BACKGROUND The relation between orthodontic treatment and temporomandibular disorders(TMDs)is under debate;the management of TMD during orthodontic treatment has always been a challenge.If TMD symptoms occur during or...BACKGROUND The relation between orthodontic treatment and temporomandibular disorders(TMDs)is under debate;the management of TMD during orthodontic treatment has always been a challenge.If TMD symptoms occur during orthodontic treatment,an immediate pause of orthodontic adjustments is recommended;the treatment can resume when the symptoms are managed and stabilized.CASE SUMMARY This case report presents a patient(26-year-old,female)with angle class I,skeletal class II and TMDs.The treatment was a hybrid of clear aligners,fixed appliances and temporary anchorage devices(TADs).After 3 mo resting and treatment on her TMD,the patient’s TMD symptom alleviated,but her anterior occlusion displayed deep overbite.Therefore,the fixed appliances with TAD were used to correct the anterior deep-bite and level maxillary and mandibular deep curves.After the levelling,the patient showed dual bite with centric relation and maximum intercuspation discrepancy on her occlusion.After careful examination of temporomandibular joints(TMJ)position,the stable bite splint and Invisible Mandibular Advancement appliance were used to reconstruct her occlusion.Eventually,the improved facial appearance and relatively stable occlusion were achieved.The 1-year follow-up records showed there was no obvious change in TMJ morphology,and her occlusion was stable.CONCLUSION TMD screening and monitoring is of great clinical importance in the TMD susceptible patients.Hybrid treatment with clear aligners and fixed appliances and TADs is an effective treatment modality for the complex cases.展开更多
Non-intrusive load monitoring is a method that disaggregates the overall energy consumption of a building to estimate the electric power usage and operating status of each appliance individually.Prior studies have mos...Non-intrusive load monitoring is a method that disaggregates the overall energy consumption of a building to estimate the electric power usage and operating status of each appliance individually.Prior studies have mostly concentrated on the identification of high-power appliances like HVAC systems while overlooking the existence of low-power appliances.Low-power consumer appliances have comparable power consumption patterns,which can complicate the detection task and can be mistaken as noise.This research tackles the problem of classification of low-power appliances and uses turn-on current transients to extract novel features and develop unique appliance signatures.A hybrid feature extraction method based on mono-fractal and multi-fractal analysis is proposed for identifying low-power appliances.Fractal dimension,Hurst exponent,multifractal spectrum and the Hölder exponents of switching current transient signals are extracted to develop various‘turn-on’appliance signatures for classification.Four classifiers,i.e.,deep neural network,support vector machine,decision trees,and K-nearest neighbours have been optimized using Bayesian optimization and trained using the extracted features.The simulated results showed that the proposed method consistently outperforms state-of-the-art feature extraction methods across all optimized classifiers,achieving an accuracy of up to 96%in classifying low-power appliances.展开更多
Since April 2004, the Asahi University Medical and Dental Center (hereinafter referred to as our center) has been providing oral appliances (hereinafter referred to as OA) to treat patients diagnosed with obstructive ...Since April 2004, the Asahi University Medical and Dental Center (hereinafter referred to as our center) has been providing oral appliances (hereinafter referred to as OA) to treat patients diagnosed with obstructive sleep apnea. The effects of using the OA and progress of 71 patients who received treatment at our center by wearing OA from March 2005 to the end of March 2016 were examined through questionnaires sent by physical mail. In 21 of 24 patients who underwent polysomnography after wearing OA, the apnea-hypopnea index (hereinafter referred to as AHI) significantly decreased after wearing OA (9.44 ± 10.37) compared to that before wearing OA (24.02 ± 13.57) (p = 8.7 × 10<sup>-8</sup>). The results showed that for patients who continuously use OA, it is necessary to have sound sleep/sleep soundly;further, the patients experienced a decrease in snoring when wearing OA, with only a few side effects on the temporomandibular joints and teeth. In addition, the closer the distance from the plane of the lower margin of the mandible to the hyoid bone after wearing OA, the more likely it was for the AHI to decrease, which suggests that wearing OA contributes to the prediction of therapeutic effects.展开更多
The model of a locally resonant (LR) epoxy/PZT-4 phononic crystal (PC)nanobeam with “spring-mass” resonators periodically attached to epoxy is proposed. The corresponding band structures are calculated by coupling E...The model of a locally resonant (LR) epoxy/PZT-4 phononic crystal (PC)nanobeam with “spring-mass” resonators periodically attached to epoxy is proposed. The corresponding band structures are calculated by coupling Euler beam theory, nonlocal piezoelectricity theory and plane wave expansion (PWE) method. Three complete band gaps with the widest total width less than 10GHz can be formed in the proposed nanobeam by comprehensively comparing the band structures of three kinds of LR PC nanobeams with resonators attached or not. Furthermore, influencing rules of the coupling fields between electricity and mechanics,“spring-mass” resonator, nonlocal effect and different geometric parameters on the first three band gaps are discussed and summarized. All the investigations are expected to be applied to realize the active control of vibration in the region of ultrahigh frequency.展开更多
Braking on low adhesion-coefficient roads, hybrid electric vehicle's motor regenerative torque is switched off to safeguard the normal anti-lock braking system (ABS) fimction. When the ABS control is terminated, th...Braking on low adhesion-coefficient roads, hybrid electric vehicle's motor regenerative torque is switched off to safeguard the normal anti-lock braking system (ABS) fimction. When the ABS control is terminated, the motor regenerative braking is readmitted. Aiming at avoiding permanent cycles from hydraulic anti-lock braking to motor regenerative braking, a novel electro-mechanical hybrid anti-lock braking system using fuzzy logic is designed. Different from the traditional single control structure, this system has a two-layered hierarchical structure, The first layer is responsible for harmonious adjustment or interaction between regenerative system and anti-lock braking system. The second layer is responsible for braking torque distribution and adjustment. The closed-loop simulation model is built. Control strategy and method for coordination between regenerative and anti-lock braking are developed. Simulation braking on low adhesion-coefficient roads with fuzzy logic control and real vehicle braking field test are presented. The results from simulating analysis and experiment show braking performance of the vehicle is perfect, harmonious coordination between regenerative and anti-lock braking function, significant amount of braking energy can be recovered and the proposed control strategy and method are effective.展开更多
Automotive industry,as an important pillar of the national economy,has been rapidly developing in recent years.But proplems such as energy comsumption and environmental pollution are posed at the same time.Electro-mec...Automotive industry,as an important pillar of the national economy,has been rapidly developing in recent years.But proplems such as energy comsumption and environmental pollution are posed at the same time.Electro-mechanical variable transmission system is considered one of avilable workarounds.It is brought forward a kind of design methods of dual-mode electro-mechanical variable transmission system rotational speed characteristics and dual-mode drive diagrams.With the motor operating behavior of running in four quadrants and the speed characteristics of the simple internal and external meshing single planetary gear train,four kinds of dual-mode electro-mechanical transmission system scheme are designed.And the velocity,torque and power characteristics of one of the programs are analyzed.The magnitude of the electric split-flow power is an important factor which influences the system performance,so in the parameters matching design,it needs to reduce the power needs under the first mode of the motor.The motor,output rotational speed range and the position of the mode switching point have relationships with the characteristics design of the planetary gear set.The analysis method is to provide a reference for hybrid vehicles' design.As the involved rotational speed and torque relationships are the natural contact of every part of transmission system,a theory basis of system program and performance analysis is provided.展开更多
Ionic Polymer-Metal Composites (IPMC) is an emerging class of Electro-Active Polymer (EAP) materials. IPMC has attractive features, such as high sensitivity and light weight, which are useful for developing novel ...Ionic Polymer-Metal Composites (IPMC) is an emerging class of Electro-Active Polymer (EAP) materials. IPMC has attractive features, such as high sensitivity and light weight, which are useful for developing novel designs in the fields of bionic actuators, artificial muscles and dynamic sensors. A Finite Element (FE) model was developed for simulating the dynamic electro-mechanical response of an IPMC structure under an external voltage input. A lumped Resisto^Capacitor (RC) model was used to describe the voltage-to-current relationship of a Nation IPMC film for the computation of electric field intensity. Moreover, the viscoelastic property of the IPMC film was considered in the model and the non-uniform bending behavior was also taken into account. Based on the proposed model and the assumption that the thicknesses of the two electrodes are the same and uniform, the optimal coating thickness of the IPMC electrode was determined. It was demonstrated that the dynamic electro-mechanical response of the IPMC structure can be predicted by the proposed FE model, and the simulation results were in good agreement with the experimental findings.展开更多
In this paper,we present the applications of Boundary Element Method(BEM) to simulate the electro-mechanical coupling responses of Micro-Electro-Mechanical systems(MEMS). The algorithm is programmed in our research gr...In this paper,we present the applications of Boundary Element Method(BEM) to simulate the electro-mechanical coupling responses of Micro-Electro-Mechanical systems(MEMS). The algorithm is programmed in our research group based on BEM modeling for electrostatics and elastostatics.Good agreement is shown while the simulation results of the pull-in voltages are compared with the theoretical/experimental ones for some examples.展开更多
In a typical discrete manufacturing process,a new type of reconfigurable production line is introduced,which aims to help small-and mid-size enterprises to improve machine utilization and reduce production cost.In ord...In a typical discrete manufacturing process,a new type of reconfigurable production line is introduced,which aims to help small-and mid-size enterprises to improve machine utilization and reduce production cost.In order to effectively handle the production scheduling problem for the manufacturing system,an improved multi-objective particle swarm optimization algorithm based on Brownian motion(MOPSO-BM)is proposed.Since the existing MOPSO algorithms are easily stuck in the local optimum,the global search ability of the proposed method is enhanced based on the random motion mechanism of the BM.To further strengthen the global search capacity,a strategy of fitting the inertia weight with the piecewise Gaussian cumulative distribution function(GCDF)is included,which helps to maintain an excellent convergence rate of the algorithm.Based on the commonly used indicators generational distance(GD)and hypervolume(HV),we compare the MOPSO-BM with several other latest algorithms on the benchmark functions,and it shows a better overall performance.Furthermore,for a real reconfigurable production line of smart home appliances,three algorithms,namely non-dominated sorting genetic algorithm-II(NSGA-II),decomposition-based MOPSO(dMOPSO)and MOPSO-BM,are applied to tackle the scheduling problem.It is demonstrated that MOPSO-BM outperforms the others in terms of convergence rate and quality of solutions.展开更多
Chinese traditional sales channels are seriously attacked by the new ones. Household appliances industry will realize the specialized divisions of. development, manufacture, sale and services completely. The model of ...Chinese traditional sales channels are seriously attacked by the new ones. Household appliances industry will realize the specialized divisions of. development, manufacture, sale and services completely. The model of sales channel in marketing is set as the core of this research; the merits and demerits of different sales channels are analyzed; the complicated selective relationship and the conflicts among the manufacturer, middlemen, and ultimate consumers, and the solutions to present multi-channels market and the developments of the sales channels are elaborated in an overall view; the opinion that the only way to develop this industry is raised to establish the competitive sales channels. The aim is to let local household appliances industry use the natural merits to build up a suitable channel rapidly and efficiently, and to speed up the self development and oeffection.展开更多
This paper presents an efficient meshless method for analyzing cracked piezoelectric structures subjected to mechanical and electrical loading. In this method, an element free Galerkin (EFG) formulation, an enriched...This paper presents an efficient meshless method for analyzing cracked piezoelectric structures subjected to mechanical and electrical loading. In this method, an element free Galerkin (EFG) formulation, an enriched basic function and some special shape functions that contain discontinuous derivatives are employed. Based on the moving least squares (MLS) interpolation approach, the EFG method is one of the promising methods for dealing with problems involving progressive crack growth. Since the method is meshless and no element connectivity data are needed, the burdensome remeshing procedure required in the conventional finite element method (FEM) is avoided. The numerical results show that the proposed method can yield an accurate near-tip stress field in an infinite piezoelectric plate containing an interior hole. In another example studying a ceramic multilayer actuator, the proposed model was found to be accurate in the simulation of stress and electric field concentrations arround the abrupt end of an internal electrode.展开更多
This paper focuses on the controller design using fuzzy sliding mode control(FSMC)with application to electro-mechanical brake(EMB)systems using BLDC Motor.The EMB controller transmits the control signal to the motor ...This paper focuses on the controller design using fuzzy sliding mode control(FSMC)with application to electro-mechanical brake(EMB)systems using BLDC Motor.The EMB controller transmits the control signal to the motor driver to rotate the motor.The torque distribution of motors is studied in this paper actually.Firstly,the model of the EMB system is established.Then the state observer is developed to estimate the vehicle states including the vehicle velocity and longitudinal force.Due to the fact that the EMB system is nonlinear and uncertain,a FSMC strategy based on wheel slip ratio is proposed,where both the normal and emergency braking conditions are taken into account.The equivalent control law of sliding mode controller is designed on the basis of the variation of the front axle and rear axle load during the brake process,while the switching control law is adjusted by the fuzzy corrector.The simulation results illustrate that the FSMC strategy has the superior performance,better adaptability to various types of roads,and shorter braking distance,as compared to PID control and traditional sliding mode control technologies.Finally,the hardware-in-loop(HIL)experimental results have exemplified the validation of the developed methodology.展开更多
Nowadays renewable energy has become a trend for energy production but its variable nature has made balancing of demand and supply of the power grid difficult. Dynamic demand management using smart appliances is propo...Nowadays renewable energy has become a trend for energy production but its variable nature has made balancing of demand and supply of the power grid difficult. Dynamic demand management using smart appliances is proposed to serve as a way that part of the regulation burden of balancing demand and supply is shifted to the demand side. However, if all appliances respond to the same frequency deviation, they may start to synchronize, causing large power overshoots and instability of the power grid. Therefore, the idea of implementing randomness into the frequency control of the appliances is proposed and this is what we call a stochastic approach. Simulators are built from scratch to model both scenarios. The effect of synchronization is analyzed and the parameters that can affect the synchronization are investigated. It has been found that the larger the contribution from the smart appliances to the power grid, the easier and faster the synchronization takes place. The stochastic approach solves the problem of synchronization and averages out the large power overshoot. However, the overall performance of stochastic operations is unacceptable due to the randomness in the operation though the mean and variance are as expected. More advanced feedback policies and schemes may be designed to achieve a better performance.展开更多
China has become the maximum household appliances manufacturing base worldwide.It is a new challenge facing the steel industry to develop the low-cost and environment-friendly sheet for household appliance industry,so...China has become the maximum household appliances manufacturing base worldwide.It is a new challenge facing the steel industry to develop the low-cost and environment-friendly sheet for household appliance industry,so Cr-free anti-fingerprint hot-dip galvanized sheet for household appliances is the upgraded product which satisfies the requirement of China household appliance industry' s nuisanceless treatment.The paper discusses the technical key points of development on Cr-free anti-fingerprint galvanized sheet for household appliances,including the development of the Cr-free anti-fingerprint chemical and the production technology of Cr-free anti-fingerprint galvanized sheet for household appliances.The paper elaborates the main compositions,physical features and properties of the Cr-free anti-fingerprint chemical, surface quality control technology,anti-fingerprint coating quality control technology,influence of anti-fingerprint film weight on corrosion resistance,conductibility,high-temperature discolouration resistance,acid resistance,alkaline resistance and solvent resistance of Cr-free anti-fingerprint hot-dip galvanized sheet, influence of anti-fingerprint coating uniformity on paintability of the sheet,influence of strip surface roughness on corrosion resistance and conductivity of the sheet and influence of strip surface quality on corrosion resistance of the sheet.Adopting the suitable Cr-free anti-fingerprint chemical and the reasonable production process parameters,the properties of the Cr-free anti-fingerprint hot-dip galvanized sheet conform to the delivery technical norms and the Cr-free anti-fingerprint hot-dip galvanized sheet becomes the new material for household appliances such as computer case.展开更多
Aim: This article investigates the increasing awareness of Obstructive Sleep Apnoea (OSA) as a potentially serious health risk and highlights the role of the dentist in managing mild to moderate OSA cases which can be...Aim: This article investigates the increasing awareness of Obstructive Sleep Apnoea (OSA) as a potentially serious health risk and highlights the role of the dentist in managing mild to moderate OSA cases which can be improved with an intra-oral mandibular advancement appliance. Methods: Data from referrals to a Prosthodontic Unit from 01-01-2019 to 18-8-2022 were analysed. Results: A total of 240 consecutive referrals to an NHS hospital where a patient was fitted with a mandibular advancement appliance (MAA) were analysed and 160 (67%) were male and 80 (33%) were female. The mean age in years was 52 (2019), 50 (2020), 52 (2021) and 51 (2022). Mean age of male referrals was 51 and female referrals was 53. Conclusion: There are a large number of patients with OSA seeking a dental device and practitioners should be aware of this treatment modality to help the medical team manage OSA. Clinical relevance: Dentists may need to have a greater understanding of OSA and be able to provide MAAs.展开更多
With the ever-increasing volume of applications of various kinds of electric drives in all spheres of human activity, the issues in improving the efficiency of the electromechanical converters of electric energy, one ...With the ever-increasing volume of applications of various kinds of electric drives in all spheres of human activity, the issues in improving the efficiency of the electromechanical converters of electric energy, one of the most important components of the electric drive (ED), are becoming increasingly important. Such issues include reducing their weight and size, improving the functional characteristics of these devices to increase their operational life and reducing the cost of manufacture. Taking full advantage of these opportunities relates to the AC and DC single-phase commutator motor (SCM), which is widely used in regulated and high-speed motor drives in home appliances and electric hand tools. The SCM is used in machinery where the load torque has a hyperbolic dependence on the rotational speed and the need to work with a large motor overload due to the “soft” mechanical characteristics of such motors.展开更多
Background: The mental, physical and social impediments cause limitation of chances in normal life as an equal level with others of the community;particularly in relation to maintain good oral hygiene and periodontal ...Background: The mental, physical and social impediments cause limitation of chances in normal life as an equal level with others of the community;particularly in relation to maintain good oral hygiene and periodontal health among the disabled patients who were receiving fixed partial denture. So the present study was performed to evaluate the periodontal tissue status among mental retardation patients with fixed prosthodontic appliances. Subjects and Methods: A total of 400 patients between the ages 18 and 50 years were clinically selected from outpatient clinics, college of dentistry, King Khalid University and rehabilitation center in Abha city, Saudi Arabia. They were divided into two equal groups as the following: group I: Two hundred mental retardation patients without fixed prosthodontic appliances (control group) and, group II: Two hundred mental retardation patients had fixed prosthodontic appliances for at least a year ago. A complete periodontal clinical examination was performed and the following indices were recorded: plaque index (PLI), gingival index (GI), and clinical attachment loss (CAL). All data was recorded and analyzed by ANOVA test. Results: The clinical results of the present study confirmed the relationship among the mental retardation, fixed prosthodontic appliances and destruction of periodontal tissues. It has been found that the severity of periodontal disease increases among the study group compared to the control group. Statistically significant differences were found in PLI, GI and CAL in the comparison between group I and II (p Conclusion: There was a negative relationship between mental retardation with a status of periodontal tissues and oral hygiene among the patients under fixed prosthodontic management.展开更多
This paper gives and analyses data-driven prediction models for the energy usage of appliances.Data utilized include readings of temperature and humidity sensors from a wireless network.The building envelope is meant ...This paper gives and analyses data-driven prediction models for the energy usage of appliances.Data utilized include readings of temperature and humidity sensors from a wireless network.The building envelope is meant to minimize energy demand or the energy required to power the house independent of the appliance and mechanical system efficiency.Approximating a mapping function between the input variables and the continuous output variable is the work of regression.The paper discusses the forecasting framework FOPF(Feature Optimization Prediction Framework),which includes feature selection optimization:by removing non-predictive parameters to choose the best-selected feature hybrid optimization technique has been approached.k-nearest neighbors(KNN)Ensemble Prediction Models for the data of the energy use of appliances have been tested against some bases machine learning algorithms.The comparison study showed the powerful,best accuracy and lowest error of KNN with RMSE=0.0078.Finally,the suggested ensemble model’s performance is assessed using a one-way analysis of variance(ANOVA)test and the Wilcoxon Signed Rank Test.(Two-tailed P-value:0.0001).展开更多
Objective: The aim of this article is to provide a detailed description for obstructive sleep apnea regarding its signs and symptoms, the way it is diagnosed, the risk factors, management, the role of dentists and ora...Objective: The aim of this article is to provide a detailed description for obstructive sleep apnea regarding its signs and symptoms, the way it is diagnosed, the risk factors, management, the role of dentists and oral appliances in treatment and consequences of untreated condition. Material and Method: Electronic searching was done in PubMed, Medline, EMBASE and CENTRAL databases. Inclusion criteria were: dental, oral and maxillofacial oriented articles. Exclusion criteria: cardiac, obesity and non dental oriented articles were excluded. Result: 59 articles meet the criteria. Conclusion: Obstructive sleep apnea (OSA) is a potentially life threatening disorder characterized by repeated collapse of the upper airway during sleep, with periodic cessation of breathing for more than ten seconds. The frequency of obstructive sleep apnea has been found to increase with age;ranging from two percent among children to two and half percent - six percent among adolescents. Overnight polysomnographic test at specialized sleep clinics remains the gold standard for diagnosing obstructive sleep apnea disorder. Management of this condition can be performed via surgical and non surgical methods. Continuous positive airway pressure represents the first line of treatment for most patients with obstructive sleep apnea.展开更多
According to the inland micro electro-mechanical system (MEMS) process technique level, a design platform of piezoresistive micro electro-mechanical accelerometer is given. This platform is much more adaptable to th...According to the inland micro electro-mechanical system (MEMS) process technique level, a design platform of piezoresistive micro electro-mechanical accelerometer is given. This platform is much more adaptable to the inland designer compared with the current MEMS CAD software. The design flow is presented in detail, and the key techique in the platform is analyzed amply. The structure design methodology is exemplified in the design of a piezoresistive accelerometer, and the accelerometer is the optimized structure for the given performance requirements. The accelerometer is now being manufactured.展开更多
基金Natural Science Foundation of Jiangsu Province, No. SBK2021021787the Major Project of the Health Commission ofJiangsu Province, No. ZD2022025and the Key Project of the Nanjing Health Commission, No. ZKX20048.
文摘BACKGROUND The relation between orthodontic treatment and temporomandibular disorders(TMDs)is under debate;the management of TMD during orthodontic treatment has always been a challenge.If TMD symptoms occur during orthodontic treatment,an immediate pause of orthodontic adjustments is recommended;the treatment can resume when the symptoms are managed and stabilized.CASE SUMMARY This case report presents a patient(26-year-old,female)with angle class I,skeletal class II and TMDs.The treatment was a hybrid of clear aligners,fixed appliances and temporary anchorage devices(TADs).After 3 mo resting and treatment on her TMD,the patient’s TMD symptom alleviated,but her anterior occlusion displayed deep overbite.Therefore,the fixed appliances with TAD were used to correct the anterior deep-bite and level maxillary and mandibular deep curves.After the levelling,the patient showed dual bite with centric relation and maximum intercuspation discrepancy on her occlusion.After careful examination of temporomandibular joints(TMJ)position,the stable bite splint and Invisible Mandibular Advancement appliance were used to reconstruct her occlusion.Eventually,the improved facial appearance and relatively stable occlusion were achieved.The 1-year follow-up records showed there was no obvious change in TMJ morphology,and her occlusion was stable.CONCLUSION TMD screening and monitoring is of great clinical importance in the TMD susceptible patients.Hybrid treatment with clear aligners and fixed appliances and TADs is an effective treatment modality for the complex cases.
文摘Non-intrusive load monitoring is a method that disaggregates the overall energy consumption of a building to estimate the electric power usage and operating status of each appliance individually.Prior studies have mostly concentrated on the identification of high-power appliances like HVAC systems while overlooking the existence of low-power appliances.Low-power consumer appliances have comparable power consumption patterns,which can complicate the detection task and can be mistaken as noise.This research tackles the problem of classification of low-power appliances and uses turn-on current transients to extract novel features and develop unique appliance signatures.A hybrid feature extraction method based on mono-fractal and multi-fractal analysis is proposed for identifying low-power appliances.Fractal dimension,Hurst exponent,multifractal spectrum and the Hölder exponents of switching current transient signals are extracted to develop various‘turn-on’appliance signatures for classification.Four classifiers,i.e.,deep neural network,support vector machine,decision trees,and K-nearest neighbours have been optimized using Bayesian optimization and trained using the extracted features.The simulated results showed that the proposed method consistently outperforms state-of-the-art feature extraction methods across all optimized classifiers,achieving an accuracy of up to 96%in classifying low-power appliances.
文摘Since April 2004, the Asahi University Medical and Dental Center (hereinafter referred to as our center) has been providing oral appliances (hereinafter referred to as OA) to treat patients diagnosed with obstructive sleep apnea. The effects of using the OA and progress of 71 patients who received treatment at our center by wearing OA from March 2005 to the end of March 2016 were examined through questionnaires sent by physical mail. In 21 of 24 patients who underwent polysomnography after wearing OA, the apnea-hypopnea index (hereinafter referred to as AHI) significantly decreased after wearing OA (9.44 ± 10.37) compared to that before wearing OA (24.02 ± 13.57) (p = 8.7 × 10<sup>-8</sup>). The results showed that for patients who continuously use OA, it is necessary to have sound sleep/sleep soundly;further, the patients experienced a decrease in snoring when wearing OA, with only a few side effects on the temporomandibular joints and teeth. In addition, the closer the distance from the plane of the lower margin of the mandible to the hyoid bone after wearing OA, the more likely it was for the AHI to decrease, which suggests that wearing OA contributes to the prediction of therapeutic effects.
基金supported by the National Natural Science Foundation of China(51979130,11847009)the Young Elite Scientists Sponsorship Program by CAST(2022QNRC001)+1 种基金the Natural Science Foundation of Jiangsu Higher Education Institutions of China(22KJB580005)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(SJCX221961)。
文摘The model of a locally resonant (LR) epoxy/PZT-4 phononic crystal (PC)nanobeam with “spring-mass” resonators periodically attached to epoxy is proposed. The corresponding band structures are calculated by coupling Euler beam theory, nonlocal piezoelectricity theory and plane wave expansion (PWE) method. Three complete band gaps with the widest total width less than 10GHz can be formed in the proposed nanobeam by comprehensively comparing the band structures of three kinds of LR PC nanobeams with resonators attached or not. Furthermore, influencing rules of the coupling fields between electricity and mechanics,“spring-mass” resonator, nonlocal effect and different geometric parameters on the first three band gaps are discussed and summarized. All the investigations are expected to be applied to realize the active control of vibration in the region of ultrahigh frequency.
基金supported by National Development and Reform Commission of China (Grant No. 2005934)
文摘Braking on low adhesion-coefficient roads, hybrid electric vehicle's motor regenerative torque is switched off to safeguard the normal anti-lock braking system (ABS) fimction. When the ABS control is terminated, the motor regenerative braking is readmitted. Aiming at avoiding permanent cycles from hydraulic anti-lock braking to motor regenerative braking, a novel electro-mechanical hybrid anti-lock braking system using fuzzy logic is designed. Different from the traditional single control structure, this system has a two-layered hierarchical structure, The first layer is responsible for harmonious adjustment or interaction between regenerative system and anti-lock braking system. The second layer is responsible for braking torque distribution and adjustment. The closed-loop simulation model is built. Control strategy and method for coordination between regenerative and anti-lock braking are developed. Simulation braking on low adhesion-coefficient roads with fuzzy logic control and real vehicle braking field test are presented. The results from simulating analysis and experiment show braking performance of the vehicle is perfect, harmonious coordination between regenerative and anti-lock braking function, significant amount of braking energy can be recovered and the proposed control strategy and method are effective.
基金supported by Foundation of National Key Lab of Vehicular Transmission of China
文摘Automotive industry,as an important pillar of the national economy,has been rapidly developing in recent years.But proplems such as energy comsumption and environmental pollution are posed at the same time.Electro-mechanical variable transmission system is considered one of avilable workarounds.It is brought forward a kind of design methods of dual-mode electro-mechanical variable transmission system rotational speed characteristics and dual-mode drive diagrams.With the motor operating behavior of running in four quadrants and the speed characteristics of the simple internal and external meshing single planetary gear train,four kinds of dual-mode electro-mechanical transmission system scheme are designed.And the velocity,torque and power characteristics of one of the programs are analyzed.The magnitude of the electric split-flow power is an important factor which influences the system performance,so in the parameters matching design,it needs to reduce the power needs under the first mode of the motor.The motor,output rotational speed range and the position of the mode switching point have relationships with the characteristics design of the planetary gear set.The analysis method is to provide a reference for hybrid vehicles' design.As the involved rotational speed and torque relationships are the natural contact of every part of transmission system,a theory basis of system program and performance analysis is provided.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 10972084).
文摘Ionic Polymer-Metal Composites (IPMC) is an emerging class of Electro-Active Polymer (EAP) materials. IPMC has attractive features, such as high sensitivity and light weight, which are useful for developing novel designs in the fields of bionic actuators, artificial muscles and dynamic sensors. A Finite Element (FE) model was developed for simulating the dynamic electro-mechanical response of an IPMC structure under an external voltage input. A lumped Resisto^Capacitor (RC) model was used to describe the voltage-to-current relationship of a Nation IPMC film for the computation of electric field intensity. Moreover, the viscoelastic property of the IPMC film was considered in the model and the non-uniform bending behavior was also taken into account. Based on the proposed model and the assumption that the thicknesses of the two electrodes are the same and uniform, the optimal coating thickness of the IPMC electrode was determined. It was demonstrated that the dynamic electro-mechanical response of the IPMC structure can be predicted by the proposed FE model, and the simulation results were in good agreement with the experimental findings.
基金The project supported by the 973 Program (G1999033108)the National Natural Science Foundation of China (10125211)
文摘In this paper,we present the applications of Boundary Element Method(BEM) to simulate the electro-mechanical coupling responses of Micro-Electro-Mechanical systems(MEMS). The algorithm is programmed in our research group based on BEM modeling for electrostatics and elastostatics.Good agreement is shown while the simulation results of the pull-in voltages are compared with the theoretical/experimental ones for some examples.
基金supported by the National Natural Science Foundation of China(71871203,52005447,L1924063)Zhejiang Provincial Natural Science Foundation of China(LY18G010017,LQ21E050014).
文摘In a typical discrete manufacturing process,a new type of reconfigurable production line is introduced,which aims to help small-and mid-size enterprises to improve machine utilization and reduce production cost.In order to effectively handle the production scheduling problem for the manufacturing system,an improved multi-objective particle swarm optimization algorithm based on Brownian motion(MOPSO-BM)is proposed.Since the existing MOPSO algorithms are easily stuck in the local optimum,the global search ability of the proposed method is enhanced based on the random motion mechanism of the BM.To further strengthen the global search capacity,a strategy of fitting the inertia weight with the piecewise Gaussian cumulative distribution function(GCDF)is included,which helps to maintain an excellent convergence rate of the algorithm.Based on the commonly used indicators generational distance(GD)and hypervolume(HV),we compare the MOPSO-BM with several other latest algorithms on the benchmark functions,and it shows a better overall performance.Furthermore,for a real reconfigurable production line of smart home appliances,three algorithms,namely non-dominated sorting genetic algorithm-II(NSGA-II),decomposition-based MOPSO(dMOPSO)and MOPSO-BM,are applied to tackle the scheduling problem.It is demonstrated that MOPSO-BM outperforms the others in terms of convergence rate and quality of solutions.
文摘Chinese traditional sales channels are seriously attacked by the new ones. Household appliances industry will realize the specialized divisions of. development, manufacture, sale and services completely. The model of sales channel in marketing is set as the core of this research; the merits and demerits of different sales channels are analyzed; the complicated selective relationship and the conflicts among the manufacturer, middlemen, and ultimate consumers, and the solutions to present multi-channels market and the developments of the sales channels are elaborated in an overall view; the opinion that the only way to develop this industry is raised to establish the competitive sales channels. The aim is to let local household appliances industry use the natural merits to build up a suitable channel rapidly and efficiently, and to speed up the self development and oeffection.
基金supported by the National Natural Science Foundation of China(10025209,10132010,and 90208002)the Research Grants Council of the Hong Kong Special Administrative Region,China(HKU 7203/03E).
文摘This paper presents an efficient meshless method for analyzing cracked piezoelectric structures subjected to mechanical and electrical loading. In this method, an element free Galerkin (EFG) formulation, an enriched basic function and some special shape functions that contain discontinuous derivatives are employed. Based on the moving least squares (MLS) interpolation approach, the EFG method is one of the promising methods for dealing with problems involving progressive crack growth. Since the method is meshless and no element connectivity data are needed, the burdensome remeshing procedure required in the conventional finite element method (FEM) is avoided. The numerical results show that the proposed method can yield an accurate near-tip stress field in an infinite piezoelectric plate containing an interior hole. In another example studying a ceramic multilayer actuator, the proposed model was found to be accurate in the simulation of stress and electric field concentrations arround the abrupt end of an internal electrode.
基金This work was supported by the National Natural Science Foundation of China under Grant[number 51575167]。
文摘This paper focuses on the controller design using fuzzy sliding mode control(FSMC)with application to electro-mechanical brake(EMB)systems using BLDC Motor.The EMB controller transmits the control signal to the motor driver to rotate the motor.The torque distribution of motors is studied in this paper actually.Firstly,the model of the EMB system is established.Then the state observer is developed to estimate the vehicle states including the vehicle velocity and longitudinal force.Due to the fact that the EMB system is nonlinear and uncertain,a FSMC strategy based on wheel slip ratio is proposed,where both the normal and emergency braking conditions are taken into account.The equivalent control law of sliding mode controller is designed on the basis of the variation of the front axle and rear axle load during the brake process,while the switching control law is adjusted by the fuzzy corrector.The simulation results illustrate that the FSMC strategy has the superior performance,better adaptability to various types of roads,and shorter braking distance,as compared to PID control and traditional sliding mode control technologies.Finally,the hardware-in-loop(HIL)experimental results have exemplified the validation of the developed methodology.
文摘Nowadays renewable energy has become a trend for energy production but its variable nature has made balancing of demand and supply of the power grid difficult. Dynamic demand management using smart appliances is proposed to serve as a way that part of the regulation burden of balancing demand and supply is shifted to the demand side. However, if all appliances respond to the same frequency deviation, they may start to synchronize, causing large power overshoots and instability of the power grid. Therefore, the idea of implementing randomness into the frequency control of the appliances is proposed and this is what we call a stochastic approach. Simulators are built from scratch to model both scenarios. The effect of synchronization is analyzed and the parameters that can affect the synchronization are investigated. It has been found that the larger the contribution from the smart appliances to the power grid, the easier and faster the synchronization takes place. The stochastic approach solves the problem of synchronization and averages out the large power overshoot. However, the overall performance of stochastic operations is unacceptable due to the randomness in the operation though the mean and variance are as expected. More advanced feedback policies and schemes may be designed to achieve a better performance.
文摘China has become the maximum household appliances manufacturing base worldwide.It is a new challenge facing the steel industry to develop the low-cost and environment-friendly sheet for household appliance industry,so Cr-free anti-fingerprint hot-dip galvanized sheet for household appliances is the upgraded product which satisfies the requirement of China household appliance industry' s nuisanceless treatment.The paper discusses the technical key points of development on Cr-free anti-fingerprint galvanized sheet for household appliances,including the development of the Cr-free anti-fingerprint chemical and the production technology of Cr-free anti-fingerprint galvanized sheet for household appliances.The paper elaborates the main compositions,physical features and properties of the Cr-free anti-fingerprint chemical, surface quality control technology,anti-fingerprint coating quality control technology,influence of anti-fingerprint film weight on corrosion resistance,conductibility,high-temperature discolouration resistance,acid resistance,alkaline resistance and solvent resistance of Cr-free anti-fingerprint hot-dip galvanized sheet, influence of anti-fingerprint coating uniformity on paintability of the sheet,influence of strip surface roughness on corrosion resistance and conductivity of the sheet and influence of strip surface quality on corrosion resistance of the sheet.Adopting the suitable Cr-free anti-fingerprint chemical and the reasonable production process parameters,the properties of the Cr-free anti-fingerprint hot-dip galvanized sheet conform to the delivery technical norms and the Cr-free anti-fingerprint hot-dip galvanized sheet becomes the new material for household appliances such as computer case.
文摘Aim: This article investigates the increasing awareness of Obstructive Sleep Apnoea (OSA) as a potentially serious health risk and highlights the role of the dentist in managing mild to moderate OSA cases which can be improved with an intra-oral mandibular advancement appliance. Methods: Data from referrals to a Prosthodontic Unit from 01-01-2019 to 18-8-2022 were analysed. Results: A total of 240 consecutive referrals to an NHS hospital where a patient was fitted with a mandibular advancement appliance (MAA) were analysed and 160 (67%) were male and 80 (33%) were female. The mean age in years was 52 (2019), 50 (2020), 52 (2021) and 51 (2022). Mean age of male referrals was 51 and female referrals was 53. Conclusion: There are a large number of patients with OSA seeking a dental device and practitioners should be aware of this treatment modality to help the medical team manage OSA. Clinical relevance: Dentists may need to have a greater understanding of OSA and be able to provide MAAs.
文摘With the ever-increasing volume of applications of various kinds of electric drives in all spheres of human activity, the issues in improving the efficiency of the electromechanical converters of electric energy, one of the most important components of the electric drive (ED), are becoming increasingly important. Such issues include reducing their weight and size, improving the functional characteristics of these devices to increase their operational life and reducing the cost of manufacture. Taking full advantage of these opportunities relates to the AC and DC single-phase commutator motor (SCM), which is widely used in regulated and high-speed motor drives in home appliances and electric hand tools. The SCM is used in machinery where the load torque has a hyperbolic dependence on the rotational speed and the need to work with a large motor overload due to the “soft” mechanical characteristics of such motors.
文摘Background: The mental, physical and social impediments cause limitation of chances in normal life as an equal level with others of the community;particularly in relation to maintain good oral hygiene and periodontal health among the disabled patients who were receiving fixed partial denture. So the present study was performed to evaluate the periodontal tissue status among mental retardation patients with fixed prosthodontic appliances. Subjects and Methods: A total of 400 patients between the ages 18 and 50 years were clinically selected from outpatient clinics, college of dentistry, King Khalid University and rehabilitation center in Abha city, Saudi Arabia. They were divided into two equal groups as the following: group I: Two hundred mental retardation patients without fixed prosthodontic appliances (control group) and, group II: Two hundred mental retardation patients had fixed prosthodontic appliances for at least a year ago. A complete periodontal clinical examination was performed and the following indices were recorded: plaque index (PLI), gingival index (GI), and clinical attachment loss (CAL). All data was recorded and analyzed by ANOVA test. Results: The clinical results of the present study confirmed the relationship among the mental retardation, fixed prosthodontic appliances and destruction of periodontal tissues. It has been found that the severity of periodontal disease increases among the study group compared to the control group. Statistically significant differences were found in PLI, GI and CAL in the comparison between group I and II (p Conclusion: There was a negative relationship between mental retardation with a status of periodontal tissues and oral hygiene among the patients under fixed prosthodontic management.
基金This work was supported by the Taif University Researchers Supporting Project Number(TURSP-2020/345),Taif University,Taif,Saudi Arabia.
文摘This paper gives and analyses data-driven prediction models for the energy usage of appliances.Data utilized include readings of temperature and humidity sensors from a wireless network.The building envelope is meant to minimize energy demand or the energy required to power the house independent of the appliance and mechanical system efficiency.Approximating a mapping function between the input variables and the continuous output variable is the work of regression.The paper discusses the forecasting framework FOPF(Feature Optimization Prediction Framework),which includes feature selection optimization:by removing non-predictive parameters to choose the best-selected feature hybrid optimization technique has been approached.k-nearest neighbors(KNN)Ensemble Prediction Models for the data of the energy use of appliances have been tested against some bases machine learning algorithms.The comparison study showed the powerful,best accuracy and lowest error of KNN with RMSE=0.0078.Finally,the suggested ensemble model’s performance is assessed using a one-way analysis of variance(ANOVA)test and the Wilcoxon Signed Rank Test.(Two-tailed P-value:0.0001).
文摘Objective: The aim of this article is to provide a detailed description for obstructive sleep apnea regarding its signs and symptoms, the way it is diagnosed, the risk factors, management, the role of dentists and oral appliances in treatment and consequences of untreated condition. Material and Method: Electronic searching was done in PubMed, Medline, EMBASE and CENTRAL databases. Inclusion criteria were: dental, oral and maxillofacial oriented articles. Exclusion criteria: cardiac, obesity and non dental oriented articles were excluded. Result: 59 articles meet the criteria. Conclusion: Obstructive sleep apnea (OSA) is a potentially life threatening disorder characterized by repeated collapse of the upper airway during sleep, with periodic cessation of breathing for more than ten seconds. The frequency of obstructive sleep apnea has been found to increase with age;ranging from two percent among children to two and half percent - six percent among adolescents. Overnight polysomnographic test at specialized sleep clinics remains the gold standard for diagnosing obstructive sleep apnea disorder. Management of this condition can be performed via surgical and non surgical methods. Continuous positive airway pressure represents the first line of treatment for most patients with obstructive sleep apnea.
文摘According to the inland micro electro-mechanical system (MEMS) process technique level, a design platform of piezoresistive micro electro-mechanical accelerometer is given. This platform is much more adaptable to the inland designer compared with the current MEMS CAD software. The design flow is presented in detail, and the key techique in the platform is analyzed amply. The structure design methodology is exemplified in the design of a piezoresistive accelerometer, and the accelerometer is the optimized structure for the given performance requirements. The accelerometer is now being manufactured.