光引发剂对紫外光固化胶粘剂性能的影响

制备了以IR651和IR1700为引发剂的紫外光(UV)固化胶粘剂,研究其感光性能和粘接性能。在曝光30s后,以IR1700为引发体系的UV固化胶粘剂的剪切强度可达8.3MPa,而引发体系为IR651的剪切强度仅为0.6MPa。比较了两种光引发剂时的感光性能,IR1700体系的感度值为2.85mJ/cm^2,而IR651的为4.03mJ/cm^2。经深度固化研究表明,IR1700具有深度光固化的优异性能。

Numerical investigation on the sensitivity of jointed rock mass strength to various factors

The mechanical properties of jointed rock masses, such as strength, deformation and the failure mechanism, can be understood only by studying the sensitivity of jointed rock mass strength (both the peak and residual strengths) to the factors that affect it. An orthogonal design of uniaxial compression tests was simulated on eighteen groups of jointed rock specimens having different geometric and mechanical properties using RFPA2D (Rock Failure Process Analysis) code. The results show that the peak strength is controlled by the geometric parameters of the joints, but that the residual strength is controlled by the mechanical prop- erties of the joint interfaces. The failure mode of jointed rock specimens is mainly shear failure. Joint quantity, or density, is the most important index that affects jointed rock mass strength and engineering quality.

Effect of strain rate and water-to-cement ratio on compressive mechanical behavior of cement mortar

Effects of strain rate and water-to-cement ratio on the dynamic compressive mechanical behavior of cement mortar are investigated by split Hopkinson pressure bar(SHPB) tests. 124 specimens are subjected to dynamic uniaxial compressive loadings.Strain rate sensitivity of the materials is measured in terms of failure modes, stress-strain curves, compressive strength, dynamic increase factor(DIF) and critical strain at peak stress. A significant change in the stress-strain response of the materials with each order of magnitude increase in strain rate is clearly seen from test results. The slope of the stress-strain curve after peak value for low water-to-cement ratio is steeper than that of high water-to-cement ratio mortar. The compressive strength increases with increasing strain rate. With increase in strain rate, the dynamic increase factor(DIF) increases. However, this increase in DIF with increase in strain rate does not appear to be a function of the water-to-cement ratio. The critical compressive strain increases with the strain rate.

Synthesis and characteristics of pH-and temperature-sensitive hydrogels of poly （DMAEMA/NIPAAm）

A kind of novel copolymer hydrogel of poly（N, N-dimethylaminoethyl methacrylate-co-N-isopropylacrylamide） （poly[DMAEMA/NIPAAm]） was synthesized by the initiation of K2S2O8, N, N＇-methylene-bis（acrylamide） （Bis） was used as the crosslinker. The effects of monomer content, pH and temperature on swelling ratio of the hydrogel were investigated; the thermo-sensitivity in deionized water and in physiological saline was determined. It showed that the swelling ratio of the hydrogel could be changed by changing the temperature or pH alternately. Both swelling ratio and LCST （Lower Critical Solution Temperature） of the hydrogel decreased with the increase of NIPAAm in the co-polymer content.

The Study of Image Segmentation Based on the Combination of the Wavelet Multi-scale Edge Detection and the Entropy Iterative Threshold Selection

This paper proposes an image segmentation method based on the combination of the wavelet multi-scale edge detection and the entropy iterative threshold selection.Image for segmentation is divided into two parts by high- and low-frequency.In the high-frequency part the wavelet multiscale was used for the edge detection,and the low-frequency part conducted on segmentation using the entropy iterative threshold selection method.Through the consideration of the image edge and region,a CT image of the thorax was chosen to test the proposed method for the segmentation of the lungs.Experimental results show that the method is efficient to segment the interesting region of an image compared with conventional methods.

Research on Brand Perceived Value of Cruise Company Based on Online Comment

With the rapid development of Intemet technology, the traditional way of information transmission has undergone tremendous changes, especially in the lntemet environment. The spread of the online word of mouth as a platform for the Interact highlights its great influence and importance. Especially in the online shopping, these reflect the user＇s point of view and attitude of the online comment has been an unprecedented attention. Online reviews have become an important medium for consumers to understand their products before they buy goods, making them an important channel for potential consumers to understand the quality of goods and services. There are many studies on online reviews, but the research on the brand awareness of cruise ship companies is almost negligible. This paper provides a reference for the construction of cruise ship brand awareness system, and combines Nvivo software to analyze the online commentary system, and provides a reference for further research on cruise brand, and prospects for future research.

The effect of experiential value, perceived quality and customer satisfaction on customer lifetime value： An example using Star Cruises

The current study represents an attempt at experiential value, perceived quality and customer satisfaction influence on customer lifetime value. The sampling frame consisted of Star Cruises purchases in Taiwan. The authors have collected yield 268 questionnaires, by screening out 13 questionnaires, including those missing value or incomplete answer, and finally a usable sample of 255 questionnaires were utilized in this study. The results show that experiential value, perceived quality and customer satisfaction have positive effects to customer lifetime value. Especially, experiential value has the strongest direct effect. Therefore, if resources are limited, the manager should focus on shaping the experiential value to increase customer lifetime value. Implications for marketing theory and practitioners are discussed, and possible directions for future research are sketched.

Approaches to Stable Operation of Shaftless Centrifugal Pump

The shaft-less impeller of the centrifugal pump, which is driven by the magnetic induction, was developed. Theimpeller rotates under the floating condition without any control device. The floating condition of the impeller isrealized by utilizing the pressure in pump casing. The pump performance and the rotational behavior of the impellerwere investigated experimentally. It has found that the floating position of the impeller become quite unstablein a partial flow rate operation. And the pressure distribution at the casing wall affects the rotational posture ofthe impeller. This paper presents the effect of the casing treatment on the rotational posture of the impeller and thepressure distribution. The reasonable casing treatment is available for the stable rotational posture of the impeller.

Application of Wavelet Transform Modulus Maxima in Raman Distributed Temperature Sensors

We proposed and demonstrated a wavelet transform modulus maxima （WTMM） de-noising method to decrease the temperature error. In this scheme, the composition scale was determined simply by the WTMM amplitude variation with the growth of the decomposition scale at 30 ℃, and the signal WTMM was obtained by the wavelet decomposition modulus on every decomposition scale based on the modulus propagating difference between the signal and noise. Then, we reconstructed the signal using the signal WTMM. Experimental results show that the proposed method is effective for de-noising, allowing for a temperature error decrease of about 1 ℃ at 40 ℃ and 50℃ comparing to the original data.