Structural Surface Crack Monitoring Method Based on Electrical Potential Technique and Modern Surface Technology

Crack monitoring plays a great role in modern structural health monitoring, however, most of the conventional crack inspections have disadvantages in terms of the accuracy, expense, reliability, durability and level of instrumentation required. Thus, development of a simple and reliable crack inspection technique that allows continuous monitoring has been desired. In this paper, electrical potential technique and modern surface technology are employed together to develop a new structural surface crack monitoring method. A special crack monitoring coating sensor based on electrical potential technique was deposited on the hot spot of the structure by modern surface technology. The sensor consists of three layers： the isolated layer, the sensing layer and the protective layer. The isolated layer is prepared by anodic oxidation technology, the sensing layer is made of ion plated copper, and the protective layer is made of silicone. The thickness of each layer is at micrometer magnitude. The electrical conductivity of the sensor is very stable, and the fatigue performance of the specimen with or without coating sensor is nearly unchanged. The crack monitoring experiment result shows that there are two sudden rises of the coating sensor electrical potential values, corresponding to different stages of the crack initiation and propagation. Since the width of the surface coating sensor is only 0.5 mm, this crack monitoring sensor can detect the propagation of cracks less than 0.5 mm long. The method proposed takes the simplicity of electrical potential technique and can monitor surface crack of nearly all kinds of structures precisely. The results of this paper may form the basis of a new crack monitoring system.

A Study of Multi-Permeating TiN/Ti Alloying Layer Using Plasma Surface Alloying Technology

TiN/Ti multi-permeating alloying layer has been formed on the low carbon steel by means of the double glow-discharge plasma surface alloying technique and hollow-cathode effect. The alloying layer was detected by axiovert 25 CA optical microscope with computer analyzing software （LEC）, GDA-2 glow discharge spectroscopy （GDS）, X-ray diffraction （XRD） and galvanochemical method. The results showed that the thickness of TiN/Ti multi-permeating alloying layer was about 10μm, the content of Ti on the surface was up to 63.48 wt% and the content of N was up to 12.46 wt%. The atom Ti and N concentrations changed gradually across the depth of the alloying layer and the preferred orientation of TiN/Ti alloying layer was crystal surface （200）. The multi-permeating alloying layer and substrate were combined through metallurgy. The surface appearances of the multi-permeating alloying layer were uniform and of a compact cellular structure. The hardness of the surface was about 1600-3000 HV0.1. The corrosion resistance of the permeating TiN/Ti alloying layer in 0.5 mol/L H2SO4 solution was greatly increased and the corrosion rate was only 0.3082 g/m^2. h.

The Fabrication of Microstructure Surface of Superhydrophobic Coating by Surface Gelation Technology

The microstructured surface of materials were fabricated by a two-step acid-base catalyzed sol-gel process. In fluorinated polymer with PTFE doping, the well-proportioned composite sols were prepared using sol-gel processing under the hydrochloric acid and deficiency of water conditions. After the substrate was coated by composite sols, and the gelation treatment on the surface of composite coating, the micrometer-scale and nanometer-scale hierarchical structures were formed in surface layer of material. XPS and TEM technologies were employed to identify that the gelation occurs just on the surface of composite coating. The morphology of coating surface was observed by SEM and AFM technologies. The microstructured surface of material can be fabricated using this inexpensive and easily controlled method on low surface energy resin materials, the super-hydrophobic coatings materials can be prepared.

CALCULATION OF THREE－DIMENSIONAL SOLDER JOINT FORMATION IN MICROELECTRONIC SURFACE MOUNT TECHNOLOGY

A finite element analysis for calculating three-dimensional(3-D) solder joint shape between chip component and substrate pad was carried out, and the effects of solder volume and pad extension beyond the edge of component on solder joint shapes were investigated. The resonable design ranges of solder volume and pad extension have been put forward.

Recent progress in microbial cell surface display systems and their application on biosensors

Microbial cell surface display technology is a recombinant technology to express target proteins on the cell membrane,which can be used to redesign the cell surface with functional proteins and peptides.Bacterial and yeast surface display systems are the most common cell surface display systems of prokaryotic and eukaryotic proteins,that are widely applied as the core elements in the field of biosensors due to their advantages,including enhanced stability,high yield,good safety,expression of larger and more complex proteins.To further promote the performance of biosensors,the biomineralized microbial surface display technology was proposed.This review summarized the different microbial surface display systems and the biomineralized surface display systems,where the mechanisms of surface display and biomineralization were introduced.Then we described the recent progress of their applications on biosensors for different types of detection targets.Finally,the outlooks and tendencies were discussed and forecasted with the expectation to provide some general functions and enlightenments to this aspect of research.

Application of High-Resolution Remote Sensing Technology in Quantitative Study on Coseismic Surface Rupture Zones: An Example of the 2008 M_w7.2 Yutian Earthquake

Objective Nowadays, high-resolution remote sensing technology has brought new changes to surveys of earthquakes, and the quantitative study of seismic faults based on this technology has become a trend in the world(Barzegari et al., 2017). An Mw 7.2 earthquake occurred in Yutian of Xinjiang on the western end of the Altyn Tagh fault on March 21 st, 2008. It is difficult to access this depopulated zone because of the high altitude and only 1–2 months of snowmelt. This study utilized high-resolution

Tribological Properties of Dimpled Surface Alloying Layer on Carbon Steel

The effect of surface structure and coating on tribological properties of 45^# carbon steel disc was analyzed. A Nd：YAG laser was used to generate rnicrodirnples on steel surfaces. Dimples with diameter of 150 rn and depth of 50 rn were distributed in an orbicular array on disc surface. Then the alloying element Mo was sputtered to 45# carbon steel disc surface by means of double glow plasma technology. Diffusion Mo alloying layer with 30min thickness and high hardness up to 0.025 was formed on the disc surface. Tribological experiments of three types samples （smooth, texturing and texturing＋alloying） were conducted with a pin-on-disc tribometer. It is found that the dimpled-samples are most effective for reducing friction in comparison with smooth steel surthces, improving the lubricating state from boundary to hydrodynamic region.

Progress in Research of Surface-plasmon-enhanced Light-emitting Diode

InGaN-based light-emitting diode(LED)as for the replacement of conventional fluorescent lighting source still needs a great effort to improve the light-extracting efficiency as well as internal quantum efficiency of LEDs.Surface plasmon technology has recently attracted considerable interest,because the spontaneous emission rate and the light extraction efficiency of a light-emitting device can be simultaneously enhanced through the coupling between an InGaN quantum well and surface plasmons.The surface plasmon-emitter coupling technique would lead to high brightness multichip white LEDs that offer realistic alternatives to conventional fluorescent light sources.In this article,the possible enhancement mechanism of surface plasmon is discussed,and then recent developments of surface-plasmon-enhanced light-emitting diode are introduced.

Study on surfce mount technology for fine pitch L type lead devices

Problems about surface mounting process for fine pitch devices and reasons on solder bridging of L type lead devices welded are depicted. Bridging mechanism and influence factors are analyzed with two-dimensional geometric model. Based on this, high-density surface mount technology ( SMT) for fine pitch L type lead devices heated by scanning laser is raised. Surface mount process for QFP208 on printed circuit board (PCB) is studied. The results of tests are that it is quite possible to solve the solder bridging of surface mounting for fine pitch devices with scanning laser-heating method.

PLASMA SPRAYING TECHNOLOGY AND ITS APPLICATION

The development of plasma spraying technology since the ITSC' 95 conference is briefly summarized. Emphasis is placed on the new achievements of plasma spraying materials, processing, coating properties , facilities and application. The state of the plasma spraying technology in China is also introduced in the paper.

New developments for vacuum coating of steel strips

Vapor deposited coatings onto strip steel are a promising alternative as functional layers for corrosion protection or high abrasion resistance.Conventional coating systems have some limits regarding environmental compatibility,the range of coating materials and application properties. Physical vapor deposition(PVD) is an environment-friendly technology and enables nearly unlimited material and process variety.Electron beam high-rate evaporation with deposition rates up to some micrometers per second is the most productive PVD technology for low cost coating.The combination of evaporation with powerful plasma is an efficient way to improve the layer properties.The developed plasma sources can be used for special plasma enhanced chemical vapor deposition(PECVD) processes too. The paper gives an overview about the latest developments in these technologies.Furthermore,the paper explains some examples of new layer stacks onto steel strips.While enhanced corrosion protection can be obtained by magnesium,aluminium or copper containing coatings other functional surface properties come more and more in the focus of interest.For instance,decorative gold colored layers,transparent scratch resistant layers,hard coatings and photo catalytic layers were deposited on running steel strips.Functional layers and layer systems for energy saving and sun energy absorption by solar thermal effects and photo voltaics are under development.The coatings are prepared under the conditions of very high deposition rates using our in-line vacuum coater for metallic strips and sheets with the name MAXI.The influence of the process and plasma parameters on the layer properties were investigated and will be demonstrated for some applications.

Preparation and characterization of HMX/NH_(2)-GO composite with enhanced thermal safety and desensitization

To improve the safety of HMX,HMX/NH_(2)-GO composite was prepared with aqueous ammonia functionalized graphene oxide(NH_(2)-GO).The composite was characterized by SEM,Zeta potential,XPS,Raman spectrum,XRD,HPLC,DSC and BAM sensitivity test.The results indicated that the functionalization with aqueous ammonia can enhance the interaction between GO and HMX,and more efficiently desensitize the explosive.The optimal impact sensitivity of the HMX/NH_(2)-GO composite can be not less than 40 J,which is also the most insensitivity compared to the previous reports prepared by coating desensitization with non-energetic desensitized material.Moreover,the potential reason for the different impact and friction sensitivity was also discussed,which may bring a novel perspective to achieve the desensitization of energetic material.

Dark-field detection method of shallow scratches on the super-smooth optical surface based on the technology of adaptive smoothing and morphological differencing

In recent years, modern optical processing technologies, such as single point diamond turning, ion beam etching, and magneto-theological finishing, arc getting break- throughs. Machining precisions of super-smooth optics have also been significantly improved. However, with increasing demands for the optical surface quality,

Isolation of Goose-origin scFv Antibodies Against Goose Parvovirus from Bacterial Display Antibody Libraries

Goose parvovirus(GPV)can cause a highly contagious and fatal gosling plague(GP)disease in goslings and muscoy ducklings.Here,three goose-origin neutralizing single chain variable fragment(scFv)antibodies against GPV SYG-61 were isolated.The genes of scFv antibodies were derived from goslings immunized with GPV SYG-61,and scFvs were subcloned into a pBSD vector for the construction of pBSD-scFv libraries.The pBSD-scFv libraries were screened following three rounds using VP2(protective antigen of GPV)as the bait by flow cytometry(FCM).After screening,the 15 clones with high mean fluorescence intensity(MFI)were isolated and sequenced.These 15 scFvs were expressed by pET-28a(+)in E.coli.The specificity and affinity of the 15 purified scFvs were successfully confirmed by ELISA.In the preliminary neutralization experiment on primary goose embryo fibroblast(GEF)in vitro,three of the 15 purified scFvs(named scFv-10,scFv-11 and scFv-50)showed significant neutralizing capacities.The study generated the first goose-origin neutralizing scFv against GPV and laid the foundation for the appearance of full-length goose-origin neutralizing monoclonal antibody against GPV.

Excitation of anti-symmetric coupled spoof SPPs in 3D SIS waveguides based on coupling

According to the electromagnetic field distributions, there exist two kinds of coupled spoof surface plasmon polaritons（SSPPs）, the symmetric and anti-symmetric modes, in the three-dimensional（3D） subwavelength spoof–insulator–spoof（SIS） waveguide. We study the dispersion and excitation of the two kinds of coupled SSPPs supported by the 3D SIS waveguide. The evolution of the dispersion with the thickness and gap width of the waveguide is numerically investigated,and we give a theoretical analysis according to the coupling mechanism. Specially, based on the coupling mechanism,we design a zipper structure, through which the excitation and propagation of the anti-symmetric coupled modes can be realized effectively.

An Ion-imprinted Silica Gel Polymer Prepared by Surface Imprinting Technique Combined with Aqueous Solution Polymerization for Selective Adsorption of Ni(Ⅱ) from Aqueous Solution

A novel Ni（Ⅱ） ion-imprinted silica gel polymer was prepared via the surface imprinting technique combined with aqueous solution polymerization by using 2-acrylamido-2-methyl-1-propanesulfonic acid（AMPS） as a functional monomer for the selective separation of Ni（Ⅱ） from aqueous solution. The sorbent showed good chemical and thermal stability. Kinetics studies indicated that the equilibrium adsorption was achieved within 10 min and the adsorption kinetics fitted well with the pseudo-second-order kinetic model. The maximum adsorption capacity of the ion-imprinted polymer towards Ni（Ⅱ） at the optimal p H of 7.0 was 66.22 mg·g^（-1）. The relative selectivity coefficients of the sorbent were 9.23, 15.71, 14.72 and 20.15 for Ni（Ⅱ）/Co（Ⅱ）, Ni（Ⅱ）/Cu（Ⅱ）, Ni（Ⅱ）/Zn（Ⅱ） and Ni（Ⅱ）/Pb（Ⅱ）, respectively. The adsorption isotherm fitted well with Langmuir isotherm model. The thermodynamic results indicated that the adsorption of Ni（Ⅱ） was a spontaneous and endothermic process. The sorbent showed good reusability evidenced by six cycles of adsorption/desorption experiments. The precision of this method is satisfactory. Thus, the prepared sorbent can be considered as a promising sorbent for selective separation of Ni（Ⅱ） in real water samples.

Microfluidic synthesis of thiourea modified chitosan microsphere of high specific surface area for heavy metal wastewater treatment

An improved biosorbent of thiourea modified chitosan microsphere（TMCM） with high specific surface,favorable mechanical strength and excellent adsorption performance had been synthesized via microfluidic technology. Polyethylene glycol was used as a significant component added in aqueous solution of chitosan to produce such microspheres through droplets forming, chemical crosslinking and pores creating. For the improvement of adsorption capacity, thiourea was considered as an excellent choice in increasing amino functional group by graft modification. The SEM, FTIR and EDS were employed to detect distinct features of TMCM. Copper（Ⅱ） was used to test the adsorption performance of TMCM. The experimental results indicated that TMCM exhibited higher adsorption capacity（q_e= 60.6 mg g_（-1）） and faster adsorption rate than that non-modified chitosan microsphere（NMCM）.The adsorption kinetic was described well by the pseudo-second order kinetic model, which suggested that chemical adsorption along with electrons transferring was dominant in adsorption process.

Load Optimization Scheduling of Chip Mounter Based on Hybrid Adaptive Optimization

A chip mounter is the core equipment in the production line of the surface-mount technology,which is responsible for finishing the mount operation.It is the most complex and time-consuming stage in the production process.Therefore,it is of great significance to optimize the load balance and mounting efficiency of the chip mounter and improve the mounting efficiency of the production line.In this study,according to the specific type of chip mounter in the actual production line of a company,a maximum and minimum model is established to minimize the maximum cycle time of the chip mounter in the production line.The production efficiency of the production line can be improved by optimizing the workload scheduling of each chip mounter.On this basis,a hybrid adaptive optimization algorithm is proposed to solve the load scheduling problem of the mounter.The hybrid algorithm is a hybrid of an adaptive genetic algorithm and the improved ant colony algorithm.It combines the advantages of the two algorithms and improves their global search ability and convergence speed.The experimental results show that the proposed hybrid optimization algorithm has a good optimization effect and convergence in the load scheduling problem of chip mounters.