Advanced Materials Research Vols. 503-504

Abstract: In this paper, we studied lasing action in dual-doped organic microcavity with cascade Forster energy transfer between polymer and two fluorescent dyes in surface emitting microcavities, which formed by sandwiching a poly(N-vinylcarzole) (PVK) film doped with 8-trishydroxyquinoline (Alq3) and 4-(dicyanomethylene)-2-tert-butyl-6 (1, 1, 7, 7-tet ramethyljulolidyl-9-enyl)-4H–pyran (DCJTB) between a distributed Bragg reflector (DBR) and a silver film mirror. The sample was optically pumped by a frequency-tripled Nd:YAG laser delivering 5.55ns pulses at 355nm with a 10Hz repetition rate. By optimizing the concentrations of Alq3 and DCJTB in PVK, a low lasing threshold of about 9.5µJ per pulse attributed to efficient cascade Forster energy transfer form PVK and Alq3 to DCJTB was obtained. The full width at half maximum (FWHM) of the emission was about 2nm with the peak wavelength at 628nm. Our results demonstrate that the PVK:Alq3:DCJTB could be a promising candidate as gain medium for red organic diode lasers.

Abstract: This paper presents an experimental investigation of the sound transmission and structural vibration characteristics of the double glazed window. The laboratory experiments were performed placing the window between reverberation chamber and anechoic chamber. The window was subject to diffuse field, approximate normal wave and oblique wave acoustic excitations. The sound transmission performances at far-field were measured. Furthermore, experimental modal analysis has been performed. The Least square complex exponential algorithm is used to extract the modal parameters, i.e. mode shapes, natural frequencies and modal damping ratio of the structure. The results also show that the highest sound transmission of this experimental double glazed window appears around the mass-air-mass resonance frequency.

Abstract: An identification method of spindle bearing fault based on rough sets theory is proposed in the article. By collecting bearing’s typical fault signal and using signal information processing techniques, vibration fault data is obtained. Then, equidistant clustering analysis method is introduced into discretization of experimental data of continuous attributes. In this way, vibration fault data table meets the requirement of rough sets data analysis. Besides, attribute importance algorithm is used in order to realize the reduction of condition attribute in the decision table. Thus, fault information which hidden in huge signal data is extracted. Therefore, simple and clear fault pattern rules are acquired. The result indicates that the method can realize fault pattern identification of spindle’s bearings and it is of great application value in practical fault pattern identification.

Abstract: A new health care fiber-coconut carbon fiber, and yarn use coconut carbon fiber and cotton blended into are introduced in this paper. And a series of performance testing and analysis about scanning electron microscopy, infrared spectrum, strength, hairiness, moisture content and acid and alkali resistance are done to the carbon fiber and coconut yam.

Abstract: This paper introduce the relationship between fracture energy of refractories and its thermal shock resistance, and research status about fracture energy of refractories. It shows that investigation on fracture energy of refractories at high temperature is positive significance for evaluation of thermal shock resistance, and wedge splitting method for fracture energy of refractories is an effective method.

Abstract: Because of big error of torque measured by hydraulic tubing tongs, tubing connections may be over or less engaged, which will result in leakage of tubing connection and abnormal annular casing pressure. The primary reason of big error was that systematic error couldn’t be verified because of indirect of hydraulic tubing tongs. To solve this problem, 10000N.m and 15000N.m hydraulic tubing tongs were designed and manufactured. The devices have received two national patents and accredited by authority of the State Department. Experimental procedures and regulations were developed. It was found that hydraulic tubing tongs worked in a stable situation and values recorded by hydraulic tubing tongs were more accurate

Abstract: According to the use, design and research of shot blasting machine equipment for years, combined with the company's actual production, the processing technology of fender has been optimized is the wearing part of shot blasting machine in the casting room, the service life of fender have more than doubled in the original ones by the actual use proof, greatly reducing the replacement frequency of fender for the company to save a lot of money.

Abstract: Chinese wind power industry is in the ascendant. The hidden fault development trend prediction technology will become increasingly important for improving the efficiency of wind turbines. Faced to the changing condition and non-stationary character of equipment, this paper proposed a data-based multi-transform domains non-linear fault trend prediction technique. The mechanical systems physical information and failure prediction value information was integrated in this technique. Multi-transform domains and non-linear dimensionality reduction method used to analysis equipment working state and extract failure feature of topology domain. This technique try to solve the problem that fault development information is often flooded by irregular state change information.

Abstract: The method to analysis the influence of error sources on the fiber optic gyroscope north seeker is presented in this paper. The influence of various error sources of the north seeker are investigated comprehensively. The simulation results indicate that the precision of gyroscope is the most important influence factor; the influence of the position rotation error and mounting error are greater than that of the inclination angle measurement error. Based on the analysis, the advisable scheme to improve the accuracy of the four-position north seeker is proposed. The experimental results met the accuracy requirement well, which proved that the compensation and error analysis method in this paper are effective and feasible.

Abstract: After a brief introduction about aerodynamic noise generation and transmission mechanisms, the influence of crosswind to vehicle interior aerodynamic noise for a production automobile sedan was investigated through full-scale aeroacoustic wind tunnel tests. Through analysis of sound pressure level of vehicle interior driver ear position and pressure fluctuation level on vehicle side window glass under different yaw angles, the following results are obtained: The frequency characteristics of vehicle interior aerodynamic noise vary as yaw angle changes under one certain wind speed. Whether on the leeside or by windward, sound pressure level increases as yaw angle goes up. Under the same yaw angle, interior noise level on the leeside is higher than that by windward. Test results between pressure fluctuation level on side window glass and vehicle interior aerodynamic noise of driver ear position show good correlation