最新刊期
卷 54 ， 期 3 ， 2020
- 摘要：Aiming at the ultra-low power consumption design of the indispensable analog-to-digital converter(ADC)in implantable medical devices, based on the low-power-consumption successive-approximation SAR ADC, a least significant bit(LSB)-first SAR ADC is presented. The LSB-first quantitative logic is mainly used for biological signals of low mobility, such as electrocardiosignal. Under the condition of fixed resolution and sampling rate, the number of quanti-ation is adjusted according to the amplitude of the varying signal, so as to achieve the purpose of reducing power consumption and compressing data amount. Only a minimum number of three quanti-ations is required to obtain a quantitative result when the signal in on the baseline or varies slowly. Global Foundry 0.18--m standard CMOS process is used to design the circuit and layout of the ADC. The post-simulation results show that at the power supply voltage of 1.8 V and the sampling rate of 1 kH-, the effective bits are 9.6 bits, and th关键词：implantable medical device;low power consumption;least significant bit-first successive approximation;analog-to-digital converter439|4|1更新时间：2025-07-09
- 摘要：To further enhance the robustness and real-time performance of path tracking predictive control for high-speed autonomous vehicle, a predictive control method for path tracking considering error feedback correction mechanism is proposed. A three-degree-of-freedom vehicle model with weak nonlinearity is established considering the longitudinal, lateral and yaw motions of the vehicle. The linear time-varying first-order approximation of the control model is reali-ed by Taylor formula expansion. The predictive state variable is introduced to construct a path tracking optimi-ation scheme. Aiming at the problems of mismatch caused by uncertainties such as vehicle parameter deviation, system time-varying and external disturbance, the error between the actual state value and the predicted one is defined, and the prediction output model with feedback correction term is obtained. The robustness of the prediction model of the path tracking control system is enhanced by the error feedback correct关键词：autonomous vehicle;path tracking;predictive control;robustness;error feedback correction437|4|9更新时间：2025-07-09
- 摘要：To investigate the effects of PODEn(a new alternative fuel with high oxygen content and cetane number)addition on fuel economy, combustion and emission characteristics of a China-- emission standard diesel engine, experiments are conducted on a turbocharged intercooled high-pressure common-rail WP12.460 diesel engine fueled with PODEn/diesel mixture in different PODEn blending ratios(volume fractions of 10%, 20%, and 30%). The results show that with increasing PODEn blending ratio, the peak values of in-cylinder pressure, in-cylinder temperature and transient heat release rate decrease and the corresponding combustion phases appear in advance. The combustion duration shortens by 0.6--2.1-(crank angle), the brake thermal efficiency increases by 2.43%, and the equivalent fuel consumption decreases by 4.23%; NOx emission increases while CO, HC and soot emissions decrease. Especially, under high load condition, CO and soot emissions关键词：polyoxymethylene dimethyl ethers(PODEn);China-- standard diesel engine;high pressure common rail;combustion and emission characteristics397|4|4更新时间：2025-07-09
- 摘要：A new contact analysis approach based on lookup table is proposed to deal with the problem of low calculation efficiency involved in wear prediction for clearance ball joint in multi-body system considering the interaction between wear and mechanical dynamics. The proposed method utili-es lookup table to store the geometric position, kinematical parameters and wear depth of discrete points on the surface of the ball joint after the contact surface is discreti-ed as regular and representative points. By checking the table, required information can be extracted to determine contact location instead of calculating the spatial distance of contact points. Accurate contact stress distribution for conformal contact with micro clearance is gained using modified Hert- model with less computational cost than finite element method. Thus, multi-body dynamics and contact wear can be integrated into the unified model efficiently. A spatial linkage mechanism with ball joints containing clearance is t关键词：spherical joint with clearance;contact detection;wear prediction;lookup table399|4|0更新时间：2025-07-09
- 摘要：To address the deficiencies of standard filters and low robustness in cooperative locali-ation system, a novel factor graph algorithm is proposed, which can be applied to indoor multiple users by fusing topology measurement provided by cameras with inertial navigation system. A topology measuring cooperative locali-ation method is further presented utili-ing the objects detection algorithm from the images. To derive a flexible optimi-ation model of the navigation solution with incorporating asynchronous sensors capabilities, the topology measuring factors and inertial navigation system factors are created in solving nonlinear optimi-ation problems. To further enhance the robustness, an improved switch constraint algorithm is developed by introducing weights decision approach considering both residuals and detection scores, and it better suits to the topology measurements. Simulations and experiments show that the rising accuracy of topology measurements improves position and velocity e关键词：topology measurement;inertial navigation system;factor graph;cooperative locali-ation;robust382|4|0更新时间：2025-07-09
- 摘要：To study the effect of applying AC electric field on the natural gas premixed flame at high initial pressures, we used a volume-constant combustion chamber, and the research object was a transient spherical flame of methane/air premixture, aiming at exploring the effects of low-frequency AC electric field and high-frequency AC electric field loaded with an effective voltage 5 kV on the combustion characteristics of methane/air premixed flames in the condition that excess air coefficient-=1.2, temperatureT=298 K and initial pressurep=300 kPa. The results showed that, under low frequency conditions, when the electric field frequencyf=40, 60, 80, 100 H-, the flame propagation speeds increased by17.41%, 6.53%, 3.99% and 1.54%; the flame combustion pressure peak increased by2.06%, 1.73%, 1.04% and 0.79%; the time for the mass burning rate reaching 100% shortened by11.96%, 10.27%, 7.78% and 3.74%, respectively. Under high frequency conditions, when the electric field frequencyf=10, 15, 20 k关键词：electric field-assisted combustion;combustion characteristics;bi-ionic wind effect;electrochemical effect330|4|0更新时间：2025-07-09
- 摘要：To investigate the effect of DC electric field on the combustion characteristics, experiments were conducted under the condition of normal temperature and initial pressure of 100 kPa, and electric field was applied on the mesh electrodes within the combustion bomb in three ways: applying negative DC electric field on both sides; applying positive DC electric field on both sides; and applying negative DC electric field on the left side and positive DC electric field on the right side. The methane/air premixed flame combustion characteristics were studied under the three kinds of electric fields. The results showed that the flame deformation, average flame propagation velocity and pressure peak all increased with the increase of the loading voltage. When the voltage amplitude was the same, the negative electric field applied on both sides had the strongest promotion effect on the flame, followed by the negative electric field on the left side and positive electric field on the right side关键词：DC electric field;combustion;electric body force;development degree of ionic wind350|4|3更新时间：2025-07-09
- 摘要：To investigate the pollution status of heavy metals in decentrali-ed water supply in a county in Northwest China and the potential ha-ards to human, 13 water cellars and 10 wells were selected. The sampling determination of the 15 common heavy metals in drinking water were carried out by inductively coupled plasma mass spectrometry technology, and the potential health risks of the heavy metal elements were systematically assessed by using the risk assessment model recommended by US EPA. The results show that the mass concentrations of Zn, Al and Cr in underground well water of the county are relatively high, but there is no phenomenon of exceeding the standard. After the well water is stored in the cellar for a period of time, the average mass concentrations of most elements except Mn, As and Ni increase in varying degrees. And even Cd content in no.3 water sample exceeds the standard. Compared with the well water, the mass concentrations of the heavy metals in rainwater are generally关键词：scattered water supply;water cellar;heavy metals;health risk350|4|2更新时间：2025-07-09
- 摘要：To overcome the shortcomings of the conventional methods for pesticides degradation, such as low efficiency, high energy consumption, and secondary pollution, a self-designed dielectric barrier discharge reactor was used to degrade pesticides on mai-e, and chlorpyrifos was chosen as the research object. The effects of chlorpyrifos degradation, as well as the surface characteristics and the nutrients of mai-e, after degradation were studied by changing the discharge parameters(discharge power, treatment time, discharge gap), initial concentration of chlorpyrifos, and argon flux. The results showed that at discharge power of 35 W, treatment time of 60 s, discharge gap of 6 mm and argon flux of 0.25 L/min, 87% of chlorpyrifos with initial concentration of 20 mg/L could be successfully degraded, which met the national standard about pesticide residues. In the process of pesticides degradation, argon plasma treatment attributed to slight etching on the surface of mai-e, which could reduce t关键词：argon plasma;chlorpyrifos;degradation efficiency;mai-e quality422|4|0更新时间：2025-07-09
- 摘要：To solve the problem that the traditional multi-view learning methods cannot fully explore the consensus information among different views, a low-rank tensor decomposition multi-view spectral clustering algorithm based on truncated nuclear norm is proposed. The similarity matrix and transition probability matrix of each view are firstly obtained, then a tensor based on multi-view transition probability matrices is constructed. Tensor singular value decomposition based tensor truncated nuclear norm is imposed to preserve the low-rank property of the common tensor. Minimi-ing the tensor truncated kernel norm, a tensor containing both shared information and high-order correlations can be obtained properly via learning. The proposed method can be efficiently optimi-ed by the alternating direction method of multipliers. Experimental results on 4 datasets show that compared with standard spectral clustering, the value of normali-ed mutual information is enhanced by 7.9%, 24.9%, 29.5% and 8.1关键词：multi-view spectral clustering;tensor;truncated nuclear norm487|4|4更新时间：2025-07-09
- 摘要：To investigate the influence of driving pattern of the modular soft robot on the oneway advancement, a six-module soft crawling robot is designed and the multi-mode motions are discussed. The six-module soft crawling robot is designed by connecting differential drive modules in serial which can move forward by transmitting traveling waves on the body. Analy-ing the relationship between the force state of inflating or deflating modules and their position interval during crawling process, the position interval model is obtained, which meets the necessary condition of one-way advancement, where the module gains advancement as inflating and the movement is transmitted forward as deflating. And 10 feasible motion modes are elicited by consulting the model. The Lagrangian dynamics model is established by taking advantage of lumped mass method, and the feasibility of the motion modes is verified by simulation in ADAMS. The feasible motion modes of the robot are verified by experiments and the关键词：modular soft robot;position interval relationship;multi-mode motion373|4|3更新时间：2025-07-09
- 摘要：In view of the current situation that the researches the adsorption capacity of diesel engine exhaust particles and the structural characteristics related to adsorption are insufficient, the adsorption capacity and structural feature of diesel engine exhaust particles under different working conditions were measured and analy-ed. Particles in diesel engine exhaust under different operating conditions(100% load, 1 500 r/min, 2 700 r/min, 3 600 r/min)were collected by diesel engine test bench. The adsorption performance of the diesel engine exhaust particles was measured by nitrogen adsorption method. The specific surface area, pore structure parameters and fractal dimension of the diesel engine exhaust particles were measured by multi-point BET method, DFT method and FHH method, respectively. The change law of particulate structure characteristic parameters with diesel engine speed was discussed, and the change law of particulate structure characteristic parameters with diesel engine sp关键词：diesel;exhaust particle;nitrogen adsorption;structural feature356|4|3更新时间：2025-07-09
- 摘要：To explore the primary and secondary factors affecting the atomi-ation performance of biodiesel, the micro-atomi-ation characteristics of B100(palm oil biodiesel),N10(90% biodiesel plus 10% n-butanol in volume)andN20(80% biodiesel plus 20% n-butanol in volume)at different orifice diameters, injection pressures and back pressures were studied by high speed photography and phase Doppler particle analy-er(PDPA)measurement system. The axial velocity of the oil droplets and the variation trend of the Sauter mean diameter(DSMD)were analy-ed. Based on the grey correlation theory, the order of four influencing factors onDSMD of biodiesel was calculated. The results showed that theDSMD of B100 decreased from 106.74 -m at the axial length of 5 mm to 57.98 -m at the axial length of 70 mm; the axial velocity andDSMD of the oil droplet decreased with the percentage of n-butanol. With the increase of the injection pressure and the decrease of the back pr关键词：biodiesel;spraying;high speed photography;Sauter mean diameter;grey correlation analysis371|4|1更新时间：2025-07-09
- 摘要：Aiming at the current researches of organic Rankine cycle(ORC)focusing on the ideal engine conditions but insufficient under real road conditions, an investigation for energy saving potential of ORC system under real road conditions is carried out. A vehicle model including the models of engine, ORC system, power transmission system and the other components is established by different templates in GT-Suite. Simulations show that the engine and ORC system models are accurate. The vehicle model is used to analyse the exhaust energy characteristics, and the operation characteristics and energy saving potential of ORC system under the new European driving cycle(NEDC)and the heavy-duty diesel truck(HHDDT)high-speed cruise road conditions. The exhaust energy fluctuates greatly under NEDC road condition, ranging from 5.8 kW to 36 kW, with the average energy recovery efficiency of 2.01%. The average exhaust energy in urban road conditions is 10.3 kW, with the average energy recovery efficiency关键词：organic Rankine cycle;vehicle simulation;road conditions;waste heat recovery356|4|1更新时间：2025-07-09
- 摘要：For identifying whether a screw locking fault occurs and its type accurately, a multi-resolution fusion convolutional neural network is proposed. To improve recognition rate and accuracy, the network uses original series data as the input. To extract multi-scale features, 1-D convolutional operation is performed on the feature maps with resolutions(data length)of 4 000, 2 000 and 1 000, respectively. In the Fusion layer, the resolution feature maps are fused by upsample, downsample and 1-1 convolution to obtain three sets of new feature maps, so that the network can obtain the global and local information of locking series. In output layer, class weighted cross entropy(CWCE)loss is used to alleviate the issue of unbalanced data in different classes by setting a penalty coefficient for loss function to strengthen the punishment for small sample categories. 3 149 screw locking series datasets are collected, and experiments are performed on this dataset. In the experiments of six categor关键词：screw;locking fault;multi-resolution fusion;convolutional neural network;class weighted cross entropy381|6|0更新时间：2025-07-09
- 摘要：To explore the melting behavior of copper foam composite materials, a visuali-ed phase-change thermal storage experimental setup was built. Foamed copper phase change materials with different thickness were prepared. The changes of the melting interface were studied by experiments, and the internal temperature distributions of pure phase-change materials and composite phase-change materials were compared. The effect of metal foam thickness on the heat transfer intensity was analy-ed. The experimental results show that natural convection plays a leading role in the melting process of pure phase-change materials. The 5 mm-thick metal foam promotes the natural convection of the upper paraffin, however the metal foam with the thickness of 10, 15 or 20 mm inhibits the natural convection of paraffin. The larger the thickness of copper foam, the greater the heat conduction intensity. There is a negative correlation between the convection heat transfer intensity and conduction heat transfer in关键词：paraffin;metal foam;visuali-ed experiment;heat transfer intensity405|4|6更新时间：2025-07-09
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