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Dense Pb(Zr0.52Ti0.42Sn0.02Nb0.04)O3 high-performance piezoceramics were prepared by spark plasma sintering. Phase structure, domain structure, and temperature-dependent electrical properties were systematically investigated. The spark-plasma-sintered ceramics possess a pure perovskite structure with rhombohedral–tetragonal (R–T) phase boundaries and a high Curie temperature of 347 °C. Reliable performance against temperature was observed. First, high strain behavior with a normalized strain d33* of 640 and 710 pm/V occurred at 25 and 150 °C, respectively, varying less than 11%. Besides, a large remnant polarization Pr of 36.9 μC/cm2 is observed at room temperature and varies less than 18% within the temperature range of 25–150 °C. In addition, an enhanced piezoelectric coefficient d33 of ∼460 pm/V was attained at a high temperature of 150 °C, manifesting a 40% enhancement with respect to the d33 value (330 pm/V) obtained at room temperature.

We studied the interplay between quantum interference (QI) and molecular asymmetry in charge transport through a single molecule. Eight compounds with five-membered core rings were synthesized, and their single-molecule conductances were characterized using the mechanically controllable break junction technique. It is found that the symmetric molecules are more conductive than their asymmetric isomers and that there is no statistically significant dependence on the aromaticity of the core. In contrast, we find experimental evidence of destructive QI in five-membered rings, which can be tuned by implanting different heteroatoms into the core ring. Our findings are rationalized by the presence of antiresonance features in the transmission curves calculated using nonequilibrium Green’s functions. This novel mechanism for modulating QI effects in charge transport via tuning of molecular asymmetry will lead to promising applications in the design of single-molecule devices.

Application of coil diameter calculation is very important in the industrial field. The demanding for the precision of control is increasingly strict. There are three methods to achieve a higher precision. They are the Count-method, Linear /Angular Velocity and Distance Calculation respectively. In the process of coiling and uncoiling, advantages and disadvantages are existed. There are different requests for realization of the functions as well. In the Siemens PLC S7-300 control system, these three methods can be used to achieve a higher precision of coil diameter calculation and control. Different improvements and adjustments, according to methods, are given in the process of the test. Some algorithm has been optimized. Finally, by using the three algorithms, the dynamic change of roll diameter can be calculated and meet the need in the course of steel strip.

Dense Pb(Zr

In this paper, a nondestructive testing method for tiny defects in precision welding tubes based on micro-focus CT device is presented, and slice images are obtained. Edge detection and morphology operations were adopted to remove air-ring artifacts in slice images. The removal methods are as follows. First, the canny orthogonal gradient operator was used to obtain the integrated edge of the welded tube. Second, the adaptive morphology method was used to fill the inner area of the welded tube, and mask images were obtained. Finally, the mask images were multiplied with the origin images, and slice images, from which air-ring artifacts were removed, could be obtained. The presented method was feasible. This method is expected to provide a better basis for the segmentation and 3D reconfiguration of tiny defects in slice images of a precision welding tube.

The major challenges of molecular electronics are the understanding and manipulation of the electron transport through the single-molecule junction. With the single-molecule break junction techniques, including scanning tunneling microscope break junction technique and mechanically controllable break junction technique, the charge transport through various single-molecule and supramolecular junctions has been studied during the dynamic fabrication and continuous characterization of molecular junctions. This review starts from the charge transport characterization of supramolecular junctions through a variety of noncovalent interactions, such as hydrogen bond, π-π interaction, and electrostatic force. We further review the recent progress in constructing highly conductive molecular junctions via chemical reactions, the response of molecular junctions to external stimuli, as well as the application of break junction techniques in controlling and monitoring chemical reactions in situ. We suggest that beyond the measurement of single molecular conductance, the single-molecule break junction techniques provide a promising access to study molecular assembly and chemical reactions at the single-molecule scale.

With growing concern over world environmental problems and increasing legislative restriction on using lead and lead-containing materials, a feasible replacement for lead-based piezoceramics is desperately needed. Herein, we report a large piezoelectric strain (d33*) of 470 pm/V and a high Curie temperature (Tc) of 243 °C in (Na0.5K0.5)NbO3-(Bi0.5Li0.5)TiO3-BaZrO3 lead-free ceramics by doping MnO2. Moreover, excellent temperature stability is also observed from room temperature to 170 °C (430 pm/V at 100 °C and 370 pm/V at 170 °C). Thermally stimulated depolarization currents (TSDC) analysis reveals the reduced defects and improved ferroelectricity in MnO2-doped piezoceramics from a macroscopic view. Local poling experiments and local switching spectroscopy piezoresponse force microscopy (SS-PFM) demonstrates the enhanced ferroelectricity and domain mobility from a microscopic view. Distinct grain growth and improvement in phase angle may also account for the enhancement of piezoelectric properties.

An indentation approach with Berkovich indenter is proposed to determine fracture toughness for ductile materials. With decrease of effective elastic modulus, an approximate linear relationship between logarithmic plastic penetration depth and logarithmic effective elastic modulus, and a quadratic polynomial relationship between the plastic penetration depths and penetration loads are exhibited by indentation investigation with Berkovich indenter. The damage constructive equation of effective elastic modulus is proposed to determine the critical effective elastic modulus at the fracture point, which is the key problem to calculate the indentation energy to fracture. The critical plastic penetration depth is identified after the critical effective elastic modulus can be predicted by conventional mechanical properties. The fracture toughness is calculated according to the equation of penetration load, plastic penetration depth and the critical plastic penetration depth.

The left and right-turning scheme of weldments was adopted to detect small porosities in laser weldments with complex structures. Detection images were obtained in this study. An algorithm that determines the optimal structure elements for morphology simulation was provided to achieve fidelity segmentation of small porosities. Mathematical models for the defect depth and deviation of bulk porosities were established based on the geometric features of laser weldments. Thus, the features of spatial distribution of small porosities were determined. To improve detection efficiency, the automatic extraction of spatial position data for bulk porosities was divided into two parts: automatic extraction of projection distance, which is important for the determination of weld porosity depth and deviation, and automatic extraction of porosity size. The porosity distribution in the longitudinal direction was obtained by automatic searching, and the features of the spatial distribution of weld porosities were procured. A 3D model of laser weldments was established to visualize the spatial distribution of porosities. Extracted data were inputted to the model, and the spatial positions of bulk porosities were visualized.

In order to study the segmentation and quantitative problem of small defects in precision weldments with complex structure, an automated image processing system was setup based on the Visual Basic 6.0 development environment. The weld zones were extracted by adopting the method of twice automatic threshold, and the small defects were segmented successfully by using sharpen, smoothing processing and background subtraction in the extracted weld zones. To determine the spatial distribution features of small defects, calculation formula of defects depth and deviation were deduced individually, and the projection distance of small defects can be extracted automatically also. The image processing system can achieve the goal of small defects segmentation and automatic extraction of projection distance. The depth and deviation of small defects can be obtained through the above deduced formula, and the longitudinal distribution of small defects can be obtained from the detection image, then the spatial distribution features of small defects can be determined.

To investigate the effect of vacuum sealing drainage (VSD) on variation of oxygen partial pressure (PtO2) and vascularization.The 12 cases of rabbit's wound models were undergoing the VSD (vacuum group, n = 6) or conventional therapy (conventional group, n = 6). Variation of PtO2 was measured by oxygen partial pressure admeasuring apparatus, expression of hypoxia inducible factor 1α (HIF-1α) mRNA was measured by real-time fluorescent quantitative PCR, content of vascular endothelial growth factor (VEGF) was measured by ELISA after tissue homogenate in 7 days. Vascular endothelial cell (VEC) and new blood capillary (NBC) of hematoxylin-eosin slice of tissue were counted by using light microscope.Average value of PtO2 of vacuum group was significant lower than conventional group (t = -99.780 to -5.305, P0.01). Expression of HIF-1α (30 minutes, 1, 6, 12 hours were 3.11 ± 0.07, 3.68 ± 0.26, 4.16 ± 0.13 and 3.91 ± 0.26 respectively) and content of VEGF (30 minutes, 1, 6, 12 hours were 103.3 ± 2.4, 134.2 ± 9.0, 167.8 ± 3.8 and 232.1 ± 9.5 respectively) of vacuum group were increased after 30 minutes and significant lower than conventional group (t = 13.038 - 80.208, P0.01), and both of them were reduced after 24 hours (P0.05). Counting numbers of VEC (2.47 ± 0.45 to 4.70 ± 0.38) and NBC (1.33 ± 0.49 to 4.33 ± 0.68) of vacuum group were increased at the same time-point and significant higher than conventional group (t = -0.670 to 16.500, P0.05).PtO2 of wound surface could be reduced significantly by VSD. Expression of HIF-1α and content of VEGF were increased by VSD for enhancing differentiated state of VEC and construction of NBC, which were better for vascularization and wound healing.

It's reviewed that the measurement methods of road surface profile and the influence of signal trend extraction of road surface profile in engineering application. The methods of signal trend extraction are analyzed and compared in recent years. The empirical mode decomposition is selected as the method of extracting signal trend in road surface profile. The decomposition process and detailed algorithm of empirical mode decomposition are introduced. Based on the decomposition and reconstruction processes of empirical mode decomposition, there is an example of road surface data which is acquired on actual road. In the example, the process of empirical mode decomposition and the result of intrinsic mode function extracted are demonstrated. The analysis and comparison results show that the method of empirical mode decomposition is simple and has obvious effect in signal trend extraction. The method of signal trend extraction can be widely applied to road surface data processing.

The efficient cooperative countermeasure against a large-scale attack is very crucial for current networks. This paper proposed an approach of cooperation based on Neighbor Distance (ND) for enhancing the performance of the distributed Intrusion Prevention System (IPS). In the model, message types transmitted between cooperation nodes are defined, and a message-based cooperation method is adopted and enhances the flexibility for system deployment. In order to reduce the redundant message, the distance between nodes is calculated and the communication region is optimized in the model, and the message distribution strategy is showed. The experimental result shows that the model decreases the IPS network load evidently.

Security has become a primary concern for providing communication in mobile ad hoc networks(MANET). Compared with a fixed network, a MANET is more vulnerable to attacks such as passive eavesdropping, data tampering and so on, so it is necessary to encrypt transmitted data to ensure its confidentiality. However, in a resource-constrained MANET, the mobile devices have limited capabilities in computation, storage and power, a single source node can not afford the whole encryption task. In this paper, we propose a relay encryption scheme based on threshold secret sharing algorithm, to enhance the data confidentiality, reliability and integrality in MANET. The basic idea is to distribute the whole encryption task to all nodes along the route, every node completes part of the encryption task instead of the single source node encrypting the whole data. In the relay encryption scheme, we divide the whole data into N shares by (T,N) threshold secret sharing algorithm. On the routing path, every node chooses several unencrypted shares and encrypts them separately. With the appropriate value of (T,N) and allocation principle for the number of shares encrypted on each node along the route, the relay encryption scheme can effectively alleviate the burden of the source node and reduce the transmission delay, meanwhile it provides a high level of security, and also improves the reliability of MANET.

To study changes in oxygen metabolism and evaluate metabolic status in tissue and cell after severe trauma, and to investigate value of monitoring oxygen metabolism in the course of development of multiple organ dysfunction syndrome (MODS) in trauma between patients.The data of 146 patients with severe trauma in Tongji Hospital were collected. The variables pertaining to oxygen metabolism were analyzed, and the data were compared between patients with risky trauma and those with severe trauma, between patients complicated with MODS and non--MODS (NMODS), and between survivors and nonsurvivors. With patients with minor trauma as control, the data were analyzed according to injury severity score (ISS), revised trauma score (RTS), acute physiology and chronic health evaluation II (APACHE II), trauma and injury severity score (TRISS(RTS)) methods for trauma and outcome study of probability of survival (Ps).Oxygen metabolism abnormality was found after trauma, and it was correlated with ISS, RTS, injured organ or region and number of injured organs, shock, systemic inflammatory response syndrome (SIRS) and respiratory complications. It was more intense in the patients with MODS. There was marked difference in the ratio of change in oxygen metabolism between MODS and NMODS groups. Oxygen deficiency metabolic variables tended to deteriorate in the non survival group. More marked changes in metabolic variables indicated severer organ dysfunction, reaching their peak values before death.Changes in level of oxygen metabolism might be closely correlated with development of MODS in trauma patients. Dynamic monitorings of metabolic status of tissue and cell are valuable in predicting the development of MODS after severe trauma.

Over the past decades, cities as gathering places of millions of people rapidly evolved in all aspects of population, society, and environments. As one recent trend, location-based social networking applications on mobile devices are becoming increasingly popular. Such mobile devices also become data repositories of massive human activities. Compared with sensing applications in traditional sensor network, Social sensing application in mobile social network, as in which all individuals are regarded as numerous sensors, would result in the fusion of mobile, social and sensor data. In particular, it has been observed that the fusion of these data can be a very powerful tool for series mining purposes. A clear knowledge about the interaction between individual mobility and social networks is essential for improving the existing individual activity model in this paper. We first propose a new measurement called geographic community for clustering spatial proximity in mobile social networks. A novel approach for detecting these geographic communities in mobile social networks has been proposed. Through developing a spatial proximity matrix, an improved symmetric nonnegative matrix factorization method (SNMF) is used to detect geographic communities in mobile social networks. By a real dataset containing thousands of mobile phone users in a provincial capital of China, the correlation between geographic community and common social properties of users have been tested. While exploring shared individual movement patterns, we propose a hybrid approach that utilizes spatial proximity and social proximity of individuals for mining network structure in mobile social networks. Several experimental results have been shown to verify the feasibility of this proposed hybrid approach based on the MIT dataset.