detailed information on using the system. Patients who registered through registration windows were randomly selected as a comparison group, and completed a questionnaire on-site.</p> <p>Results</p> <p>A total of 5641 patients using the online booking service were available for data analysis. Of them, 500 were randomly selected, and 369 (73.8%) completed a telephone interview. Of the 500 patients using the usual queuing method who were randomly selected for inclusion in the study, responses were obtained from 463, a response rate of 92.6%. Between the two registration methods, there were significant differences in age, degree of satisfaction, and total waiting time (<it>P </it>< 0.001). However, gender, urban residence, and valid waiting time showed no significant differences (<it>P </it>> 0.05). Being ignorant of online registration, not trusting the internet, and a lack of ability to use a computer were three main reasons given for not using the web-based appointment system. The overall proportion of non-attendance was 14.4% for those using the web-based appointment system, and the non-attendance rate was significantly different among different hospital departments, day of the week, and time of the day (<it>P </it>< 0.001).</p> <p>Conclusion</p> <p>Compared to the usual queuing method, the web-based appointment system could significantly increase patient's satisfaction with registration and reduce total waiting time effectively. However, further improvements are needed for broad use of the system.</p

Planet formation: The case for large efforts on the computational side

Modern astronomy has finally been able to observe protoplanetary disks in reasonable resolution and detail, unveiling the processes happening during planet formation. These observed processes are understood under the framework of disk-planet interaction, a process studied analytically and modeled numerically for over 40 years. Long a theoreticians' game, the wealth of observational data has been allowing for increasingly stringent tests of the theoretical models. Modeling efforts are crucial to support the interpretation of direct imaging analyses, not just for potential detections but also to put meaningful upper limits on mass accretion rates and other physical quantities in current and future large-scale surveys. This white paper addresses the questions of what efforts on the computational side are required in the next decade to advance our theoretical understanding, explain the observational data, and guide new observations. We identified the nature of accretion, ab initio planet formation, early evolution, and circumplanetary disks as major fields of interest in computational planet formation. We recommend that modelers relax the approximations of alpha-viscosity and isothermal equations of state, on the grounds that these models use flawed assumptions, even if they give good visual qualitative agreement with observations. We similarly recommend that population synthesis move away from 1D hydrodynamics. The computational resources to reach these goals should be developed during the next decade, through improvements in algorithms and the hardware for hybrid CPU/GPU clusters. Coupled with high angular resolution and great line sensitivity in ground based interferometers, ELTs and JWST, these advances in computational efforts should allow for large strides in the field in the next decade.Comment: White paper submitted to the Astro2020 decadal surve

Planet formation: The case for large efforts on the computational side

Modern astronomy has finally been able to observe protoplanetary disks in reasonable resolution and detail, unveiling the processes happening during planet formation. These observed processes are understood under the framework of disk-planet interaction, a process studied analytically and modeled numerically for over 40 years. Long a theoreticians' game, the wealth of observational data has been allowing for increasingly stringent tests of the theoretical models. Modeling efforts are crucial to support the interpretation of direct imaging analyses, not just for potential detections but also to put meaningful upper limits on mass accretion rates and other physical quantities in current and future large-scale surveys. This white paper addresses the questions of what efforts on the computational side are required in the next decade to advance our theoretical understanding, explain the observational data, and guide new observations. We identified the nature of accretion, ab initio planet formation, early evolution, and circumplanetary disks as major fields of interest in computational planet formation. We recommend that modelers relax the approximations of alpha-viscosity and isothermal equations of state, on the grounds that these models use flawed assumptions, even if they give good visual qualitative agreement with observations. We similarly recommend that population synthesis move away from 1D hydrodynamics. The computational resources to reach these goals should be developed during the next decade, through improvements in algorithms and the hardware for hybrid CPU/GPU clusters. Coupled with high angular resolution and great line sensitivity in ground based interferometers, ELTs and JWST, these advances in computational efforts should allow for large strides in the field in the next decade

Multi-objective parameter optimization strategy based on engine coordinated control for improving shifting quality

In order to address the poor shifting quality issue of a certain model of heavy-duty vehicles, a multi-objective parameter optimization strategy based on engine coordinated control is proposed. This strategy aims to improve shifting quality by reducing the sliding friction work and impact during the shifting process. The Non-Dominated Sorting Genetic Algorithm II (NSGA-II) is employed to perform multi-objective optimization on the coordinated control parameters, which include external control torque of the engine, start of fuel cut-off timing, and duration of fuel cut-off. By comparing the performance of different parameter combinations in terms of sliding friction work and impact, the optimal parameter combination is determined. Through bench testing verification, it has been demonstrated that utilizing the optimized parameters for engine coordinated control during the torque phase of the shifting process can significantly enhance shifting quality. This strategy provides an effective solution for addressing shifting quality issues

In vivo and in vitro activity of genistein in osteoporosis

Background : Osteoporosis is conventionally treated with synthetic estrogens. However, the serious side effects of hormone replacement therapy (HRT) hampers the clinical use of estrogens. Hence, alternatives for estrogens are being explored, one of which is the isoflavone, genistein. Many studies show that genistein may exert positive effects on bone. However, there are also studies which report no overall association between genistein intake and bone marrow density (BMD) and fracture rates. The effect of genistein on bone loss is still controversial. Aims : In this study, we evaluated both in vivo and in vitro pharmacological effects of genistein in osteoporosis. Materials and Methods : MTT and ALP activity assays were performed to evaluate genistein′s in vitro activity on MC3T3-E1 cells. The OVX rat model was used to test genistein′s in vivo effects by determination of BMD and bone calcium and phosphorus content after treatment for 12 weeks. Results and Conclusions : The data showed that 10 -6 M genistein both increased the number of MC3T3-E1 cells and elevated ALP activity significantly. In vivo, 9 or 18 mg/kg doses of genistein were found to prevent osteoporosis after 12 weeks treatment. Thus, our results indicated that genistein may be an alternative for HRT in prevention of postmenopausal osteoporosis

Microstructure and Mechanical Properties of AlN/Al Joints Brazing by a Sputtering Al/Cu Bilayer Film Solder

This paper presents a magnetron sputtering Al/Cu bilayer film solder to realize the brazing of AlN ceramic and Al metal. The effect of different temperatures on the structure and mechanical properties of brazed joints is studied. The results show that the sputtered Al particles have a sputtering wetting effect on AlN ceramic. The contact angle of molten Al on AlN ceramic with Al film deposited at 700 &deg;C is as low as about 30&deg;. While the contact angle of molten Al on AlN ceramic without Al film deposited at 1000 &deg;C is about 89&deg;. There is a large amount of Cu enrichment in brazed joints at 600 &deg;C. The weld structure is a mixture of Al solid solution and AlCu compound. The shear strength of the brazed joint is only 70.6 MPa, and the joint fracture shows a large number of brittle fracture morphologies. With the increase of brazing temperature, the phenomenon of Cu enrichment in the joint gradually weakens, and the weld structure gradually transforms into a solid solution of Cu in Al. The shear strength of the brazed joint continues to increase, and the joint fracture morphology gradually changes from brittle fracture to furrow-like plastic fracture morphology. When the brazing temperature is increased to 660 &deg;C, the distribution of Cu in the joint is evenly dispersed, and the shear strength of the brazed joint reaches the highest value of 107.8 MPa. The joint fracture is completely furrow-like plastic fracture morphological composition