Electro-optic (EO) polymers, possessing high EO coefficient and low dielectric constant, are considered to be a new generation of nonlinear optical materials that have great application prospect in photo-communication, information storage, and data processing. The host-guest structure of EO polymers is the most typical one in this field. However, the phase separation during polarization between the host polymer and the guest nonlinear optical molecule (NLO) limits potential applications of the material. To solve the problem, a new synthetic method was designed in this paper. First, 2,4-dinitroaniline was grafted to phenol polyphosphazene by chemical method for polar improvement of the main chain. Then, another small NLO molecule was mixed into the polymer by physical method for further improvement of EO coefficient. The preparation process was studied and the structure of the product was characterized. The effects of different NLO mixing proportions and different polarizing temperatures on EO coefficient were investigated in details. Orientation stability of the sample was tested. Experimental results show that our products possess not only high EO coefficient but also good phase stability, which makes them good candidates for the application in information technology.
The present work was a study on global reaction rate of methanol synthesis. We measured experimentally the global reaction rate in the internal recycle gradientless reactor over catalyst SC309. The diffusion-reaction model of methanol synthesis was suggested. For model we chose the hydrogenation of CO and CO2 as key reaction. CO and CO2 were key components in our model. The internal diffusion effectiveness factors of CO and CO2 in the catalyst were calculated by the numerical integration. A comparison with the experiment showed that all the absolute values of the relative error were less than 10%. The simulation results showed that decreasing reaction temperature and catalyst diameter were conducive to reduce the influence of the internal diffusion on the methanol synthesis.
A new type of electro-optic (EO) polymer is prepared in this work. The main chain of the EO polymer is made of polyphosphazenes, and the side chain consists of carbazole based nitro azobenzene. The principle and method of preparation are given and the characteristics of this material are studied in details. The polymer with an EO coefficient of 35 pm/V has fine stability and can be easily processed. It also shows photoconductivity due to the carbazole group. This polymer thin film is obtained through performance improvement. Terahertz (THz) wave can be detected using the device, which is made of the new polymer. Owing to its fascinating properties, this new type of EO polymer has the potential to be widely applied in photorefractive materials as well as for emission and detection of THz radiation.
Hemodialysis is the main alternative therapy for patients with end-stage renal disease; most of the hemodialysis centers in China are not designed together with the inpatient ward. During the hospitalization period, hemodialysis patients often move back and forth between wards and hemodialysis rooms because of the treatment needed. Hemodialysis patients are a special group of hospitalized patients, most of them are elderly patients. The overall basic diseases of the patients vary very much, and the cause of the disease is complex. Moreover, the chronic inflammation progresses slowly, and immune function declines. Some of the patient are seriously ill or even hav organ failure. All these factors affect the patients in general. Therefore, the transfer safety of patients during hospitalization is facing great challenges. The researchers reviewed the status of transshipment research in Chinese hemodialysis patients and laid the foundation for the research and development of related handover tools and perfect handover mode in the future.
PtSn/Al2O3 catalysts with a given loading of 1 wt% Pt and 1 wt% Sn were prepared by co-impregnation or successive impregnation with aqueous solutions of Pt, Sn precursors and a commercial alumina. The catalysts were characterized by N2 adsorption, H2-TPR (H2 temperature-programmed reduction), H2-pulse chemisorption, XPS (X-ray photoelectron spectroscopy) and CO-FTIR (Fourier transform infrared spectroscopy), and tested in the hydrogenation of acetic acid. The results showed that the preparation method affected both the chemical properties and their performance in the hydrogenation of acetic acid. Sn enrichment on the catalysts surface was observed on the co-impregnated catalyst and catalyst in which the Pt precursor had been loaded first. It was found that the modification of Pt was a function of the sequence of Sn addition as revealed by CO-FTIR. Co-impregnated catalyst showed the highest activity and ethanol selectivity.
Objective To investigate the infection rate of hepatitis C virus among the ambulatory patients and in-patients of a tertiary teaching hospital, and study the demographic factors related to the prevalence of hepatitis C virus infection.
Methods All patients tested for hepatitis C virus antibody from July 2008 to July 2009 in Peking Union Medical College Hospital were enrolled in this cross-sectional analysis. The prevalence of hepatitis C virus infection was compared according to age, gender, and departments, respectively. Among patients with positive serology hepatitis C virus marker, the positivity of hepatitis C virus RNA was analysed.
Results Among 29 896 subjects included, the hepatitis C virus antibody of 494 patients were positive (1.7%). When patients were divided into 9 age groups, the age specific prevalence of hepatitis C virus antibody were 0.2%, 1.7%, 1.2%, 1.1%, 1.5%, 1.9%,2.6%, 2.4% and 2%, respectively. The prevalence of hepatitis C virus antibody in non-surgical department and surgical department was 3% and 1%, respectively. The prevalence of hepatitis C virus antibody of males was higher than that of the females. Total of 194 patients with positive hepatitis C virus antibody were tested for hepatitis C virus RNA, the RNA level of 113 patients (58.2%) were higher than the low detection limit.
Conclusions The prevalence of hepatitis C virus antibody was relatively high among patients of general tertiary hospital. Age group of 60-69, males and patients in non-surgical departments were factors associated with high rate of hepatitis C virus infection.
To analyze the literature status and research hotspots of Science Citation Index (SCI)-related ostomy in the world and to provide references for scientific research and clinical work in the stoma care field.
Based on the Web of Science core database and its own analysis function, HistCite analysis software and Excel were used to study the published research about ostomy patients.
A total of 1,262 articles were published between 1910 and 2016 with the authors from 48 countries and regions, 1,347 research institutions, published in 321 journals, with 4,048 first authors and coauthors; globally, there was a trend of slow growth in the number of authors every year. The study in the USA was absolutely in the lead position, and Canada and Turkey were more active. China's circulation volume was the 15th in the world. The periodical that published most often was the Journal of Wound Ostomy and Continence Nursing The most interdisciplinary surgical studies were surgery and nursing, where these should be considered important. The most prolific author in the field was "Grant", and the highest cited article was entitled as "Living with a stoma: a review of the literature".
The related research of global stoma is constantly developing. The research hotspot is nursing before and after stoma surgery. China and the USA are leading countries in research. They should follow the recent trend to improve the depth and breadth of the research in the field.
In order to effectively solve condensation and icing problems of radiosonde in low-temperature environment at high altitude, humidity sensor heated automatic alternately to remove pollution and improve the measurement accuracy. Heat experiments obtained the curve of rising temperature and responsible time on heated twin humidity sensor in normal temperature and pressure, by expanded responsible curve to obtain heated model of twin heated humidity sensor and by the analysis of heating model, use DMC and PID control for heating respectively. Simulation results show that the DMC control meets the practical requirements of measure at high altitude.
Spinel LiMn2O4 has been synthesized by a glycerol-assisted combustion synthesis method. The phase composition and morphologies of the compound were ascertained by X-ray diffraction (XRD) and scanning electron microscope (SEM). The electrochemical characterization was performed by using CR2032 coin-type cell. XRD analysis indicates that single phase spinel LiMn2O4 with good crystallinity has been obtained as a result of 5 h treatment at 600 °C. SEM investigation indicates that the average particle size of the sample is 200 nm. The initial discharge specific capacity of the LiMn2O4 is 123 mAh/g at a current density of 30 mA/g. When the current density increased to 300 mA/g, the LiMn2O4 offered a discharge specific capacity of 86 mAh/g. Compared with the LiMn2O4 prepared by a conventional solution combustion synthesis method at the same temperature, the prepared LiMn2O4 possesses higher purity, better crystallinity and more uniformly dispersed particles. Moreover, the initial discharge specific capacity, rate capability and cycling performance of the prepared LiMn2O4 are significantly improved.