Artificial Intelligence Based Multi-Scenario mmWave Channel Modeling for Intelligent High-Speed Train Communications

A large amount of mobile data from growing high-speed train(HST)users makes intelligent HST communications enter the era of big data.The corresponding artificial intelligence(AI)based HST channel modeling becomes a trend.This paper provides AI based channel characteristic prediction and scenario classification model for millimeter wave(mmWave)HST communications.Firstly,the ray tracing method verified by measurement data is applied to reconstruct four representative HST scenarios.By setting the positions of transmitter(Tx),receiver(Rx),and other parameters,the multi-scenarios wireless channel big data is acquired.Then,based on the obtained channel database,radial basis function neural network(RBF-NN)and back propagation neural network(BP-NN)are trained for channel characteristic prediction and scenario classification.Finally,the channel characteristic prediction and scenario classification capabilities of the network are evaluated by calculating the root mean square error(RMSE).The results show that RBF-NN can generally achieve better performance than BP-NN,and is more applicable to prediction of HST scenarios.

Cooperative Covert Communication in Multi-Antenna Broadcast Channels

With the gradual popularization of 5G communications,the application of multi-antenna broadcasting technology has become widespread.Therefore,this study aims to investigate the wireless covert communication in the two-user cooperative multi-antenna broadcast channel.We focus on the issue that the deteriorated reliability and undetectability are mainly affected by the transmission power.To tackle this issue,we design a scheme based on beamforming to increase the reliability and undetectability of wireless covert communication in the multi-antenna broadcast channel.We first modeled and analyzed the cooperative multi-antenna broadcasting system,and put forward the target question.Then we use the SCA(successive convex approximation)algorithm to transform the target problem into a series of convex subproblems.Then the convex problems are solved and the covert channel capacity is calculated.In order to verify the effectiveness of the scheme,we conducted simulation verification.The simulation results show that the proposed beamforming scheme can effectively improve the reliability and undetectability of covert communication in multi-antenna broadcast channels.

Dilation,discrimination and Uhlmann's theorem of link products of quantum channels

We establish the Stinespring dilation theorem of the link product of quantum channels in two different ways,discuss the discrimination of quantum channels,and show that the distinguishability can be improved by self-linking each quantum channel n times as n grows.We also find that the maximum value of Uhlmann's theorem can be achieved for diagonal channels.

Continuous-Time Channel Prediction Based on Tensor Neural Ordinary Differential Equation

Channel prediction is critical to address the channel aging issue in mobile scenarios.Existing channel prediction techniques are mainly designed for discrete channel prediction,which can only predict the future channel in a fixed time slot per frame,while the other intra-frame channels are usually recovered by interpolation.However,these approaches suffer from a serious interpolation loss,especially for mobile millimeter-wave communications.To solve this challenging problem,we propose a tensor neural ordinary differential equation(TN-ODE)based continuous-time channel prediction scheme to realize the direct prediction of intra-frame channels.Specifically,inspired by the recently developed continuous mapping model named neural ODE in the field of machine learning,we first utilize the neural ODE model to predict future continuous-time channels.To improve the channel prediction accuracy and reduce computational complexity,we then propose the TN-ODE scheme to learn the structural characteristics of the high-dimensional channel by low-dimensional learnable transform.Simulation results show that the proposed scheme is able to achieve higher intra-frame channel prediction accuracy than existing schemes.

Influence of variable viscosity and double diffusion on the convective stability of a nanofluid flow in an inclined porous channel

The influence of variable viscosity and double diffusion on the convective stability of a nanofluid flow in an inclined porous channel is investigated.The DarcyBrinkman model is used to characterize the fluid flow dynamics in porous materials.The analytical solutions are obtained for the unidirectional and completely developed flow.Based on a normal mode analysis,the generalized eigenvalue problem under a perturbed state is solved.The eigenvalue problem is then solved by the spectral method.Finally,the critical Rayleigh number with the corresponding wavenumber is evaluated at the assigned values of the other flow-governing parameters.The results show that increasing the Darcy number,the Lewis number,the Dufour parameter,or the Soret parameter increases the stability of the system,whereas increasing the inclination angle of the channel destabilizes the flow.Besides,the flow is the most unstable when the channel is vertically oriented.

Cooperative activation of sodium channels for downgrading the energy efficiency in neuronal information processing

The Hodgkin–Huxley model assumes independent ion channel activation,although mutual interactions are common in biological systems.This raises the problem why neurons would favor independent over cooperative channel activation.In this study,we evaluate how cooperative activation of sodium channels affects the neuron’s information processing and energy consumption.Simulations of the stochastic Hodgkin–Huxley model with cooperative activation of sodium channels show that,while cooperative activation enhances neuronal information processing capacity,it greatly increases the neuron’s energy consumption.As a result,cooperative activation of sodium channel degrades the energy efficiency for neuronal information processing.This discovery improves our understanding of the design principles for neural systems,and may provide insights into future designs of the neuromorphic computing devices as well as systematic understanding of pathological mechanisms for neural diseases.

Identification of transient receptor potential channel genes and functional characterization of TRPA1 in Spodoptera frugiperda

Spodoptera frugiperda is a highly destructive pest that has become a global problem due to its robust reproductive and migratory capabilities.Transient receptor potential(TRP)channels,which constitute a vast ion channel family,play pivotal roles in sensing the external environment and maintaining internal homeostasis in insects.TRP channels have been widely investigated for their critical roles in regulating various insect behaviors in recent years.In this study,we identified 15 TRP gene loci encoding 26 transcripts in the genome of S.frugiperda and analyzed their expression profiles at different developmental stages.The results revealed that S.frugiperda possesses four TRPC genes,six TRPA genes,one TRPM gene,two TRPV genes,one TRPN gene,and one TRPML gene,while a canonical TRPP is absent.Moreover,the SfruTRPA1 was functionally characterized using the Xenopus oocyte expression system.The results showed that SfruTRPA1 is activated by temperature increases from 20 to 45℃,and there is no significant desensitization after repeated stimuli within the same temperature range.Additionally,SfruTRPA1 is activated by certain natural chemicals,including allyl isothiocyanate(AITC)and cinnamaldehyde(CA).These findings provide valuable insights to the TRP genes in S.frugiperda.

Oscillatory Dynamics of a Spherical Solid in a Liquid in an Axisymmetric Variable Cross Section Channel

The dynamics of a solid spherical body in an oscillating liquid flow in a vertical axisymmetric channel of variable cross section is experimentally studied.It is shown that the oscillating liquid leads to the generation of intense averaged flows in each of the channel segments.The intensity and direction of these flows depend on the dimensionless oscillating frequency.In the region of studied frequencies,the dynamics of the considered body is examined when the primary vortices emerging in the flow occupy the whole region in each segment.For a fixed frequency,an increase in the oscillation amplitude leads to a phase-inclusion holding effect,i.e.,the body occupies a quasi-stationary position in one of the cells of the vertical channel,while oscillating around its average position.It is also shown that the oscillating motion of a liquid column generates an averaged force acting on the body,the magnitude of which depends on the properties of the body and its position in the channel.The quasi-stationary position is determined by the relative density and size of the body,as well as the dimensionless frequency.The behavior of the body as a function of the amplitude and frequency of fluid oscillation and relative size is discussed in detail.Such findings may be used in the future to control the position of a phase inclusion and/or to strengthen mass transfer effects in a channel of variable cross section by means of fluid oscillations.

Mechanism of Thermally Radiative Prandtl Nanofluids and Double-Diffusive Convection in Tapered Channel on Peristaltic Flow with Viscous Dissipation and Induced Magnetic Field

The application of mathematical modeling to biological fluids is of utmost importance, as it has diverse applicationsin medicine. The peristaltic mechanism plays a crucial role in understanding numerous biological flows. In thispaper, we present a theoretical investigation of the double diffusion convection in the peristaltic transport of aPrandtl nanofluid through an asymmetric tapered channel under the combined action of thermal radiation andan induced magnetic field. The equations for the current flow scenario are developed, incorporating relevantassumptions, and considering the effect of viscous dissipation. The impact of thermal radiation and doublediffusion on public health is of particular interest. For instance, infrared radiation techniques have been used totreat various skin-related diseases and can also be employed as a measure of thermotherapy for some bones toenhance blood circulation, with radiation increasing blood flow by approximately 80%. To solve the governingequations, we employ a numerical method with the aid of symbolic software such as Mathematica and MATLAB.The velocity, magnetic force function, pressure rise, temperature, solute (species) concentration, and nanoparticlevolume fraction profiles are analytically derived and graphically displayed. The results outcomes are compared withthe findings of limiting situations for verification.

Clinical efficacy and safety of double-channel anastomosis and tubular gastroesophageal anastomosis in gastrectomy

BACKGROUND With the continuous progress of surgical technology and improvements in medical standards,the treatment of gastric cancer surgery is also evolving.Proximal gastrectomy is a common treatment,but double-channel anastomosis and tubular gastroesophageal anastomosis have attracted much attention in terms of surgical options.Each of these two surgical methods has advantages and disadvantages,so it is particularly important to compare and analyze their clinical efficacy and safety.AIM To compare the surgical safety,clinical efficacy,and safety of double-channel anastomosis and tubular gastroesophageal anastomosis in proximal gastrectomy.METHODS The clinical and follow-up data of 99 patients with proximal gastric cancer who underwent proximal gastrectomy and were admitted to our hospital between January 2018 and September 2023 were included in this retrospective cohort study.According to the different anastomosis methods used,the patients were divided into a double-channel anastomosis group(50 patients)and a tubular gastroesophageal anastomosis group(49 patients).In the double-channel anastomosis,Roux-en-Y anastomosis of the esophagus and jejunum was performed after proximal gastric dissection,and then side-to-side anastomosis was performed between the residual stomach and jejunum to establish an antireflux barrier and reduce postoperative gastroesophageal reflux.In the tubular gastroesophageal anastomosis group,after the proximal end of the stomach was cut,tubular gastroplasty was performed on the distal stump of the stomach and a linear stapler was used to anastomose the posterior wall of the esophagus and the anterior wall of the stomach tube.The main outcome measure was quality of life 1 year after surgery in both groups,and the evaluation criteria were based on the postgastrectomy syndrome assessment scale.The greater the changes in body mass,food intake per meal,meal quality subscale score,and total measures of physical and mental health score,the better the condition;the greater the other indicators,the worse the condition.The secondary outcome measures were intraoperative and postoperative conditions,the incidence of postoperative long-term complications,and changes in nutritional status at 1,3,6,and 12 months after surgery.RESULTS In the double-channel anastomosis cohort,there were 35 males(70%)and 15 females(30%),33(66.0%)were under 65 years of age,and 37(74.0%)had a body mass index ranging from 18 to 25 kg/m2.In the group undergoing tubular gastroesophageal anastomosis,there were eight females(16.3%),21(42.9%)individuals were under the age of 65 years,and 34(69.4%)had a body mass index ranging from 18 to 25 kg/m2.The baseline data did not significantly differ between the two groups(P>0.05 for all),with the exception of age(P=0.021).The duration of hospitalization,number of lymph nodes dissected,intraoperative blood loss,and perioperative complication rate did not differ significantly between the two groups(P>0.05 for all).Patients in the dual-channel anastomosis group scored better on quality of life measures than did those in the tubular gastroesophageal anastomosis group.Specifically,they had lower scores for esophageal reflux[2.8(2.3,4.0)vs 4.8(3.8,5.0),Z=3.489,P<0.001],eating discomfort[2.7(1.7,3.0)vs 3.3(2.7,4.0),Z=3.393,P=0.001],total symptoms[2.3(1.7,2.7)vs 2.5(2.2,2.9),Z=2.243,P=0.025],and other aspects of quality of life.The postoperative symptoms[2.0(1.0,3.0)vs 2.0(2.0,3.0),Z=2.127,P=0.033],meals[2.0(1.0,2.0)vs 2.0(2.0,3.0),Z=3.976,P<0.001],work[1.0(1.0,2.0)vs 2.0(1.0,2.0),Z=2.279,P=0.023],and daily life[1.7(1.3,2.0)vs 2.0(2.0,2.3),Z=3.950,P<0.001]were all better than those of the tubular gastroesophageal anastomosis group.The group that underwent tubular gastroesophageal anastomosis had a superior anal exhaust score[3.0(2.0,4.0)vs 3.5(2.0,5.0),Z=2.345,P=0.019]compared to the dual-channel anastomosis group.Hemoglobin,serum albumin,total serum protein,and the rate at which body mass decreased one year following surgery did not differ significantly between the two groups(P>0.05 for all).CONCLUSION The safety of double-channel anastomosis in proximal gastric cancer surgery is equivalent to that of tubular gastric surgery.Compared with tubular gastric surgery,double-channel anastomosis is a preferred surgical technique for proximal gastric cancer.It offers advantages such as less esophageal reflux and improved quality of life.

Degree of Freedom Analysis for Holographic MIMO Based on a Mutual-Coupling-Compliant Channel Model

Degree of freedom(DOF)is a key indicator for spatial multiplexing layers of a wireless channel.Traditionally,the channel of a multiple-input multiple-output(MIMO)half-wavelength dipole array has a DOF that equals the antenna number.However,recent studies suggest that the DOF could be less than the antenna number when strong mutual coupling is considered.We utilize a mutual-coupling-compliant channel model to investigate the DOF of the holographic MIMO(HMIMO)channel and give a upper bound of the DOF with strong mutual coupling.Our numerical simulations demonstrate that a dense array can support more DOF per unit aperture as compared with a half-wavelength MIMO system.

The Effects of the Longitudinal Axis of Loading upon Bending, Shear and Torsion of a Thin-Walled Cantilever Channel Beam

Three aluminium channel sections of US standard extruded dimension are mounted as cantilevers with x-axis symmetry. The flexural bending and shear that arise with applied axial torsion are each considered theoretically and numerically in terms of two longitudinal axes of loading not coincident with the shear centre. In particular, the warping displacements, stiffness and stress distributions are calculated for torsion applied to longitudinal axes passing through the section’s centroid and its web centre. The stress conversions derived from each action are superimposed to reveal a net sectional stress distribution. Therein, the influence of the axis position upon the net axial and shear stress distributions is established compared to previous results for each beam when loading is referred to a flexural axis through the shear centre. Within the net stress analysis is, it is shown how the constraint to free warping presented by the end fixing modifies the axial stress. The latter can be identified with the action of a ‘bimoment’ upon each thin-walled section.

2022-2023年山东省A(H1N1)pdm09流感病毒HA、NA基因变异特征分析

目的 了解山东省2022-2023流感监测年度分离的A(H1N1)pdm09亚型流感病毒血凝素(hemagglutinin,HA)和神经氨酸酶(neuraminidase,NA)基因的变异特征,为流感的防控提供科学依据。方法 从流感监测网络实验室分离的流感毒株中按地市随机选取14株A(H1N1)pdm09亚型流感毒株,以WHO推荐的当季疫苗株为参考进行全基因组测序,并采用荧光法开展神经氨酸酶抑制(neuraminidase inhibition,NI)实验以评估药物敏感性。结果 山东省2022-2023年度分离的A(H1N1)pdm09流感病毒属于6B.1A分支中的5a.2a进化簇,核苷酸序列比对分析显示,HA和NA基因与2021-2023年度北半球疫苗株A/Victoria/2570/2019的亲缘关系较为接近,同源性分别为98.5%~98.7%和98.8%~99.1%。氨基酸序列分析显示,HA蛋白有20个位点发生了氨基酸序列变异,并发现1株病毒可能发生抗原漂移,有3株病毒发生了HA蛋白糖基化位点的缺失。NA酶相关重要位点未发生变异。NI实验显示,所测流感毒株均对抗流感病毒药物敏感。结论 所监测毒株与疫苗株整体同源性很高,但氨基酸存在一定程度变异,今后有必要持续开展流感病毒基因变异特征监测以了解流感流行的风险,以及评价基因变异对流感疫苗和治疗药物效果的影响。

基于Na-BP-DME@C阳极的长寿命准固态钠-空气电池

钠-空气电池因其能量密度高、成本低而成为金属-空气电池领域的研究热点。然而,以金属钠为阳极的钠-空气电池存在钠枝晶生长、金属钠界面稳定性差以及金属钠的反应活性高等问题,限制了钠-空气电池的快速发展。为解决上述问题,将联苯钠与导电炭黑复合材料Na-BP-DME@C作为阳极,单壁碳纳米角(SWCHNs)作为催化剂,构建准固态钠-空气电池。基于Na-BP-DME@C阳极的准固态钠-空气电池表现出优异的电化学性能,其电压差为1.5 V,功率密度为3.32 mW/cm^(2),在0.1 mA/cm^(2)电流密度下可稳定循环459 h(约459次)。

Na-Mn共掺对磷酸铁锂正极材料结构与性能的影响

利用碳热还原法成功制备了Li_(0.97)Na_(0.03)Fe_(7/8)Mn_(1/8)PO_(4)正极材料,运用XRD、SEM、EDS和电化学测试等手段对其晶体结构、形貌、元素分布和电化学性能进行研究,并结合第一性原理计算分析材料性能提升的机理。结果表明,Na-Mn掺杂一方面导致LiFePO_(4)晶格畸变,晶格体积增大,扩大了锂离子迁移通道,为锂离子嵌入/脱出提供更大的空间;另一方面使材料在电化学性能上表现出优异的高倍率性能和循环稳定性。Na-Mn掺杂有利于提高材料的锂离子扩散系数和电导率,从而提高其电化学性能。基于第一性原理计算结果表明,Na-Mn共掺杂使LiFePO_(4)晶格膨胀,晶格体积增大,并促使带隙宽度减小,增强了费米能级附近的电子态密度,提高了材料的电子电导率和锂离子迁移率。

行为m-NA随机变量阵列的完全收敛性

利用截尾方法和矩不等式,在更一般的条件下对m-NA阵列行和的收敛性进行了研究,并得到了m-NA阵列的完全收敛性.所得结果改进了文献[6]的研究结果。

Dynamic Evolutionary Game-based Modeling,Analysis and Performance Enhancement of Blockchain Channels

The recent development of channel technology has promised to reduce the transaction verification time in blockchain operations.When transactions are transmitted through the channels created by nodes,the nodes need to cooperate with each other.If one party refuses to do so,the channel is unstable.A stable channel is thus required.Because nodes may show uncooperative behavior,they may have a negative impact on the stability of such channels.In order to address this issue,this work proposes a dynamic evolutionary game model based on node behavior.This model considers various defense strategies'cost and attack success ratio under them.Nodes can dynamically adjust their strategies according to the behavior of attackers to achieve their effective defense.The equilibrium stability of the proposed model can be achieved.The proposed model can be applied to general channel networks.It is compared with two state-of-the-art blockchain channels:Lightning network and Spirit channels.The experimental results show that the proposed model can be used to improve a channel's stability and keep it in a good cooperative stable state.Thus its use enables a blockchain to enjoy higher transaction success ratio and lower transaction transmission delay than the use of its two peers.

Stress wave analysis of high-voltage pulse discharge rock fragmentation based on plasma channel impedance model

High-voltage pulse discharge(HVPD)rock fragmentation controls a plasma channel forming inside the rock by adjusting the electrical parameters,electrode type,etc.In this work,an HVPD rock fragmentation test platform was built and the test waveforms were measured.Considering the effects of temperature,channel expansion and electromagnetic radiation,the impedance model of the plasma channel in the rock was established.The parameters and initial values of the model were determined by an iterative computational process.The model calculation results can reasonably characterize the development of the plasma channel in the rock and estimate the shock wave characteristics.Based on the plasma channel impedance model,the temporal and spatial distribution characteristics of the radial stress and tangential stress in the rock were calculated,and the rock fragmentation effect of the HVPD was analyzed.

Fiber cladding dual channel surface plasmon resonance sensor based on S-type fiber

Fiber cladding surface plasmon resonance(SPR)sensors have few structures,and a clad SPR sensor based on S-type fiber is proposed in this paper.This new type of fiber cladding SPR sensor was formed by electrofusing an S-shaped structure on the fiber to couple the light in the fiber core to the cladding.In this paper,the effects of fiber parameters on the performance of the sensor were studied by simulation and experiment.Based on the conclusion that the smaller the core diameter is,the closer the working band of the SPR resonance is to long wavelengths,and that the geometric characteristics mean that a multimode fiber can receive the fiber cladding light from a small core diameter few-mode fiber,a dual channel SPR sensor with a double S-type fiber cascade was proposed.In the refractive index detection range of 1.333–1.385refractive index units(RIU),the resonant working band of channel I is 627.66 nm–759.78 nm,with an average sensitivity of 2540.77 nm/RIU,and the resonant working band of channel II is 518.24 nm–658.2 nm,with an average sensitivity of2691.54 nm/RIU.The processing method for the S-type fiber cladding SPR sensor is simple,effectively solving the problem of this type of SPR sensor structure and the difficult realization of a dual channel.The sensor is expected to be used in the fields of medical treatment and biological analysis.

Na_(2)O对锂铝硅微晶玻璃析晶及性能的影响

采用熔融法制备了不同Na_(2)O含量的透明锂铝硅微晶玻璃,通过DSC、XRD、FESEM等测试方法研究了不同Na_(2)O含量对玻璃析晶及性能的影响。结果表明:Na_(2)O的引入能显著降低玻璃的转变温度和析晶温度,抑制LiAlSi_(4)O_(10)晶相的析出。但Na_(2)O的引入促使微晶玻璃中析出Li_(2)Si_(2)O_(5)新相,并且随着Na_(2)O引入量的增加,Li_(2)Si_(2)O_(5)转变为主晶相。由于晶体尺寸均为纳米级,主晶相的转变对透过率影响较小,微晶玻璃的可见光透过率均高于85%。主晶相的转变有效增强了微晶玻璃的机械性能,其弯曲强度由300 MPa提升至331 MPa。Na_(2)O的引入有效增强了Na-K交换,Na_(2)O含量为4%(质量分数)的Li 2O-Al_(2)O_(3)-SiO_(2)微晶玻璃在410℃的KNO_(3)熔盐中交换6 h后,维氏硬度由7.108 GPa提升至7.403 GPa,弯曲强度由331 MPa提升至470 MPa。