Accretion onto a Kiselev black hole

We consider accretion onto a Kiselev black hole. We obtain the fundamental equations for accretion without the back-reaction. We determine the general analytic expressions for the critical points and the mass accretion rate and find the physical conditions the critical points should fulfill. The case of polytropic gas are discussed in detail. It turns out that the quintessence parameter plays an important role in the accretion process.Comment: 7 page

Factors influencing information service quality of the information platform of Wenzhou Municipal People's Hospital

Along with the global trend of informatization, Internet has become a new mainstream media form following such forms as print media, television and broadcast media, via which people can access information services. As a country with the largest number of netizens around the world, China enjoys improving social information services based on the Internet. With such a large quantity of network users, it is inevitable for China's hospitals at various levels to provide patients and the public with information services by setting up their own official websites. This research investigates the factors affecting the information service quality of Wenzhou People's Hospital (WZPH) and by means of Delphi method, statistical analysis and other research methods, formulates the Evaluation Indicator System for the Information Service Quality of WZPH's Information Platform. The research applies this system to the empirical research on the information service quality of the hospital's website and then makes a comparative analysis between the research results and traffic data of the websites of other hospitals over the same period. Next, the research identifies the factors affecting the information service quality of WZPH's website and finds out how the hospital may increase its website users and traffic through improving its service quality. This research starts with the determination of the objectives, significance, research problems, framework, contents and methods of the research. In the following literature review, the research sorts out papers on hospital websites and theories on service quality, users' information needs and customer satisfaction in a systematic way. Based on the literature review as well as expert consultations and theoretical review, the research determines the approach to examining the information service quality of WZPH's information platform and works out the initial set of evaluation dimensions and indicators of the information service function and quality of the hospital's website. Then, via two rounds of expert consultations, the research figures out the weights of these indicators and further assigns values to each of them. On this basis, the research establishes a research framework and a comprehensive evaluation model for the information service quality of WZPH's information platform. In the end, the research conducts two surveys respectively on the information service quality of WZPH's information platform before and after its overall revision by using Hospital Website Information Service Evaluation Form and Virtual User Questionnaire, and makes a correlation analysis based on the survey results and the flow data of other hospitals' websites over the same period. The analysis draws a conclusion that the website of WZPH, as the information platform of the hospital, is the only carrier to deliver information service, thus playing a vital role in WZPH's overall service quality. In other words, the website of WZPH affects the hospital's overall service quality to a large extent. The comprehensive service function of WZPH's website are important to the quality improvement of the hospital's information service and directly affect the information service quality, the number of users as well as utilization rate of the website

Aligned Graphene Nanoribbons and Crossbars from Unzipped Carbon Nanotubes

Aligned graphene nanoribbon (GNR) arrays were made by unzipping of aligned single-walled and few-walled carbon nanotube (CNT) arrays. Nanotube unzipping was achieved by a polymer-protected Ar plasma etching method, and the resulting nanoribbon array was transferred onto any substrates. Atomic force microscope (AFM) imaging and Raman mapping on the same CNTs before and after unzipping confirmed that ~80% of CNTs were opened up to form single layer sub-10 nm GNRs. Electrical devices made from the GNRs (after annealing in H2 at high temperature) showed on/off current (Ion/Ioff) ratios up to 103 at room temperature, suggesting semiconducting nature of the narrow GNRs. Novel GNR-GNR and GNR-CNT crossbars were fabricated by transferring GNR arrays across GNR and CNT arrays, respectively. The production of ordered graphene nanoribbon architectures may allow for large scale integration of GNRs into nanoelectronics or optoelectronics.Comment: published in Nano Researc