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In order to evaluate the viability of frequency equipment in complex electromagnetic environment, the electromagnetic radiation effect evaluation model of random noise is established based on the analysis of the blocking effect mechanism of frequency equipment. Through MATLAB calculation, the corresponding relationship table between the ratio of the critical interference field strength effective value of single frequency continuous wave and sinusoidal amplitude modulation wave and the key parameters of the model is given, and the prediction method of noise electromagnetic interference of frequency equipment is proposed. Taking a Beidou navigation receiver as the test object, the accuracy of the noise electromagnetic radiation blocking effect model is verified by single frequency continuous wave, random noise and narrowband noise electromagnetic radiation blocking effect test, and the maximum error is only 1.51 dB, which indicates that the model and prediction method proposed in this article can accurately evaluate and predict the electromagnetic radiation interference of random noise.

The quantification capability of high-resolution mass spectrometry (HRMS) has received increasing interest from analysts. In this study, we present a method for analyzing 37 glucocorticoids in chicken muscle using UHPLC-Q-Orbitrap MS with parallel reaction monitoring (PRM). The analytes were extracted using acetonitrile (ACN) containing 0.1% formic acid and subjected to commercial PRiME HLB solid-phase extraction (SPE) cartridge clean-up. Under optimized conditions, the analytes were separated on an analytical column and subsequently detected using a high-resolution hybrid quadrupole/Orbitrap mass spectrometer coupled with PRM scan mode. The Q-Orbitrap with PRM exhibited remarkable sensitivity, with limits of quantification (LOQs) ranging from 0.08 μg kg−1to 7.59 μg kg−1. To validate the method, we conducted intra- and inter-day tests using a blank matrix sample at different spiking levels. The achieved results demonstrated satisfactory recovery values (74.1–97.5%) and precise results (RSDs < 15%) for all the studied analytes. In application, we found dexamethasone with 6.5 μg kg−1and fluorometholone with 3.9 μg kg−1in two chicken samples. These findings suggest that the UHPLC-Q-Orbitrap system, in conjunction with the SPE sample preparation method, has great potential as a routine quantification approach for multiple glucocorticoid residues in chicken samples.

This study investigated the occurrence of coccidiostat residues in chicken meat and conducts a probabilistic health risk assessment. A total of 277 samples were collected from various regions in southeast China, and 3 coccidiostat residues and 1 metabolite were analyzed by UHPLC-MS/MS. The spiking recoveries of instrumental analysis were ranged from 90.2% to 98.3%. The distribution showed detection frequencies for diclazuril (11.19%) and nicarbazin (9.45%), with average concentrations of 1.78 μg/kg and 1.12 μg/kg, respectively. Maximum values were 71.8 μg/kg for diclazuril, 221 μg/kg for nicarbazin, 144 μg/kg for toltrazuril, and 84.3 μg/kg for toltrazuril sulfone. No significant differences in residue concentrations were observed across different sampling years and months; however, certain months showed higher average levels, potentially linked to environmental factors influencing Eimeriaparasite life cycles. The study also revealed higher concentrations of nicarbazin in samples from farmer's markets than stores. Risk assessment based on dietary exposure indicated that estimated daily intakes of coccidiostats were significantly lower than the acceptable daily intake, which indicated no public health risk. However, the potential long-term ecological and agricultural impacts of coccidiostat residues necessitate ongoing surveillance and responsible use in poultry farming.

A method for the determination of 15 steroid hormones in farmed fish by liquid chromatography–orbital ion trap mass spectrometry has been developed and validated. The method involved sample preparation with acetonitrile extraction and clean-up, and separation in the LC using a C18column. The orbital ion trap MS was operated at a resolution of 35 000 FWHM in selected ion monitoring mode. An ion source with heated electrospray ionization was used in positive ionization mode. The samples were prepared by solid-phase extraction. The limit of quantification of steroid hormones in fish samples was 2 μg kg−1. Good linearity was observed since correlation coefficients were more than 0.99 for all compounds. Recoveries of spiked fish samples (2 μg kg−1and 20 μg kg−1) ranged from 80.8% to 112.6% with relative deviations less than 15%. The method was successfully applied to detect steroid hormones in real farmed fish samples at the μg kg−1level.

As nanoscale reinforcements, the graphene and graphene oxide nanoplates exhibit distinct mechanical and physical properties. The determination of the effective elasto-plastic behavior of nanoplate/ceramic nanocomposites and the different filling effects of graphene and graphene oxide nanoplate deserve systematic investigation. In this work, we intend to uncover how the graphene and graphene oxide nanoplates affect the macroscopic elasto-plastic characteristics of ceramic matrix nanocomposites and what differences in both nanoplates enhancements. A homogenization model is first utilized for determining the effective elastic parameters of nanoplate/ceramic composite with a perfect interface. Then the slightly weakened interface model is introduced to characterize the sliding effects of nanoplates in a ceramic matrix, and the effective elastic parameters of such nanoplates filled composites incorporating the interfacial sliding effects are explicitly formulated. Furthermore, a nonlinear micromechanics model is developed to investigate the macroscopic elastoplasticity and the yield behavior of graphene and graphene oxide nanoplate-filled ceramic nanocomposites subjected to confining pressure. The filling effects of the two kinds of nanoplates on the mechanical properties of such nanocomposite are comparatively examined. The calculated results demonstrate that types of the nanoplates and the imperfect interfaces between nanoplates and ceramic matrix have significant influences on the effective elasto-plastic behaviors of the nanoplate composites.

Simulation experiments were performed to investigate the characteristics of information extraction in multiple-image radiography (MIR) based on geometrical optics approximation. Different Poisson noise levels were added to the simulation, and the results show that Poisson noise deteriorates the extraction results, with the degree of refraction > USAXS > absorption. The effects of Poisson noise are negligible when the detector’s photon counts are about 1000 ph/pixel. A wider sampling range allows more accurate extraction results, but a narrower sampling range has a better signal-to-noise ratio for high Poisson noise levels, e.g., PN(10). The sampling interval can be suitably increased with a minor impact on the extraction results for low Poisson noise levels (PN(10000)). The extraction results are incomplete because a portion of the sample-rocking curve is beyond the sampling range. This induces artifacts in the images, especially for strong refraction and USAXS signals. The artifacts are not obvious when the refraction angle and standard deviation of the USAXS are smaller than the sampling range by an order of magnitude. In general, the absorption barely affects the extraction results. However, additional Poisson noise will be generated when the sample is made of high-Zelements or has a large size due to the strong absorption. Here, the extraction results will deteriorate, and additional exposure time is required. This simulation provides important details on practical applications of MIR, with improvements in information extraction.

Conventional X-ray tube-based cone-beam computed tomography (CX-CBCT) systems have great potential in industrial applications. Such systems can rapidly obtain a three-dimensional (3D) image of an object. Conventional X-ray tubes fulfill the requirements for industrial applications, because of their high tube voltage and power. Continuous improvements have been made to CX-CBCT systems, such as imaging time shortening, acquisition strategy optimization, and imaging software development, etc. In this study, a CX-CBCT system is developed. Additionally, some improvements to the CX-CBCT system are proposed based on the hardware conditions of the X-ray tube and detector. A near-detector (ND) geometry condition is employed to obtain a sharper image and larger detection area. An improved acquisition strategy is proposed to simplify operations and reduce total imaging time. In the ND geometry condition, a simplified method called FBP slice stacking (SS-FBP) is proposed, which can be applied to 3D image reconstruction. SS-FBP is time-saving relative to traditional methods. Furthermore, imaging software for the CX-CBCT system is developed in the MATLAB environment. Several imaging experiments were performed. The results suggest that the CX-CBCT system works properly, and that the above improvements are feasible and practical.

A method has been developed for quantitative analysis of vitamin K1in vegetables and fruits by LC-MS/MS. The method employed a neutral aluminum oxide column for sample clean-up. Considering matrix effects, an isotope standard (vitamin K1-D7) was added to correct matrix interferences, as well as pretreatment losses and instrument variability. Spiked recoveries in model matrices were 88.3–90.1% for spinach, 84–110% for lotus roots, and 108–115.6% for grapes. The relative standard deviations (RSDs) were 1.0–7.1% for intra-day and 2.8–8.8% for inter-day. The limit of detection (LOD) and limit of quantification (LOQ) were 0.001 mg kg−1and 0.004 mg kg−1, respectively. The method is sensitive and reliable, which is successfully applied to different vegetable and fruit matrices. Vitamin K1in fruit samples ranged from 0.008 mg kg−1to 0.401 mg kg−1, and in vegetable samples from 0.0032 mg kg−1to 3.973 mg kg−1.

Currently the settlement and deformation of factory building structure is monitored using total stations and other more conventional measuring instruments, it is difficult to reflect the health of the structure timely and accurately. In order to change the situation, we establish a set of system for real-time monitoring of deformation and safety warning. The system is formed of sensing layer, transport layer and application layer. Sensing layer is composed of static force level and biaxial inclinometer. The system can be used in dynamic real-time factory structure safety monitoring, also applied to other similar structural monitoring. This paper will study the system components and principle, early warning systems grading, calculation of real-time deformation of roof frame, laboratory test scheme and verification. Experiments showed that the system is suitable for the actual factory structure monitoring, while the choice of static force level and biaxial inclinometer of precision to meet the requirements.

Reasonable traffic system design and management has vital significance to ensure the safe and smooth traffic operation of urban complex and urban traffic system. Based on the characteristics of urban complex, this paper analyzed intelligent traffic system design of underground garage of urban complex. The paper proposed a reasonable traffic system design method to ensure the smoothness and safety of urban complex traffic. Meanwhile the full-video intelligent parking garage management system with advantages of safe and advanced technology was adopted to realize user-friendly, intelligent and automation traffic management. Through intelligent traffic system design research of urban complex underground garage proposed in this paper, the operation efficiency of the underground garage was improved and the parking function and evacuation capacity of underground garage was brought into full play.

A real-time information management system for building construction (RIMBC), which is supported by the network technology, geographical information technology and office automation technology, is designed. This management system integrated the design data, survey data and test data can be used for the real-time search, management and update of design, survey documents by technical sections of functional departments in the field of construction engineering. This study gives a comprehensive and detailed depiction for the logical structure, entity structure, system process planning, database structure, subsystem structure and personnel training of RIMBC.

According to the correlation characteristics of risk factors in highway tunnel engineering construction, based on the risk identification and analysis of accidents, the interactive correlations among these risk factors are analyzed by Delphi Method. This paper adopts the decision making trial and evaluation laboratory (DEMATEL) method to analyze the risk of tunnel engineering construction. Then, a comprehensive influencing coefficient of various risk factors is calculated by a comprehensive influencing matrix, the reason-result chart for these risk factors is made, and the key risk factor influencing the tunnel engineering construction is obtained. The result shows that DEMATEL method is effective for the risk analysis of tunnel engineering construction via the case study of Wulong Tunnel construction in China.

Taking a project of Hangzhou as the example, a new management method named oppression construction method was proposed in soft soil of deep foundation pit engineering management. This method was based on the foundation pit excavation by layer and section. Through timely supporting of foundation pit and construction information management, the foundation pit supporting exposure time and exposed to the breadth and height was decreased. Thus the excavation process to the periphery environment influence was effectively reduced. It provided beneficial reference for the future of deep foundation pit engineering construction management.

By using imbalance thrust force method, the slope stability factor based on three-dimensional slide block was deduced. According to the borehole data of highway, the TIN data layer and grid data layer for three-dimensional slope stability analysis were carried out by use of ArcMap. The value of each gird cell of different layers are picked up as slide block, it makes convenience in the slope stability analysis. Considering the property of bedding landslide, the three-dimensional slope stability analysis program based on VBA of ArcGIS is put forward in this paper. Taking one of the large rocky landslides as an example, the results of the three-dimensional stability analysis with slope before and after excavation, as well as the different water level conditions are compared. Furthermore, the directive significance of the three-dimensional method in landslide harness engineering was discussed.

In this paper, according to the characteristics of near-fault earthquakes, combined with the strong ground motion attenuation law in China, the nonstationary power spectrum of bidirectional ground motion input is obtained through random vibration analysis. By introducing the pseudo excitation algorithm, the evolutionary power spectral density (PSD) of acceleration at the engineering bedrock is handled as the nonstationary pseudo input, and the Hardin-Drnevich hyperbolic model is utilized to take into account the nonlinearity of soil layer. On this basis, finite element method in the time domain and frequency domain are used for seismic response analysis of soil profile. Values including various time-varying power spectral density of the dynamic response, time varying RMS and time-dependent reliability at different threshold can be obtained by calculating, which provides a basis for the analysis of the foundation dynamic reliability assessment.

This paper describes both the development and the mechanism of carbon fiber-reinforced polymer (CFRP), through Abaqus finite element software simulations to complete before and after joining the CFRP plate bending performance in two cases of RC beams, as well as in the loads of the load-displacement relations and stress-strain relationship, through the control of different pre-split value of working conditions, and the comparison of the data of the actual concrete beam experimental results prove that the Abaqus finite element of the feasibility and effectiveness in CFRP research, provide a reference for the actual project.

Engineering bridge construction is a very complicated system work. The potential risk would occur frequently in the process from construction preparation to completion. The bridgework has fundamental features in huge investment, complex technology, broad engineering, long project life cycle and big impact if an accident happened. Compared to other highway construction process,there are more risks in the process of the bridgework. According to the method of steel tube concrete composite column bridge pier construction on bridge engineering, this thesis identifies the bigger risk factors in the procedure with the analytic hierarchy process. Combined with the technology of the MIDAS/CIVIL and imitating upper structure construction of actual construction process, it quantificationally analyses the construction risk. This could be for the reference to risk analysis on bridge project construction.

The subway in a city of China is located in an alluvial plain. There are many universities and residential distribution districts. The vibration influence in corresponding zone of the subway should be made evaluation before construction. Based on the parameters of dynamic soil test, the one-dimensional elastic column is used to simulate for computation of the vertical vibration of the subway site. Considered the nonlinear and pseudo-damping of soil, the ground accelerations calculated are shown in this paper. Finally, according to the results of computation of the vibration response and comparing with the interrelated code authors present the relevant conclusion for environmental assessment for moving vibration of subway in this city.

A new technology of initiative protection for lightning stroke based on electric field cancellation theory is presented in this paper. The real time lightning detection system and the active protection equipment are adopted. By using this new method, the protection technology of direct lightning stroke can be changed from little current triggering to weakening the electric field near the weapon system, and the down leader of charged thundercloud can be repulsed by the artificial opposed field. So the lightning discharge condition in this protection region can be destructed, and the lightning hazard to the protected equipment is eliminated radically. It effectively reduces the electromagnetic radiation, ground potential reaction and step voltage caused by the high current along conducting wire in the conventional lightning rod protection technology.

Abstract In pursuit of a better understanding of the relationship between wet sliding friction and bulk viscoelastic properties of elastomer compounds, especially the contribution from different reinforcing fillers, the linear thermorheological behavior, the nonlinear dynamic moduli under shear deformation (for strain up to about 140%), and the wet sliding friction have been characterized in detail for crosslinked compounds of low-cis polybutadiene filled with different reinforcing fillers including carbon black, graphitized carbon black, and precipitated silica. We examine the scenario of possible extra energy dissipation via higher harmonic excitation in rubber compounds coupled with dynamic deformation consisting of components at many frequencies during sliding of rubber on a rough surface. While no straightforward explanation is identified relating the observed difference in wet sliding friction arising from different fillers to the bulk viscoelastic properties, some unexpected viscoelastic features arising from the compounds are observed.

For properly chosen elastomer compounds, thermorheological characterization is combined with an examination of the variation of the wet sliding friction with temperature. A conceptual argument leads to the assumption that the wet sliding friction should maximize at the energy dissipation peak associated with the dynamic softening transition at a characteristic frequency determined by the sliding speed and the effective smallest surface asperity scale. The dynamic softening transition is characterized with the peak in tan δ/G'ⁿ, where tan δ is the loss tangent, G' is the elastic modulus, and n is a constant between 0 and 1. The William–Landel–Ferry transform is uncritically applied for extrapolating the position of the peak in tan δ/G'ⁿ at high frequencies. Even based on the criterion of tan δ, the results obtained on a concrete surface indicate that the effective smallest asperity scale is of order of 100 μm. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2467–2478, 2004

The wet-sliding friction characteristics of rubber compounds made of high cis-polybutadiene were examined with a British pendulum skid tester at room temperature. Three series of compounds were prepared—unfilled or filled with carbon black at two different levels. The bulk viscoelastic properties as characterized by the bulk glass-transition temperature for the compounds were systematically adjusted by changing the crosslinking density via sulfur vulcanization. In fact, the dynamic mechanical glass-transition temperature for the compounds ranges between approximately −100 and 20 °C. Consequently, the wet-sliding friction of these rubber compounds is dramatically affected. With increasing compound glass-transition temperature, the wet-sliding friction increases to a maximum and then decreases. However, the rate of increase or decrease varies with the amount of filler in the compounds. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 757–771, 2003

The characteristics of electrorheological (ER) responses in an emulsion system have been examined for the first time. The emulsion system consists of a chlorinated paraffin oil and a silicone oil; these two liquids have similar dielectric constants, but the former liquid is 1000 times more conductive than the latter liquid. The mismatch in electric properties between the dispersed phase and the dispersing medium can be reversed in an emulsion by inverting the phase distribution. Transient ER responses in the emulsion system have been studied over a range of shear rates following step changes (on/off) of an external dc electric field. The relative response strength characterizing the ER effect increases with the field strength and with the volume fraction of silicone oil, but decreases with increasing shear rate imposed. The paraffin oil-in-silicone oil emulsion exhibits a response much stronger than that observed in the phase-reversed silicone oil-in-paraffin oil emulsion. No negative ER response is detected in the silicone oil-in-paraffin oil emulsion. With an optical microscope, very different microscopic response characteristics are observed for the phase-reversed emulsions under static conditions, and this can be explained according to the leaky dielectric liquid model of Taylor.

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Homozygous familial hypercholesterolaemia is a rare life-threatening disease characterised by markedly elevated LDL cholesterol concentrations and accelerated atherosclerosis. Few studies have focused specifically on this group of patients, especially in China. We set out to investigate the phenotypical characteristics and the genotype–phenotype correlations of homozygous familial hypercholesterolaemia in China.