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In this article, circular waveguide TE11 mode excitations characterized by high mechanical strength and small radial length, and features essential for air drilling downhole applications with hostile working condition, are proposed for the first time. The excitation employing a single rectangular loop is initially proposed. To analyze the working principle, the distribution of the electromagnetic field is studied and the corresponding equivalent circuit model is established. Furthermore, the variation of S-parameters with respect to the geometrical dimensions of the loop is summarized to assist in the design process. To verify the mechanical strength, the stresses on the loop under a high-speed airstream, random vibration, and impact by a metal block are studied through simulation. In addition, another excitation that employs a symmetrical rectangular loop is proposed. Comparatively, this structure offers improved performance on mechanical strength and transmission efficiency, however, with narrower bandwidth. The two excitations are optimized for the ISM band, taking into account both mechanical strength and electric performance comprehensively. The prototypes have been fabricated and measured. The measurements are in agreement with the simulations, demonstrating the practicality of the proposed excitations.

The safety and efficiency of drilling engineering are greatly impeded by destructive vibrations of drill string in air drilling, such as stick-slip, bit-bounce and their coupled vibrations. To avoid or suppress these vibrations improving the stability of drilling operations, revealing the occurrence mechanisms of abovementioned harmful vibrations are indispensable by investigating dynamics characteristics of drill string system. In this paper, an axial-torsional coupled dynamics model that can capture the motion behaviors of bottom hole assembly (BHA) is established adopting the lumped parameter method. Subsequently, a rate of penetration (ROP) model appropriating for air drilling is obtained firstly by linear fitting means. Meanwhile, a novel discontinuous support model is established to describe the bit-formation interactions. Then, BHA dynamics are discussed using numerical simulations under different vibration scenarios: normal operation; stick-slip; bit-bounce; bit-bounce and stick-slip combination. Subsequently, in two drilling modes: the continuous and intermittent drilling, the vibration mitigation strategies and dynamics sensibility study of BHA are carried out based on the parametric analysis. The results show that increasing torsional stiffness of drill-pipes, appropriately adjusting rotation speed of top driven system and dynamic weight on bit (WOB) are deemed as an effective strategy suppressing or eliminating stick-slip and bit-bounce vibrations of BHA. Suggest that the rotation speed of top driven system and dynamic WOB are 5 rad/s and 3.5 kN, respectively. Finally, the constructed probability maps allow to driller to choose reasonable mechanical parameters, thereby realizing smooth drilling operation in the air drilling.

In the petroleum drilling industry, the smoothly functioning vibrating screens play a critical role in control of solid–liquid and recovery of drilling fluid. Due to the mechanical coupling, the surface of the vibrating screen tends to produce unbalanced swings, which makes the motion trajectory inconsistent with the situation at the center of mass, thus affecting the screening efficiency. In order to reveal the reasons for the unbalanced swings of the vibration system and the principle of the trajectory equilibrium characteristics (TECs), the self-synchronization characteristics of two eccentric rotors (ERs) driven by elliptical trajectory dual-motor vibrating system are investigated. The kinematic differential equations of the vibration system are determined by the Lagrange method. Then, the conditions of synchronization and stability of the vibration system are determined, respectively, by the small parameter average approach and the Routh–Hurwitz criterion. Subsequently, the impact of the structural parameters about the synchronization stability is examined by numerical discussion. Furthermore, the effectiveness of the theoretical research is confirmed by comparing the results between dynamics simulation and experiment under different structural parameters. Finally, by focusing on the analysis of the trajectories of different measuring points in the experiment, the relevant conclusions on how to reduce the unbalanced swings and maintain the TECs of the vibration system are obtained. The elliptical trajectory form of the system is most affected by the motor installation angle and installation distance in vibrating body, while less affected by the installation deflection angle and installation offset distance between the motors. In addition, the elliptical trajectories of the oscillating body are in a good equilibrium when reducing the swing angle of the vibration system, in other words, increasing the installation angle and reducing the installation distance of the exciters in the stable state.

Purpose: Addressing the current issue of over-simplification in the dynamics model of the drillstring system. The purpose of this paper is to study the dynamic response characteristics of drillstring, borehole wall, bit and rock coupling system under different drilling parameters. Methods: In this work, a nonlinear coupling finite element mathematical model of the entire well section is established, incorporating the drillstring, cone bit, rock, and borehole wall during the air drilling process. A new boundary condition of hook load at the top and weight on bit at the bottom is adopted. Additionally, the discontinuous support model is introduced to establish the contact relationship between the tricone bit and the formation. To minimize low-frequency dissipation, we use NOCH-α method to solve dynamic equations of drillstring system. Results: The analysis results show that the response of drill string in horizontal section is the most sensitive when drilling parameters change. To a certain extent, with the decrease of weight on bit(WOB) and rotational speed, the dynamic buckling amplitude of the drillstring decreases, the contact force and frequency between drillstring and borehole wall are reduced, the bit-bounce and stick–slip motion disappear gradually, and the vibration frequency and amplitude of the drilling system are lessened. Conclusion: The results are consistent with the actual drilling data in the field. The coupling model of drill string system can provide theoretical reference for the optimization of drilling parameters and vibration control of drill string system.

Protein function annotation has been one of the longstanding issues in biological sciences, and various computational methods have been developed. However, the existing methods suffer from a serious long-tail problem, with a large number of GO families containing few annotated proteins. Herein, an innovative strategy named AnnoPRO was therefore constructed by enabling sequence-based multi-scale protein representation, dual-path protein encoding using pre-training, and function annotation by long short-term memory-based decoding. A variety of case studies based on different benchmarks were conducted, which confirmed the superior performance of AnnoPRO among available methods. Source code and models have been made freely available at: https://github.com/idrblab/AnnoPROand https://zenodo.org/records/10012272

The purpose of the present work is to investigate the corrosion sensitivity of pipelines of oil and gas wells under complex environmental conditions (i.e., the primary and secondary relationship of the influence of different environmental factors on pipeline corrosion). The orthogonal experiment is introduced to design the experimental scheme. The weight loss method is employed to analyze the average corrosion rate of N80 steel under different environmental conditions. And then the scanning electron microscope is used to explore the surface and cross-section corrosion morphology of the corrosion products. Besides, the components of corrosion products are obtained by the energy spectrum analysis. The research results indicate that H2S partial pressure is the most sensitive factor to the corrosion of N80 pipeline and the influence of CO2partial pressure on corrosion of N80 pipeline is weaker than Cl−concentration and temperature in the South China Sea. The study can help the oil drilling engineering search for direct and effective corrosion inhibitors under complex environmental conditions.

The stability and synchronization characteristics of vibrating system cannot be ignored to get a better form of motion. In the present work the stability and synchronous characteristics of dual-rotors vibrating system considering the material effects are studied. Firstly, the equations of motion about the vibrating system are solved using Lagrange theory, Newton’s laws of motion and momentum theorem. Then the stability of the system is discussed based on the theory of nonlinear dynamics and Poincare theory using numerical simulation. Further the effect rules of material with different mass on phase difference of dual-rotors are revealed. Finally, the reliability and correctness of theoretical analysis and numerical simulation are verified approximately based on a prototype experiment in which the amplitude errors of vertical displacement about test point P1 and P2 are within the allowable limits of experimental error. It can be concluded that the stability of the system and the synchronous characteristics of dual-rotors decline with the mass ratio of material to vibrating body increasing.

In a vibrating screen machinery, two eccentric rotors (ERs) are actuated by swung and fixed motors. When the working efficiency of vibrating screens is the highest, the motion trajectory of the vibrating body is an ellipse. However, to implement elliptical trajectory, the ideal synchronization between the two ERs must be needed. Hence, the self-synchronous theory and synchronous control method for the vibrating screen machinery are explored. First, the mathematic model of the vibration system is deduced based on Lagrange equation; then, the synchronous condition and stability criterion are inferred from averaged small parameter method. In addition, the synchronization controllers, related to speed and phase of the ERs, are designed by with sliding mode control (SMC), and the master–slave control strategy is applied to design the control structure. Meanwhile, the stability performance of the controllers is demonstrated by Lyapunov theory and Hurwitz condition. Finally, computer simulations are implemented to validate the theoretical reliability of self-synchronization and synchronous control. The simulation results show that the system can be self-synchronized, but the ideal synchronization is difficult to achieve when the two ERs are self-synchronously rotated, which leads to non-ideal dynamic characteristics; nevertheless, the ideal synchronization can be implemented by the proposed synchronous control method.

The heterogeneity and complexity of glycosylation hinder the depth of site-specific glycoproteomics analysis. High-field asymmetric-waveform ion-mobility spectrometry (FAIMS) has been shown to improve the scope of bottom-up proteomics. The benefits of FAIMS for quantitative N-glycoproteomics have not been investigated yet. In this work, we optimized FAIMS settings for N-glycopeptide identification, with or without the tandem mass tag (TMT) label. The optimized FAIMS approach significantly increased the identification of site-specific N-glycopeptides derived from the purified immunoglobulin M (IgM) protein or human lymphoma cells. We explored in detail the changes in FAIMS mobility caused by N-glycopeptides with different characteristics, including TMT labeling, charge state, glycan type, peptide sequence, glycan size, and precursor m/z. Importantly, FAIMS also improved multiplexed N-glycopeptide quantification, both with the standard MS2 acquisition method and with our recently developed Glyco-SPS-MS3 method. The combination of FAIMS and Glyco-SPS-MS3 methods provided the highest quantitative accuracy and precision. Our results demonstrate the advantages of FAIMS for improved mass spectrometry-based qualitative and quantitative N-glycoproteomics.

Disulfide bonds between cysteine residues are important post-translational modifications in proteins that have critical roles for protein structure and stability, as redox-active catalytic groups in enzymes or allosteric redox switches that govern protein function1–4. In addition to forming disulfide bridges, cysteine residues are susceptible to oxidation by reactive oxygen species, and are thus central not only to the scavenging of these but also to cellular signalling and communication in biological as well as pathological contexts5,6. Oxidized cysteine species are highly reactive and may form covalent conjugates with, for example, tyrosines in the active sites of some redox enzymes7,8. However, to our knowledge, regulatory switches with covalent crosslinks other than disulfides have not previously been demonstrated. Here we report the discovery of a covalent crosslink between a cysteine and a lysine residue with a NOS bridge that serves as an allosteric redox switch in the transaldolase enzyme of Neisseria gonorrhoeae, the pathogen that causes gonorrhoea. X-ray structure analysis of the protein in the oxidized and reduced state reveals a loaded-spring mechanism that involves a structural relaxation upon redox activation, which is propagated from the allosteric redox switch at the protein surface to the active site in the protein interior. This relaxation leads to a reconfiguration of key catalytic residues and elicits an increase in enzymatic activity of several orders of magnitude. The redox switch is highly conserved in related transaldolases from other members of the Neisseriaceae; for example, it is present in the transaldolase of Neisseria meningitides(a pathogen that is the primary cause of meningitis and septicaemia in children). We surveyed the Protein Data Bank and found that the NOS bridge exists in diverse protein families across all domains of life (including Homo sapiens) and that it is often located at catalytic or regulatory hotspots. Our findings will inform strategies for the design of proteins and peptides, as well as the development of new classes of drugs and antibodies that target the lysine–cysteine redox switch9,10.

Background: Traditional vibrating system has the characteristics of poor isolation ability and easy to plug the screen. Purpose: To enhance vibration isolation ability and probability of screen plugging during the operation of vibrating screens, an anti-resonance system with dual-motor and double-frequency actuation is proposed. Method: For mastering the dynamic characteristics of the system, the self-synchronization mechanism and stability of the eccentric rotors bonded in the induction motor is explored. First, the dynamic equation of the system is established using Lagrange method. Subsequently, the synchronization criterion between the eccentric rotors is studied by small parameter method. In light of Hamilton principle, the stability of the synchronous states of the rotors is determined. Besides, the influence of the structural parameters on vibration isolation ability and synchronization characteristics is discussed by numerical computation. Finally, according to Runge-Kutta principle, some simulation results are obtained to verify the validity of the self-synchronization and vibration isolation in this paper. Results and conclusions: The results show that the synchronous state of the eccentric rotors is mainly effected by installation angle of the motors; the ability of the vibration isolation is mostly determined by spring stiffness and rotor mass. The present findings should give theoretical direction to design the anti-resonance system with double-frequency actuation.

With the rapid development of petroleum exploitation industry, vibrating screen actuated with a single frequency is unsuitable to separate cuttings from drilling fluid, since it usually results in screen blocking. Hence, for solving the above-mentioned problem, tri-motor excitation with double-frequency in far resonance system is introduced. This paper aims to explore the self-synchronization mechanism of the proposed system. First, dynamic equation is established according to physical model of the system. Then, displacement response of the system in steady state is obtained with dynamic formulas. Subsequently, synchronous condition among the three exciters is determined by small parameters method, and criterion of synchronous stability among the three exciters is derived by Poincare-Lyapunov method. Finally, in light of the differential motion equation, Runge-Kutta principle is assigned to validate the reliability of self-synchronous theory and the stability of the double-frequency system. The results indicate that electromagnetic torques of low-frequency motors are dynamically antisymmetric in synchronous operation, and synchronous ability of the system is determined by the mass ratio among the rotors. In addition, stable phase difference among the rotors is significantly influenced by the structural parameters of the system. And this study will be helpful for the improvement of separation technology.

The unreasonable dynamic characteristics results in decrease of screening efficiency of the vibrating screen. However, the synchronous behavior of motors is key factor to determine dynamic characteristics of the screens. In this paper, two unbalanced rotors actuated with motors in a three-dimensional space are proposed. To understand the synchronous mechanism, the dynamic equation of the system is firstly confirmed based on Lagrangian formulation; meanwhile, synchronization condition of the system is calculated with average and small parameter method; then, synchronization stability of the system is explored by Lyapunov method; finally, some numerical simulations are given to validate the theoretical computations. It is found that, to implement the stable synchronous rotation between the rotors, the values of the parameter in this system must be satisfied by synchronous condition and synchronous stability; the synchronous state is determined by the rotation direction, the damping ratio, the frequency ratio, and the motor position; the system is a planar motion when the identical mass rotors oppositely actuated, but the system is a spatial motion in the other cases.

Protein N-glycosylation is ubiquitous in the brain and is closely related to cognition and memory. Alzheimer’s disease (AD) is a multifactorial disorder that lacks a clear pathogenesis and treatment. Aberrant N-glycosylation has been suggested to be involved in AD pathology. However, the systematic variations in protein N-glycosylation and their roles in AD have not been thoroughly investigated due to technical challenges. Here, we applied multilayered N-glycoproteomics to quantify the global protein expression levels, N-glycosylation sites, N-glycans, and site-specific N-glycopeptides in AD (APP/PS1 transgenic) and wild-type mouse brains. The N-glycoproteomic landscape exhibited highly complex site-specific heterogeneity in AD mouse brains. The generally dysregulated N-glycosylation in AD, which involved proteins such as glutamate receptors as well as fucosylated and oligomannose glycans, were explored by quantitative analyses. Furthermore, functional studies revealed the crucial effects of N-glycosylation on proteins and neurons. Our work provides a systematic multilayered N-glycoproteomic strategy for AD and can be applied to diverse biological systems.

Highly polarizable mixed-anion structural building units (SBUs) have been demonstrated as promising candidates for high-performing optical crystals. In this work, two new mixed-anion SBUs of [GeOSe3] and [GeO3S] are first designed through partial isovalent substitution of chalcogen atoms by O atoms in the classical [GeQ4] (Q = S, Se) tetrahedra. On the basis of these SBUs, two new quaternary oxychalcogenides, Sr3Ge2O4Se3and SrGe2O3S2, are successfully synthesized. Sr3Ge2O4Se3crystallizes in the noncentrosymmetric space group R3mand possesses unique zero-dimensional [Ge2O4Se3]6–units consisting of highly distorted [GeOSe3] tetrahedra and [GeO4] tetrahedra through a shared O atom. It displays intriguing potential as an infrared nonlinear optical material with a wide band gap (2.96 eV) and moderate second harmonic generation intensity (0.8 × AgGaS2). SrGe2O3S2belongs to the centrosymmetric space group P21/cand features 2∞[Ge2O3S2]2–layers formed by the corner-shared [GeO3S] tetrahedra. Moreover, the large birefringence of SrGe2O3S2(calculated Δn= 0.22–0.17 from 0.4 to 4.0 μm) gives it a potential as a birefringent material. Theoretical calculations revealed the crucial effects of mixed-anion [GeOSe3] and [GeO3S] units on the moderate second harmonic generation response and large birefringence. The discovery of new mixed-anion SBUs of [GeOSe3] and [GeO3S] will guide the exploration of new functional oxychalcogenides.

Reliable and efficient computation method is a pursuing goal to master the dynamic characteristics in complex dynamics system. Reliability and efficiency of the numerical computations for inertial coupling systems are compared with Runge–Kutta method and a new piecewise-Laplace (PL) method. The undamped vibration, damped vibration, and external excitations of the systems are investigated and calculated through the two numerical algorithms. Meanwhile, semi-analytical solutions of the proposed systems are solved with the PL method. For the comparison of reliability and efficiency of the methods and comprehension of the dynamic characteristics of the inertial coupling system, numerical computations are implemented in this paper. In addition, based on the same computational conditions, the solving time of the numerical calculations is quantitatively compared with two numerical methods. It is indicated that the PL method is more efficient and accurate for solving the problem of dynamics system, because the calculated results implemented by the PL method are continuous everywhere in whole time-history. If a given accuracy of the calculated results is desired, the PL method may need shorter time to compute for solving the dynamic equation than the RK method.

In this paper, a novel design for vibrating screens, called the triple-rotor-pendula system, is presented in a dual-super-far resonance system, which makes it possible to produce wanted vibrations with self-adjustable of the synchronization state between unbalanced rotors. To grasp the synchronization characteristics of the system, the dynamics equation of the triple-rotor-pendula system is primarily derived by adopting Lagrange’s equations. Next, the displacement responses of the system in steady state are obtained by Laplace’s transform method. Meanwhile, considering the average method with revised small parameter, the synchronization implement of the system is ascertained on condition that the absolute values of residual electromagnetism torques between two arbitrary motors are less than or equal to their load torque differences. Then, according to Routh–Hurwitz theorem and generalized Lyapunov equation, the criterion of synchronization stability of the system is obtained. Finally, the simulation computations confirm the results of analytical investigations, which show that the theoretical analysis for the synchronization behavior of the triple-rotor-pendula system is feasible. It can be known that the synchronization state of the system is influenced by mass ratio coefficients, structure parameters, rotating directions, and frequency ratios.

The present research works focuses on the control synchronization of anti-resonance vibration system (ARVS) with two eccentric rotors driven by the motors. The small parameters average method and Hamilton’s criterion are employed to analyze the self-synchronous theory of the proposed system from the views of mechanics and mathematics. The research results show that the zero-phase synchronization between two motors is difficult to carry out owing to its own weak coupling property; the ideal dynamic characteristics of the ARVS are easily destroyed by the material quality fluctuation. Therefore, the controllers of the angular speed and phase angle are designed by using the sliding mode control (SMC) algorithm with master-slave control structure. And then Lyapunov theory is used to prove the stability of the controllers. Moreover, some simulation results are given to explore the feasibility and validity of the proposed controllers. The results indicate that the zero-phase synchronization between two motors can be performed by using the proposed control strategy; meanwhile, the ideal dynamic characteristics of the ARVS can be maintained by the proposed controllers with the material quality fluctuation; additionally, a strong robustness of the control system is carried out to reject the structural parametric interferences to the dynamic characteristics. The results can provide a control method for the engineering design of the anti-resonance vibration machine and help anti-resonance vibration machine adapt to more complex working environment.

Vibrating screen is the pivotal equipment of solid control in drilling mud purification system. With the continuous upgrading of rapid drilling technology, the conventional single-body vibrating screen with the same-frequency excitation is difficult to satisfy the needs of current drilling operations. Therefore, a newly dual-body vibration absorption system model with double-frequency excitation is proposed to improve the mechanical performance of screening equipment. To grasp the dynamic characteristics of the vibration system, the synchronization mechanism and stability criterion are theoretically studied by modified small parameter average method and Poincare-Lyapunov method. Meanwhile, the vibration absorption ability, coupling torque and synchronization state of the system are numerically discussed. Lastly, the electromechanical coupling model of system is established by Runge-Kutta method to verify the reliability of theoretical analysis and numerical calculation. According to the results of research, the synchronous characteristics are mainly determined by the installation position of motors and the mass ratio of eccentric rotors. Besides, the synchronization ability between identical-frequency motors is stronger than different frequency motors. The present work can provide theoretical direction for designing of new screening equipment.

Cuttings accumulation in horizontal wells has become an important engineering problem. In this research, the influence of normal drill pipe and cuttings removal device on debris migration behavior are studied by using the CFD-DEM (Computational Fluid Dynamics and Discrete Element Method) coupling approach. The efficiency of cuttings removal is evaluated by the cuttings concentration and cuttings removal time. In addition, the experiment is employed to study the cuttings migration law under different rotational speed of drill pipe, fluid inlet velocities and drill string assembly. According to the numerical and experimental results, cuttings concentration and removal time are obviously decreased by improving inlet fluid velocity and drill pipe rotating speed. The cuttings removal time with cuttings removal device is decreased in range of 32.9%–71.8% compared with the normal drill pipe. The reliability of the designed device is validated by results, which provides guidance for cuttings removal in horizontal wells.

In this paper, a nonlinear mathematics model for axial-torsional-lateral dynamics of drillstring system equipped with a PDC bit in curved wells is established and analyzed. In the proposed model, using the finite element method, the drillstring structure is spatially discretized by Euler-Bernoulli beam elements with twelve degrees of freedom. Based on rock surface morphology of bit-rock interaction, a more realistic cutting and friction model with state-dependent delay effects is introduced to represent the bit-rock interaction. Meanwhile, a new top boundary condition is proposed to simulate the desired weight on bit (WOB). The nonlinear dynamic model is discretized in time-domain employing the generalize-αmethod, and the modified Newton iteration method is employed to calculate displacement response at the while-time step. Finally, the parametric analysis is carried out for discussing the influences of weight on bit and rotating speed on the nonlinear vibration of the drillstring system, respectively.

The problem is motivated by observations of a rotor-pendula system, which derived from a new shale shaker. To grasp the dynamic characteristics of the shale shaker, the key research is exploring the synchronous mechanism for the system, since synchronous state between rotors is closely related to the dynamic characteristics of the system. In this paper, the dynamic equation of the rotor-pendula system is firstly derived by applying Lagrange’s equations. Through Laplace’s transformation method, the approximate responses of the system in synchronous state are obtained, which is determined coupling coefficients and synchronous state of the system. Then, the synchronous balance equation and the stability criterion of the system are obtained with Poincaré method on which stable phase difference and synchronous behavior can be ascertained. To verify the correctness of the theoretical analysis, numerical simulations are implemented by Runge–Kutta method, and it is shown that the synchronous behavior is determined by the geometry parameters, coupling coefficients, and rotor rotation direction.

Considering the prevention and management of the major emergencies in China and the increasingly severe environmental security situations, a visualization emergency solution, based on a mobile mapping system is proposed. This paper studies the key technologies of a mobile mapping system in emergency management. It considers the design of a total factor and full-texture real map, which is measurable and can be marked through the mobile mapping technology. It also proposes the application of a real map in emergency cases, which has large practical significance.

Seed orchards of Chinese pine, Pinus tabuliformis, are in a transition period from first generation to advanced generation. During this crucial period, evaluation of seed production in seed orchards is essential. Female strobili production is an important factor in seed production. This study examined the variation and stability in female strobili production in a first-generation clonal seed orchard of Chinese pine in years 9, 10, 13, 14, 20 and 21 after grafting in 1974. The results showed significant variation in female strobili production among clones, years, and interactions between clones and years. Correlations in female strobili production between years were significant. The repeatability for female strobili production within the examined years ranged from 0.47 to 0.87. The relative stability of female strobili production varied among clones, with regression coefficients among individual clones and an environmental index ranging from 0.13 to 2.81. The productivity index in different clones ranged from -1.09 to 1.83. Yield stability of female strobili among clones could be estimated from female strobili production. Clones could be divided into three groups according to their stability and productivity parameters. The results of this research provide guidance for evaluating clones in existing seed orchards, as well as some basic information for seed orchard management and advanced-generation seed orchard establishment.

Doubly-fed induction generator has become one of most popular generators driven by wind due to its superior behavior in power system. Because of the different physical structures between doubly-fed induction generation units and normal synchronous units, they behave differently in the failure of power system. Based on the analysis of transient behavior of doubly-fed induction generator units, the transient stability of power system integrated with doubly fed induction generator considering different integrating points is discussed. The simulation results verify the validity of the conclusion at the last of this paper.

Lectin microarrays are increasingly used as screening tools with a high potential for glycobiology analysis, providing a high-sensitivity profiling of complex glycan features in a short time, without the need for the release of glycan. The application of the technology for the rapid differential glycan profiling of target samples resulted in the discovery of new glycan-related biomarkers for disease detection and particular types of glycobiology studies. Additionally, lectin microarrays might offer many opportunities for further innovation, and their range of applications in the life sciences promises to be greatly expanded. Herein, we describe the advances in the fabrication and detection of lectin microarray technologies and their application, which herald even more exciting breakthroughs in the coming decade.

Close attention has been paid to the power generation using renewable energy such as the widespread energy and solar energy. After the integration of large-scale renewable energy, more uncertain factors are brought to the power system, which badly influences systems planning and operation. The wind power, photovoltaic power and load are random but correlative, therefore, it is more logical to study the influence exerted by the integration of renewable energy when considering the uncertainty and it is meaningful to the power systems planning and operation. Based on the summary and survey of previous studies, the technical route of power system analysis concerning the correlation of wind power, photovoltaic power and load is proposed in this paper and some key technologies are discussed. The study of correlation offers valuable analysis and recommendations to the connection of large-scale wind and solar power base.

In this paper, full-density Al-Zn-Mg-Cu-Zr powder metallurgy (P/M) alloy is prepared by hot-press sintering in vacuum at 600°C. Experiments are conducted to evaluate the effects of Zn additive in the range of 7.2-8.4 wt.% on the microstructure and mechanical properties of Al-Zn-Mg-Cu-Zr alloys. X-ray diffraction (XRD), scanning electron microstructure (SEM) and electron probe micro-analyzer (EPMA), and mechanical properties such as tensile strength are measured. The porosity decreases gradually with increasing of Zn and it achieves 0.01% with a density of 2.95 g/cm3 at 8.4% Zn. The tensile strength reaches the maximal value of 436 MPa at 8.4% Zn.

In order to reduce screen plugging and screen pasting, improve the efficiency of screening, a kind of dual-frequency vibrating screen was introduced. It had been used three exciting motors. We established the mechanical model of this vibrating screen, and used Matlab-simulink software to analyze the trajectory changes of screen surface, influenced by mass moment rate, initial phase differences and installation position between high and low frequency exciting motors. The results of the study indicate that, the rate of mass moment and difference of initial phase angle have great influence on the motion trail pattern and amplitude of vibration of the screen, and the installation position of high-frequency exciting motor have less influence on screen surface trajectory under the condition of exciting motors’ parameters given in this article. When designing dual-frequency vibrating screen, we can use the method of this paper to select appropriate rate of mass moment, difference of initial phase angle and so on, and achieve the expected motion trajectory of vibrating screen.

In order to study the stress distribution of dual-frequency vibrating screen and ensure the screen box has sufficient strength and longevity, a finite element model of dual-frequency vibrating screen was built, and the stress, modes and fatigue life of the screen box were analyzed. The results indicate that, the stress concentration appears at the contacting parts between the crossbeam and the stiffener of motor seat, the crossbeam, L-type stiffening plate, baffle of material added and screen box. The middle of crossbeam and the L-type stiffening plate are weaker parts of fatigue, they are easily fatigue failure under high frequency vibration.

Build-time estimation function of Rapid Prototyping (RP) plays an important role in optimisation of process parameters, job scheduling, job pricing and quoting. The common estimation function in most RP systems is not sufficient to give the accuracy of build time required for Selective Laser Sintering (SLS) process. Finding an appropriate method to estimate the build time for the SLS is very important. Six Sigma methodology has been applied in many different engineering domains and it is now being used in the process of Rapid Prototyping Manufacturing. This paper reviews the Six Sigma methodology and its Define, Measure, Analyse, Improve and Control (DMAIC) model, and finds the main factors in build-time estimation of the SLS process. From the results of experiments a new estimation model which reduces the estimation errors was developed.

Tbx6 is critical for somite specification and myogenesis initiation. It has been shown that Activin/Nodal, VegT/Nodal, FGF, and BMP signaling pathways are involved early in specifying mesoderm or later in patterning mesoderm, and Xnot plays roles in setting up the boundary between notochord and paraxial mesoderm. In this study, we introduce the dominant negative form of above genes into embryos to evaluate if they are responsible for regulating Tbx6 expression. The results show that: (1) Activin/Nodal and VegT/Nodal signals are necessary for both initiation and maintenance of Tbx6 expression, and Nodal is sufficient to induce ectopic Tbx6 expression; (2) FGF signal is necessary for the initiation and maintenance of Tbx6, but it is not sufficient to induce Tbx6 expression; (3) BMP is also necessary for the expression of Tbx6, and the induction of Tbx6 expression by BMP is dose dependent; (4) Xnot has no effect on the expression of Tbx6. Our results suggest that several signaling pathways are involved in regulating Tbx6 expression, and pave the route to reveal the molecular mechanism of initiating myogenesis.

• Sliding mode control strategy is employed to control synchronization of vibration system excited with double-frequency. • The controlled synchronization theory and the self-synchronous mechanism of the vibration system are analyzed. • The proposed control method can successfully implement zero-phase difference motion of the double-frequency system. • Tracking controllers of velocity and phase have strong robustness to restrain the variation of geometrical parameters. In petroleum exploitation industry, self-synchronous vibrating screen excited with dual-frequency cannot obtained an ideal synchronization motion state due to its own inherent coupling characteristics, which is unsuitable to separate cuttings from drilling fluid. Thus, for solving the above-mentioned problem, a controlled system of two eccentric rotors (ERs) actuated with double-frequency is proposed by considering sliding mode control (SMC) method. Firstly, motion differential equation in each direction is established according to physical model of the vibration system. Then, self-synchronous mechanism between high-frequency rotor and low-frequency rotor is gradually analyzed by small parameters method and Poincare–Lyapunov theory, and it is revealed that the self-synchronous vibration system cannot implement a stable phase difference on account of the existence of velocity error and phase error. Subsequently, combining the SMC algorithm with master-slave control (MSC) structure, tracking controllers of velocity error and phase error are systematically designed to control the synchronization state of the dual-frequency system. Finally, Runge–Kutta method is assigned to validate the reliability of theory and the stability of system. Comparing controlled synchronization with self-synchronization, the results demonstrate that the phase difference between the rotors can be accurately stabilized at zero by the proposed control strategy. Meanwhile, the designed control system has strong robustness to restrain the dynamic behavior of vibration system under parameter variations. This study will be helpful for the improvement of separation technology. [ABSTRACT FROM AUTHOR]

Nowadays, two exciters vibration system played an indispensable role in a majority of machinery and devices, such as vibratory feeder, vibrating screen, vibration conveyer, vibrating crusher, and so on. The stability of the system and the synchronous characteristics of two exciters are affected by material motion. However, those effects of material on two exciters vibration system were studied very little. Based on the special background, a mechanical model that two exciters vibration system considering material motion is proposed. Firstly, the system's dynamic equations are solved by using Lagrange principle and Newton's second law. Then, the motion stability of the system when material with different mass move on the vibrating body is analyzed by Poincare′mapping and numerical simulation methods, and the motion forms of the material are also studied. Meanwhile, the frequency responses of the vibrating body are analyzed. Finally, the influence of material on the phase difference of the two exciters is revealed. It can be concluded that with the mass ratio of the material to the vibrating body increasing, the system's motion evolves from stable periodic motion to chaotic state, the synchronization ability of two exciters decline, and the unpredictability of abrupt change about the phase difference increases. Further, the uncertainties of both the abrupt change of phase difference and the collision location affect each other and eventually lead to the instability of the system.

To improve the reliability and accuracy of dynamic machine in design process, high precision and efficiency of numerical computation is essential means to identify dynamic characteristics of mechanical system. In this paper, a new computation approach is introduced to improve accuracy and efficiency of computation for coupling vibrating system. The proposed method is a combination of piecewise constant method and Laplace transformation, which is simply called as Piecewise-Laplace method. In the solving process of the proposed method, the dynamic system is first sliced by a series of continuous segments to reserve physical attribute of the original system; Laplace transformation is employed to separate coupling variables in segment system, and solutions of system in complex domain can be determined; then, considering reverse Laplace transformation and residues theorem, solution in time domain can be obtained; finally, semi-analytical solution of system is given based on continuity condition. Through comparison of numerical computation, it can be found that precision and efficiency of numerical results with the Piecewise-Laplace method is better than Runge-Kutta method within same time step. If a high-accuracy solution is required, the Piecewise-Laplace method is more suitable than Runge-Kutta method.