Providing insight into exchange coupling within nanomagnetism:mechanism,micromagnetic simulation,synthesis and biomedical application

Exchange coupling within nanomagnetism is a rapidly evolving field with significant implications for that plays a crucial role in the development of magnetic nanomaterials.Manipulating exchange coupling interaction enables the magnetic systems to overcome limitations associated with size-dependent magnetic behavior within nano scale,thereby improving their magnetic properties and providing for superior performance in biomedical applications compared with single-phase magnetic materials.Understanding the underlying mechanism of exchange coupling and its impact on macroscopic magnetic properties is crucial for the design and application of such magnetic materials.This review provides an overview of recent advances in interfacial exchange coupling among different magnetic modalities-ferromagnetism,ferrimagnetism,and antiferromagnetism-based on core-shell magnetic nanoparticles(MNPs).Additionally,this review discusses micromagnetic simulations to gain insights into the relationship between the microscopic magnetic structure(size,shape,composition,and exchange coupling)and the resulting macroscopic properties.The controlled synthesis of MNPs is summarized,including one-step method and two-step method.The precise manipulation of interfacial characteristics is of great importance,albeit challenging,as it allows for the finetuning of magnetic properties tailored for specific applications.The review also explores potential applications of coreshell MNPs in magnetic resonance imaging,hyperthermia therapy,targeted drug delivery,and advanced neuromodulation.

Application of an Organophosphorus Compound-DEPBT as Coupling Reagent in Liquid Phase Peptide Synthesis

DEPBT, a novel coupling reagent containing phosphorus, was used in synthesis of pentapeptide Boc-Ile-Asn-Met-Trp(For)-Gly.OMe by solution method.

Optimal Markovian Couplings and Applications

This paper is devoted to studying a new topic:optimal Markovian couplings,mainly for time-continuous Markov processes.The study emphasizes the analysis of the coupling opera- tors rather than the processes.Some constructions of optimal Markovian couplings for Markov chains and diffusions are presented,which are often unexpected.Then,the results are applied to study the L^2-convergence for Markov chains and for a diffusion on compact manifold.The estimate of the convergent rate provided by this method can be sharp.

A Two-folded Impact Analysis of Schema Changes on Database Applications

Database applications are becoming increasingly popular, mainly due to the advanced data management facilities that the underlying database management system offers compared against traditional legacy software applications. The interaction, however, of such applications with the database system introduces a number of issues, among which, this paper addresses the impact analysis of the changes performed at the database schema level. Our motivation is to provide the software engineers of database applications with automated methods that facilitate major maintenance tasks, such as source code corrections and regression testing, which should be triggered by the occurrence of such changes. The presented impact analysis is thus two-folded： the impact is analysed in terms of both the affected source code statements and the affected test suites concerning the testing of these applications. To achieve the former objective, a program slicing technique is employed, which is based on an extended version of the program dependency graph. The latter objective requires the analysis of test suites generated for database applications, which is accomplished by employing testing techniques tailored for this type of applications. Utilising both the slicing and the testing techniques enhances program comprehension of database applications, while also supporting the development of a number of practical metrics regarding their maintainability against schema changes. To evaluate the feasibility and effectiveness of the presented techniques and metrics, a software tool, called DATA, has been implemented. The experimental results from its usage on the TPC-C case study are reported and analysed.

An Efficient Three-Dimensional Coupled Normal Mode Model and Its Application to Internal Solitary Wave Problems

We present an efficient three-dimensional coupled-mode model based on the Fourier synthesis technique. In principle, this model is a one-way model, and hence provides satisfactory accuracy for problems where the forward scattering dominates. At the same time, this model provides an efficiency gain of an order of magnitude or more over two-way coupled-mode models. This model can be applied to three-dimensional range-dependent problems with a slowly varying bathymetry or internal waves. A numerical example of the latter is demonstrated in this work. Comparisons of both accuracy and efficiency between the present model and a benchmark model are also provided.

Inductively coupled plasma mass spectrometry (ICP-MS) and its application in life sciences

Inductively-coupled plasma mass spectrometry (ICP-MS) has made much progress since its birth in the late 1990s. This paper will give a rather systematic overview on the use of this technique in new devices and technologies related to plasma source, sample-introducing device and detecting spectrometer etc. In this overview, an emphasis will be put on the evaluation of the ICP- MS technique in combination with a series of physical, chemical and biological techniques, such as laser ablation (LA), capillary electrophoresis (CE) and high performance liquid chromatograph (HPLC), along with their representative high accuracy and high sensitivity. Finally, comprehensive and fruitful applications of the ICP-MS and its combinative techniques in the detection of trace metallic elements and isotopes in complex biological and environmental samples will be revealed.

THEORY AND APPLICATION OF FRACTIONAL STEP CHARACTERISTIC FINITE DIFFERENCE METHOD IN NUMERICAL SIMULATION OF SECOND ORDER ENHANCED OIL PRODUCTION

A kind of second-order implicit fractional step characteristic finite difference method is presented in this paper for the numerically simulation coupled system of enhanced （chemical） oil production in porous media. Some techniques, such as the calculus of variations, energy analysis method, commutativity of the products of difference operators, decomposition of high-order difference operators and the theory of a priori estimates are introduced and an optimal order error estimates in l^2 norm is derived. This method has been applied successfully to the numerical simulation of enhanced oil production in actual oilfields, and the simulation results ate quite interesting and satisfactory.

Theory and application of numerical simulation method of capillary force enhanced oil production

A kind of second-order implicit upwind fractional step finite difference methods are presented for the numerical simulation of coupled systems for enhanced （chemical） oil production with capillary force in the porous media. Some techniques, e.g., the calculus of variations, the energy analysis method, the commutativity of the products of difference operators, the decomposition of high-order difference operators, and the theory of a priori estimate, are introduced. An optimal order error estimate in the l2 norm is derived. The method is successfully used in the numerical simulation of the enhanced oil production in actual oilfields. The simulation results are satisfactory and interesting.

Research progress on 2D ferroelectric and ferrovalley materials and their neuromorphic application

Two-dimensional(2D)ferroelectric and ferrovalley materials have recently received extensive attention due to their significant advantages for modern electronic devices,such as miniaturization,low-dissipation,non-volatility,and multi-functionality.More interestingly,the couplings between the ferroic orders in these materials have enriched the development of intelligent devices,especially in neuromorphic computing.In this paper,the research progress of 2D ferroelectric and ferrovalley materials is introduced and the coupling effects between them are also described.Then,we briefly introduce recent neuromorphic computing reports based on 2D ferroelectric materials and give perspectives on ferrovalley neuromorphic devices.

油气藏相变岩石力学理论方法及应用场景

针对部分油气藏钻采过程中的固态烷烃相关混合物受热相变、超压砂体瞬间泄压触发砂体液化流动和孔隙充填物降压气化引发骨架垮塌3个典型的相变岩石力学现象,系统分析了目前在理论认识、实验方法、数学表征方面的研究进展,同时探讨了3个相变岩石力学现象对应的工程应用场景,揭示了其力学规律及工程应用效果,在此基础上,讨论了油气藏相变岩石力学目前所面临的挑战、潜在的发展趋势与亟待探索的方法。研究表明:不同的油气藏相变岩石力学现象需要采用相应的、特殊的实验及数学方法开展研究,确定其独特的多场耦合力学响应机制,以有效指导资源开采控制、致灾程度评价、地层稳定分析等。为满足该学科的发展需要,未来需挖掘更多油气资源开采中的相变岩石力学问题,开发特定的新型实验设备,借助人工智能与数字孪生技术,实现岩石相态变化力学过程的实时仿真与动态可视化。

Dynamic simulation of urbanization and eco-environment coupling:Current knowledge and future prospects

Urbanization and eco-environment coupling is a research hotspot.Dynamic simulation of urbanization and eco-environment coupling needs to be improved because the processes of coupling are complex and statistical methods are limited.Systems science and cross-scale coupling allow us to define the coupled urbanization and eco-environment system as an open complex giant system with multiple feedback loops.We review the current state of dynamic simulation of urbanization and eco-environment coupling and find that:(1)The use of dynamic simulation is an increasing trend,the relevant theory is being developed,and modeling processes are being improved;(2)Dynamic simulation technology has become diversified,refined,intelligent and integrated;(3)Simulation is mainly performed for three aspects of the coupling,multiple regions and multiple elements,local coupling and telecoupling,and regional synergy.However,we also found some shortcomings:(1)Basic theories are inadequately developed and insufficiently integrated;(2)The methods of unifying systems and sharing data are behind the times;(3)Coupling relations and the dynamic characteristics of the main driving elements are not fully understood or completely identified.Additionally,simulation of telecoupling does not quantify parameters and is not systemically unified,and therefore cannot be used to represent spatial synergy.In the future,we must promote communication between research networks,technology integration and data sharing to identify the processes governing change in coupled relations and in the main driving elements in urban agglomerations.Finally,we must build decision support systems to plan and ensure regional sustainable urbanization.

A novel forced motion apparatus with potential applications in structural engineering

This paper reviews the development of forced motion apparatuses(FMAs) and their applications in wind engineering. A kind of FMA has been developed to investigate nonlinear and nonstationary aerodynamic forces considering the coupled effects of multiple degrees of freedom(DOFs). This apparatus can make section models to vibrate in a prescribed displacement defined by a numerical signal in time domain, including stationary and nonstationary movements with time-variant amplitudes and frequencies and even stochastic displacements. A series of validation tests show that the apparatus can re-illustrate various motions with enough precision in 3 D coupled states of two linear displacements and one torsional displacement. To meet the requirement of aerodynamic modeling, the flutter derivatives of a box girder section are identified, verifying its accuracy and feasibility by comparing with previously reported results. By simulating the nonstationary vibration with time-variant amplitude, the phenomena of frequency multiplication and memory effects are examined. In addition to studying the aerodynamics of a bluff body under large amplitudes and nonstationary vibrations, some potential applications of the proposed FMA are discussed in vehicle-bridge-wind dynamic analysis, pile-soil interaction, and line-tower coupled vibration aerodynamics in structural engineering.

磁共振无线充电技术:进展与展望

无线充电技术具有非接触、自动化以及易维护的供能特性,可以有效解决未来智能物联网(AIoT)在大规模应用时的能量供应难题.在现有无线充电技术中,磁共振无线充电技术在能量传输效用与空间自由度上有着更为均衡的技术优势,已成为当今无线充电领域的研究热点,拥有更为广阔的应用前景.为此,大致回顾了磁共振无线充电技术的发展历程并对其相关背景概念进行了简要概述.对近年的磁共振无线充电技术相关研究进行了系统梳理,并基于设计动机和技术实现从反馈通信、优化调度、感知应用、安全保障4个角度出发,详细总结了对应工作的基本原理、实施方法等核心内容,为后续的研究提供了有效参考.其中,根据传输方式将反馈通信方面工作分为两大类,根据系统结构将优化调度方面工作分为两大类,根据应用场景从三大类介绍感知应用方面工作,根据保障对象将安全保障方面工作分为三大类.最后在上述工作的基础上,讨论了磁共振无线充电技术现有工作的可改进之处,并对未来研究方向进行了展望.

温湿耦合大体积混凝土早龄期损伤试验研究

针对大体积混凝土温湿耦合损伤特性及其风险评价问题,依托上海某超大型污水处理厂工程,根据现场试验数据,研究了大体积混凝土结构内部温湿度空间分布及其时变规律;结合文献调查,探讨了多场耦合条件下混凝土在养护过程中水化度、抗拉强度、弹性模量等计算方法的工程适用性以及参数的合理取值,并对养护期混凝土结构损伤风险进行了定量评价。研究结果对大体积混凝土结构工程的抗裂防渗状态和质量评价具有借鉴意义。

Thermal management by manipulating electromagnetic parameters

Electromagnetic absorbing materials may convert electromagnetic energy into heat energy and dissipate it.However,in a high-power electromagnetic radiation environment,the temperature of the absorbing material rises significantly and even burns.It becomes critical to ensure electromagnetic absorption performance while minimizing temperature rise.Here,we systematically study the coupling mechanism between the electromagnetic field and the temperature field when the absorbing material is irradiated by electromagnetic waves.We find out the influence of the constitutive parameters of the absorbing materials(including uniform and non-uniform)on the temperature distribution.Finally,through a smart design,we achieve better absorption and lower temperature simultaneously.The accuracy of the model is affirmed as simulation results aligned with theoretical analysis.This work provides a new avenue to control the temperature distribution of absorbing materials.

Application of Pore Evolution and Fracture Development Coupled Models in the Prediction of Reservoir "Sweet Spots" in Tight Sandstones

The Chang-63 reservoir in the Huaqing area has widely developed tight sandstone ＂thick sand layers, but not reservoirs characterized by rich in oil＂, and it is thus necessary to further study its oil and gas enrichment law. This study builds porosity and fracture development and evolution models in different deposition environments, through core observation, casting thin section, SEM, porosity and permeability analysis, burial history analysis, and ＂four-property-relationships＂ analysis.

4 K high frequency pulse tube cryocooler used for terahertz space application

Terahertz(THz) frequency region, defined from0.1 to 10 THz, is an important frequency band for radio astronomy and atmospheric science. As NbN Superconductor-Insulator-Superconductor(SIS) mixers used for terahertz detection, which are studied by the Purple Mountain Observatory(PMO), Chinese Academy of Sciences(CAS), work at 8–10 K, and require condition of micro vibrations, its astronomical observation in aerospace is limited by suitable refrigeration method. 4 K high frequency pulse tube cryocooler developed by Key Laboratory of Space Energy Conversion Technologies(SECT), Technical Institute of Physics and Chemistry(TIPC), CAS, offers an opportunity for the application of SIS mixers. This article introduces the progress of the two-stage high frequency pulse tube cryocooler researched by TIPC. The cryocooler has reached a no load temperature of 4.5 K which is the lowest temperature for this kind of cryocooler reported so far. The successful coupling between the THz component and the high frequency pulse tube cryocooler lays a solid foundation for space detection in the terahertz band.

基于修正Manson-Halford模型的破碎机销轴疲劳分析

以双级锤式破碎机为研究对象,考虑销轴所受载荷的加载次序和载荷之间相互作用对销轴疲劳损伤的影响,对Manson-Halford(M-H)非线性疲劳损伤模型进行了修正,并通过试验数据验证了修正后模型的准确性和可靠性;考虑到破碎过程中锤头与销轴之间存在的非线性碰撞接触和物料颗粒对销轴受力的影响,利用MFBD-DEM双向耦合的方法获取了销轴的动态载荷;最后基于修正后M-H模型对销轴进行了疲劳分析。结果表明,与现有模型相比修正后的M-H模型寿命预测的误差最小;基于修正后M-H模型计算得到销轴的最小疲劳寿命为9.918×10^(6)次(165 h);利用MFBD-DEM双向耦合方法对双级锤式破碎机等大型破碎设备进行疲劳分析是合理可行的。

An improved pulse coupled neural networks model for semantic IoT

In recent years,the Internet of Things(IoT)has gradually developed applications such as collecting sensory data and building intelligent services,which has led to an explosion in mobile data traffic.Meanwhile,with the rapid development of artificial intelligence,semantic communication has attracted great attention as a new communication paradigm.However,for IoT devices,however,processing image information efficiently in real time is an essential task for the rapid transmission of semantic information.With the increase of model parameters in deep learning methods,the model inference time in sensor devices continues to increase.In contrast,the Pulse Coupled Neural Network(PCNN)has fewer parameters,making it more suitable for processing real-time scene tasks such as image segmentation,which lays the foundation for real-time,effective,and accurate image transmission.However,the parameters of PCNN are determined by trial and error,which limits its application.To overcome this limitation,an Improved Pulse Coupled Neural Networks(IPCNN)model is proposed in this work.The IPCNN constructs the connection between the static properties of the input image and the dynamic properties of the neurons,and all its parameters are set adaptively,which avoids the inconvenience of manual setting in traditional methods and improves the adaptability of parameters to different types of images.Experimental segmentation results demonstrate the validity and efficiency of the proposed self-adaptive parameter setting method of IPCNN on the gray images and natural images from the Matlab and Berkeley Segmentation Datasets.The IPCNN method achieves a better segmentation result without training,providing a new solution for the real-time transmission of image semantic information.

“双碳”目标下民用建筑用户侧储能应用展望与策略

探索“双碳”目标下民用建筑用户侧储能应用前景和应用策略,分析建筑用户侧储能安全性等问题,探讨建筑光储直柔、储能创新技术的推广应用,并提出利用用户侧储能构建多样性自备电源的策略。