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After rocks are damaged under stress loading, the changes of their microstructural and mechanical properties are major factors that affect construction safety in geotechnical engineering projects. Studying the microstructures and mechanical behaviors of stress-damaged rocks can help better guide construction and reduce construction risks for geotechnical engineering projects. In this study, a sandstone was first artificially predamaged and then subsequently subjected to scanning electron microscopy (SEM) analysis, computed tomography (CT) scanning, and uniaxial compression testing. Afterwards, the rock microstructures were three-dimensionally (3D) reconstructed, and the pores were classified and characterized based on their diameters. Moreover, the microstructural and mechanical parameters of the rock were subjected to significance analysis. The results showed that as the stress-induced damage ( σ i ) increased, the uniaxial compressive strength ( σ c ) of the soft rock decreased by 13.7–31.8%; as σ i increased from 11.2 to 19.6 MPa, the elastic modulus (E) of the soft rock increased by up to 28.8%; and as σ i increased beyond 19.6 MPa, there was a significant (22.3%) decrease in E. Stress-induced damage significantly affected the spatial distribution of the pores’ structure of the soft rock. Changes in the spatial structure of the pores led to the formation of cracks. The microstructural parameters of the stress-damaged soft rock were correlated with its mechanical parameters.

A nonintegrable Korteweg–de Vries equation with variable coefficients is investigated in this paper. Due to the existence of variable coefficients, the equation becomes nonintegrable, which leads to the invalidity of the traditional analytical methods to obtain soliton solutions. In order to overcome this difficulty, the variational approach is employed in this paper. The variational principle corresponding to this nonintegrable equation is established. Based on that, the first- and second-order nonautonomous soliton solutions are derived. We note that the obtained solutions can be degenerated to the integrable cases. Properties of the nonautonomous solitons and influence of the variable coefficients are discussed.

Optical Fiber Current Transformer (FOCT) is susceptible to various types of noise, which leads to a decrease in its measurement accuracy, especially when the primary current is small. Improving its signal-to-noise ratio is one of the key technologies of FOCT. This article comprehensively analyzes FOCT's optical signal noise, signal detection noise and noise sources introduced by the external environment, and gives the calculation method of FOCT SNR. The influence of different noise sources on the signal-to-noise ratio is simulated through theory, and the FOCT signal-to-noise ratio optimization design plan is proposed. It is pointed out that the receiver optical power can be increased, increasing the number of sensitive optical fibers of the sensor head and selecting the appropriate closed-loop feedback phase modulation bias operating point method can effectively improve the signal-to-noise ratio and has been verified by experiments. Based on this design FOCT prototype, rated current of 600 A when meet GB / T 20840.8-2007 predetermined 0.2S level requirements, and the SNR is 30.2dB at 1% rated current, the ratio error is less than 0.61%, the phase error is less than 12.39′.

In order to meet the high-speed response requirements of DC fiber-optic current transformer (FOCT) in flexible DC transmission engineering, the step response characteristics of DC FOCT and its dynamic performance improvement methods are studied. The discrete mathematical model of DC FOCT is established and analyzed by simulation. The key parameters affecting the step response characteristics of DC FOCT are transit time, forward channel gain, filter order, and communication delay. A step response test platform for DC FOCT is built, and the step response characteristics of DC FOCT are tested. The experimental results are consistent with the simulation analysis. It is shown by experimental results that the step response rise time of the DC FOCT is less than 40μs after parameter optimization, meeting the relevant application requirements.

Under investigation in this paper is a higher-order nonlinear Schrodinger equation which can describe the propagation of ultrashort pulse in the inhomogeneous optical fiber. Lax pair and conservation laws are constructed from which the integrability of the equation can be verified. Nonautonomous breathers and rogue waves for the equation are derived based on the Darboux transformation (DT) and generalized DT, respectively. Influence of the group-velocity dispersion, third- and forth-order dispersion and gain or loss coefficient on the propagation and interaction of the nonautonomous breathers and rogue waves, is also discussed specifically. There exist two types of nonautonomous breathers. Expressions of the quasi-periods for the two types of nonautonomous breathers are given and the effects of coefficients on the quasi-periods are also discussed. Gain or loss coefficient affects the background for the nonautonomous breather, while third-order dispersion has an influence on the trajectory of the nonautonomous breather. Group-velocity dispersion affects the range of the nonautonomous rogue wave. In addition, group-velocity dispersion also produces a skew angle and the skew angle rotates in the clockwise direction with the increase of group-velocity dispersion. When forth-order dispersion coefficient is taken as a linear function of distance, the structure of rogue wave pair can be formed. The separation and relative locations for the two constituents of rogue wave pair are affected by the coefficients of the linear function.

Soil conditioning is of great significance for tunneling in soft ground with earth pressure balance shield (EPBS) machines, which leads to safe, highly efficient, and high-quality tunneling. To study the effects of soil conditioning on properties of a clay-sand-gravel mixed soil encountered in an EPBS tunneling project in Beijing, a series of geotechnical test methods was carried out based on laboratory test in this paper. The decay behaviors of foam particles generated by the Waring-Blender method were studied first using the image particle analysis system, and then the feasibility of soil conditioning on the mixed soil was qualitatively and quantitatively assessed through the mixing test, slump test, and friction coefficient test. The preliminary test results indicate that drainage of water in liquid film plays an important role in the decay of foam microstructure. The viscosity and flowability of the conditioned soil were modified dramatically by using various amount of water and foam, and a suitable state meeting the requirement of EPBS machines was obtained. The net power and mixing time, which reflects the interaction between the blending rods and tested soils, as well as the slump value, providing the overall indication for liquidity of the conditioned soils, and friction coefficient, reflecting the friction between steel and tested soils, were used to provide insight into the variation in viscosity and flowability of the tested soils.

When machining Inconel 718, tool wear is a serious problem, which affects the quality of workpiece. In order to analyze the wear mechanism in dry machining Inconel 718 with cemented carbide tool, the wear morphology of tool was observed by CCD and scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectrometer in this paper. The results showed that at low cutting speed, the formation and shedding of the built-up-edge caused severe cutting tool breakage. When the cutting speed reached 40 m/min, the tool material fell off from the tool substrate in the form of wear debris, which was the main reason for tool wear. In addition, the elements diffusion between the tool and the workpiece and oxidation reaction accelerated the formation and falling off of wear debris. According to the tool wear mechanism, a tool wear prediction model was established. In machining Inconel 718, the excellent experimental agreement have been obtained in the prediction of wear in cemented carbide tool.

In order to investigate the effect of fissure and temperature on deep-seated rock, uniaxial compression experiments were conducted on rock-like material with different fissure angle at different temperatures. We investigated the influence of fissure angle and temperature on strength and the influence of fissure on failure mode of the rock. Also, we simulated the uniaxial compression experiment of rock-like material with ABAQUS. The results of experiments and simulations confirmed that the strength of rock-like material decreased with increasing temperatures and the strength decreased first then increased with increased fissure angle. The crack initiation started from the tips of the pre-existing fissure and we could speculate via the simulation that the reason of the crack initiation was stress concentration on fissure tips.

In this study, the non-specific immunostimulatory effect of alginate oligosaccharides (AOSs) with three types of molecular weights, namely, A 1 = below 1 kD (polymerization of 2–5), A 2 = 1 kD to 2 kD (polymerization of 5–10), and A 3 = 2 kD to 4 kD (polymerization of 10–20), as well as their two types of corresponding purified uronic acid oligomers (mannuronate and guluronate oligomers) on sea cucumber ( Apostichopus japonicus ) coelomocyte were investigated in vitro. Coelomocytes cultured in L-15 medium containing different AOS concentrations (0, 50, 100, 200, or 400 μg mL − 1 ) were sampled, and non-specific immune responses, such as phagocytic capacity, reactive oxygen species, lysozyme activity, peroxidase activity, total nitric oxide synthase and acid phosphatase activity were determined and compared with those of the control samples (i.e., treatments without immunostimulants) after exposure to AOS for 3, 6, 12, or 24 h. Most of the above mentioned immune parameters were significantly ( P 1 group showed better effects on phagocytic capacity, lysozyme activity, peroxidase activity and total nitric oxide synthase of coelomocytes because of the higher increase, earlier appearance, and longer duration time than those of the A 2 and A 3 groups. Furthermore, among the significant differences of various molecular weights of the AOS groups relative to the control sample, these immune parameters in mannuronate or guluronate oligomer groups were all significantly higher than those in the control sample ( P 1 mannuronate group had a higher increase in phagocytic activity than that of guluronate, and no significant difference was observed in other immune parameters between corresponding mannuronate and guluronate oligomer groups. These results indicated that AOS could enhance the non-specific immune response of sea cucumber coelomocytes in vitro and provided basic information regarding AOS as a potential immunostimulant in sea cucumber culture.

The effect of a commercially available compound probiotics product containing Bacillus subtilis YB-1 (50%) and Bacillus cereus YB-2 (50%) fed to sea cucumbers, Apostichopus japonicus (Selenka) on challenge infections and non-specific immune responses was assessed. Sea cucumbers (were randomly allocated into nine aquariums at a density of 30 sea cucumbers per tank and triplicate groups) were fed diets containing 0 (control), 107 and 1010 cfu (g diet)−1 of the probiotics mixture for 32 days. The growth factors and immunological parameters were measured. In addition, the effects on resistance against Vibrio alginolyticus infection were also evaluated. The results indicate that all the immunological parameters (phagocytic activity, superoxide anion production, lysozyme activity, catalase activity and phenoloxidase activity) measured and the growth rate of sea cucumbers fed 1010 cfu of the probiotics mixture were significantly (P 0.05), Bacillus sp. levels were significantly elevated in sea cucumbers fed the probiotics mixture (P

Most nuclear island built its foundation on the bed rock. Generally the bearing capacity of these bed rocks is very high and the settlements of these buildings are very small. But in some cases we should consider the nonlinear part of the bed rock deformation when the bedrock is sandstone, Siltstone and Shale ect. under the foundation. Because these Metamorphic deformations are mostly creep deformation. This article analyzed settlements of a nuclear island’s foundation which are much greater than it were being designed. The deformation of sandstone is very large when with high load on top of it. Long time of deformation can bring many problems in nuclear power plant, such as pipe tolerance, building connection problem, cable connection problem and can make damage of them. Compared observed dates and a calculation result by using FEM software. And here gives a simple calculation method on nuclear island foundation settlement on sandstone.

This feeding trial was conducted to determine the vitamin E requirement of sea cucumber (Apostichopus japonicus) and to study the effects of vitamin E on nonspecific immune parameters. Commercial sea cucumber diets supplemented with 0, 50, 100, 200, 500 or 1000 mg kg−1 vitamin E were fed to juvenile sea cucumber (7.96 ± 0.01 g) for 60 days. Specific growth rate and total coelomocyte counts were maximized in sea cucumber fed diets supplemented with 100 mg kg−1 vitamin E. Reactive oxygen species production was maximized at 50 mg kg−1 vitamin E, whereas superoxide dismutase activity was the highest in sea cucumber fed diets supplemented with 100 mg kg−1 vitamin E. The vitamin E concentration in the body wall of the sea cucumber increased as the vitamin E level in the diet increased. Analysis of specific growth rate and total coelomocyte counts of the sea cucumber indicated that 88–92 mg kg−1 vitamin E is required for maximal growth and nonspecific immune responses of A. japonicus and that 114.7 mg kg−1 vitamin E is required to minimize lipid peroxidation levels.

The red turpentine beetle (RTB), Dendroctonus valens LeConte (Coleoptera: Curculionidae), which is native to North America, is an invasive wood-boring insect species in China with disastrous consequences. Plant quarantine is an important method to hinder the invasion of this species. In order to distinguish RTB from the other four closely related bark beetles, Scolytus schevyrewi Semenov, Xyleborus artecomans Schedl, Xyleborus interjectus Blandford and Blastophagus minor Hartig, which are frequently intercepted at Chinese ports, we developed a nested polymerase chain reaction (PCR) assay. The specificity of the nested PCR primers to recognize RTB was confirmed by the failure to amplify genomic DNA from the other four Scolytinae species. The sensitivity was approximately 40 pg of a recombinant RTB plasmid. We evaluated the validity of the assay by analyzing bark beetles intercepted at quarantine stations. Our findings demonstrate that this specific molecular method allows for the rapid identificat...

Fiber optical current transformer (FOCT) can be influenced by a variety of external factors (such as ambient temperature, vibration, shock, electromagnetic interference, etc.) and internal factors (such as degradation of optoelectronic devices, increase of optical loss, etc.) in the field operation process, these factors cause the change of internal key state parameters in FOCT, thus reduced the accuracy and reliability of the product. To solve this problem, five key state parameters of FOCT, which are junction temperature of SLDs, transmitting optical power of SLD, half-wave voltage of phase modulator, working temperature of fiber sensing coil and the received optical power of photodetector, were proposed in this paper, the analysis and experiment of these parameters were given, the impact of key state parameters on FOCT accuracy is descripted quantitatively for the first time, further, the methods for monitoring and controlling each key state parameters were proposed respectively with experimental verification. The test results show that the ratio error and phase error of the FOCT product used state monitoring is small than 0.1% and 3 min respectively over a temperature range −40 °C–+70 °C The study provides a technical guidance for the key parameter design and performance optimization of FOCT products, supplied basic model and data support for the inline monitoring and early warning to FOCT operation state, it will be helpful to improve the stability and reliability of FOCT products in long-term operation.

Microring-resonator filters were fabricated based On Silicon on Insulator(SOI) nano-wire waveguide,adopting Electron-Beam photolithography(EBL) and Inductive-Coupled-Plasma(ICP) etching technology,etc.The cross-section size of the strip waveguides were(350～500 nm)×220 nm,respectively,and the bending radius of the microring was around 5 μm.The measured results show that performance of devices are much better with waveguide width 450 nm,the free spectral range(FSR) is 16.8 nm,and extinction ratio(ER) around the wavelength 1 550 nm is 22.1 dB.After thermally tuned,the tuning bandwidth reaches 4.8 nm,and the tuning efficient is 0.12 nm/℃.Meanwhile,multi-channel filters were fabricated and studied based on single-ring and double-ring.After experiments,some conclusions were drawn: crosstalk exists in the signal transmission in multi-channel filters,mainly among different transmission channels,and the crosstalk is fairly distinct when there are signals input to add ports.

Virtual assembly (VA) is a key technology for virtual manufacturing systems. So far, CAD systems are still the main modeling tools for the VA system. There isn’t a standard data exchange criterion to transfer the data directly from CAD systems to VA applications, consequently an original data decomposition and information translation method (DDITM) was timely proposed to achieve the decomposition and translation. The information of the assembly bodies in the CAD system was divided into geometry information, topology information, and assembly information, etc., which were transferred to the VA application separately. The geometry information including the surface information was translated by the data translation interface (DTI) developed, the topology information was translated by a five-hierarchy topology structure (FHTS) constructed, and the assembly information was translated with database technology. A systematic architecture was formed with the interaction between the geometry information and the topology information, and the assembly information and the topology. Finally an experimental VA system was set up to verify the DDITM, and an assembly simulation was implemented to verify the assembly information further, which proves the translated information is precise and sufficient.

An efficient fabrication scheme of buried ridge waveguide devices is demonstrated by UV-light imprinting technique using organic-in organic hybrid sol-gel Zr-doped SiO2 materials. The refractive indices of a guiding layer and a cladding layer for the buried ridge waveguide structure are 1.537 and 1.492 measured at 1550 nm, respectively. The tested results show more circular mode profiles clue to existence of the cladding layer. A buried ridge single-mode waveguide operating at 1550 nm has a low propagation loss (0.088 dB/cm) and the 1 x 2 MMI power splitter exhibits uniform outputs, with a very low splitting loss of 0.029 dB at 1549 nm.

A triplexer is fabricated based on SOI arrayed waveguide gratings (AWGs). Three wavelengths of the triplexer operate at different diffraction orders of an arrayed waveguide grating. The signals of 1490 nm and 1550 nm, which are input from central input waveguide of an AWG, are demultiplexed and the signal of 1310 nm, which is input from central output waveguide of an AWG, is uploaded. The tested results show that the downloaded and uploaded signals have flat-top response. The insertion loss is 9 dB on chip, the nonadjacent crosstalk is less than -30 dB for 1490 nm and 1301 nm, and is less than -25 dB for 1550 nm, the 3 dB bandwidth equates that of the input light source.

Silica-based 64-channel arrayed waveguide gratings (AWGs) with double functions and 0.4 nm (50 GHz) channel spacing have been designed and fabricated. On the same component, Gauss and flat-top output response spectra are obtained simultaneously. The test results show that when the insertion loss ranges from 3.5 dB to 6 dB,the crosstalk is better than -34 dB, the 1 dB bandwidth is 0.12 nm, the 3 dB bandwidth is 0,218 nm, and the polarization-dependent loss (PDL) is less than 0.5 dB for Gauss response. When the insertion loss ranges,from 5.8 dB to 7.8 dB, the crosstalk is better than -30 dB, the 1 dB bandwidth is 0.24 nm, the 3 dB bandwidth is 0.33 nm, and the PDL is less than 0.2 dB for flat-top response.

The PV inverter model and its control strategy are researched, and then analyzes the various characteristics of interconnection and integration, establishing a selection criteria for dynamic reactive power compensation equipment's capacity and form, the output characteristics and selection of operational mode is discussed, the LVRT of PV power plant under unusual conditions is researched, based on which the PV power plant's LVRT capability enhancement of dynamic reactive power compensation equipment is researched. Through simulation, Huadian Jiayuguan 10MWp PV power project meet the integration conditions, theory and simulation is accurate, this accumulate some experience for our future development of PV power plant.

An efficient real-time simulation system for 3-axis NC milling using microcomputers is described in this paper. In this system, the workpiece is represented with an extended Z-map structure and is displayed on screen using isometric projection. After the NC code file was generated and interpreted by an NC instruction translator, a material removal process was simulated just like that performed on real NC milling machine tools driven by NC instructions. The whole process is real-time displayed on the screen; meanwhile alarm messages are given to the operator when interference between milling cutter and workpiece occurs. The simulation result is displayed using a visual realism technique, from which gross programming errors can be checked with ease. The function of each module in this simulation system is discussed in detail using an example. This system simulates NC milling processes efficiently on a microcomputer platform.

A monolithic integrated variable attenuator multiplexer/demultiplexer is demonstrated. It is composed of a 16-channel 200 GHz silica-based arrayed waveguide grating and an array of Mach—Zehnder interferometer thermo-optic variable optical attenuators. The integrated device is fabricated on a quartz substrate, which eliminates the process of depositing the undercladding layer and reduces the power consumption compared with a device fabricated on a silicon substrate. The insertion loss and crosstalk of the integrated device are −5 dB and less than −22 dB, respectively. The power consumption is only 110 mW at the attenuation of 20 dB per channel.

H5 photonic crystal (PC) microcavities co-implanted with erbium (Er) and oxygen (O) ions were fabricated on silicon-on-insulator (SOI) wafers. Photoluminescence (PL) measurements were taken at room temperature and a light extraction enhancement of up to 12 was obtained at 1.54 μm, as compared to an identically implanted unpatterned SOI wafer. In addition, we also explored the adjustment of cavity modes by changing the structural parameters of the PC, and the measured results showed that the cavity-resonant peaks shifted towards shorter wavelengths as the radius of the air holes increased, which is consistent with the theoretical simulation.

Micro ring resonator (MRR) filters based on a silicon on insulator (SOI) nanowire waveguide are fabricated by electron beam photolithography (EBL) and inductive coupled plasma (ICP) etching technology. The cross-section size of the strip waveguides is 450 × 220 nm2, and the bending radius of the micro ring is around 5 μm. The test results from the tunable filter based on a single ring show that the free spectral range (FSR) is 16.8 nm and the extinction ratio (ER) around the wavelength 1550 nm is 18.1 dB. After thermal tuning, the filter's tuning bandwidth reaches 4.8 nm with a tuning efficiency of 0.12 nm/°C Meanwhile, we fabricated and studied multi-channel filters based on a single ring and a double ring. After measurement, we drew the following conclusions: during the signal transmission of multi-channel filters, crosstalk exists mainly among different transmission channels and are fairly distinct when there are signals input to add ports.

An ultra compact triplexing filter was designed based on a silicon on insulator (SOI) nanowire arrayed waveguide grating (AWG) for fiber-to-the-home FTTH. The simulation results revealed that the design performed well in the sense of having a good triplexing function. The designed SOI nanowire AWGs were fabricated using ultraviolet lithography and induced coupler plasma etching. The experimental results showed that the crosstalk was less than −15 dB, and the 3 dB-bandwidth was 11.04 nm. The peak wavelength output from ports a, c, and b were 1455, 1510 and 1300 nm, respectively, which deviated from our original expectations. The deviation of the wavelength is mainly caused by 45 nm width deviation of the arrayed waveguides during the course of the fabrication process and partly caused by material dispersion.

Virtual assembly, as a typical application of Virtual Reality (VR), provides an efficient tool to optimise assembly planning and evaluation. In this paper, a VR-based Assembly Planning and Training System (VR-APTS) is introduced. Using a Computer-Aided Design (CAD) assembly model as input, the system can output one or several good assembly sequences with the application of an intelligent bionic algorithm. Key techniques in the development of VR-APTS are discussed. A novel information decomposition and transformation method is put forward to transform data from CAD to VR, and a geometric constraint-based virtual environment is set up to support interactive assembly planning and evaluation. First, an initial optimal assembly sequence is generated by virtual disassembly and ant colony optimisation algorithm. Then, this initial sequence is evaluated by virtual assembly simulation, a more practical and optimal assembly sequence is replaned. This is an iterative process until the best assembly sequence is obtained. An application case is studied to demonstrate the basic advantages of the system for assembly planning and training.