bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical Analysis of Piezoelectric Signal of PVDF Membrane Flapping Wing in Flight
Authors: Cheng Yun , Li Daochun 
Published: March 2020

Abstract
As an organic piezoelectric material, polyvinylidene fluoride (PVDF) can be utilized to fabricate thin film with high mechanical properties, and this film can be used to form flapping wing membrane. This type of wing with piezoelectric effect can solve the problems of the flight conditions measurement of flapping-wing micro aerial vehicles (FMAVs) in practical flapping flight. This study focuses on analysing the voltage outputs generated by PVDF membrane, and proposes two output voltage signal characteristics that can be used to deduce the flight conditions of FMAV, i.e. the voltage wave scale and voltage wave phase difference. The linear plate theory and unsteady aerodynamics coupling with piezoelectric equation are adopted to calculated the voltages generated by inertia and aerodynamic forces. The reasons and applications of scale and phase difference are analysed and discussed, and practical examples are demonstrated to illustrate specific impacts on these two signals.
Review of IGBT Junction Temperature Extraction and Estimation Methods
Authors: Qiu X Z , Zhang G R , Chen W J , Yu T , Hou X M , Zhang Q Z , Xu G Q 
Published: March 2020

AbstractIGBT is widely used in photovoltaic power generation, aerospace, electric vehicles, ships and other power electronic equipment due to its advantages such as simple driving, high power level, low power consumption, and good thermal stability. As the core component of power electronic equipment, IGBT has always been a major concern for manufacturers and users. Excessive temperature is considered to be the main cause of IGBT failure. In order to meet the needs of high reliability in these applications, it is important to manage and control the temperature of the IGBT. Therefore, how to estimate or measure the junction temperature of IGBT is the focus of research on IGBT reliability. This article introduces several published methods for measuring junction temperature, focuses on the Temperature sensitive electrical parameters (TSEP) method and thermal resistance network method, and conducts experimental verification through the IGBT double-pulse test platform. Trying to provide help for future junction temperature detection work.
Preparation of PZT Thin Film/Ni Particle Composite Magnetoelectric Materials
Authors: Di Yongjiang , Chen Sijing , Jiang Yang , Jia Bi , Cao Pengjun 
Published: March 2020

Abstract
Lead Zirconium Titanate (PZT) thin film magnetoelectric materials have widely application in controllable sensing and tuneable microwave devices. The PZT film ferroelectric domain was designingly distributed and reversed by using the piezoelectric power response technique. The magnetoelectric composite of PZT film and Ni particle was prepared by the ferroelectric spontaneous polarization separation photogenerated carrier, reduction Ni atom deposition on the PZT thin film ferroelectric positive domain region. The optical morphology, XRD and SEM morphology show that the Ni particles deposited on the PZT film increase first and then become more uniform with the extension of deposition time. The deposition time closely relate to the deposition effect of Ni particles, and the deposition effect is more obvious with time. After the photo-deposition, the surface particles of the unexcited domain film are scattered after the photo-deposition, and the shape of the deposited particles region in which the Ni particles are reduced is substantially similar to the write-domain pattern, and the particle diameter is about 10-20 nm.
Design of Stealth Bulletproof Material Based on Sub-Wavelength Absorbing Structure
Authors: Zhang Han , Zhang Zekui , Li Baoyi 
Published: March 2020

Abstract
When stealth bulletproof materials achieve performance through simple superposition of layers and layers, there is a problem that the weigh is heavier, and the coating or patch is easy to fall off, and the absorption rate is lower. In order to reduce the weight, broaden the frequency band, and increase the absorption rate, functional integrated design method base on absorbing sub-wavelength structure is adopted. According to the design principle of the absorbing sub-wavelength structure, a lightweight ballistic material is used as its dielectric substrate. Microstructure graphics are designed on the bulletproof medium. With the fusion of stealth and ballistic performance, the design of a new wide-band stealth ballistic material was completed. Test results show that the absorbing sub-wavelength structure based on the lightweight bulletproof material has an absorption rate of more than 90% in a wide frequency band of 4GH to 18GHz and 27GHz to 40 GHz. which does not affect the ballistic performance of the ballistic material itself, and reduces the stealth material layer in the stealth ballistic material. The effect of reducing thickness and weight loss is achieved. The feasibility of this method is verified, which is of great significance for improving the combat capability of new functional vehicles.
Harmless Preexisting Crack in Structures Made of Hydrogen-Embrittlement Sensitive Materials under Monotonic Tension
Authors: Liu He , Hamada Shigeru , Noguchi Hiroshi 
Published: March 2020

Abstract
The interaction of hydrogen with the dislocations in the plastic zone of preexisting cracks (pre-cracks) in engineering components generally degrades the ultimate tensile strength (UTS). Hence, the crack effect coupled with hydrogen-embrittlement (HE) is widely believed to be harmful in engineering applications. However, in this study, the UTS of shallow pre-cracked structures made of interstitial-free (IF) steel, which is a hydrogen-embrittlement sensitive material, may not be wakened in hydrogen environment. Results of cylinder specimens with saturated hydrogen were experimentally and microscope-analytically compared with that of specimens without hydrogen. Then, this anti-common-sense influence of hydrogen was attributed as follows: (1) the crack propagation assisted by hydrogen enhanced localized plasticity (HELP) is stable before the onset of plastic instability because of high fracture instability toughness; and (2) the plastic strain localization at tips of the pre-crack and secondary cracks resists the onset of plastic instability. Additionally, the applicability of such a shallow crack effect coupled with HE presented by this study in engineering applications was discussed.
Study on Microstructure and Mechanical Properties of TP321 Thick-Walled Stainless Steel Tube by CMT Welding
Authors: Lu Hailong 
Published: March 2020

Abstract
The CMT welding process of TP321 thick-walled stainless steel pipe was analyzed. The tensile properties, microstructures and phase composition of the welded joint were tested, and the effect of welding current on the microstructures and properties was studied. The results show that for the CMT welding of TP321 thick-walled stainless steel pipe, when the optimum welding current is 110A, the maximum tensile strength of welded joints reaches 643 MPa, 92.7% of base metal, and the elongation reaches 58.7%. The fracture location of welded joints is heat-affected zone, basically ductile fracture. With the increase of welding heat input, the precipitation of ferrite and carbide gradually increases in the weld structure of TP321 stainless steel. When the current is too high, the brittle σ phase of ferrite transformation will decrease, resulting in the decrease of strength and plasticity of welded joints.
Comparative Experimental Study on Mechanical Properties of Rubber Band and Metal Spring
Authors: Huang Yan , He Songlin 
Published: March 2020

Abstract
The tensile tests of a metal spring and a rubber band are studied comparatively. It is found that the elastic force of rubber band is proportional to its elongation in a certain range of deformation, which satisfies Hooke’s theorem. This is same as the result of the metal spring. By comparing the vibration property of the systems composed of metal spring and rubber band respectively, it is found that the property of “intrinsic” damped vibration of the rubber band oscillator is completely different from that of the viscous damped vibration of the harmonic oscillator. It is concluded that the static mechanical property of rubber band is similar to that of metal spring, but its dynamic mechanical property is completely different from that of metal spring.
The Dry Friction Damping Model and Vibration Characteristics of a Cylindrical Shell Structure with Damping-Ring
Authors: Nie Y Q , Jiang X H , Wang Y R , Wang N M 
Published: March 2020

Abstract
To effectively solve the design problem of the damping ring used in the rotating thin cylindrical shell structure of aeroengine, a dynamic analysis model of the combined structure is established, based on its natural modal analysis. The analytical expression of the friction force and the critical slipping angle is derived with reference to the basic theory of mechanics of materials, and also the predicting method of damping work and damping ratio is demonstrated based on the macro sliding model. For the given structure model, the dry friction damping characteristics of the damping ring are studied. The results show that there exist a critical speed and if exceeding it, the damping ring cannot work functionally. Under an identical nodal diameter and vibration stress, the damping ratio increases first and then decreases with the increasing speed with the increase of rotating speed. When the speed is constant, the lower the nodal diameter, the higher the damping ratio it provided. For a given nodal diameter and speed, as the allowable vibration stress increases, the damping ratio rises first and then decreases. In addition, the damping ratio has a linear relationship with the cross-section width of the damping ring.
Preparation and Characterization of β-Cyclodextrin Nanosponges and Study on Enhancing the Solubility of Insoluble Nicosulfuron
Authors: Liu Xiaofang , Li Wei , Xuan Guangshan 
Published: March 2020

Abstract
Nicosulfuron (NSF) is a water-insoluble and unstable sulfonylurea herbicide, which is mainly used in the treatment of stems and leaves after the corn seedling stage. Nanosponges (NS) have more interaction sites and higher drug encapsulation capabilities. In this paper, three kinds of β-cyclodextrin nanosponges (CDNS) were prepared by crosslinking β-cyclodextrin with diphenyl carbonate (DPC), pyromellitic dianhydride (PMDA) and epichlorohydrin (EP), respectively. The NSF-loaded CDNS were characterized by TEM, FTIR, DSC, TGA and XRD. The solubility, stability and biological activity of NSF were studied. The results showed NSFEP-CDNS could significantly enhance the solubility of NSF. In vitro release test, the cumulative release of NSF-EP-CDNS was 90.11%. Compared with pure NSF and NSF oil suspension, NSF-EP-CDNS had the strongest inhibitory effect on acetolactate synthase (ALS). In conclusion, CDNS have beneficial effects on the solubility, stability and biological activity of NSF.
Detection of Mercury Ions in Aqueous Solution by Fluorescence Spectrometry
Authors: Wang Chenguang , Zhao Yaxin , Lv Kuilin , Zhou Ziran , Lin Peng , Lv Yuguang 
Published: March 2020

Abstract
This paper proposes a simpler and operable method to replace the traditional detection method and detect the mercury ion in water samples quickly and easily. Firstly, the rhodamine derivatives are synthetised, then a rhodamine derivative fluorescent molecular probe is constructed and adopted to detect mercury ions in water samples. In order to detect mercury ions in aqueous solutions, the fluorescence spectroscopy was adopted in this experiment, and rhodamine derivatives were used as fluorescent molecular probes. The rhodamine and its corresponding derivatives were used to detect mercury ions in aqueous solutions. Different metal ions and different chlorides were added to the solution of the compound. Only the one with the addition of mercury ion shows a peak at 555 nm. Therefore, it is concluded that the mercury ion derivative has a better response to metal mercury ion.
Research on Lower Extremity Exoskeleton System Based on Elastic Energy Storage Components
Authors: Guo Kai , Zhao Shasha , Liu Bin , Liu Yongfeng , Zhang Yingying , Yang Hongbo 
Published: March 2020

Abstract
In this paper, we study the field of rehabilitation walker technology. The passive energy storage gravity support exoskeleton is suitable for patients with lower limb dysfunction or limited function caused by lower limb joint, muscle tissue damage or bone disease. The equipment studied in this paper can assist patients to carry out normal ground walking and up and down stairs, realize patient self-care, slow down the patient’s physiological pain, and reduce the economic and energy burden of the patient’s family members. As the proportion of the elderly population continues to rise, the physiological decline during the aging process makes the elderly’s limbs less flexible, with limb motor dysfunction and lower limb motor dysfunction. Manual laborers have long been engaged in labor with repetitive and long working hours. It is easy to cause occupational chronic musculoskeletal injuries or other occupational diseases by maintaining the same or improper working posture for a long time.
Effects of Multi-walled Carbon Nanotubes on the Microwave Absorbing Properties of Magnetorheological Elastomers
Authors: Ye Fengchao , He Xingsheng , Zheng Jiajia 
Published: March 2020

Abstract
The microwave absorbing properties of carbonyl iron particles (CIPs) based magnetoheological elastomer (MRE) filled with multi-walled carbon nanotubes (MWCNTs) were examined. Absorbents including the CIPs and MWCNTs were mixed and added to the silicone rubber (SR) matrix for further compression molding and vulcanization. The complex permittivity and complex permeability were measured over a frequency range of 2-18GHz. As the MWCNT weight percentage increased, the reflection loss (RL) of the MRE composites changed significantly, which is attributed to the impedance mismatch. The MRE composites containing 28 wt% CIPs and 0.1 wt% MWCNTs with a thickness of 3 mm display dual resonance peaks with a maximum RL of -53 dB and the effective frequency bandwidth (RL<-10dB) reaches 7.7 GHz. This suggests that the MRE composites could serve as a potential candidate for absorbing incident microwave with excellent flexibility.
Formation of Carbon Nanofibers Grafted with TiO2 Nanosheets as Advanced Anodes for Lithium Ion Batteries
Authors: Guo Yan , Fan Na , Li Changyan 
Published: March 2020

Abstract
Titanium dioxide (TiO2)-based materials, including various polymorphic TiO2 and several titanates, have been extensively studied for potential negative electrode materials for next-generation lithium ion batteries (LIBs). And it is indispensable to design a reasonable nanostructure. Novel nano-heterostructures composed of TiO2 nanosheets on the surface of carbon nanofibers (CNF) have been synthesized by growing hydrogen titanate nanosheets on the CNF backbone, and then followed by thermal conversion to TiO2 nanosheets. Owing to their structural advantages, the hybrid CNF@TiO2 electrode delivers high capacities of 292 mAh g−1 at a current density of 200 mA g−1 with outstanding capacity retention over 200 cycles.
Preparation and Physical Properties of Polyethylene/Carbon Nanotubes/Nanosilver Composite
Authors: Ge Feifan , Yao Wei-Hua , Lin Xu , Jui-Chin-Chen  , Jiang Lin , Tsou Chi-Hui 
Published: March 2020

Abstract
In this paper, nanosilver and carbon nanotubes was melt blended with HDPE and pet respectively to prepare HDPE/CNT/nanosilver and PET/CNT/nanosilver composites with antibacterial effect. After the preparation of samples, SEM, DSC, TGA, mechanical properties and antibacterial properties were tested. The possibility of preparing new materials by this method is studied. Compared with pure HDPE, when the content of CNT/nanosilver is 0.1 phr, the tensile strength of HDPE/CNT/nanosilver composite reach to the max value.
Fused Deposition Modeling of Montmorillonite Modified Poly (Lactic Acid)/Sunflower Seed Husk Composites
Authors: Song Xiaohui , Song Pinghui , Qin Huadong , Meng Hangyu 
Published: March 2020

AbstractAbstracts.This work presents the fused deposition modelling of Poly (lactic acid)/sunflower seed husk/montmorillonite (PLA/SSH/MMT) composites filaments. The SSH was treated with NaOH followed by silane. The rheological behavior, thermal stability and the tensile properties were determined. The results showed that the onset temperature at the maximum degradation rate reached to the highest at 5 wt% SSH and 15 wt% MMT. The tensile strength was enhanced to 45.8 MPa by incorporation of 15wt% MMT. The utilization of FDM and SSH reduced the cost of PLA filament by about 35%, and make a good using of the wastes.
Designing and Fabrication of WC
p
/Cu Metal-Matrix Composite by Pressureless Infiltration Technique
Authors: Liu Guojun , Cheng Tuo 
Published: March 2020

Abstract
The WC
p
particulate reinforced Cu matrix composite has been designed and fabricated via spontaneous infiltration technique for the course experiment of Metal Matrix Composite. The influence of main processing parameters, including infiltration method as well as temperature on the microstructures, phase compositions and the hardness is investigated. The results show that both the fraction of WC and the hardness show a gradual decline with the increasing of infiltration temperature.
Optimal Design of a 3D Printed Composite Micro-Perforated Silencer for Engine Intake Noise Control
Authors: Chen Wan , Lu Chihua , Liu Zhien 
Published: March 2020

Abstract
Micro-perforated panel (MPP) is a new sound-absorbing material with wide frequency band and high absorption characteristics. In this paper, to reduce medium-high frequency intake noise of a car engine under accelerating working conditions, a composite MPP silencer with a serial-parallel coupling mode is presented. Moreover, based on the numerical calculation method of the presented MPP silencer, the Isight software is utilized to integrate relevant simulation software, and then the multi-island genetic algorithm (MIGA) is adopted to optimize the average transmission loss of the silencer. Finally, the optimized silencer is 3D printed for impedance tube testing and vehicle testing. The results demonstrate that the optimization design process of the proposed composite MPP silencer is reasonable; and after adopting the optimized silencer, the objective wideband intake noise is effectively attenuated and the sound pressure level is reduced by 8 dB(A) when the engine is at 3525 r/min, providing a promising way of vehicle noise control.
Removal of Mercury from Simulated Natural Gas by SO2 Activated Petroleum Coke
Authors: Yan Qituan , Zhu Mingqing , Li Jian , Duan Yufeng , Han Zhongxi , Zhang Xiang , Wang Shuying 
Published: March 2020

Abstract
A preparation method based on the carbon-thermal reduction reaction was proposed to make petroleum coke-based mercury adsorbent. The effects of activation agent flow rate, time and inlet mercury concentration on mercury removal were investigated. Mercury adsorption experiments were carried out on a fixed-bed reactor system under simulated natural gas atmosphere. Meanwhile, the mercury removal mechanism was put forward based on the characterization results, including surface area and micropore structure, element contents and active chemical functional groups. The results show that the raw petroleum coke (RPC) has almost no mercury removal capacity while the mercury removal efficiency of the sulfur activated petroleum coke (SPC) is greatly improved. After activation, specific surface area and micropores increased significantly. The sulfur content increased as well. Meanwhile, the relative content of non-oxidative sulfur forms and oxygen functional groups of SPC are significantly higher than RPC. The optimum parameters of activation agent flow rate and time of 100 mL/min and 1.5 h are reached in this experiment, respectively.
An Evolution-Based Uncertainty Analysis Method for Bending Fatigue Failure of Involute Spur Gears
Authors: Yu Guoqing , Shi Boqiang , Shen Yanhua , Duan Guochen 
Published: March 2020

Abstract
An evolution-based uncertainty analysis model of bending fatigue failure of involute spur gears is presented. The fluctuation of transmit torque and rotational velocity of gears are introduced to the mild wear model of gear flanks. Then a novel simulation model of tooth profile evolution is developed to describe the change of meshing parameters, which include the tooth load, load angle and bending moment arm. The critical tooth-root bending stress is influenced by these time-varying parameters. Based on the evolution-based uncertainty analysis method, the load is approximately obeying logarithmic normal distribution, the load angle and bending moment arm are approximately obey geometric Brownian motion. Then the critical tooth-root bending stress is calculated as a logarithmic normal distribution quantity over time. Finally, the prediction model of time dependent reliability of the bending load capacity of spur gears is proposed.
Experimental Research on Anchoring Behavior of Chemical Anchor Bolt under Repeated Loading
Authors: Xu Chengxiang , Gu Yong , Peng Sheng 
Published: March 2020

Abstract
To study the anchoring behavior of chemical anchors under repeated loading, 33 test pieces were designed and fabricated based on the specifications. Each 3 test pieces were 1 set, that is, 1 set of comparative test pieces and 10 sets of test pieces, respectively, for static force. Bonding and anchoring performance tests for loading and reloading. Through the analysis of the test phenomena and results, the following conclusions are drawn: when the loading load exceeded 0.9 times the ultimate bearing capacity of the anchor; when the loading load was equal to 0.6 or 0.75 times, the test piece would undergo splitting damage after the set number of loading times, and its bearing capacity would increase. As the number of loading increased, the energy consumption would gradually decrease, and the decreasing amplitude would gradually increase. Compared with constant amplitude loading and variable amplitude loading, it is found that the slip value of variable amplitude loading increased by 42.1% and the bearing capacity decreased by 12%, which indicated that variable amplitude loading has a great influence on the bonding and anchoring performance of specimens.
Analysis of Real-World Fuel Consumption Characteristics of Heavy-Duty Commercial Diesel Vehicle Based on OBD Method
Authors: He Weinan , Cheng Ying , Liu Ying , Wang Changyuan , Fang Xiyu , Feng Qian , Zhu Xin 
Published: March 2020

Abstract
In this paper, heavy-duty commercial diesel vehicles were selected for the actual road, vehicle emission test system (PEMS), C-WTVC and CATC test, and each test was connected to the OBD remote monitoring equipment. Through PEMS test and C-WTVC test, the instantaneous fuel consumption data and carbon balance fuel consumption data of OBD remote monitoring equipment are compared within 10%, which proves that OBD remote monitoring has good accuracy. The fuel consumption of the actual road test normalized to CATC is 10.8%-88.0% higher than that of the ministry of industry and information technology type certification, with an average value of 45.1%. The fuel consumption under the normalized C-WTVC condition is 10.1%∼76.6% higher than that under the type approval of the ministry of industry and information technology, with an average value of 40.0% 23.9%. This difference is relatively smaller than that under the normalized to CATC. It is of great significance to correctly guide the development and calibration of vehicles and promote the research and application of vehicle energy conservation and emission reduction technologies suitable for China’s traffic characteristics and actual use characteristics.