Boosting efficiency and stability of 2D alternating cation perovskite solar cells via rational surface-modification: Marked passivation efficacy of anion

Two-dimensional(2D) alternating cation(ACI) perovskite surface defects,especially dominant iodine vacancies(V_Ⅰ) and undercoordinated Pb^(2+),limit the performance of perovskite solar cells(PVSCs).To address the issue,1-butyl-3-methylimidazolium trifluoro-methane-sulfonate(BMIMOTF) and its iodide counterpart(BMIMI) are utilized to modify the perovskite surface respectively.We find that BMIMI can change the perovskite surface,whereas BMIMOTF shows a nondestructive and more effective defect passivation,giving significantly reduced defect density and suppressed charge-carrier nonradiative recombination.This mainly attributes to the marked passivation efficacy of OTF-anion on V_Ⅰ and undercoordinated Pb^(2+),rather than BMIMI^(+) cation.Benefiting from the rational surface-modification of BMMIMOTF,the films exhibit an optimized energy level alignment,enhanced hydrophobicity and suppressed ion migration.Consequently,the BMIMOTF-modified devices achieve an impressive efficiency of 21.38% with a record open-circuit voltage of 1.195 V,which is among the best efficiencies reported for 2D PVSCs,and display greatly enhanced humidity and thermal stability.

Identification of Deleterious Single Amino Acid Polymorphism Using Sequence Information Based on Feature Selection and Parameter Optimization

Most of the human genetic variations are single nucleotide polymorphisms (SNPs), and among them, non-synonymous SNPs, also known as SAPs, attract extensive interest. SAPs can be neural or disease associated. Many studies have been done to distinguish deleterious SAPs from neutral ones. Since many previous studies were based on both structural and sequence features of the SAP, these methods are not applicable when protein structures are not available. In the current paper, we developed a method based on UMDA and SVM using protein sequence information to predict SAP’s disease association. We extracted a set of features that are independent of protein structure for each SAP. Then a SVM-based machine-learning classifier that used grid search to tune parameters was applied to predict the possible disease associa-tion of SAPs. The SVM method reaches good prediction accuracy. Since the input data of SVM contain irrelevant and noisy features and parameters of SVM also affect the prediction performance, we introduced UMDA-based wrapper approach to search for the ‘best’ solution. The UMDA-based method greatly improved prediction performance. Com-pared with current method, our method achieved better performance.

Modelling and fabrication of wide temperature range Al_(0.24)Ga_(0.76)As/GaAs Hall magnetic sensors

Silicon Hall-effect sensors have been widely used in industry and research fields due to their straightforward fabrication process and CMOS compatibility.However,as their material property limitations,technicians usually implement complex CMOS circuits to improve the sensors’performance including temperature drift and offset compensation for fitting tough situation,but it is no doubt that it increases the design complexity and the sensor area.Gallium arsenide(GaAs)is a superior material of Hall-effect device because of its large mobility and stable temperature characteristics.Concerning there is no specified modelling of GaAs Hall-effect device,this paper investigated its modelling by using finite element method(FEM)software Silvaco TCAD®to help and guide GaAs Hall-effect device fabrication.The modeled sensor has been fabricated and its experimental results are in agreement with the simulation results.Comparing to our previous silicon Hall-effect sensor,the GaAs Hall-effect sensor demonstrates potential and reliable benchmark for the future Hall magnetic sensor developments.

Energy Efficient and Intelligent Mosquito Repellent Fuzzy Control System

Mosquitoes are of great concern for occasionally carrying noxious diseases(dengue,malaria,zika,and yellow fever).To control mosquitoes,it is very crucial to effectively monitor their behavioral trends and presence.Traditional mosquito repellent works by heating small pads soaked in repellant,which then diffuses a protected area around you,a great alternative to spraying yourself with insecticide.But they have limitations,including the range,turning them on manually,and then waiting for the protection to kick in when the mosquitoes may find you.This research aims to design a fuzzy-based controller to solve the above issues by automatically determining a mosquito repellent’s speed and active time.The speed and active time depend on the repellent cartridge and the number of mosquitoes.The Mamdani model is used in the proposed fuzzy system(FS).The FS consists of identifying unambiguous inputs,a fuzzification process,rule evaluation,and a defuzzification process to produce unambiguous outputs.The input variables used are the repellent cartridge and the number of mosquitoes,and the speed of mosquito repellent is used as the output variable.The whole FS is designed and simulated using MATLAB Simulink R2016b.The proposed FS is executed and verified utilizing a microcontroller using its pulse width modulation capability.Different simulations of the proposed model are performed in many nonlinear processes.Then,a comparative analysis of the outcomes under similar conditions confirms the higher accuracy of the FS,yielding a maximum relative error of 10%.The experimental outcomes show that the root mean square error is reduced by 67.68%,and the mean absolute percentage error is reduced by 52.46%.Using a fuzzy-based mosquito repellent can help maintain the speed of mosquito repellent and control the energy used by the mosquito repellent.

Saddlepoint Approximation Method in Reliability Analysis:A Review

The escalating need for reliability analysis(RA)and reliability-based design optimization(RBDO)within engineering challenges has prompted the advancement of saddlepoint approximationmethods(SAM)tailored for such problems.This article offers a detailed overview of the general SAM and summarizes the method characteristics first.Subsequently,recent enhancements in the SAM theoretical framework are assessed.Notably,the mean value first-order saddlepoint approximation(MVFOSA)bears resemblance to the conceptual framework of the mean value second-order saddlepoint approximation(MVSOSA);the latter serves as an auxiliary approach to the former.Their distinction is rooted in the varying expansion orders of the performance function as implemented through the Taylor method.Both the saddlepoint approximation and third-moment(SATM)and saddlepoint approximation and fourth-moment(SAFM)strategies model the cumulant generating function(CGF)by leveraging the initial random moments of the function.Although their optimal application domains diverge,each method consistently ensures superior relative precision,enhanced efficiency,and sustained stability.Every method elucidated is exemplified through pertinent RA or RBDO scenarios.By juxtaposing them against alternative strategies,the efficacy of these methods becomes evident.The outcomes proffered are subsequently employed as a foundation for contemplating prospective theoretical and practical research endeavors concerning SAMs.The main purpose and value of this article is to review the SAM and reliability-related issues,which can provide some reference and inspiration for future research scholars in this field.

Fault Analysis of Wind Power Rolling Bearing Based on EMD Feature Extraction

In a wind turbine,the rolling bearing is the critical component.However,it has a high failure rate.Therefore,the failure analysis and fault diagnosis of wind power rolling bearings are very important to ensure the high reliability and safety of wind power equipment.In this study,the failure form and the corresponding reason for the failure are discussed firstly.Then,the natural frequency and the characteristic frequency are analyzed.The Empirical Mode Decomposition(EMD)algorithm is used to extract the characteristics of the vibration signal of the rolling bearing.Moreover,the eigenmode function is obtained and then filtered by the kurtosis criterion.Consequently,the relationship between the actual fault frequency spectrum and the theoretical fault frequency can be obtained.Then the fault analysis is performed.To enhance the accuracy of fault diagnosis,based on the previous feature extraction and the time-frequency domain feature extraction of the data after EMD decomposition processing,four different classifiers are added to diagnose and classify the fault status of rolling bearings and compare them with four different classifiers.

Traffic-Aware VDC Embedding in Data Center： A Case Study of FatTree

Virtualization is a common technology for resource sharing in data center.To make efficient use of data center resources,the key challenge is to map customer demands(modeled as virtual data center,VDC) to the physical data center effectively.In this paper,we focus on this problem.Distinct with previous works,our study of VDC embedding problem is under the assumption that switch resource is the bottleneck of data center networks(DCNs).To this end,we not only propose relative cost to evaluate embedding strategy,decouple embedding problem into VM placement with marginal resource assignment and virtual link mapping with decided source-destination based on the property of fat-tree,but also design the traffic aware embedding algorithm(TAE) and first fit virtual link mapping(FFLM) to map virtual data center requests to a physical data center.Simulation results show that TAE+FFLM could increase acceptance rate and reduce network cost(about 49%in the case) at the same time.The traffic aware embedding algorithm reduces the load of core-link traffic and brings the optimization opportunity for data center network energy conservation.

Modeling of a triple reduced surface field silicon-on-insulator lateral double-diffused metal–oxide–semiconductor field-effect transistor with low on-state resistance

An analytical model for a novel triple reduced surface field（RESURF） silicon-on-insulator（SOI） lateral doublediffused metal–oxide–semiconductor（LDMOS） field effect transistor with n-type top（N-top） layer, which can obtain a low on-state resistance, is proposed in this paper. The analytical model for surface potential and electric field distributions of the novel triple RESURF SOI LDMOS is presented by solving the two-dimensional（2D） Poisson＇s equation, which can also be applied to single, double and conventional triple RESURF SOI structures. The breakdown voltage（BV） is formulized to quantify the breakdown characteristic. Besides, the optimal integrated charge of N-top layer（Q_（ntop）） is derived, which can give guidance for doping the N-top layer. All the analytical results are well verified by numerical simulation results,showing the validity of the presented model. Hence, the proposed model can be a good tool for the device designers to provide accurate first-order design schemes and physical insights into the high voltage triple RESURF SOI device with N-top layer.

Dual-band and polarization-insensitive terahertz absorber based on fractal Koch curves

We report the design, fabrication, and characterization of a dual-band and polarization-insensitive metamaterial ab-sorber （MA）, which consists of periodically arranged fractal Koch curves acting as the top resonator array and a metallic ground plane separated by a dielectric spacer. Compared with conventional MAs, a more compact size and multi-frequency operation are achieved by using fractal geometry as the unit cell of the MA. Both the effective medium theory and the multi- reflection interference theory are employed to investigate the underlying physical mechanism of the proposed terahertz MA, and results indicate that the latter theory is not suitable for explaining the absorption mechanism in our investigated struc-ture. Two absorption peaks are observed at 0.226 THz and 0.622 THz with absorptivities of 91.3% and 95.6% respectively and good agreements between the full-wave simulation and experimental results are achieved.

Effect of ZnO-B_2O_3 Glass Addition on the Microwave Dielectric Properties of BaO-Nd_2O_3-TiO_2-Bi_2O_3 System

The effect of ZnO-B2O3（ZB） glass addition on the sintering behavior, microstructures and microwave dielectric properties of BaO-Nd2O3-TiO2-Bi2O3 （BNTB） system was investigated with the aid of X-ray diffraction, scanning electron microscopy and capacitance meter. It is found that the ZB glass addition, acting as a sintering aid, can effectively lower the sintering temperature of BNTB system to 850 ℃. The dielectric constant of BNTB-ZB ceramics increases with the increase of soaking time and the value of dielectric loss decreased with increasing soak time. The optical dielectric properties at 1 GHz of ε=74, tan δ=4×10^-4, and TCC=25 ppm/℃ were obtained for the BNTB system doped with 25 wt% ZB glass sintered at 850 ℃ for 2 h, representing that the BNTB-ZB ceramics could be promising for multilayer low temperature co-fired ceramics applications.

Temperature Dependence of Optically Erased Two-Wave Mixing in Ce:KNSBN

The intensity response of an optically erased photorefractive two-wave mixing to the erase beam is studied by using the coupling wave equation and the band-transport model.The concepts of response strength and the minimum response intensity are introduced and their temperature dependence is investigated.A 2-fold increase in the response strength and 4-fold decrease in minimum response intensity have been experimentally observed in Ce:KNSBN at 633 nm when the crystal temperature is raised from 320 to 370K.These experimental results are in agreement with theoretical analysis and show that the response property can be improved by changing the crystal temperature.

Optimal migration path of Ag in HfO_2: A first-principles study

First-principles calculations are used to investigate the migration path of Ag in the HfO2-based resistive random access memory（Re RAM）. The formation energy calculation suggests that there are two different sites（site 1 and site 3） for the incorporation of Ag atoms into the HfO2 unit cell. Thermodynamic analysis shows that the motion of Ag atom in the HfO2 supercell appears to be anisotropic, which is due to the fact that the Ag atom at site 3 moves along the [1ˉ11] orientation,but the Ag atom at site 1 moves along the [001] orientation. The migration barriers of the Ag atoms hopping between neighboring unit cells are calculated along five different orientations. Difficulty in producing motion of the Ag atom varies with the migration barrier： this motion is minimized along [1ˉ11] orientation. Furthermore, The optimal circulation path for Ag migration within the HfO2 supercells is obtained, and is found to be approximately along the [1ˉ11] orientation.Therefore, it is proposed that the positive voltage should be applied along this orientation, the conduction filament may form more easily, which could improve the response time and reduce the power consumption in Re RAM applications.

High threshold voltage enhancement-mode GaN p-FET with Sirich LPCVD SiN_(x) gate insulator for high hole mobility

In this work,the GaN p-MISFET with LPCVD-SiN_(x) is studied as a gate dielectric to improve device performance.By changing the Si/N stoichiometry of SiN_(x),it is found that the channel hole mobility can be effectively enhanced with Si-rich SiN_(x) gate dielectric,which leads to a respectably improved drive current of GaN p-FET.The record high channel mobility of 19.4 cm2/(V∙s)was achieved in the device featuring an Enhancement-mode channel.Benefiting from the significantly improved channel mobility,the fabricated E-mode GaN p-MISFET is capable of delivering a decent-high current of 1.6 mA/mm,while simultaneously featuring a negative threshold-voltage(VTH)of–2.3 V(defining at a stringent criteria of 10μA/mm).The device also exhibits a well pinch-off at 0 V with low leakage current of 1 nA/mm.This suggests that a decent E-mode operation of the fabricated p-FET is obtained.In addition,the VTH shows excellent stability,while the threshold-voltage hysteresisΔVTH is as small as 0.1 V for a gate voltage swing up to–10 V,which is among the best results reported in the literature.The results indicate that optimizing the Si/N stoichiometry of LPCVD-SiN_(x) is a promising approach to improve the device performance of GaN p-MISFET.

High performance carrier stored trench bipolar transistor with dual shielding structure

We propose a novel high performance carrier stored trench bipolar transistor(CSTBT)with dual shielding structure(DSS-CSTBT).The proposed DSS-CSTBT features a double trench structure with different trench profiles in the surface,in which a shallow gate trench is shielded by a deep emitter trench and a thick oxide layer under it.Compared with the conventional CSTBT(con-CSTBT),the proposed DSS-CSTBT not only alleviates the negative impact of the shallow gate trench and highly doped CS layer on the breakdown voltage(BV),but also well reduces the gate-collector capacitance CGC,gate charge Q_(G),and turn-off loss E_(OFF)of the device.Furthermore,lower turn-on loss E_(ON)and gate drive loss E_(DR)are also obtained.Simulation results show that with the same CS layer doping concentration N_(CS)=1.5×10^(16)cm^(-3),the BV increases from 1312 V of the con-CSTBT to 1423 V of the proposed DSS-CSTBT with oxide layer thickness under gate(T_(og2))of 1μm.Moreover,compared with the con-CSTBT,the C_(GC)at V_(CE)of 25 V and miller plateau charge(Q_(GC))for the proposed DSS-CSTBT with T_(og2)of 1μm are reduced by 79.4%and 74.3%,respectively.With the VGEincreases from 0 V to 15 V,the total QGfor the proposed DSS-CSTBT with T_(og2)of 1μm is reduced by 49.5%.As a result,at the same on-state voltage drop(V_(CEON))of 1.55 V,the E_(ON)and E_(OFF)are reduced from 20.3 mJ/cm^(2)and 19.3 mJ/cm^(2)for the con-CSTBT to8.2 mJ/cm^(2)and 9.7 mJ/cm^(2)for the proposed DSS-CSTBT with T_(og2)of 1μm,respectively.The proposed DSS-CSTBT not only significantly improves the trade-off relationship between the V_(CEON)and E_(OFF)but also greatly reduces the E_(ON).

A Survey on Smart Collaborative Identifier Networks

The current Internet architecture was designed on the basis of a triple bindings model, which could meet the needs of the early Internet. However, with the tremendous growth of the Internet and the continuous innovations of applications, the triple bindings(namely, control/data binding, resource/location binding and user/network binding) have given rise to many problems for the Internet, such as scalability, mobility, and security. In order to solve these problems, many network techniques have been developed. Besides, novel future Internet architectures including Information-Centric Networks and Software-Defined Networks have emerged. However, these architectures only partially decouple the triple bindings. To completely separate the triple bindings, Smart Collaborative Identifier Networks(SINET) is proposed. There have been many research efforts on SINET, which built the foundation of SINET being a promising future Internet. In this paper, we comprehensively introduce SINET and these related research works. We start by introducing the motivation for SINET, explain its fundamental concepts and how it can make a difference. Next, we present in details the design principles of every layer in SINET, explaining how it can decouple the triple bindings and solve the problems of the current Internet. Finally, we discuss the state-of-theart challenges in SINET. We investigate the ongoing research works and commercial products in SINET, with aspects such as scalability, mobility, security and reliability.

POLYNOMIAL MODEL BASED FAST FRACTIONAL PIXEL SEARCH ALGORITHM FOR H.264/AVC

This paper proposed a novel fast fractional pixel search algorithm based on polynomial model. With the analysis of distribution characteristics of motion compensation error surface inside fractional pixel searching window, the matching error is fitted with parabola along horizontal and vertical direction respec-tively. The proposed searching strategy needs to check only 6 points rather than 16 or 24 points, which are used in the Hierarchical Fractional Pel Search algorithm (HFPS) for 1/4-pel and 1/8-pel Motion Estimation (ME). The experimental results show that the proposed algorithm shows very good capability in keeping the rate distortion performance while reduces computation load to a large extent compared with HFPS algorithm.

A Cognitive Memory-Augmented Network for Visual Anomaly Detection

With the rapid development of automated visual analysis,visual analysis systems have become a popular research topic in the field of computer vision and automated analysis.Visual analysis systems can assist humans to detect anomalous events(e.g.,fighting,walking alone on the grass,etc).In general,the existing methods for visual anomaly detection are usually based on an autoencoder architecture,i.e.,reconstructing the current frame or predicting the future frame.Then,the reconstruction error is adopted as the evaluation metric to identify whether an input is abnormal or not.The flaws of the existing methods are that abnormal samples can also be reconstructed well.In this paper,inspired by the human memory ability,we propose a novel deep neural network(DNN)based model termed cognitive memory-augmented network(CMAN)for the visual anomaly detection problem.The proposed CMAN model assumes that the visual analysis system imitates humans to remember normal samples and then distinguishes abnormal events from the collected videos.Specifically,in the proposed CMAN model,we introduce a memory module that is able to simulate the memory capacity of humans and a density estimation network that can learn the data distribution.The reconstruction errors and the novelty scores are used to distinguish abnormal events from videos.In addition,we develop a two-step scheme to train the proposed model so that the proposed memory module and the density estimation network can cooperate to improve performance.Comprehensive experiments evaluated on various popular benchmarks show the superiority and effectiveness of the proposed CMAN model for visual anomaly detection comparing with the state-of-the-arts methods.The implementation code of our CMAN method can be accessed at https://github.com/CMANcode/CMAN_pytorch.

Effect of Bi_2O_3 Additive on the Microstructure and Dielectric Properties of BaTiO_3-Based Ceramics Sintered at Lower Temperature

High performance X8R dielectric ceramics were prepared by dopingBi2O3 to BaTiO3-based ceramics.The effect of small amounts（≤1.2 mol%） ofBi2O3 additive on the microstructure and dielectric properties of BaTiO3-based ceramics have been investigated.The Bi2O3 ,acting as a sintering additive,can effectively lower the sintering temperature of BaTiO3-based ceramics from 1300 to 1130 °C.The bulk density of BaTiO3-based ceramics increased and reached the maximum value with increasingBi2O3 content.The dielectric constant increased with increasingBi2O3 until it reached the maximum value with 0.8 mol%Bi2O3 additive,and the dielectric loss decreased with increasingBi2O3 content.Optimal dielectric properties of ε=2470,tanδ=0.011 and △ε/ε 25 ≤±9%（-55-150 °C） were obtained for the BaTiO3-based ceramics doped with 0.8 mol%Bi2O3 sintered at 1130 °C for 6 h.

Design and analysis of a bang-bang PLL for 6.25 Gbps SerDes

An analysis illustrates the loop nonlinear performance in a bang-bang PLL. A third-order equivalent model is deduced to give an approximate evaluation of the loop parameters. The architecture of the proposed phase detector is composed of four master-slave DFFs and two XORs based on the current mode logic circuit. A no-load architecture is introduced in the XOR design. The oscillator is designed with an LC VCO implementation for the jitter requirement. A simple voltage-to-current converter is proposed to drive the loop filter. The loop filter design is described in detail, which is important to ensure the nonlinear loop stability. The chip is fabricated in a 0.18 μm CMOS technology. The experimental results show that it can achieve the frequency range of 2.995 to 3.35 GHz, and a phase noise of-118.38 dBc/Hz at 1 MHz offset. The frequency to voltage gain is 270 MHz/V. The chip consumes less than 81 mW with 1.8 V supply voltage, and it occupies a 0.5 mm2 area.

Structure and magnetic properties of NiCuZn ferrite materials with La doping

Ni0.3Cu0.07Zn0.63Fe2-xLaxO4 ferrites were prepared by solid phase method and sintered at 1,150 ℃ for 6 h.The phase formation,microstructure,and magnetic properties of samples were investigated.With doping of La3＋,the samples contain two phases：LaFeO3 and NiCuZn ferrites.Scanning electron microscope （SEM） image shows that La doping constrains the growth of NiCuZn ferrite,which is more uniform.La doping improves magnetic properties of NiCuZn ferrite when x ≤ 0.03.The saturation magnetization （Ms） increases first;when x =0.03,the highest value is 75.35 A.m2.kg-1.The permeability increases to the maximum value with frequency and then decreases with the concentration of La3＋ increasing.When x =0.03,the maximum value of real permeability at 1 MHz is 333.5,and the loss angle tangent （tanδ） is not more than 0.02.La doping improves the properties of NiCuZn ferrite,which can be applied to low-frequency filters.