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A weak circumferential resolution of defects in the corner part of engineering components brings great challenges to quantitative non-destructive testing. Especially for the corner of carbon fiber reinforced plastics (CFRP), the complex wave propagation behaviors caused by the elastic anisotropy, laminate structure, and curved surface make the information of defects hard to be distinguished, which finally results in a poor imaging resolution. The surface adaptive ultrasonic (SAUL) method for CFRP corner is investigated, and an improved strategy, focusing in receiving (FiR) of SAUL signals is proposed here. With an isotropic plexiglass as a comparison, the effectiveness of FiR is verified by finite element simulations and experiments. The elastic properties of CFRP corner are accurately characterized and a finite element model is established. On this basis, the wave propagation behavior in the corner is studied, and the influence of the water distance h on the maximum amplitude (MAD) and signal-to-noise ratio (SNR) at the defect is analyzed. The results show that the structural noise can be eliminated, and the imaging quality and SNR can be improved by optimizing the h. After FiR, the maximum increase of defect amplitude is about 9.5 dB and 13.2 dB for plexiglass and CFRP, respectively. Meanwhile, the maximum relative error in length is reduced by 16.7% in plexiglass, and by 13.4% for the 3-mm delamination in CFRP. The strategy would be promising to improve the detection quality of the corner in curved components. [ABSTRACT FROM AUTHOR]

Photothermal agent accompanying with thermally responsive materials, displays well controlled drug release property, which is well-received as an outstanding design strategy for simultaneous photothermal/chemotherapy in cancer. Cyanine dye, as the prestigious photothermal agent has shown great potential due to its preeminent near-infrared absorbance and excellent thermal conversion efficiency. However, their inherent defect such as inferior photothermal stability, high leakage risk and poor therapy efficacy limit their further application in cancer therapy. Hence, a facile and universal strategy to make up these deficiencies is developed. Chemotherapeutic drug DOX and cyanine dye were loaded into polydopamine (PDA) nanoparticles. The PDA encapsulation dramatically improved the photothermal stability of cyanine dye. Attributed by the PDA structure feature, the thermo-sensitive small molecule glyamine (Gla) is introduced into the PDA surface to lessen leakage. The Gla can form a dense encapsulation layer on the dopamine surface through hydrogen bond. This newly fabricated Cyanine/DOX@PDA-Gla nanopaltform is characterized with NIR light/pH dual-responsive property, high NIR photothermal conversion performance and fluorescence guided chemo-photothermal therapy. [ABSTRACT FROM AUTHOR]

Highlights The primary objective of the paper is the numerical and experimental investigation related to the damage recognition effects for CFRP tubes of four dynamic parameters. Four damage identification indexes consisting of natural frequency‐based index, Mode Shape‐based index (MS), Mode Shape Curvature‐based index (MSC), and Modal Flexibility Curvature‐based index (MFC) are established by analyzing the dynamic parameter data obtained before and after damage occurs. The performances of dynamic parameters are thoroughly discussed in the context of numerical simulations and experiment. The results indicate that the effect of natural frequency is not as significant as that of mode shape. MFC has the most notable effectiveness out of the four indexes. The simulation peak index pair is predicted to rise from 0.3 to 0.6 as the damage in the simulation model increases by 25% from 12.5%, indicating that MFC can feedback the damage degree. Moreover, the circumferential curvature index exhibits superior performance compared to the axial curvature index. To enhance the accuracy of the axial curvature index, it is proposed to increase the number of measuring sites along the tube's long direction. Damage identification indexes of four dynamic parameters are established. Discuss the identification ability of dynamic parameters by simulation and test. Two numerical models of CFRP tube with delamination damage are established. Impact and modal tests are executed to study the ability of four indexes. [ABSTRACT FROM AUTHOR]

In order to solve the problem that image information is not effectively utilized because of unclear traffic video images and random jitter between image sequences, this paper has studied how to achieve stability of traffic video images and proposed an improved Mean Shift algorithm about how to conduct object centroid registration in compensation for the deviations in space localization and on this basis, how to select kernel window width to eliminate the errors in scale positioning. This algorithm gets the tracking effect and computation analysis of improved Mean Shift from the perspective of applications; removes or relieves the impact motion has on imaging, improves the quality of the video image information obtained, automatically adjusts the size of window according to the scale changes of moving object in the image, and effectively enhances the stability and real-time of object tracking. The experiment has proven that the algorithm of this paper is practical to some extent. [ABSTRACT FROM AUTHOR]

• This paper presents a solution methodology for the rotor system with bolted joint. • The presented solution methodology is verified by the Newmark method. • The 3X and 5X of the rotating frequency are found in the spectrum. • The rotating speed corresponding to 5X's peak precedes the critical speed. • The findings of spectral characteristics are verfied by the experimental test. The bolted joint is commonly used to connect several parts of aero-engine rotor system. Several papers have studied the nonlinear vibration responses of bolted rotor systems. However, the frequency spectrum characteristics of bolted rotor systems are not fully revealed. Aiming at this issue, this study develops a dynamic model of the bolted rotor system, where the piecewise stiffness characteristic is considered. A solution methodology is presented by incorporating the piecewise stiffness into the incremental harmonic balance method. The effects of unbalance and preload on the dynamic characteristics are discussed. Moreover, the stiffness and damping of the support structure and bolted joint are identified based on the particle swarm optimization algorithm and experimental results. Furthermore, the experimental study on a bolted rotor test rig is conducted to verify the accuracy of the identified parameters and the model. The simulation and experimental results indicate that 3X and 5X of the rotating frequency can be observed. Besides, the rotating speed corresponding to 5X's peak is different from the critical speed, and the peak of 5X precedes the primary resonance peak. [ABSTRACT FROM AUTHOR]

The similitude theory helps to understand the physical behaviors of large structures through scaled models. Several papers have studied the similitude of shock issues. However, the dynamic similitude for shock responses of coupled structures is rarely incorporated in open studies. In this paper, scaling laws are derived for the shock responses and spectra of coupled structures. In the presented scaling laws, the geometric distortion and energy loss are considered. The ability of the proposed scaling laws is demonstrated in the simulation and experimental cases. In both cases, the similitude prediction for the prototype's time-domain waveform and spectrum is conducted with the scaled model and scaling laws. The simulation and experimental cases indicate that the predicted shock responses and spectra agree well with those of the prototype, which verifies the proposed scaling laws for predicting shock responses. [ABSTRACT FROM AUTHOR]

The support structure of a rotor system is subject to vibration excitation, which results in the stiffness of the support structure varying with the excitation frequency (i.e., the dynamic stiffness). However, the dynamic stiffness and its effect mechanism have been rarely incorporated in open studies of the rotor system. Therefore, this study theoretically reveals the effect mechanism of dynamic stiffness on the rotor system. Then, the numerical study and experimental verification are conducted on the dynamic stiffness characteristics of a squirrel cage, which is a common support structure for aero-engine. Moreover, the static stiffness experiment is also performed for comparison. Finally, a rotor system model considering the dynamic stiffness of the support structure is presented. The presented rotor model is used to validate the results of the theoretical analysis. The results illustrate that the dynamic stiffness reduces the critical speed of the rotor system and may lead to a new resonance. [ABSTRACT FROM AUTHOR]

Objective: To examine the effects of prenatal maternal depression, anxiety and stress, and postnatal depression on infant early neurodevelopment, and the sex dimorphism.Study Design: We used data from 3379 mother-infant pairs from the Shanghai Birth Cohort. Maternal mental health was assessed using the Center for Epidemiological Studies-Depression Scale, Zung Self-Rating Anxiety Scale, Perceived Stress Scale at mid-pregnancy, and the Edinburgh Postnatal Depression Scale at postpartum. Infant neurodevelopment was evaluated using the Ages & Stages Questionnaires and Bayley Scales at ages 6, 12, and 24 months, respectively. Linear mixed models and linear regression models were used.Results: Among 3379 mothers, 11.07 %, 5.42 %, and 34.85 % of women experienced depression, anxiety, and elevated stress, separately. As maternal prenatal mental scores increased per 1SD, infant social-emotional scores decreased -2.82 (-3.86, -1.79) vs -2.86 (-3.94, -1.79) for depression, -2.34 (-3.38, -1.31) vs -2.72 (-3.81, -1.64) for anxiety, and -2.55 (-3.60, -1.50) vs -3.41 (-4.48, -2.35) for stress among boys and girls at age 24 months, respectively. Associations were also observed on social-emotional and communication scores in boys and girls, and fine motor in girls at age 6 and 12 months. These associations were not observed for postpartum depression.Limitation: Generalizability of the results to other population remains to be determined.Conclusions: Prenatal maternal depression, anxiety, and stress were negatively associated with infant early neurodevelopment, which were not observed for postpartum depression. We underscore the importance of maternal prenatal mental health in optimizing infant neuropsychiatric development. [ABSTRACT FROM AUTHOR]

Similitude laws can be used to extrapolate the vibration characteristic of a small, inexpensive, and easily tested model into structural behavior for the full-size prototype. In this article, a systematic similitude approach is proposed to predict the natural frequency, mode shape, and vibration response of composite laminated plates. The emphasis of this article is to predict the vibration characteristic of composite laminated plates in an effective and convenient way. Sensitivity analysis (SA) is introduced to improve the prediction accuracy of natural frequency. For distortion similarity, the prediction accuracy is improved close to 5%. Modal assurance criterion (MAC) measures the consistency of mode shapes of the full-size prototype and scaled models. The influence of stacking sequence on mode consistency is investigated. Similitude based on virtual mode and statistical energy (SVMSE) is proposed to extrapolate the transient response of the prototype to simulate the shock environment, such as satellite–rocket separation, etc. In conclusion, the prediction accuracy of natural frequency, mode consistency, and response coincidence are considered comprehensively to extrapolate the vibration characteristic of the full-size laminated plates. [ABSTRACT FROM AUTHOR]

Simple Summary: Cancer remains a serious health problem owing to its high morbidity and mortality. Immunotherapy, represented by anti-programmed death-1D1/anti-PD-Ligand 1 treatments, has become one of the most important methods for cancer treatment. However, there are still some challenges in this method such as low response rate, limited therapeutic targets, and unclear underlying molecular mechanisms of immune checkpoints. Thus, in this review, we aim to focus on the proliferative role of fifteen immune checkpoints that occur in various tumors. This has provided more clarity on the functions and mechanisms of immune checkpoints in tumors, especially on their proliferation role. This may provide better insights in developing more therapeutic targets and strategies in tumor immunotherapy. Cancer remains a serious social health problem, and immunotherapy has become the major treatments in tumor treatment. Additionally, improving the efficiency and safety of treatment is necessary. Further, more therapy targets are warranted for future tumor treatments. In this review, in addition to examining the currently recognized role of immune regulation, we focus on the proliferative role of 15 immune checkpoints in various tumors, including PD1, PD-L1, FGL1, CD155, CD47, SIRPα, CD276, IDO1, SIGLEC-15, TIM3, Galectin-9, CD70, CD27, 4-1BBL, and HVEM. We managed to conclude that various immune checkpoints such as PD1/PD-L1, FGL1, CD155, CD47/SIRPα, CD276, and SIGLEC-15 all regulate the cell cycle, and specifically through Cyclin D1 regulation. Furthermore, a variety of signal pathways engage in proliferation regulation, such as P13K, AKT, mTOR, and NK-κB, which are also the most common pathways involved in the regulation of immune checkpoint proliferation. Currently, only PD1/PD-L1, CD47/SIRPα, TIM3/Galectin-9, and CD70/CD27 checkpoints have been shown to interact with each other to regulate tumor proliferation in pairs. However, for other immune checkpoints, the role of their receptors or ligands in tumor proliferation regulation is still unknown, and we consider the enormous potential in this area. An increasing number of studies have validated the various role of immune checkpoints in tumors, and based on this literature review, we found that most of the immune checkpoints play a dual regulatory role in immunity and proliferation. Therefore, the related pathways in proliferation regulation can served the role of therapy targets in tumor therapy. Further, great potential is displayed by IDO1, SIGLEC-15, 4-1BBL, and HVEM in tumor proliferation regulation, which may become novel therapy targets in tumor treatment. [ABSTRACT FROM AUTHOR]

Pollination precision and efficiency have been deemed to be important driving forces in floral evolution. Herkogamy reduction is a main mechanism to increase pollination precision. Secondary pollen presentation (SPP), by which pollen is presented on other floral organs especially pistils, has been widely accepted as a special mechanism to increase pollen transfer precision through spatial reduction of the anther–stigma distance, that is, minimized herkogamy. This overlooks a potential driving force, that is expanding the pollination niche through converting pollen thieves and nectar robbers into effective pollinators. We selected two species as study models with typical pistillate SPP, Pavetta hongkongensis Bremek. (Rubiaceae) and Scaevola taccada (Gaertn.) Roxb. (Goodeniaceae). In both species, two distinct pollinator functional groups were recognized. Short‐tongued bees and flies fed on pollen on stigmas but also stole pollen from anthers and robbed nectar, whereas long‐tongued hawkmoths and butterflies only collected nectar. Emasculation had no influence on long‐tongued pollinators, but significantly decreased the visitation frequency of short‐tongued visitors and fruit set, compared to intact flowers, demonstrating short‐tongued visitors did not effectively pollinate and acted merely as pollen thieves or nectar robbers when SPP was absent. Data from the two plant species clearly indicated pistillate SPP has additional adaptive advantages of converting ineffective visitors into pollinators and consequently widening the pollination niche, which could help plants overcome environmental stochasticity. Our results suggest that multiple selective forces drive the evolution of SPP and the minimization of herkogamy. [ABSTRACT FROM AUTHOR]

Elastic ring squeeze film damper (ERSFD) is extensively used in industrial rotating systems due to its excellent noise control and vibration suppression characteristics. However, the oil film sealing and leakage has a profound effect on the mechanical and vibration characteristics of the ERSFD and the ERSFD-rotor during operation. The sealing and leakage reduce the axial flow of the oil film, leading to changes in the initial boundary conditions of the flow field, which in turn affects the oil film pressure and damping coefficient of ERSFD. Meanwhile, the sealing causes an increase in the oil film force of ERSFD, which in turn affects the response of the rotor system. But there is relatively little research on the impact of sealing and leakage on the dynamic performances of ERSFD-rotor. In this paper, a mathematical model of ERSFD under different sealing conditions (no end seal, complete end seal, piston ring seal, O-ring seal) is established by changing the initial boundary equations of the flow field of ERSFD and the coupled solution of the Reynolds equation of ERSFD with different sealing and leakage boundary equations is realized. Then, the characteristics of oil film pressure and force of ERSFD under different sealing conditions is studied. After that, an ERSFD-rotor model considering oil film sealing and leakage is established based on displacement compatibility conditions and force balance principles. Meanwhile, the impact of sealing and leakage on the amplitude-frequency relation and sudden imbalance of an ERSFD combined support rotor is researched. The research results reveal that good sealing can significantly increase the damping of the system, thereby reducing the vibration amplitude of the ERSFD-rotor system. In addition, good sealing conditions can also shorten the transient process of sudden unbalanced excitation. Finally, the effectiveness of some simulation results was verified through experiments on the ERSFD rotor test bench. • This paper proposes a model of ERSFD under different sealing conditions by coupling different boundary equations. • The dynamic characteristics of oil film pressure and force of ERSFD under different sealing conditions are analyzed. • The impact of different sealing and leakage conditions on vibration amplitude and damping of ERSFD rotor is analyzed. • Experimental testing for the amplitude frequency response of ERSFD-rotor with no end seal is carried out. [ABSTRACT FROM AUTHOR]

In actual engineering practice of the variable stator vane (VSV) adjustment mechanism, it has been found that the deformation beyond design conditions of the kinematic chain formed from the linkage ring to the blades influences the motion accuracy of the mechanism the most. In this paper, the static stiffness model of the components system, formed from the linkage ring to the blades, is developed and then a motion compensation method based on the stiffness model is proposed. The correctness of the stiffness model is verified by the FEA method. With the model, influence factors such as blade quantity on the stiffness are characterized. In order to investigate the engineering applicability of the stiffness model, the motion compensation model is applied to the dynamic analysis and contrasts with the experimental results of two test benches designed based on the real VSV mechanisms. As a result, the validity of the stiffness model and the value of the proposed method are both well affirmed. • Deformable components are extracted to form the components system. • The components system stiffness is theoretically evaluated. • The concept of motion compensation based on the stiffness model is proposed. • The stiffness model is applied to the dynamic analysis of test rigs. • The proposed model is recognized through experiments. [ABSTRACT FROM AUTHOR]

Bolted joints are the major connection form to hold the aero-engine rotor system as a discontinuous entirety. What is noteworthy is that the bolt assembly process (BAP) directly relates the uniformity of preload and the symmetry of joint stiffness when the rotor comes to assembly, thereby introducing a heightened level of complexity and unpredictability to the dynamic response of the rotor system. In this paper, the effect of BAP on the stiffness softening of bolted flange joints is analyzed based on a finite element contact model. Then, a bolted joint rotor system finite element model is established to discuss the magnitude-frequency characteristic under three assembly sequences of bolts. The rotor vibration response is further compared between the three sequences considering the stiffness loss. Finally, the theoretical studies are verified by a rotor test rig. Results demonstrate that the stiffness softens to varying degrees with the increase of external load, and the softening mechanism is intricately associated with the contact state of the joint interfaces. Intriguingly, joint stiffness and its softening law are also affected by the BAP, leading to substantial discrepancies in rotor critical speed and vibration response among different assembly sequences. It is further observed that the tangential stiffness softening complicates the dynamic properties of the rotor system and enhances the nonlinear features. [ABSTRACT FROM AUTHOR]

The purpose of this article is to study the coupling effects of support stiffness on geometric scaling factor powers of the rotor-bearing system and predict vibration characteristics of a prototype by scaled models accurately. Associated to the least-squares–based similitude method, the discrete iteration method proposed evaluates the estimated scaling laws under variable (instable) powers and further broadens the restriction of boundary conditions in scaling laws, which is the main finding in this article. The discrete iteration method does not need to establish a physical model but directly uses input and output parameters to establish output scaling laws. The complete scaled model and geometric distorted model are selected as study cases to prove the effectiveness and accuracy of the discrete iteration method. The vibration characteristics of the rotor-bearing system are obtained by the finite element method with validation by experimental test for the natural characteristics. The comparison between the prediction results and those without the discrete iteration method shows that discrete iteration method can significantly improve the accuracy for predicting the prototype. [ABSTRACT FROM AUTHOR]

The boundary element method- (BEM-) based free field recovery technique (FFRT) has been proposed to recover the free field radiated by an arbitrarily shaped source from the mixed field that would be measured in a noisy environment. However, that technique requires that the boundary integral equation should be established on an enclosed hologram surface surrounding the source, which means that the hologram surface should be discretized into elements and the measurement points should be located on the nodes of the elements. For large-scale or mid-high frequency problems, it makes the total number of measurement points huge since it should obey the criterion of more than six elements per wavelength, which put forward very high requirements for holographic data measurement. To overcome this problem, a more flexible BEM-based FFRT without the restriction on the locations of measurement points is proposed in this study. In virtue of this, a three-dimensional scanning measurement method can be applied to acquire holographic data with high efficiency. The effectiveness of the proposed method is validated by two numerical simulations and an experiment. [ABSTRACT FROM AUTHOR]

Track irregularities induce potential risks to the safety and stability of railway track systems. This paper proposes a novel methodology to identify vertical and lateral track irregularities. The method involves measuring system-based attitude calculation and a model-based unknown input observer estimator, based on the dynamic responses of distributed multi-sensors on the vehicle and bogie. First, a mechanical model of wheel-rail contacts is built with dynamic methods. The model considers the different directions of motion for a railway vehicle and consists of two bogies and four wheelsets. Based on the multi-sensor acceleration measurement, the vertical and lateral acceleration signals of the vehicle and bogies are integrated into the displacement signal. Then a state-space description of the vehicle suspension model is established for inverse dynamical analysis to extract the input signals. A suitable unknown input observer is constructed to estimate the track irregularities by transforming the state space equations of the vehicle into an augmented system that can monitor the track irregularities in-service. This method provides an opportunity to reduce the costs of the monitoring infrastructure and provide quicker and more reliable information about the status of a track. [ABSTRACT FROM AUTHOR]

This article presents a novel system identification method for the dynamic parametrical model of the rotor-bearing system based on the Nonlinear Auto-Regressive with exogenous inputs (NARX) model, where the physical parameter of the system appears as coefficients in the model. Customarily, the NARX model-based modeling techniques require random signals as input, which leads to the rotor-bearing system that cannot be modeled using such techniques. To solve this issue, an improved system identification method, defined as the frequency sweep system identification approach is proposed in this paper. Firstly, the frequency domain version modeling framework with a physical parameter is derived based on the traditional modeling framework of the dynamic parametrical model. And then, the candidate model term dictionary corresponding to the frequency domain version modeling framework is derived. The Predicted Residual Sums of Squares based Extended Forward Orthogonal Regression algorithm is applied to identify the dynamic parametrical model of the rotor system. The model obtained by using the proposed method is validated based on the Model Predicted Output method. Finally, an experimental case of the rotor-bearing test rig is demonstrated to show the feasibility of the proposed method for real-world scenarios. Both the numerical and experimental studies illustrating the feasibility of the proposed modeling method, which provides a reliable model for time-domain response prediction and dynamic analysis of the rotor system. [ABSTRACT FROM AUTHOR]

Nowadays, the research of photothermal-chemical co-therapy provides new ideas for the treatment of cancer. However, the harsh photothermal temperature hinders the clinical development of photothermal therapy. To ensure low-temperature photothermal-chemical combined therapy, a safe and feasible drug delivery system is highly desirable. Herein, through one step co-precipitation method, ginsenoside Rb1-based nanovehicles composed of the hydrophobic drug doxorubicin, the photochemical reagent Cypate and the heat shock protein inhibitor gambogic acid was prepared, resulting from the amphiphilicity and membrane permeability of Rb1. Encouragingly, this platform exhibited excellent biocompatibility and rapid cellular uptake, both of which led to significant and irreversible death of breast cancer cells under the trigger of short-term near-infrared light. [ABSTRACT FROM AUTHOR]

In rotating machines, bolted joints are widely employed to connect adjacent disks to make multiple parts into an integrated one. The contact interface, subjected to tangential force introduced by unbalanced forces during normal operation, influencing the rotor dynamics, especially in the presence of relative speed, is of interest for investigations. However, there are little researches on the rotor dynamics considering the contact interface friction of the bolted disk joint. Thus, a dynamic model of the rotor-bearing system is established, which considers the friction at the contact interface between disks, nonlinear oil-film force, etc. The nonlinear dynamic phenomena of the rotor system were investigated using the fourth-order Runge–Kutta method. Bifurcation diagrams, vibration waveforms, frequency spectrums, shaft orbits, and Poincaré maps are used to demonstrate the diversity of the system responses. The results indicate that the rotor system exhibits a rich diversity motion states, such as periodic-1 motion, multiple periodic motion, and quasi-periodic motion. The parametric study about the effect of friction coefficient on rotor dynamics is also conducted in the present work, which shows that a larger friction coefficient will lead the system enters into an unstable motion state at high rotating speed, and make the system enters into multiple periodic bifurcations at a higher rotating speed. The corresponding results can contribute to the further understanding of the nonlinear dynamic characteristics of the bolted joint rotor-bearing system. [ABSTRACT FROM AUTHOR]

Background: As the birth policy has been adjusted from one-child-one-couple to universal two-child-one-couple in China, there is an increasing number of women undergoing a second pregnancy after a previous cesarean section (CS). Undertaking an elective repeat CS (ERCS) has been taken for granted and has thus become a major contributor to the increasing CS rate in China. Promoting trial of labor after CS (TOLAC) can reduce the CS rate without compromising delivery outcomes. This study aimed to investigate Chinese obstetricians' perspectives regarding TOLAC, and the factors associated with their decision-making regarding recommending TOLAC to pregnant women with a history of CS under the two-child policy.Methods: A cross-sectional survey was carried out between May and July 2018. Binary logistic regression was used to determine the factors associated with the obstetricians' intention to recommend TOLAC to pregnant women with a history of CS. The independent variables included sociodemographic factors and perceptions regarding TOLAC (selection criteria for TOLAC, basis underlying the selection criteria for TOLAC, and perceived challenges regarding promoting TOLAC).Results: A total of 426 obstetricians were surveyed, with a response rate of ≥83%. The results showed that 31.0% of the obstetricians had no intention to recommend TOLAC to pregnant women with a history of CS. Their decisions were associated with the perceived lack of confidence regarding undergoing TOLAC among pregnant women with a history of CS and their families (odds ratio [OR] = 2.31; 95% CI: 1.38-1.38); obstetricians' uncertainty about the safety of TOLAC for pregnant women with a history of CS (OR = 0.49; 95% CI: 0.27-0.96), and worries about medical lawsuits due to adverse delivery outcomes (OR = 0.14; 95% CI: 0.07-0.31). The main reported challenges regarding performing TOLAC were lack of clear guidelines for predicting or avoiding the risks associated with TOLAC (83.4%), obstetricians' uncertainty about the safety of TOLAC for women with a history of CS (81.2%), pregnant women's unwillingness to accept the risks associated with TOLAC (81.0%) or demand for ERCS (80.7%), and the perceived lack of confidence (77.5%) or understanding (69.7%) regarding undergoing TOLAC among pregnant women and their families.Conclusion: A proportion of Chinese obstetricians did not intend to recommend TOLAC to pregnant women with a history of CS. This phenomenon was closely associated with obstetricians' concerns about TOLAC safety and perceived attitudes of the pregnant women and their families regarding TOLAC. Effective measures are needed to help obstetricians predict and reduce the risks associated with TOLAC, clearly specify the indications for TOLAC, improve labor management, and popularize TOLAC in China. Additionally, public health education on TOLAC is necessary to improve the understanding of TOLAC among pregnant women with a history of CS and their families, and to improve their interactions with their obstetricians regarding shared decision making. [ABSTRACT FROM AUTHOR]

We present an effective approach to favorably modify the electronic structure of PbSe using Ag doping coupled with SrSe or BaSe alloying. The Ag 4d states make a contribution to in the top of the heavy hole valence band and raise its energy. The Sr and Ba atoms diminish the contribution of Pb 6s2 states and decrease the energy of the light hole valence band. This electronic structure modification increases the density‐of‐states effective mass, and strongly enhances the thermoelectric performance. Moreover, the Ag‐rich nanoscale precipitates, discordant Ag atoms, and Pb/Sr, Pb/Ba point defects in the PbSe matrix work together to reduce the lattice thermal conductivity, resulting a record high average ZTavg of around 0.86 over 400–923 K. [ABSTRACT FROM AUTHOR]

We present an effective approach to favorably modify the electronic structure of PbSe using Ag doping coupled with SrSe or BaSe alloying. The Ag 4d states make a contribution to in the top of the heavy hole valence band and raise its energy. The Sr and Ba atoms diminish the contribution of Pb 6s2 states and decrease the energy of the light hole valence band. This electronic structure modification increases the density‐of‐states effective mass, and strongly enhances the thermoelectric performance. Moreover, the Ag‐rich nanoscale precipitates, discordant Ag atoms, and Pb/Sr, Pb/Ba point defects in the PbSe matrix work together to reduce the lattice thermal conductivity, resulting a record high average ZTavg of around 0.86 over 400–923 K. [ABSTRACT FROM AUTHOR]

For the characterization of joint contact model of the variable stator vane (VSV) mechanism, the dry friction properties of joint materials must be taken into account. In this paper, the important parameters characterizing the joint contact model are experimentally tested, and then the characterized contact model containing the parameters is utilized for the dynamic analysis of a principle-level VSV mechanism test rig, including the dry friction rotary pair. Firstly, the friction tests and the vibration tests induced by the friction process are carried out. Then an ideal comprehensive dynamic model of the scaled system of VSV mechanism's single kinematic chain is established through the Lagrange multiplier method. The friction coefficient values obtained from the test are embedded into the contact force model considering friction factors and compared with other macro models. The accuracy of the hybrid contact model is verified through a one-shot contact-impact simulation and the corresponding displacement is measured for evaluation with accuracy of established ideal dynamic model. Finally, the influence of different driving methods on the dynamic characteristics of the system is analyzed. • Characterization of joint contact model considering friction based on experiment. • Dynamic model of scaled VSV mechanism is established. • Application joint contact model to dynamic analysis of scale mechanism. [ABSTRACT FROM AUTHOR]

Objective: To determine whether pre-eclampsia is associated with polymorphisms in superoxide dismutase (SOD) genes among mother-father-infant triads.Methods: We did this follow-up cohort study at 17 urban hospitals in Canada between October 1, 2008, and September 30, 2010. We recruited Canadian participants who had participated in the International Trial of Antioxidant Supplementation for the Prevention of Pre-eclampsia. Saliva specimens were collected for DNA extraction. The SOD1 +35A/C (rs2234694) and SOD2 Ala16Val C/T (rs4880) single-nucleotide polymorphisms (SNPs) were genotyped.Results: Dual presence of the SOD2 Ala16Val TT variant among mother-father pairs (n=657) was associated with an increased risk of pre-eclampsia when compared with the absence of the TT variant among the mother-father pairs (7/48 [14.6%] vs 11/339 [3.2%]; adjusted odds ratio 6.80, 95% confidence interval 2.32-19.95; P<0.001). By contrast, presence of a single T variant in mother-father pairs (16/270 [5.9%]) or mother-infant pairs (8/179 [4.5%]) was not associated with pre-eclampsia. The SOD1 +35A/CSNP was not associated with pre-eclampsia.Conclusion: The SOD2 Ala16Val SNP might be involved in paternal influence on the maternal predisposition to pre-eclampsia. Genotyping of mother-father pairs could be a promising strategy to identify pre-eclampsia genes. [ABSTRACT FROM AUTHOR]

Background: The COVID-19 pandemic has caused more than 462,417 deaths worldwide. A large number of patients with severe COVID-19 face death in hospital. Hospice care is truly a philosophy of care that delivers patient-centred care to the terminally ill and their families. Hospice care could provide many benefits for patients, families, and for hospice caregivers. The aim of this study is to investigate hospice care self-efficacy and identify its predictors among Chinese clinical medical staff in COVID-19 isolation wards of designated hospitals. Methods: A cross-sectional design was used. The Hospice Care Self-Efficacy, Self-Competence in Death Work Scale, Positive Aspects of Caregiving, and Simplified Coping Style Questionnaires were administered between February and April 2020. A total of 281 eligible medical staff responded to the questionnaires, with a response rate of ≥78.9%. Results: The mean score of hospice care self-efficacy was 47.04 (SD = 7.72). Self-efficacy was predicted by self-competence in death work (B = 0.433, P < 0.001), positive aspects of caregiving (B = 0.149, P = 0.027), positive coping (B = 0.219, P < 0.001), giving hospice care to dying or dead patients before fighting against COVID-19 (B = -1.487, P = 0.023), occupational exposure while fighting against COVID-19 (B = -5.244, P = 0.004), holding respect for life and professional sentiment as motivation in fighting against COVID-19 (B = 2.372, P = 0.031), and grade of hospital employment (B = -1.426, P = 0.024). The variables co-explained 58.7% variation of hospice care self-efficacy. Conclusion: Clinical nurses and physicians fighting COVID-19 reported a moderate level of hospice care self-efficacy during this pandemic. Exploring the traditional Chinese philosophy of life to learn from its strengths and make up for its weaknesses and applying it to hospice care may provide a new framework for facing death and dying during the COVID-19 pandemic. Continuous hospice care education to improve self-competence in death work, taking effective measures to mobilize positive psychological resources, and providing safer practice environments to avoid occupational exposure are also essential for the improvement of the hospice care self-efficacy of clinical nurses and physicians. These measures help caregivers deal effectively with death and dying while fighting against the COVID-19 pandemic. [ABSTRACT FROM AUTHOR]

The finite size of a sound-absorbing material may lead to inaccurate results when measuring the acoustical properties of the material using the free-field measurement methods. In this study, a method of estimating the acoustical properties of locally reactive finite materials is proposed by combining a sound field model established by the boundary element method with an iteration algorithm. The proposed method takes the finiteness of the material into account, meaning that the size effect is removed and accurate results can be obtained. Numerical simulations and experiments of two kinds of materials, including a rigid floor and a porous material, are carried out to verify the validity of the proposed method. Results demonstrate that the proposed method is effective in estimating the acoustical properties of these two kinds of materials. Besides, a detailed analysis of the influences of the sample size, the source location, and the receiving point position is done in the simulations. [ABSTRACT FROM AUTHOR]

In this study, we investigate the dynamic scaling laws of geometrically similitude models and systems for predicting their vibration characteristics accurately. A determination method of scaling laws based on least square method for calculating weighted powers of scaling factors is proposed for the first time. Taking geometric parameters as input (design) parameters and vibration characteristics parameters as output parameters, the weighted powers of scaling factors are calculated by least squares similitude method (LSSM) with several design models, and then scaling factors of the output parameters are obtained by combining weighted powers and corresponding scaling factors. Applicability of the LSSM is verified in the following two cases with rectangular plate and rotor-bearing system that the stiffness of supports is taken into account. The vibration characteristics are calculated by using finite element method in MATLAB and compared with simulation analysis software ANSYS. As a result, stable weighted powers and good predictions are obtained for two cases. [ABSTRACT FROM AUTHOR]

A dynamic model of the rotor-bearing system with bolted joint structure is set up based on the Lagrange's equations, which considers the bearing clearance, the gyroscopic effect and the initial deformation due to the non-uniform preload. The nonlinear dynamic responses of the system were obtained by using the Runge–Kutta–Fehlberg method, and then the influence of the radial bearing clearance on the nonlinear dynamic behaviors of the rotor system is studied by means of bifurcation diagram, frequency spectrum, shaft orbits and Poincaré maps. The results indicate that the larger bearing clearance will make the system enter into chaotic motion at a lower rotating speed. In addition, with the increase in bearing clearance, the duration of the chaotic motion becomes longer. Furthermore, the influence of initial deformation on the stability of the bolted joint rotor system with bearing clearance is studied. The results show that when the bearing clearance is present, the instability speed of the rotor system will gradually rise with the increase in initial deformation. Meanwhile, as the bearing clearance continuously increases, the regions of the chaotic motion become less and smaller, and the motion state should be completely changed under certain initial deformation. The related results can provide guidance for the optimization and design of the bolted joint rotor-bearing system. [ABSTRACT FROM AUTHOR]

In practice, it is usually difficult to estimate the characteristic parameters of a system due to the system nonlinearity and uncertainty. To address this problem, in this study, the characteristic parameters of a nonlinear system are identified by using a data driven method based on the best discretization of the Nonlinear Differential Equation (NDE) model of the system. The best discretization of a NDE model is firstly determined, and then the discretized model, known as the Nonlinear Auto Regressive with eXegenous input (NARX) model, is determined by using the Least Squares (LS) algorithm from the input and output data of system. A case study is discussed to validate the proposed system parameter identification method, where the characteristic parameters of a rotating blade-casing system are evaluated under a bandwidth rub impact in the horizontal direction with noise. The result shows that the identified model can be used to describe the characteristics of the underlying system accurately, which provides a reliable model for the dynamic analysis, control of rotating blade-casing system. Used the input and output datum of system and the functional relationship between parameters and coefficients of NARX model to confirm these key parameters. Image 1 • Four different discrete methods are compared and the best discretization of a NDE model is confirmed. • The function relationship between characteristic parameters of systems and coefficients of NARX model is discussed. • The error of each discrete method is analyzed theoretically. • A novel identification method, referred as the DDM, is utilized to identify the parameters of a rotating blade-casing system. [ABSTRACT FROM AUTHOR]

C26H31N5NiO8, monoclinic, P21/n (no. 14), a = 12.554(3) Å, b = 12.401(3) Å, c = 18.718(5) Å, β = 107.844(3)°, V = 2774.0(12) Å3, Z = 4, Rgt(F) = 0.0438, wRref(F2) = 0.1175, T = 153(2) K. [ABSTRACT FROM AUTHOR]

This study investigates the determination approach of distorted scaling laws for predicting the dynamic characteristic of an aero engine's blisk. Based on the dynamic scaling laws of typical thin-walled structures, an assumption of geometrically complete scaling laws is firstly proposed and numerically validated. For distorted models of disk thickness, in order to simplify the design procedure, a simplification condition is proposed and applied to the first 10 orders' distorted scaling laws (blade-dominated vibrations) by combining sensitivity analysis. Next, the 11th-14th orders' distorted scaling laws are determined for disk-dominated vibrations. Numerical validation demonstrates that distorted scaling laws possess a good accuracy. Finally, the applicability of these new scaling laws is validated by the experimental data. The results indicate that, by using the new scaling laws, the simple models can predict vibration characteristics of blisk by employing similitude models. [ABSTRACT FROM AUTHOR]

The Ordos Basin is the largest petroliferous basin in China, where the Chang 7 Member shale serves as the major source rock in the basin, with an area of more than 100,000 km2. So far, sedimentary and geochemical characterizations have rarely been conducted on the shale in shallow (< 1000 m) areas in the southeastern part of the basin, but such characterizations can help identify the genesis of organic-rich shale and promote the prediction and recovery of shale oil. In this paper, several outcrop sections of the Chang 7 Member in the Tongchuan area were observed and sampled, and sedimentary and geochemical characterizations were conducted for the well-outcropped YSC section. The study results show that the Chang 7 Member shale is widely distributed laterally with variable thickness. The organic-rich shale is 7–25 m thick in total and exhibits obvious horizontal variation in mineral composition. In the eastern sections, the shale contains organic matter of Type II2–III and is low in thermal maturity, with high clay mineral content, low K-feldspar content, and no pyrite. In the western sections, the shale contains Type II1 organic matter and is low in thermal maturity, with high clay mineral, K-feldspar, and pyrite contents. The YSC section reveals three obvious intervals in vertical mineral composition and organic abundance. The Chang 7 Member organic-rich shale (TOC > 10%) contains mainly sapropelite and liptinite, with Type II kerogen. It is generally characterized by a hydrocarbon potential of more than 70 mg/g, low maturity, and shallow–semideep lacustrine facies. In the western sections, the shale, still in a low maturity stage, has a higher hydrocarbon potential and is optional for shale oil recovery. However, the Chang 7 Member shale in the study area is highly heterogeneous and its shale oil recovery is practical only in the organic-rich intervals. [ABSTRACT FROM AUTHOR]

Abstract Data acquisition is one of the key steps in near-field acoustic holography. Most of the existing measurement methods become time-consuming or even impractical when the total number of measurement points is excessively large, for example for the sound field reconstruction of a large-scale source or for a mid-high frequency problem. Alternatively, a three-dimensional scanning near-field acoustic holography (3DSNAH) method is hereby proposed to overcome such problems providing the sound field is time stationary. Data measurement at a large number of points can be accomplished in a matter of minutes by using scanning measurements to acquire the holographic data. The data is then used in an inverse boundary element method to obtain a detailed reconstruction of the sound field radiated by the sound source. Comparison with the traditional point-by-point measurement method demonstrates that the proposed method can acquire holographic data of good quality and reconstruct the sound field with a reasonable accuracy, which verifies the feasibility of the 3DSNAH. [ABSTRACT FROM AUTHOR]

Highlights • A kind of dynamic parametrical model is identified for the analysis and design on nonlinear systems. • An improved Extended Forward Orthogonal Regression algorithm is proposed to promote the efficiency in computation. • The proposed algorithm can circumvent the overfitting problem. • An iterative design that produces a sequence of suboptimal models is applied in the modeling process. Abstract In this study, the identification of a Nonlinear Auto-Regressive with exogenous inputs (NARX) model of nonlinear systems, where the physical parameters of interest for the system design appear explicitly as coefficients in the model, is studied. The model is a dynamic parametrical model, referred as the NARX model with parameters of interest for design (NARX-M-for-D). An improved algorithm, known as the Iterative Extended Forward Orthogonal Regression (IEFOR), is proposed to identify the NARX-M-for-D of nonlinear systems. Firstly, a common-structured model, referred to as the “initial model”, is established through the traditional Extended Forward Orthogonal Regression (EFOR) algorithm. Then an iterative process is applied to revise the initial model such to produce an improved model of the system, which is referred to as the “common model” in this study. Finally, functional relationships of the common model coefficients are established to determine the NARX-M-for-D of the system. Both the simulation and experimental studies are discussed to illustrate the application of the new algorithm. The results indicate that, by using the IEFOR algorithm, the established model can accurately predict the system out response and remain the merit of efficiency in computation. The new algorithm is expected to be applied in the identification of nonlinear systems in engineering practice. [ABSTRACT FROM AUTHOR]

Abstract: Sb‐doped and GeTe‐alloyed n‐type thermoelectric materials that show an excellent figure of merit ZT in the intermediate temperature range (400–800 K) are reported. The synergistic effect of favorable changes to the band structure resulting in high Seebeck coefficient and enhanced phonon scattering by point defects and nanoscale precipitates resulting in reduction of thermal conductivity are demonstrated. The samples can be tuned as single‐phase solid solution (SS) or two‐phase system with nanoscale precipitates (Nano) based on the annealing processes. The GeTe alloying results in band structure modification by widening the bandgap and increasing the density‐of‐states effective mass of PbTe, resulting in significantly enhanced Seebeck coefficients. The nanoscale precipitates can improve the power factor in the low temperature range and further reduce the lattice thermal conductivity (κlat). Specifically, the Seebeck coefficient of Pb0.988Sb0.012Te–13%GeTe–Nano approaches −280 µV K−1 at 673 K with a low κlat of 0.56 W m−1 K−1 at 573 K. Consequently, a peak ZT value of 1.38 is achieved at 623 K. Moreover, a high average ZTavg value of ≈1.04 is obtained in the temperature range from 300 to 773 K for n‐type Pb0.988Sb0.012Te–13%GeTe–Nano. [ABSTRACT FROM AUTHOR]

The aim of the present study was to improve the conventional wire-guided localization biopsy (WGLB) of breast microcalcifications to overcome disadvantages associated with the procedure, including inaccurate localization and large specimen volume. The novel approach described in the present study was termed double wire-guided localization and rotary cutting biopsy (DWGLB). Prior to surgery, the precise localization of the lesions was assessed using two wires under the assistance of mammography X-ray and ultrasound, followed by complete excision of the lesions using a novel rotary cutting tool. The cylindrical specimen was placed on a scaled specimen holder for pathological examination. DWGLB was performed in 108 patients with the classification of as Breast Imaging Reporting and Data System score 4A. Percutaneous localization of the lesions guided by a mammography X-ray and ultrasound were successful in all 108 lesions (100%) with one puncture attempt. The lesions were precisely excised in all of 108 patients, and included 13 malignant lesions (DCIS of breast in 7 cases, DCIS with focal invasive carcinoma in 3 cases and invasive ductal carcinoma in 3 cases). The average distance of the BARD Dualok to the lesion was 4.1 mm; the average weight of specimens was 8.5 g. Compared with WGLB, DWGLB offers several advantages, including more accurate localization of lesions, a more standardized biopsy method and a smaller specimen volume. DWGLB can also provide the precise position of lesions in the specimen for further pathological examination. [ABSTRACT FROM AUTHOR]

To better suppress low-frequency vibrations of flexible manipulators induced by the rotation of motors and eccentricity, a novel type of tuned particle damper (TPD) is designed by combining the advantages of classical dynamic vibration absorber (DVA) and particle dampers (PD). Compared to traditional DVAs, this TPD can reduce additional mass and effectively broaden the frequency band of the DVA. Firstly, an equivalent theoretical model is established to describe the frequency tuning principle of the designed TPD. Based on the theory of a single particle damper, the equivalent damping and stiffness of the particles are calculated through an approximate approach. Then, a three-degree-of-freedom vibration model of the manipulator system with the TPD is built, and the dynamical characteristic of the primary resonance for the coupled system are analyzed by the perturbation method. Finally, the experimental platform is set up to verify the theoretical results. A manipulator is applied to test the low-frequency vibration absorption of the designed TPD, and the vibration suppression effect is discussed both in theoretical analysis and experiments. [ABSTRACT FROM AUTHOR]

This research proposes a novel type of variable stiffness tuned particle damper (TPD) for reducing vibrations in boring bars. The TPD integrates the developments of particle damping and dynamical vibration absorber, whose frequency tuning principle is established through an equivalent theoretical model. Based on the multiphase flow theory of gas-solid, it is effective to obtain the equivalent damping and stiffness of the particle damping. The dynamic equations of the coupled system, consisting of a boring bar with the TPD, are built by Hamilton's principle. The vibration suppression of the TPD is assessed by calculating the amplitude responses of the boring bar both with and without the TPD by the Newmark-beta algorithm. Moreover, an improvement is proposed to the existing gas-solid flow theory, and a comparative analysis of introducing the stiffness term on the damping effect is presented. The parameters of the TPD are optimized by the genetic algorithm, and the results indicate that the optimized TPD effectively reduces the peak response of the boring bar system. [ABSTRACT FROM AUTHOR]

• This paper presents a similitude method considering the vibration consistency. • The proposed method can improve the prediction accuracy of vibration responses. • The accuracy of proposed method is validated by comparing with existing methods. • The comparison results are verified by numerical and experimental studies. Similitude theory can be utilized to perform scaled experiments and facilitate the understanding of physical behaviors of large structures. However, the prediction accuracy in partial similitude is still needed to be improved. To address the problem, a partial similitude method is presented to improve the prediction accuracy. The vibration consistency is satisfied by developing the scaling laws of critical speed. In addition, the scaling laws of vibration response are developed after ensuring consistency. The ability and performance of the presented method are demonstrated using a simulation case study and an experiment case study. In both case studies, the presented method is utilized to reproduce the vibration responses of the prototype, which includes the predictions of resonant and non-resonant responses. Besides, the prediction results of the existing methods are also provided for comparison. In the numerical case, the errors of the proposed method are less than 3% in predicting the vibration amplitude. In the experimental case, the minimum and maximum errors are 0.1% and 14.4%, respectively. Moreover, the proposed method can achieve better performance than the current methods. [Display omitted] [ABSTRACT FROM AUTHOR]

C26H27ClN8NiO7, triclinic, P1̄ (no. 2), a = 9.893(2) Å, b = 11.503(2) Å, c = 13.295(3) Å, α = 78.77(3)°, β = 70.52(3)°, γ = 83.40(3)°, V = 1397.0(6) Å3, Z = 2, Rgt(F) = 0.0423, wRref(F2) = 0.1032, T = 153.15 K. [ABSTRACT FROM AUTHOR]

We study the drag force and diffusion coefficient with respect to a moving heavy quark in a D-instanton background, which corresponds to the Yang–Mills theory in the deconfining, high-temperature phase. It is shown that the presence of the D-instanton density tends to increase the drag force and decrease the diffusion coefficient, reverse to the effects of the velocity and the temperature. Moreover, the inclusion of the D-instanton density makes the medium less viscous. [ABSTRACT FROM AUTHOR]

The entropic force has been recently argued to be responsible for dissociation of heavy quarkonia. In this paper, we analyze R 2 corrections and R 4 corrections to the entropic force, respectively. It is shown that for R 2 corrections, increasing λ G B (Gauss–Bonnet factor) leads to increasing the entropic force. While for R 4 corrections, increasing λ (’t Hooft coupling) leads to decreasing the entropic force. Also, we discuss how the entropic force changes with the shear viscosity to entropy density ratio, η ∕ s , at strong coupling. [ABSTRACT FROM AUTHOR]

In recent decades, studies have reported that inflammation serves key roles in epilepsy and that high mobility group box protein-1 (HMGB1) may be involved in status epilepticus. However, it has not been reported whether HMGB1 participates in the pathogenesis of status epilepticus through the regulation of the p38 mitogen-activated protein kinase (p38MAPK) signalling pathway. In the present study, Sprague-Dawley rats were randomly divided into four groups as follows: Control, status epilepticus (SE), dimethyl sulfoxide treatment (DMSO + SE), and glycyrrhizin treatment (GL + SE) groups. Behavioural changes were then evaluated using the Racine score. In the hippocampus, the protein expression levels of HMGB1 were assessed using western blotting, the neuronal damage was evaluated using haematoxylin and eosin staining and transmission electron microscopy, and the activation of microglia was assessed using immunochemistry and immunofluorescence. The results demonstrated that, in the hippocampal region, HMGB1 existed in neurons and astrocytes and the protein expression levels of HMGB1, p38MAPK and phosphorylated-p38MAPK were significantly inhibited after treatment with GL. Furthermore, GL could alleviate neuronal injury in the CA1 region of the hippocampus and prevented HMGB1 translocation from the nucleus into the cytoplasm in these areas. These findings expand the understanding of how HMGB1 may participate in SE and lay a foundation for evaluation of HMGB1 as a drug target. [ABSTRACT FROM AUTHOR]

The Variable Stator Vane (VSV) mechanism is utilized to adjust the stator vane angles so as to delay the compressor stall. Establishing the dynamic model of the system, which is the basis to obtain different joint characteristics more in line with the real case, is worth analyzing. In this work, a comprehensive dynamic model of the scaled system of VSV mechanism's single kinematic chain by the Lagrange multiplier method is built, thus the spatial plane joint characteristic's effects on the behavior of the scaled system are investigated. Since a full-scale facility is unavailable for testing sometimes, the technique of similarity scaling is resorted to establishing the scaled principle-level model which has a certain relationship with the prototype in structure and material and so on. Then an example of the dynamic modeling procedure of the spatial RSSR mechanism included in the scaled model is presented with the aim of establishing a guide to model the whole system. Therefore, the equation of motion of the scale system is expediently established using some systematic method. Finally, inertial navigation sensors are used to measure the corresponding displacement for evaluation with accuracy of the established dynamic model. • Principle-level test rig design based on so-called similitude theory. • Dynamic model of scaled VSV mechanism is established. • The conformal contact model is applied, closer to the actual contact situation. • The rotation angle is measured using the inertial navigation system. • The rotation matrix of the rigid body based on the rotation axis vector is explained. [ABSTRACT FROM AUTHOR]

A similarity method for rotating composite blades in thermal environment is developed for the problems of difficulty, time consumption, high cost, and risk in the dynamic test under a high-temperature environment. Within this study, a set of scaling laws are derived for thin-walled composite plates based on their dynamic models and the applicability of the scaling laws is demonstrated in the similitude design of composite blades. The present dynamic model takes into account thermal stress and centrifugal stiffening effect. Analytical calculations show that the scaled models at relatively low temperatures can well reproduce the dynamic characteristics of their corresponding prototypes at high temperatures when taking into account the scaling of temperature change and rotational speed. • Thermal stress and centrifugal stiffening effect are considered in the dynamic model. • The scaling laws for temperature change, rotational speed, natural frequency, and acceleration response are deduced. • Models at low temperatures are used to predict prototypes in high-temperature operating environments. • The scaling laws for thin-walled composite plates are applicable to the prediction of composite blades. [ABSTRACT FROM AUTHOR]

We study the destruction of heavy quarkonium due to the entropic force in a deformed AdS5 model. The effects of the deformation parameter on the interdistance and the entropic force are investigated. The influence of the deformation parameter on the quarkonium dissociation is analyzed. It is shown that the interdistance increases in the presence of the deformation parameter. In addition, the deformation parameter has the effect of decreasing the entropic force. These results imply that the quarkonium dissociates harder in a deformed AdS background than in a usual AdS background, in agreement with earlier findings. [ABSTRACT FROM AUTHOR]

To solve the distributed task allocation problems of search and rescue missions for multiple unmanned aerial vehicles (UAVs), this paper establishes a dynamic task allocation model under three conditions: 1) when new targets are detected, 2) when UAVs break down and 3) when unexpected threats suddenly occur. A distributed immune multi-agent algorithm (DIMAA) based on an immune multi-agent network framework is then proposed. The technologies employed by the proposed algorithm include a multi-agent system (MAS) with immune memory, neighbourhood clonal selection, neighbourhood suppression, neighbourhood crossover and self-learning operators. The DIMAA algorithm simplifies the decision-making process among agents. The simulation results show that this algorithm not only obtains the global optimum solution, but also reduces the communication load between agents. [ABSTRACT FROM AUTHOR]

0D transition metal phosphides (TMPs) nanocrystals (NCs)-2D ultrathin black phosphorus (BP) heterostructure (Ni2P@BP) have been synthesized via a facile sonication-assisted exfoliation followed by a solvothermal process. Compared with the bare BP, the specially designed Ni2P@BP architecture can enhance the electrical conductivity (from 2.12 × 102 to 6.25 × 104 S m-1), tune the charge carrier concentration (from 1.25 × 1017 to 1.37 × 1020 cm-3), and reduce the thermal conductivity (from 44.5 to 7.69 W m-1 K-1) at 300 K, which can be considered for multiple applications. As a result, the Ni2P@BP exhibits excellent Li storage properties and high hydrogen evolution reaction electrocatalytic activities. The Ni2P@BP shows improved Li diffusion kinetics (e.g., the Li ions diffusion coefficient increases from 1.14 × 10-14 cm2 s-1 for pure BP nanosheets to 8.02 × 10-13 cm2 s-1 for Ni2P@BP). In addition, the Ni2P@BP electrode sustains hydrogen production with almost unchanged activity over 3000 cycles, which indicates its good chemical stability when operating under strong reducing environment. [ABSTRACT FROM AUTHOR]

Rapid developments in materials science and biological mechanisms have greatly boosted the research discoveries of new drug delivery systems. In the past few decades, hundreds of nanoparticle-based drug carriers have been reported almost on a daily basis, in which new materials, structures, and mechanisms are proposed and evaluated. Standing out among the drug carriers, the hybrid nanoparticle systems offer a great opportunity for the optimization and improvement of conventional chemotherapy. By combining several features of functional components, these hybrid nanoparticles have shown excellent promises of improved biosafety, biocompatibility, multifunctionality, biodegradability, and so forth. In this Personal Account, we highlight the recent research advances of some representative hybrid nanoparticles as drug delivery systems and discuss their design strategies and responsive mechanisms for controlled drug delivery. [ABSTRACT FROM AUTHOR]