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Selective transformations at the more sterically hindered sites of organic molecules represent a frontier in the ability to precisely modify molecules. The lack of effective synthetic methods stands in stark contrast to the large number of encumbered sites encountered in molecules of interest. Here, we demonstrate that 1,2-bis(boronates) undergo selective alkynylation and alkenylation at the more sterically hindered C–B bond. Our preliminary mechanistic studies disclosed that this reaction can proceed through two convergent pathways involving direct coupling of sterically encumbered site versus 1,2-boron migratory coupling. Notably, this method facilitated convenient access to alkenyl and alkynyl boron products, which can be diversified by an array of transformations.

This work presents the first method for generating tetrahedral-based volume meshes dedicated to the NURBS-enhanced finite element method (NEFEM). Built upon the developed method of generating feature-independent surface meshes tailored for NEFEM, the proposed mesh generation scheme is able to grow volume elements that inherit the feature-independence by using the surface mesh as the initial boundary discretisation. Therefore, the generated tetrahedral elements may contain triangular faces that span across multiple NURBS surfaces whilst maintaining the exact boundary description. The proposed strategy completely eliminates the need for de-featuring complex watertight CAD models. At the same time, it eliminates the uncertainty originated from the simplification of CAD models adopted in industrial practice and the error introduced by traditional isoparametric mesh generators that produce polynomial approximations of the true boundary representation. Thanks to the capability of having element faces traversing multiple geometric surfaces, small geometric features in the CAD model no longer restrict the minimum element size, and the user-required mesh spacing in the generated mesh is better satisfied than in traditional meshes that require local refinement. To demonstrate the ability of the proposed approach, a variety of CAD geometries are meshed with the proposed strategy, including examples relevant to the fluid dynamics, wave propagation and solid mechanics communities.

The conversion of commercially available chiral sulfinamides into pharmaceutically useful chiral sulfoximines viadirect SIV-functionalization is synthetically attractive but challenging due to the competitive reaction of N-functionalization. Herein, we disclose a novel strain-release strategy to access stereospecific and chemoselective SIV-arylation and alkenylation of sulfinamides using arynes and strained cyclic alkynes. This method tolerates an unprecedented chemical diversity of functional groups attached to the nitrogen center (N–R). The origin of the high SIV-selectivity is elucidated by density functional theory calculations, suggesting a stepwise mechanism for the aryne substrates and a concerted mechanism for the cyclic alkynes.

A novel copper-catalyzed cross-coupling reaction of sulfinamides and aryl boronic acids is developed. The reaction is highly chemoselective and stereospecific, which allows mild synthesis of optically pure sulfoximines with broad scope and functional group tolerance. The utility of this method is demonstrated by the asymmetric synthesis of pharmaceutical intermediates.

Graphical abstract:

•Gap junction protein alpha 4 (GJA4) on fibroblasts is involved in promoting fibroblast activation in colorectal cancer (CRC).•GJA4 promote epithelial mesenchymal transition (EMT) through a fibroblast-dependent pathway.•GJA4 may act synergistically with M2 macrophages to limit t cell infiltration by stimulating the formation of an immune-excluded desmoplasic barrier.•GJA4 was significantly correlated with pathological stage and D2 dimer.

During direct energy deposition (DED) process, the deposited material undergoes complex thermo-mechanical processing from subsequent thermal cycles. Dynamic recrystallization (DRX) can be activated under suitable strain and temperature conditions, which can induce grain refinement and homogenization. In this work, the evolution of temperature and thermal strain are experimentally measured, and the corresponding evolution of grain morphology, geometric dislocation density (GND), dislocation morphology and misorientation map under multiple thermal cycles during laser-DED of 316L stainless steel are investigated. Results show that DRX is activated during the 8th to 85th thermal cycles, during which temperature evolves in the range of 730 K – 800 K – 700 K and the corresponding strain evolves in the range of 4.5% – 7.0% – 5.3%. Nucleated grains grow by consuming grain boundary energy, with original columnar grains swallowed. Equiaxed grains are formed at the end of 90 thermal cycles. Dynamic recovery (DRV) would occur during the thermal cycling process, with the formation of sub-grains, the increased GNDs and the random grain misorientations through dislocation movement and entanglement promoted by high temperature and accumulated strain.

Gut microbiota is a complex microecosystem, which is called the second genome of the human body. Herbal medicine can balance tumor-suppressing bacteria and tumor-promoting bacteria and exert its anti-cancer effect by regulating gut microbiota. Traditional Chinese medicine (TCM) has a history of thousands of years in prevention and treatment of diseases in China. In recent decades, TCM has been shown to have an obvious advantage in prolonging the survival time and improving the living quality of patients with cancer. Notably, gut microbiota has become a new pathway to understanding TCM. In this review, we will focus on gut microbiota and tumor progression, especially the diversity, functionality and metabolites of gut microbiota affected by TCM in various cancer. We will also discuss the potential mechanism of gut microbiota for exploring TCM in anti-cancer effect. This article aims to comprehensively review the anti-cancer research of TCM by regulating gut microbiota, and address future perspectives and challenges of gut microbiota in TCM intervention for cancer.

An efficient organocatalytic enantioselective synthesis of chiral 1,4-benzodioxepines is described. By proper incorporation of an intramolecular oxetane desymmetrization process, a range of benzylic alcohols bearing an internal oxetane reacted in the presence of a suitable chiral phosphoric acid catalyst to form chiral 1,4-benzodioxepines with high enantioselectivity. This process provides a new catalytic asymmetric example of direct synthesis of seven-membered heterocycles with good stereocontrol.

Low temperature is one of the most important abiotic factors inhibiting growth, productivity, and distribution of rapeseed (Brassica napusL.). Therefore, it is important to identify and cultivate cold-tolerant germplasm. The objective of this study was to figure out the mechanism of chilling (4 and 2°C) and freezing (–2 and –4°C) stresses along with a control (22°C) in B. napuscultivars (1801 and C20) under controlled environment (growth chamber). The experiment was arranged in a complete randomized design with three replications. Our results exhibited that under chilling and freezing stresses, the increment of proline accumulation, soluble sugar and protein contents, and antioxidant enzyme activity were enhanced more in 1801 cultivar compared with C20 cultivar. At –2 and –4°C, the seedlings of C20 cultivar died completely compared with 1801 cultivar. Hydrogen peroxide (H2O2) and malondialdehyde contents (MDA) increased in both cultivars, but when the temperature was decreased up to –2 and –4°C, the MDA and H2O2contents continuously dropped in 1801 cultivar. Moreover, we found that leaf abscisic acid (ABA) was enhanced in 1801 cultivar under chilling and freezing stresses. Additionally, the transcriptional regulations of cold-tolerant genes (COLD1, CBF4, COR6.6, COR15,and COR25) were also determined using real-time quantitative PCR (RT-qPCR). RT-qPCR showed that higher expression of these genes were found in 1801 as compared to C20 under cold stress (chilling and freezing stresses). Therefore, it is concluded from this experiment that 1801 cultivar has a higher ability to respond to cold stress (chilling and freezing stresses) by maintaining hormonal, antioxidative, and osmotic activity along with gene transcription process than C20. The result of this study will provide a solid foundation for understanding physiological and molecular mechanisms of cold stress signaling in rapeseed (B. napus).

We report on the development of metal dielectric gratings (MDG) including two layers of gold film and a silica layer, which is simple and has enough broadband with 105 nm over 90%. The measured laser-induced damage threshold (LIDT) on the grating surface is 0.40  J/cm^2 at a pulse duration of 32 fs, which is twice more than that of gold gratings, and the initial damage comes from nodule defects. Laser-induced ionization theory is first used to study the effect of nodule defects on LIDT of MDG and predict the maximum LIDT of the perfect MDG. The prediction value of the MDG without nodule defects is 0.60  J/cm^2 on the grating surface, which has tremendous application potential in petawatt-class laser systems.

Pharmaceutical contaminants are causing great attention for the public people, urgently requiring to be eliminated from the environment. Herein, commercial pharmaceutical carbamazepine was chosen as a model to be degraded by a heterogeneous Fenton system using natural pyrite as catalyst. The catalyst was characterized by X-ray diffraction apparatus, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. The elements composition and chemical states of pyrite changed significantly after the Fenton reaction, which promoted the production of active species in the electron transfer process. The degradation efficiency of carbamazepine (2.5?mg/L) can reach 99.71% after 30?min with 0.3?g/L of pyrite and 5?mM of H2O2, respectively. The reaction system was suitable for a wide range of pH (3–9). The environmental adaptability examination of pyrite showed that humic acid (HA) had inhibitory effects on the degradation of carbamazepine. While the changes of degradation efficiency of carbamazepine were inconspicuous in the presence of NO3-and SO42-, indicating strong anti-interference to environment common anions. Free-radical capturers suggested that hydroxyl radical (·OH), superoxide radical (·O2-), and singlet oxygen (1O2) participated in the degradation of carbamazepine. This research has offered a new strategy of “treating wastes with wastes” to use pyrite to remove emerging pollutants.

The equi-biaxial tensile test is often required for parameter identification of anisotropic yield function and it demands the special testing technique or device. Instead of the equi-biaxial tensile test, the plane strain test carried out with the traditional uniaxial testing machine is suggested to provide the experimental data for calibration of anisotropic yield function. This simplified method by using plane strain test was adopted to identify the parameters of Yld2000-2d yield function for 5xxx aluminum alloy and AlMgSi alloy sheets. The predicted results of yield stresses, anisotropic coefficients and yield loci by the proposed method were very similar with the experimental data and those by the equi-biaxial tensile test. It is validated that the plane strain test is effective to provide experimental data instead of equi-biaxial tensile test for calibration of Yld2000-2d yield function.

The Yoshida-Uemori combined kinematic and isotropic hardening model is widely applied to numerical prediction of spring-back during sheet metal forming process. With the experimental plastic behavior of aluminum alloy AA5182-O sheet under single cyclic loading, the semi-analytical method was presented to calibrate the parameters of Yoshida-Uemori hardening model. Meanwhile, an inverse identification method was suggested by parameter optimization for minimizing the error between the experimental and predicted results. By comparing the two methods, the Yoshida-Uemori hardening model identified by inverse method is found to be more accurate for description of the Bauschinger effect than the one identified by semi-analytical method, especially for transient softening phenomenon.

A numerical simulation study of collision effect on damage evolution in electromagnetic forming (EMF) was presented. EMF technology can greatly improve the forming limit of metal sheet duo to the high rate. However, collision behavior is also an important factor for the formability of sheet. Free form model and conical die model were carried out to study the effect of collision behavior on mechanical properties of Al alloy sheet. The EMF process of 1050 Al alloy sheet was analyzed and discussed by numerical analysis software LS-DYNA. The combined strategy of boundary element method and finite element method was adopted to realize the coupling calculation of electromagnetic field and structural field. Based on the GTN material model, the evolution of void volume fraction of 1050 Al sheet were calculated and analyzed. Comparing the free form model results and the die form model results, showed that the collision behavior could reduce the void volume fraction of sheet, but excessively high collision speed lead to the sheet rebound, which aggravated the damage of material and reduce the accuracy of the product. Therefore, the appropriate discharge voltage in this work was found to improve mechanical property of sheet on the premise of forming precision.

Melatonin is a naturally occurring compound in plants. Here, we tested the effect of exogenous melatonin on rapeseed (Brassica napusL.) grown under salt stress. Application of 30 µmol L−1melatonin alleviated salt-induced growth inhibition, and the shoot fresh weight, the shoot dry weight, the root fresh weight, and the root dry weight of seedlings treated with exogenous melatonin increased by 128.2, 142.9, 122.2, and 124.2%, respectively, compared to those under salt stress. In addition, several physiological parameters were evaluated. The activities of antioxidant enzymes including peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) were enhanced by 16.5, 19.3, and 14.2% compared to their activities in plants without exogenous melatonin application under salt stress, while the H2O2content was decreased by 11.2% by exogenous melatonin. Furthermore, melatonin treatment promoted solute accumulation by increasing the contents of proline (26.8%), soluble sugars (15.1%) and proteins (58.8%). The results also suggested that higher concentrations (>50 µmol L−1) of melatonin could attenuate or even prevent the beneficial effects on seedling development. In conclusion, application of a low concentration of exogenous melatonin to rapeseed plants under salt stress can improve the H2O2-scavenging capacity by enhancing the activities of antioxidant enzymes such as POD, CAT and APX, and can also alleviate osmotic stress by promoting the accumulation of osmoregulatory substances such as soluble proteins, proline, and water soluble glucan. Ultimately, exogenous melatonin facilitates root development and improves the biomass of rapeseed seedlings grown under salt stress, thereby effectively alleviating the damage of salt stress in rapeseed seedlings.

We identify three themes in the current research on nostalgia and acculturation. First, different types of nostalgia (i.e., home-culture and host-culture nostalgia) have distinct effects on immigrants' and sojourners' identification with home or host culture, affecting the integration of home and host cultural identities. Second, nostalgia during acculturation plays a crucial role in facilitating self-continuity among immigrants and sojourners moving across different cultures. Third, nostalgia affects the majority-group members’ attitude towards immigrants and sojourners in the host culture. We conclude by highlighting three challenges for future research on nostalgia and acculturation: the content of types of nostalgia, the moderating role of individual differences, and the functions of nostalgia at various acculturation stages.

RNA sequencing of the sensitive GH01 variety of Brassica napusL. seedling roots under 12 h of waterlogging was compared with previously published data of the ZS9 tolerant variety to unravel genetic mechanisms of waterlogging tolerance beyond natural variation. A total of 2 977 genes with similar expression patterns and 17 genes with opposite expression patterns were identified in the transcription profiles of ZS9 and GH01. An additional 1 438 genes in ZS9 and 1 861 genes in GH01 showed strain specific regulation. Analysis of the overlapped genes between ZS9 and GH01 revealed that waterlogging tolerance is determined by ability to regulate genes with similar expression patterns. Moreover, differences in both gene expression profiles and abscisic acid (ABA) contents between the two varieties suggest that ABA may play some role in waterlogging tolerance. This study identifies a subset of candidate genes for further functional analysis.

MicroRNAs (miRNAs) are emerging as important regulators in various pathobiological processes in cancer. Genistein, as a major isoflavonoid isolated from dietary soybean, possesses a wide variety of biological activities particularly in cancer prevention. However, the molecular mechanisms by which genistein elicits its effects on ovarian cancer cells have not been fully elucidated. In this study, we reported that expression of miR-27a was higher in human ovarian cancer relative to benign ovarian tissues. Meanwhile, transfection of SKOV3 cells with the inhibitor of miR-27a suppressed growth and migration of tumor cells. Our study also found that treatment of ovarian cancer cells with genistein caused an inhibition of ovarian cancer cell growth and migration. Further cellular mechanistic studies revealed that genistein down-regulated miR-27a expression, which was accompanied by significantly increased expression of Sprouty2, a putative miR-27a target gene. Taken together, our findings reveal that oncogenic miR-27a plays an important role in ovarian cancer cell growth and metastasis, and genistein, as nontoxic inactivators of miRNA, can block ovarian cancer cell growth and migration, offering novel insights into the mechanisms of genistein therapeutic actions.

Established a dynamic model of recrystallization dislocation, proposed MC algorithm simulation describing grain growth behaviors that can explain VSR eliminate component residual stress mechanism from the micro, which can provide an intuitive visualization. Used MATLAB programming grain growth of the grain in the different MC steps simulate images, to discuss the grain size distribution and the energy change in different MC steps, while compared the simulation results with the existing sample dislocation configuration electron microscopy photos around the VSR. It reflects the same trend, which can show that the MC method in numerical simulation of grain growth can fully reflect component microstructure evolution around VSR. Micro explains the VSR mechanism of residual stress relief member which provides intuitive visual basis.

Aiming at the problem of long time power interruption and clutch master-slave friction plates wore seriously which greatly shorten the life of clutch during shifting process of AMT, a overrunning AMT without separation process of clutch when shifting is designed. This paper has analyzed structural characteristics and shift principle of overrunning AMT. Through force analysis on the jointing process of roller overrunning clutch, the mathematical model and dynamic model of transmission system are established. Finally, the shifting impact of shifting process is analyzed based on computer simulation. The simulation results indicate that vehicle longitudinal degree of jerk meets the requirement of vehicle comfort.

Road load spectrum is not only the prerequisites of fatigue reliability analysis and test of AMT(Automated Manual Transmission) actuating mechanism, but also the input and boundary conditions of CAE(Computer Aided Engineering). Based on analysis of AMT motion and force, the measuring points of road load spectrum are determined, and the accelerometers and strain gauges are installed. Then the road load spectrum of AMT actuating mechanism is collected on Xiangfan Automobile Proving Ground according to related standards. At the same time the acquired road load spectrum is analyzed, such as pretreatment, repeatability checking and statistical analysis. The results indicate that the acquired road load spectrum is well reliable and repeatable, which provides effective basic data for design, analysis and verification of AMT actuating mechanism.

The influence of electromagnetic coupling and mechanical coupling on control property in dynamic emulation system is analyzed. the coupled system is a dual-input dual-output system.The load torque changes will cause the variation of speed in the system and the speed changes also affect the variation of load torque. The mathematic model of the system based on decoupling control are given. The compensation module can be installed to the system in order to make subsystems almost independent of each other. Simulation and comparison is taken by MATLAB / Simulink software between decoupled system and original system. Result shows that the coupling control method can improve the precision of the control system and fasten response.

Four new indole alkaloids, plasiaticines A-D (1–4), together with two known ones, were isolated from the seeds of Plantago asiatica. The structures of the new compounds were elucidated on the basis of comprehensive analysis of spectroscopic data. All compounds were tested for their cytotoxic activity, and all compounds except 4were tested for their acetylcholinesterase (AChE) inhibitory activities.

Fatigue in ferroelectric oxides has been a long lasting research topic since the development of ferroelectric memory in the late 1980s. Over the years, different models have been proposed to explain the fatigue phenomena. However, there is still debate on the roles of oxygen vacancies and injected charges. The main difficulty in the study of fatigue in ferroelectric films is that the conventional vertical sandwich structure prevents direct observation of the microscopic evolution through the film thickness during the electric field cycling. To circumvent this problem, we take advantage of the large in-plane polarization of BiFeO3and conduct direct domain and local electrical characterizations using a planar device structure. The combination of piezoresponse force microscopy and scanning kelvin probe microscopy allows us to study the local polarization and space charges simultaneously. It is observed that charged domain walls are formed during the electrical cycling, but they do not cause polarization fatigue. After prolonged cycling, injected charges appear at the electrode/film interfaces, where domains are pinned. When the pinned domains grow across the channel, macroscopic fatigue appears. The role of injected charges in polarization fatigue of BiFeO3is clearly demonstrated.

The novel strain-driven morphotropic phase boundary (MPB) in highly strained BiFeO3thin films is characterized by well-ordered mixed phase nanodomains (MPNs). Through scanning probe microscopy and synchrotron X-ray diffraction, eight structural variants of the MPNs are identified. Detailed polarization configurations within the MPNs are resolved using angular-dependent piezoelectric force microscopy. Guided by the obtained results, deterministic manipulation of the MPNs has been demonstrated by controlling the motion of the local probe. These findings are important for an in-depth understanding of the ultrahigh electromechanical response arising from phase transformation between competing phases, enabling future explorations on the electronic structure, magnetoelectricity, and other functionalities in this new MPB system.

We report a green and efficient method for chemoselective deoxidization of graphene oxide viathe ultraviolet irradiation catalyzed with 2,2,6,6-tetramethyl-4-piperidinol. While the sp2-hybridized oxygen functional groups are removed after the reduction, the epoxy and hydroxyl groups are retained in the chemoselectively reduced graphene oxide (CrGO). The obtained CrGO nanosheets exhibit the high solubility and excellent electronic stability, which allows for the fabrication of thin film devices through a solution processing. As a proof of concept, a CrGO-based write-once-read-many-times memory device with the desirable stability and long-time operation is fabricated.

Aiming at relieving processing of annular hob, a applicable method—circumferential relieving method is proposed, this paper describes the principle of relieving processing and implementation method, also proposes a method of computer control, the device which could be mounted on the worktable of hobbing machine to realize circumferential relieving The results showed that method and device proposed in the paper are practicable.

The paper focused on the effect of tool edge preparation of indexable carbide insert on cutting temperature, force and tool wear. The initial wear experiments were carried out to measure flank wear and two criteria to evaluate the effect of tool edge preparation were proposed. The cutting temperature measurement utilized tool-work thermocouple and revealed that the cutting temperature of honed insert was lower. The cutting force measurement with a strain gauge dynamometer showed that tangential cutting force Fz, feed force Fx would be increased and radius force Fy would be decreased after tool edge preparation.

The continuous rolling and sizing processes for producing non-quenching and non-tempering 36Mn2V steel pipes used in oil well were studied by the thermomechanical simulation test in this paper. The results showed clearly that the final microstructure was influenced by deformation temperature and stain applied. When continuous rolling temperature was controlled at 1050℃ and strain at about 0.5 or above, dynamic recrystallization was completed and fine austenitic grain was obtained. When sizing temperature was controlled at 850℃ or below and strain at about 0.2 or above, fine acicular ferrite was obtained with properties satisfying the requirement of the high quality pipe. The results of the study provided reliable data for the controlled rolling and sizing processes for the production of the 36Mn2V steel pipes.

The study focused on surface burn of titanium alloy (TC4) in the grinding process using a novel segmented cup wheel with internal cooling structure. The threshold burn temperature was found in grinding TC4. Plastically deformed coating layers and micro-cracks were observed on ground surface by SEM (Scanning Electronic Microscopy) and depth of microstructure alterations was more than 180 microns in high temperature. Finally, a novel wheel with internal cooling structure was developed for reducing grinding temperature and suppressing surface burn.

Parameter testing is the most important process during ballast production, only the products whose parameters conformed to the standard could be passed to the next procedure. A quality information system was designed to replace the manual operation. Based on the computer controlled auto-test facilities, the information system recorded the performance parameters of the ballasts in real time, the statistics of product quality such as the fail ratio was performed periodically. When the fail ratio exceeds the set thresholds, an alarming e-mail will be sent automatically to the related managers and designers. The adoption of database makes history data searched and reviewed conveniently, and the statistics provide a powerful tool for analysis and decision-making. Application of the system have shortened the time for defects statistics and evaluation, and helped to improve the production efficiency and product quality.

Two industrial produced non-quenching and non-tempering steels 40Mn2V and 36Mn2V had been tested by Gleeble-1500 thermal simulation machine to simulate MPM rolling, sizing and cooling process. The cooling rate in the air noticeably affected the final property of different size pipes. According to the measured practical cooling rates of different size pipes, appropriate size pipes with cooling rate at range of 0.9℃/s~1.6℃/s and 1.6 ℃/s~2.1℃/s can be picked out to use steel 40Mn2V and 36Mn2V to produce grade N80 OCTG(Oil Country Tubular Goods) with steady property respectively. This result had been used in practical production, which greatly improved the property stability of grade N80 OCTG.

Motorcycle Ride Comfort is the important performance of motorcycle. In this paper, a rigid-flexible coupling virtual prototype is developed with CATIA, ADAMS and NASTRAN tools. Combined with motorcycle road simulator, the simulation platform of motorcycle ride comfort is built. Then with the input of pulse road, motorcycle ride comfort is simulated, and the simulation results are verified by experiment results. It indicates that the simulation results have a high credibility and the road simulator provides a good method of verification for simulation of motorcycle ride comfort.

The principle of remote parameter control(RPC) and test method of road simulator test are analyzed, and the road simulation test of motorcycle is implemented with road simulator produced by MTS company. Firstly, by disposing strain gauge and accelerometer, the load spectrum of motorcycle is sampled when the motorcycle runs on gravel road and concrete road with constant speed. Then using the front and rear axle acceleration as desired response signals, the simulation iteration and road simulation test are conducted. At last, the key problems of motorcycle road simulation test are solved. The result shows that the desired response signals and the monitor signals are well matched, and the road load spectrum of motorcyle is accurately reproduced.

The motorcycle dynamics simulation method based on the road simulation test and virtual prototype is developed, and a rigid-flexible coupling virtual prototype with test platform of motorcycle is created with CATIA, NASTRAN and ADAMS software. According to two-channel tire-coupled road simulator of MTS Systems Corporation, the simulation model and platform are repetitively refined to fairly high precision by comparing simulation results with experimental results. The iterated excitation signal based on real road load or typical spectrum of different roads is imported into the virtual test platform, the comfort and durability tests of motorcycle can be undertaken to replace road simulator, the test period and cost are greatly reduced, and test security is increased.

Based on the stimulation and restriction of road simulation, the 5-DOF motorcycle multi-body dynamic model is derived, and the differential equation of motion and state-space formulation are developed according to Lagrange Equation. By iterating the load spectra, which was sampled on Hainan Proving Ground, the driving signal of motorcycle road simulation is obtained. With the driving signal as input, the motorcycle dynamics is simulated using MATLAB program, then the simulation and experiment are compared. The result shows that motorcycle dynamics can be analyzed and estimated precisely by combining road simulation with computer simulation.

An analytical expression for calculating the reflection-peak wavelengths (RPWs) of a uniform sampled fiber Bragg grating (SFBG) with the multiple-phase-shift (MPS) technique is derived through Fourier transform of the index modulation. The new expression can accurately depict the RPWs incorporating various parameters such as the duty cycle and the DC index change. The effectiveness of the derived expression is further confirmed by comparing the RPWs estimated from the expression with the simulated reflective spectra using the piecewise uniform method. And the reflective spectrum has been well optimized by introducing the Gaussian apodization function to suppress the sidelobes without any wavelength shift on the RPWs. Then, a high-channel-count comb filter based on MPS is proposed by cascading two or more SFBGs with different Bragg periods but with the same RPWs. Noticeably, the RPWs of the new structured SFBG can also be accurately calculated through the expression. Furthermore, the number of spectral channels can be controlled by choosing gratings with specified difference Bragg periods.

Polarization-resolved dynamics of mutually coupled vertical-cavity surface-emitting lasers with asymmetrical injections is studied. For one laser, the injection parameters, such as injection rate, lasing frequency, and propagation phase, are set to fixed values, while for the other laser these parameters are taken as variables. The results show that asymmetrical injections have great influence on the dynamics and polarization state of the system. Subjected to injections with different degrees of asymmetry, the lasers can experience bifurcations in the original polarization, polarization switching to the orthogonal direction, or emission with both of the two linearly polarized modes.

Influences of polarization-selected mutual injection on polarization switching behaviors of vertical-cavity surface-emitting lasers (VCSELs) are investigated numerically. For the polarization-preserved (PP) injection, the x mode is selected and is injected mutually into the two lasers. The two lasers show nearly identical polarization-switching (PS) behaviors, even if frequency detuning is nonzero. For the polarization-rotated (PR) injection, the x mode is selected and rotated 90° before being injected into the two lasers. When frequency detuning is considered, the two lasers show totally different PS properties, and mutual injection will switch to unidirectional injection with varying parameters. In both the cases of PP and PR injection, the partitions that correspond to different emission states and the switching points of the two VCSELs are mapped in the parameter space of injection rate and bias current. Furthermore, for each different emission state, the output dynamics and synchronization performance are evaluated in the time domain.

Polarization switching (PS) of two mutually coupled vertical-cavity surface-emitting lasers (VCSELs) are studied numerically. A group of dimensionless rate equations is derived to describe our model. We focus on the influences of coupling rate and frequency detuning on PS dynamics. In the polarization-preserved mutual-injection case, x-polarization mode injection will defer the occurrence of PS, while y-polarization mode injection will lead PS to occur at a lower current. These influences will be weakened by frequency detuning. The effects of polarization-rotated injection are contrary to those of polarization-preserved injection. For polarization-rotated injection, two coupled VCSELs show really different PS characteristics if frequency detuning is nonzero. Besides in the L-I curves, we also find a region of values of the injection current where one laser emits in pure polarization mode, and the other laser emits in the orthogonal direction.

Driving behaviors at intersections are complex. At intersections, drivers face more traffic events than elsewhere and are thus exposed to more potential errors with safety consequences. Drivers make real-time responses in a stochastic manner. This study used hidden Markov models (HMMs) to model the driving behavior of through-going vehicles on major roads at intersections. Observed vehicle movement data were used to estimate the model. A single HMM was used to cluster movements when vehicles were close to the intersection. The reestimated clustered HMMs could more accurately predict vehicle movements compared with traditional car-following models.