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Solid-state refrigeration which is environmentally benign has attracted considerable attention. Mechanocaloric (mC) materials, in which the phase transitions can be induced by mechanical stresses, represent one of the most promising types of solid-state caloric materials. Herein, we have developed a thermodynamic phenomenological model and predicted extraordinarily large elastocaloric (eC) strengths for the (111)-oriented metal-free perovskite ferroelectric [MDABCO](NH4)I3 thin-films. The predicted room temperature isothermal eC ΔSeC/Δσ (eC entropy change under unit stress change) and adiabatic eC ΔTeC/Δσ (eC temperature change under unit stress change) for [MDABCO](NH4)I3 are −60.0 J K−1 kg−1 GPa−1 and 17.9 K GPa−1, respectively, which are 20 times higher than the traditional ferroelectric oxides such as BaTiO3 thin films. We have also demonstrated that the eC performance can be improved by reducing the Young’s modulus or enhancing the thermal expansion coefficient (which could be realized through chemical doping, etc.). We expect these discoveries to spur further interest in the potential applications of metal-free organic ferroelectrics materials towards next-generation eC refrigeration devices.

In order to obtain the effect of second phases on Charpy impact energy and crack propagation behavior of Hastelloy N sheet, Charpy notched impact toughness test have been accomplished with different directions (RD, ND) of V-notch after solution treatment. The fracture morphology and microstructure are observed by optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). It is shown that the dominant second phases in Hastelloy N after solution treatment includes molybdenum-riched Ni-Mo phase, which dissolve some elements such as chromium, silicon and ferrum, and a few carbides. The Charpy impact energy of sample 2# (RD) is 225J, almost twice as much as sample 1# (ND). Based on the reconstruction of morphology and distribution of second phases, the mechanism for effect of second phases on crack propagation behavior is discussed. The islands of second phase particles modify the stress triaxiality state, resulting in the propagation path of crack in 2# is totally different from that in 1#.

While extensive experimental activities have been carried out to study the phase transitions and ferroelectric properties of BaZrxTi1-xO3 solid solutions, the corresponding theoretical understanding is largely lacking due to the unavailability of thermodynamic potentials for this system. In this work, an eighth-order polynomial of thermodynamic potential for BaZrxTi1-xO3 (x≤0.3) solid solutions is established based on the existing potential coefficients of BaTiO3 and theexperimentally measured phase diagram of BaZrxTi1-xO3 solid solutions. It is then employed to predict and understand the domain structures and switching for BaZrxTi1-xO3 (x ≤0.3) single crystals using phase-field simulations. The simulated domain structures and switching are consistent with thermodynamic analysis and available experimental measurements, validating the established thermodynamic potential. It is expected that this thermodynamic potential will find wide applications to studying the phase transitions and ferroelectric properties of BaZrxTi1-xO3 (x ≤0.3) bulk and nanoscale materials.

Background: Intrahepatic biliary cystadenoma (IBC) is a rare benign cystic tumor of the liver with carcinogenic potential. Due to its low incidence and lack of specific clinical symptoms and signs, IBC is easily confused with other cystic liver lesions; even today, IBC mistakenly underwent fenestration and drainage according to the hepatic cyst in adverse conditions consequences for patients.Methods: The clinical data of six patients with pathologically defined IBC, admitted to the Department of Hepatobiliary Surgery of the Affiliated Hospital of Guangdong Medical University from January, 2011, to July, 2021 were retrospectively analyzed.Results: Four patients (4/6) were diagnosed with IBC preoperatively, administrated the surgery, and discharged successfully. One patient underwent single-port laparoscopic fenestration and drainage of liver cyst, cyst wall biopsy, intraoperative pathology revealed IBC, then open left hemihepatectomy. Another patient underwent laparoscopic fenestration and drainage of hepatic cyst. Intraoperative pathologic diagnosis from cyst wall biopsy showed a simple hepatic cyst, but the final pathological diagnosis was IBC. The remaining liver volume was insufficient to undergo liver resection; the patient was again referred to our institution after four months with right upper quadrant pain. Computed tomography revealed extensive abdominal nodules, considered malignant transformation, and the patient died three months later.Conclusion: Since atypical IBC is easily misdiagnosed as hepatic cysts, and we propose paying attention to cystic wall morphology and cyst fluid properties during the operation. At the same time, it is recommended that patients diagnosed with liver cysts undergo intraoperative pathological diagnosis and strengthen communication with pathologists to deepen understanding of IBC, which avoids missed diagnosis, wrong operation, or even secondary operation.

Stimulated by the outstanding colossal permittivity behavior achieved in trivalent and pentavalent cations co-doped rutile TiO2 ceramics, the co-doping effects on the dielectric behavior of Ba0.4Sr0.6TiO3 ceramics were further explored. In this work, (Al + Nb) co-doped Ba0.4Sr0.6TiO3 ceramics were synthesized via a standard solid state ceramic route. The structural evolution was analyzed using X-ray diffraction patterns and Raman spectra. Dense microstructures with no apparent change of grain morphology were observed from the scanning electron microscopy. A huge enhancement of dielectric permittivity was obtained with 1 mol% (Al + Nb) doping and excellent dielectric performances (er ∼ 20,000, tanδ ∼ 0.06 at 1 kHz) were achieved after further heat treatment. The formation of electron pinned defect dipoles localized in grains may account for the optimization of dielectric behaviors and the corresponding chemical valence states were confirmed from the XPS results.

Porous texture of graphene-hydrogel electrode material is critical for the performance of supercapacitors. In this work, the pore channels are controlled by two aspects, including the graphene oxide concentration and the pressure for fabricating hydrogel electrodes. It is found that the sample starting from 3 mg ml−1 graphene oxide shows the largest specific capacitance of 297 F g−1 at a current density of 0.5 A g−1 in 2 M KOH solution after the hydrothermal process. By increasing the pressure to 10 MPa, the electrochemical performance can be further improved to 330 F g−1. This good performance is mainly attributed to the preferable specific surface area (2110 m2 g−1) and the dense laminated structure under the optimizing preparation conditions. Besides, the cycle measurement demonstrates the excellent cycling stability of the samples, while 88% of its initial capacitance can be retained after 10,000 cycles.

The oxalate co-precipitation method was employed to synthesize nanocrystalline Ba0.4Sr0.6TiO3 having an average particle size of 100 nm. The conventional sintering (CS) and spark plasma sintering (SPS) methods were used to fabricate Ba0.4Sr0.6TiO3 ceramics with different microstructures. The SPS sample presented uniformly dense microstructure and ultrafine grains, while abnormal grain growth and some pores were discerned in the CS sample. The differences in microstructure significantly affected the dielectric properties and energy storage performance of the ceramics. The dielectric constant of the SPS sample was high (eʹ ˜1200), its dielectric loss was low (tanδ ˜0.003), and the sample presented diffuse phase transition and high breakdown strength (Eb = 260 kV/cm) at room temperature. Compared with the CS sample, the maximum energy storage density and energy storage efficiency of the SPS sample were increased from 0.61 to 1.20 J/cm3 and 72.6% to 91.6%, respectively. All results revealed that SPS is a powerful technique to produce dense ceramics with high energy storage performance.

Magnetoelectric effect is directly measured in the Ba4(SmxLa1-x)2Fe2Nb8O30 ceramics, which is rarely reported in tungsten bronze ceramics. Besides, the effects of Sm-substitution on the crystal structure, dielectric, ferroelectric and magnetic properties have been systematically studied. XRD Rietveld refinement confirms all the ceramics to be single phase with space group of P4bm. With the increase of x, Ba4(SmxLa1-x)2Fe2Nb8O30 ceramics transform from paraelectric to ferroelectric. The compositions of x = 0.9, 0.95 and 1 show first-order ferroelectric phase transitions above room temperature. Compared to composition x = 0, the dielectric constant of other compositions exhibits frequency stability and the dielectric loss decreases apparently at room temperature. The ferroelectricity improves with increasing x, which can be ascribed to the increased A2-A1 ionic radius difference. Meanwhile, the magnetic hysteresis loops are obtained for some compositions. All the results approve Ba4(SmxLa1-x)2Fe2Nb8O30 (x = 0.9, 0.95, 1) ceramics as room temperature multiferroic materials with intrinsic magnetoelectric effect.

Ba4Sm2FexTi4-2xNb6+xO30 (x = 0, 0.5, 1, 1.5, 2) ceramics were prepared by standard solid-state reaction, and the filled tungsten bronze phase with space group P4bm was confirmed for all compositions. Systematic investigation of the Fe-substitution effects on dielectric, ferroelectric as well as magnetic properties was conducted. As the value of x increased, the Curie temperature (Tc) shifted from 562 K to 411 K, which was consistent with the DSC results. The coercive field (Ec) also decreased monotonously from 90 kV/cm (x = 0) to 20 kV/cm (x = 2), suggesting that the substitution of Fe promoted the ferroelectric domain switching. Compared with Ba4Sm2Ti4Nb6O30 (x = 0), simultaneously enhanced ferroelectric and magnetic properties were realized for x = 1, 1.5 and 2. This work is expected to provide a guide for designing new multiferroic materials.

(Sr x Ba 1- x ) 4 Sm 2 Fe 2 Nb 8 O 30 ( x = 0, 0.1, 0.2, 0.3, 0.4) ceramics with tetragonal bronze structure were prepared by the standard solid-state method. With the increase of x , (Sr x Ba 1- x ) 4 Sm 2 Fe 2 Nb 8 O 30 ceramics transform from ferroelectric to paraelectric. The composition x = 0 shows first-order ferroelectric transition with T c above room temperature. The other compositions exhibit broad dielectric peaks with frequency dispersion, indicating a relaxor ferroelectric transition. Saturated P-E hysteresis loops and obvious peaks in the charging current–field ( J-E ) curves are observed at room temperature for x = 0 and 0.1 while paraelectric characteristics are detected for the others. Magnetic hysteresis loops are obtained for all the compositions and the remanent moment increases monotonously from 0.14 emu/g to 1.21 emu/g with the increasing concentration of Sr. All the results are expected to provide valuable guidance for searching new multiferroic tungsten bronze ceramics.

Barium zirconate titanate (BaTi0.7Zr0.3O3) ceramics were prepared via spark plasma sintering (SPS) and conventional solid-state sintering (CS). Both samples exhibited single phase nature as confirmed from the X-ray diffraction analysis. Compared with CS sample, more homogeneous microstructure with smaller grain size was observed in the SPS sample, which greatly improved the dielectric strength of BaTi0.7Zr0.3O3 ceramics from 40 (CS) to 170 kV/cm (SPS). Although the polarization of SPS sample was lower than that of CS sample under the same applied electric field, the maximum energy storage density was improved to 0.51 J/cm3, which was about 4.5 times higher than that of the CS sample (0.12 J/cm3). Moreover, finite element simulation on the local dielectric field distribution was carried out, and the effects of microstructure on the dielectric strength were further confirmed.

Carbon materials derived from pollen for supercapacitor electrode are feasibly prepared through a hydrothermal process with controlled content of ammonium borofruoride (NH4BF4) and subsequent carbonization. The effect of NH4BF4 on the morphology, microstructure, chemical state, texture structure and the electrochemical performance of the products are studied. It is found that the sample treated by 0.015 g ml−1 NH4BF4 during the hydrothermal process shows the highest specific surface area of 526 m2 g−1 as well as the largest specific capacitance of 205 F g−1 at a current density of 0.5 A g−1 in 2 M KOH solution [128% of the sample hydrothermal treated without NH4BF4 (161 F g−1) at the same specific current]. The cycle measurement demonstrates the excellent cycling stability of CH-0.015, while 96.2% of its initial capacitance can be retained after 10000 cycles. Furthermore, the contribution of electrical double-layer capacitance and the pseudocapacitance of the samples is uncovered.

Carbon aerogel/xerogel can be easily tuned to have hierarchical pores ranging from micropores to macropores. Nitrogen doping is considered to enhance the wettability and conductivity of the carbon electrode, hence improve the electrochemical performance. To prepare N-doped carbon xerogel and study the effects on the structure and the electrochemical performance of resorcinol and formaldehyde derived carbon xerogel, a series of Resorcinol-Melamine-Formaldehyde derived N-doped carbon xerogel were prepared by a facile sol-gel process and ambient drying method. With the increasing amount of melamine, the inside channels become larger, which contributes to faster ion transport and smaller charge transfer resistance (Rct). The Nitrogen content in carbon xerogel is also increased, enhancing the capacitance of carbon electrode by pseudocapacity effect, while damaging the rate performance by introducing more defects and larger degree of disorder. As a result, the best electrochemical performance is achieved in the RM-6-4 sample (resorcinol:melamine = 6:4), showing the largest capacitance of 139 F g−1.

Electrostatic capacitors with high charge/discharge speed and long cycle lifetime play an essential role in advanced electronic and electrical power systems. However, their low energy density (usually less than 1 J cm−3) has limited their development. In this study, core–shell structured Ba0.4Sr0.6TiO3@SiO2 nanoparticles were synthesized by a wet-chemical method, and dense ceramics with enhanced energy storage density were fabricated by spark plasma sintering (SPS). In situ TEM and DSC techniques were used to investigate the interface reaction between Ba0.4Sr0.6TiO3 and SiO2. The results revealed that the secondary phase ((Ba,Sr)2TiSi2O8) was unavoidable, but it could be suppressed due to the low sintering temperature and short sintering period used in the SPS technique. With the increasing SiO2 coating amount, the polarization decreased monotonously, whereas the dielectric breakdown strength increased to a maximum of 400 kV cm−1 and then decreased slightly. The enhancement in the dielectric breakdown strength was ascribed to the formation of nanosized (Ba,Sr)2TiSi2O8 coating on Ba0.4Sr0.6TiO3 grains, whereas the subsequent degradation of performance might have been caused by the sub-micrometric secondary phase precipitated at the grain boundaries. The effect of microstructure on the breakdown strength was further confirmed by numerical simulation using COMSOL. As a result, the Ba0.4Sr0.6TiO3 ceramics with 8 mol% SiO2 showed a maximum energy storage density of 1.60 J cm−3 at 400 kV cm−1 with an ultrahigh energy efficiency of 90.9%. This study opens an effective way for the design of high-performance dielectric ceramics.

Barium strontium titanate (Ba 0.3 Sr 0.7 TiO 3 , BST) ceramics have been prepared by conventional sintering (CS) and spark plasma sintering (SPS). The effects of phase constitution and microstructure on dielectric properties, electrical breakdown process and energy storage properties of the BST ceramics were investigated. The X-ray diffraction analysis and dielectric properties measurements showed that the cubic and tetragonal phase coexisted in the SPS sample while the CS sample contained only tetragonal phase. Much smaller grain size, lower porosity, fewer defects and dislocation were observed in SPS samples, which greatly improved the electrical breakdown strength of the Ba 0.3 Sr 0.7 TiO 3 ceramics. The enhanced breakdown strength of the SPS samples resulted in an improved maximum electrical energy storage density of 1.13 J/cm 3 which was twice as large as that of the CS sample (0.57 J/cm 3 ). Meanwhile, the energy storage efficiency was improved from 69.3% to 86.8% by using spark plasma sintering.

Dense Ba0.4Sr0.6TiO3ceramics with fine grains and uniform microstructure were prepared by sol-gel method and spark plasma sintering (SPS). The dielectric properties, microstructures, and energy storage performance of spark plasma sintered Ba0.4Sr0.6TiO3 ceramics were evaluated. Fine Ba0.4Sr0.6TiO3 powders were synthesized by sol-gel method at above 750 °C. SPS technique showed its advantages in suppressing exaggerated grain growth and increasing the relative density of Ba0.4Sr0.6TiO3ceramics. Diffuse phase transition and nearly linear P-E behavior were observed in all samples. Moderate dielectric constant (∼960), low dielectric loss (∼0.003), high electrical breakdown strength (∼240 kV/cm), significantly enhanced energy storage density (∼1.23 J/cm3) and ultrahigh energy storage efficiency (∼94.52%) were obtained in Ba0.4Sr0.6TiO3 ceramics by using sol-gel method and spark plasma sintering.

The first-exit problem of strongly nonlinear oscillators with multi-degrees-of-freedom (MDOF) is studied theoretically in this paper. The excitations are modelled as wide-band random noises. When there is no internal resonance, the equations of motion of the original system are reduced to a set of averaged Ito stochastic differential equations (SDEs) after stochastic averaging. Two partial differential equations (PDEs), namely the backward Kolmogorov equation governing the conditional reliability function and the Pontryagin equation governing the mean first-exit time, are established under appropriate boundary and (or) initial conditions. The theoretical method is applied to study a 3-DOF strongly nonlinear system. Long expressions of drift and diffusion coefficients of the averaged Ito SDEs are obtained by using software Mathematica. The qualitative boundary conditions of the associated backward Kolmogorov equation and the Pontryagin equation are quantified by examining the behaviour of drift coefficients at the lower boundary. The method of finite difference is used to solve the corresponding high-dimensional PDEs. Monte Carlo simulation is performed to verify the validity of the proposed theoretical method.

(100 − x ) wt%Ba 0.4 Sr 0.6 TiO 3 – x wt%MgO composite ( x = 3, 5, 10) were prepared by spark plasma sintering (SPS) and their phase constitutions, microstructure and electrical energy storage properties were investigated. It was found that the reaction between Ba 0.4 Sr 0.6 TiO 3 and MgO was suppressed due to low sintering temperature and short sintering period. The Curie temperature of BST/MgO composite is independent of the MgO content, which confirms the absence of chemical interdiffusion between BST and MgO. Diffuse phase transition was observed due to the reduced grain size and lack of sufficient chemical diffusion during SPS process. The dielectric breakdown strength of Ba 0.4 Sr 0.6 TiO 3 /MgO composite was greatly improved, which results in a significant improvement of maximum energy storage density. The high dielectric breakdown strength of 300 kV/cm, highest maximum energy storage density of 1.50 J/cm 3 and high energy storage efficiency of 88.5% were obtained in 95 wt%Ba 0.4 Sr 0.6 TiO 3 –5 wt%MgO composite.

The crystal structures, domain structures, dielectric strengths and electrocaloric effects of spark plasma sintered Ba 0.7 Sr 0.3 TiO 3 and Ba 0.7 Sr 0.3 Ti 0.997 Mn 0.003 O 3 ceramics have been investigated. The densification can be enhanced by the spark plasma sintering (SPS) process without obvious grain growth, where the fine ferroelectric domain structures are obtained. The content of tetragonal phase in Ba 0.7 Sr 0.3 TiO 3 ceramics prepared by the SPS process is lower than that in the counterpart prepared by the conventionally sintering process, but it will increase again by partially substituting titanium with 0.3 mol% manganese ions. The dielectric strength can be significantly enhanced by the spark plasma sintering process, which can be improved further by Mn-substitution, and consequently the electrocaloric temperature change, Δ T , increases. Meanwhile, the electrocaloric strength has been enhanced by the spark plasma sintering process, which should be attributed to combined effects of domain wall density the content of ferroelectric phase in the present ceramics.

To enhance the reliability of the stochastically excited structure, it is significant to study the problem of stochastic optimal control for minimizing first-passage failure. Combining the stochastic averaging method with dynamical programming principle, we study the optimal control for minimizing first-passage failure of multidegrees-of-freedom (MDoF) nonlinear oscillators under Gaussian white noise excitations. The equations of motion of the controlled system are reduced to time homogenous diffusion processes by stochastic averaging. The optimal control law is determined by the dynamical programming equations and the control constraint. The backward Kolmogorov (BK) equation and the Pontryagin equation are established to obtain the conditional reliability function and mean first-passage time (MFPT) of the optimally controlled system, respectively. An example has shown that the proposed control strategy can increase the reliability and MFPT of the original system, and the mathematical treatment is also facilitated.

AbstractBa1−xSrxTiO3 (x = 0·3, 0·35) ceramics are fabricated by spark plasma sintering (SPS) technique and conventional sintering (CS) route. Their microstructures are determined together with the dielectric and ferroelectric properties. The grain sizes of SPS samples are smaller than those of CS. The differential scanning calorimetry data show that almost no latent heat associated with phase transition can be detected in the SPS sintered ceramics. Raman spectroscopy analysis suggests that the tetragonal phase increases with increasing the grain size, and the higher content of tetragonal phase leads the superior dielectric properties in CS sintered samples. Transmission electron microscopy analysis indicates that domain structure heavily relies on the grain size of ceramics. The poor ferroelectric properties of SPS ceramics are originated from the incomplete development of the tetragonal structure.

Preparation of LuFe2O4 ceramics under vacuum environment was investigated together with the structural, dielectric, and magnetic characterization. Single-phase LuFe2O4 could be obtained by the present process and the crystal structure was identified to be rhombohedral in space group R3¯m. An obvious dielectric relaxation with activation energy of 0.29 eV was observed between 175 and 275 K. The Neel temperature of the present ceramics was ~250 K, and a reentrant spin glass transition was indicated at ~216 K. Two anomalies were observed in the DSC curve, which were relative with the ferrimagnetic transition and 2D–3D charge ordering transition of LuFe2O4. Meanwhile, a remarkable decrease appeared in the dielectric constant of the as-magnetized LuFe2O4 sample, implying the magnetodielectric effect in the present ceramics.

The appearance of pilotage system has brought unprecedented convenience and innovation to ship pilotage. however, these systems also brought some potential risks, such as the limitations of these data timeliness, reliability, stability of the system and so on. Pilotage is a system engineering ,which related to both human influence and external factor .A sole factor is likely to generate enormous losses, safety is most important part of pilotage. In order to ensure the safety of the ship’s pilotage .Comprehensive assessment of the pilotage system is necessary, of the ship. Forthputting the fuzzy comprehensive evaluation method,this paper establish the assessment system, and take comprehensive performance assessment of the pilot system, which entitled us a digital evaluation of the pilot system.

Fused silica was prepared by different approaches, and the microwave dielectric properties were investigated. For the fused silica sintered at 1100°C by solid-state sintering, the dielectric constant (er) and Qf value increased with increasing the sintering time up to 5 h, while the temperature coefficient of resonant frequency (τf) decreased. The optimal properties with low er of 3.72, high Qf value of 44,300 GHz, and low τf of −14.4 ppm/°C were achieved when sintered at 1100°C for 5 h. The microwave dielectric properties could be further improved by other preparing approaches, as listed below: er = 3.90, Qf = 63,500 GHz, τf = −5.7 ppm/°C for spark plasma sintering, and er = 3.83, Qf = 122,100 GHz, τf = −8.3 ppm/°C for melting method. The results showed that fused silica was a good candidate as a microwave substrate material.

This paper presents an investigation on the mechanical properties of bamboos Mao Zhu (Phyllostachys Pubescens) strengthened with carbon fiber reinforced polymer (CFRP) and used as the substitute of steel substructures for a low carbon construction. At first, a series experimental study is carried out to investigate the compressive strength, bending strength and tensile strength of Mao Zhu, which is strengthened with CFRP by different ways. Then the mechanical properties of bamboos with different strengthening methods of CFRP are compared. The most efficient strengthening method is suggested for the carbon fiber strengthened bamboos, with such method the compressive strength and bending strength of Mao Zhu could be increased more than 30% and 44% compared with that of Mao Zhu without strengthening. Finally this paper discusses the advantages of the carbon fiber strengthened bamboos used as the substitutes of the steel substructures, for example the purlins and bracings of steel portal frame structures. The effective use of the bamboos as the substitutes of steel substructures will reduce the steel amount used in the steel portal frame structure, which is commonly used as low-rise factory building structure worldwide.

The dynamic meshing characteristics of gear drives have been a major concern in the design of power transmission systems as they affect vibration, acoustic noise, durability and efficiency. Gaining a more comprehensive understanding of the dynamic meshing characteristics of continuous engaged gear drives is a key to the development of power transmission systems. In this paper, a dynamic contact finite element analysis method, considering the variation of the engaged teeth pairs, the loaded elastic and contact deformations, and the sliding friction, is presented for the dynamic meshing characteristics analysis of continuous and elastic engaged gear drives. Various kinds of continuous engaged gear models under low and high speed condition are simulated and compared using the presented method. The tooth profile modification was designed based on the simulation results. Moreover, the effects of the tooth profile modification, the sliding friction and the time-varying meshing stiffness upon the dynamic meshing characteristics of continuous engaged gear drives are discussed in detail. The results show that the method is not only effective in designing and evaluating the tooth profile modification, but also in studying the dynamic meshing characteristics of continuous engaged gear drives with realistic time-varying meshing stiffness and tooth sliding friction. The present method could provide an effective tool for vibration mechanism study and dynamic design of the continuous engaged gear drives considering more influence factors.

With the development of high-performance computers, the contact finite element analysis (FEA) method has become more and more popular for studying both the static and dynamic behaviors of gear drives. In this paper, a precise tooth profile modification (TPM) approach of the helical gear pairs is presented first. The type and amount of the TPM are accurately determined by the static contact FEA results. Then dynamic contact simulations for the helical gear pairs with and without TPM are, respectively, carried out to evaluate the effect of the presented TPM approach on vibration reduction. No additional assumptions and simplifications are required for the static and dynamic contact analysis models. Vibration comparison experiments are also carried out on an open power flow test rig. Both the simulated and experimental results show that the presented precise TPM of helical gears is effective on vibration reduction around the working load, and the dynamic contact simulation is effective in estimating the effect of the TPM on vibration reduction in the designing stage.

Structure, dielectric response, and magnetic properties of Y3Fe5−xAlxO12 (x = 0, 0.5, 1, 2, and 3) ceramics were investigated. X-ray diffraction (XRD) patterns indicate a single phase with garnet structure in space group Ia3d for all sintered samples. Rietveld refinement of XRD data suggest that Al3+ substitutes for Fe3+ at tetrahedral sites. All the samples show a giant dielectric response which originates from the charge carrier hopping between the Fe2+ and Fe3+. The activation energy of the hopping process increases with increasing Al substitution. The a-d super-exchange interaction becomes weak as the content of Al increases, which results in the decrease of saturation magnetizations and magnetic ordering temperatures.

Background: Epidemiological statistics has shown that there are approximately 1.2 million new cases of lung cancer diagnosed every year and the death rate of these patients is 17.8%. Earlier diagnosis is key to promote the five-year survival rate of these cancer patients. Some tumor markers have been found to be valuable for earlier diagnosis, but a single marker has limitation in its sensitivity and specificity of cancer diagnosis. To improve the efficiency of diagnosis, several distinct tumor marker groups are combined together using a mathematical evaluation model, called artificial neural network (ANN). Lung cancer markers have been identified to include carcinoembryonic antigen, carcinoma antigen 125, neuron specific enolase, @b"2-microglobulin, gastrin, soluble interleukin-6 receptor, sialic acid, pseudouridine, nitric oxide, and some metal ions. Methods: These tumor markers were measured through distinct experimental procedures in 50 patients with lung cancer, 40 patients with benign lung diseases, and 50 cases for a normal control group. The most valuable were selected into an optimal tumor marker group by multiple logistic regression analysis. The optimal marker group-coupled ANN model was employed as an intelligent diagnosis system. Results: We have presented evidence that this system is superior to a traditional statistical method, its diagnosis specificity significantly improved from 72.0% to 100.0% and its accuracy increased from 71.4% to 92.8%. Conclusions: The ANN-based system may provide a rapid and accurate diagnosis tool for lung cancer.

A precise approach for the tooth profile modification (TPM) of helical gear is presented in the paper based on the static contact finite element analysis (FEA). The high-precision finite element model of helical meshing gear pairs is established. The type and amount of TPM are accurately determined by the static contact FEA results. The dynamic contact simulations of helical gears with and without tooth modification are investigated to estimate the vibration reduction effect of the TPM. Moreover the numerical simulations are compared with the experimental results. Both results show that the proposed precise TPM of helical gears is effective on vibration reduction around the working load, and the dynamic contact simulation is effective on estimating the vibration reduction influence of the TPM.

(1 − x )Ba 0.4 Sr 0.6 TiO 3 / x CaCu 3 Ti 4 O 12 composite ceramics were prepared by spark plasma sintering. Sintering behavior, microstructures and dielectric properties of the composite ceramics were investigated by XRD, SEM, EDS and dielectric spectrometer. Dense composite ceramics consisting of Ba 0.4 Sr 0.6 TiO 3 phase and CaCu 3 Ti 4 O 12 phase were prepared at 800 °C for 0 min. The dielectric loss of the composite ceramic decreased with increasing amount of Ba 0.4 Sr 0.6 TiO 3 , and the high dielectric constant were retained. Moreover, the better temperature stability of dielectric constant was obtained. These improvements of dielectric characteristics have great scientific significance for potential application.

Ilex Cornuta L is an important medicinal plant. Flavonoid compounds are its main biological compontents. AlCl3 method was identified as the appropriate determination method for total flavonoids content of extract obtained from the leaves of Ilex Cornuta L.. The proposed method was validated by the linearity, reproducibility, and recovery experiments. Good linearity was observed with the regression coefficient(R2= 0.999). The recovery rate was in the range of 94.9% and 110.0%, and the relative standard deviation was 2.8%, which indicated that the proposed method was credible. In addition, the extraction parameters including Ethanol concentration, solid-liquid ratio, extraction time and extraction times were optimized by means of an orthogonal design.

Hybrid improper ferroelectricity is induced by the coupling of oxygen octahedral rotation and tilt, and it may provide a promising way to develop new room-temperature single-phase multiferroic materials with a strong magnetoelectric effect. Though ferroelectric polarizations are confirmed by the electric hysteresis loops at room temperature, the ferroelectric-paraelectric phase transition has not been well understood. In the present work, the crystal structures, dielectric properties, and phase transition behaviors of Ruddlesden-Popper Sr3–xCaxSn2O7 ceramics are thoroughly determined. Ferroelectricity is confirmed through the polarization-electric field hysteresis loops at room temperature, and the Curie temperature is identified by the variable-temperature differential scanning calorimetric analysis and dielectric characterization. The polarizations and Curie temperatures of the present ceramics increase with increasing the calcium content. An improper ferroelectric transition is experimentally evidenced by a small dielectric constant and a step variation of dielectric constant around the Curie temperature, and the thermal hysteresis of dielectric constant confirms the first order transition nature. Moreover, the fitting result of Landau phase transition theory also suggests the first-order improper ferroelectric transition nature. The variable-temperature Raman result implies a tetragonal paraelectric phase above TC. The present work confidently confirms the first-order hybrid improper ferroelectric transitions in the present ceramics, and ferroelectric properties can be readily tuned by substituting the cations at the A-site.

Multiferroic ceramics in BaO–Y 2 O 3 –Fe 2 O 3 –Nb 2 O 5 system were synthesized and their dielectric, ferroelectric and magnetic properties were evaluated. XRD results showed that the ceramic composite consists of a major phase of tetragonal tungsten bronze structured Ba 2 YFeNb 4 O 15 , and minor phases of monoclinic YNbO 4 and hexagonal Ba 3 Fe 2 Nb 6 O 21 . Three dielectric relaxations were observed in the temperature range from 125 to 575 K. The relaxor dielectric behavior in the temperature range from 125 to 350 K was attributed to the random occupation of Fe 3+ and Nb 5+ ions at B site of the tungsten bronze structure. The electrode polarization and the inhomogeneous structure contributed to the high-temperature and middle-temperature dielectric relaxations, respectively. Both the ferroelectric hysteresis loop and the magnetic hysteresis loop were measured, which suggested that the synthesized ceramic composite was a promising candidate of multiferroics.