Near-Field Focusing With Subwavelength Thickness Metalenses via Electromagnetic Susceptibility Models

The design mentality of an optimal metalens model, based on the electromagnetic susceptibility, a synthesis of subwavelength-thick metasurfaces (MSs) is presented in this paper. First, based on the finite difference method of generalized sheet transition conditions, the surface susceptibility function of the MS with spatial discontinuities can be determined. Then, the paper analyzed the remaining corresponding physical field conditions for the scale of metalens. In order to adapt to the physical limitations encountered in the near-field focusing of the metalens, a standard parabolic phase design is proposed in this paper, and its upsides and downsides of the two-phase processing in different aspects are compared. Using COMSOL software with numerical simulation, it can be seen that the standard design can easily obtain high resolution in the near field, while the focusing effect is more stable when the focal length is small by the parabolic phase design.

Focusing on the tetra-partite synapse in Parkinson’s disease research using human patient-derived neurons

Parkinson’s disease(PD)was first described as a neurological disease by Dr.James Parkinson in 1817 as a“shaking palsy”.Since that time,much more is known about the pathophysiology of PD yet the disease is still uncurable.The hallmark of the disease is often considered Lewy body neural inclusions in the substantia nigra pars compacta and other brain areas,although not all patients have these inclusions.The patients exhibit massive neuronal cell loss in the substantia nigra pars compacta,which is associated with the motor symptoms of tremor,bradykinesia,rigidity,and postural instability.PD is the second most common neurodegenerative disease after Alzheimer’s disease with a prevalence of around 1%of individuals over the age of 60.

Stimulated Raman scattering microscopy with phase-controlled light focusing and aberration correction for rapid and label-free, volumetric deep tissue imaging

We report a novel stimulated Raman scattering(SRS)microscopy technique featuring phase-controlled light focusing and aberration corrections for rapid,deep tissue 3D chemical imaging with subcellular resolution.To accomplish phasecontrolled SRS(PC-SRS),we utilize a single spatial light modulator to electronically tune the axial positioning of both the shortened-length Bessel pump and the focused Gaussian Stokes beams,enabling z-scanning-free optical sectioning in the sample.By incorporating Zernike polynomials into the phase patterns,we simultaneously correct the system aberrations at two separate wavelengths(~240 nm difference),achieving a~3-fold enhancement in signal-to-noise ratio over the uncorrected imaging system.PC-SRS provides>2-fold improvement in imaging depth in various samples(e.g.,polystyrene bead phantoms,porcine brain tissue)as well as achieves SRS 3D imaging speed of~13 Hz per volume for real-time monitoring of Brownian motion of polymer beads in water,superior to conventional point-scanning SRS 3D imaging.We further utilize PC-SRS to observe the metabolic activities of the entire tumor liver in living zebrafish in cellsilent region,unraveling the upregulated metabolism in liver tumor compared to normal liver.This work shows that PCSRS provides unprecedented insights into morpho-chemistry,metabolic and dynamic functioning of live cells and tissue in real-time at the subcellular level.

Journal of Dermatologic Science and Cosmetic Technology: Focusing on skin health and beauty

We are pleased to announce that the Journal of Dermatologic Science and Cosmetic Technology,organized by the Guangdong Cosmetics Association,China and produced by KeAi(founded by China Science Publishing&Media Ltd.and Elsevier),will be officially released online on the ScienceDirect platform.This journal will serve as a high-level,international,and interdisciplinary academic exchange platform in the fields of dermatologic science and cosmetic technology.Its aim is to publish relevant research findings in dermatologic science and innovative cosmetic technologies,provide a comprehensive understanding of future trends in the cosmetics industry,and promote international exchange and cooperation between dermatologic science and the cosmetics industry.

Two dimensional subdiffraction focusing beyond the near-field diffraction limit via metasurface

Near-field plates with the capabilities of modulating the near-field pattern and forcing the incident wave to a subwavelength spot have been experimentally investigated at microwave wavelengths.Their superlensing properties result from the radiationless electromagnetic interference.However, the material's loss and limitations of state-of-the-art nanofabricating technology pose great challenges to scale down the microwave near-field plates to the infrared or optical region.In this paper, a related but alternative approach based on metasurface is introduced which breaks the near-field diffraction limit at mid-infrared region(10.6 μm).The metasurface consists of periodic arrangement of chromium dipolar antennas with the same geometry but spatially varying orientations, which plays the dual roles in achieving the prescribed amplitude modulation and the abrupt π phase change between the subwavelength neighboring elements.As a result, a two dimensional subdiffraction focus as small as 0.037λ~2 at ~0.15λ above the metasurface is presented.In addition, the broadband response and ease fabrication bridge the gap between the theoretical investigation and valuable applications, such as near-field data storage, subdiffraction imaging and nanolithography.

The Near-Field Microwave Focusing in the Layer Mediums

This paper deals with the microwave focusing in the layer mediums near the antenna aperture. Based on the plane-wave spectrum theory, the relationship between the Hertz potential and the electromagnetic field is discussed. An approach to the description of the field distribution in the layer mediums in case of an arbitary field source is proposed. Given the focusing current distribution over the antenna aperture, the field distribution of the focal region is worked out. In describing the field distribution over the focal region, the integration of spectrum functions in the spectrum domain (kx,ky) is carried out instead of the complicated Fresnel integral. The approximations are obtained by the saddle-point integration. Comparison with experimental results demonstrates the validity of the approach.

FOCUS-PDCA在降低在新生儿院内尿布性皮炎发生率的应用研究

探讨FOCUS -PDCA在新生儿院内尿布性皮炎管理的应用效果。方法 选取2023年6月1日至2023年9月30日入住新生儿患儿 379例,按入院时间先后顺序分为对照组(2023年6月1号-2023年7月31号)和试验组(2023年8月1号-2023年9月31号)。对照组采取常规护理方案,试验组采取运用FOCUS -PDCA进行修订相关流程、护理常规、开展针对性培训、加强督查与干预等循环管理。比较2组新生儿院内尿布性皮炎发生率。结果 试验组院内尿布性皮炎发生率为9.2‰,低于对照组的25.2 ‰(χ2=4.410578,P<0.05);且2023年8月、9月新生儿院内尿布性皮炎的发生率分别为15.8‰、11.8‰,整体呈一个下降的趋势。结论 采用FOCUS -PDCA进行循环管理,实施培训、督查与干预用于新生儿住院患者管理,可降低其院内尿布性皮炎的发生率。

Three-dimensional isotropic microfabrication in glass using spatiotemporal focusing of high-repetition-rate femtosecond laser pulses

To improve the processing efficiency and extend the tuning range of 3D isotropic fabrication,we apply the simultaneous spatiotemporal focusing(SSTF)technique to a high-repetition-rate femtosecond(fs)fiber laser system.In the SSTF scheme,we propose a pulse compensation scheme for the fiber laser with a narrow spectral bandwidth by building an extra-cavity pulse stretcher.We further demonstrate truly 3D isotropic microfabrication in photosensitive glass with a tunable resolution ranging from 8μm to 22μm using the SSTF of fs laser pulses.Moreover,we systematically investigate the influences of pulse energy,writing speed,processing depth,and spherical aberration on the fabrication resolution.As a proof-of-concept demonstration,the SSTF scheme was further employed for the fs laser-assisted etching of complicated glass microfluidic structures with 3D uniform sizes.The developed technique can be extended to many applications such as advanced photonics,3D biomimetic printing,micro-electromechanical systems,and lab-on-a-chips.

Properties of focused Laguerre–Gaussian beam propagating in anisotropic ocean turbulence

We analyze the properties of a focused Laguerre–Gaussian(LG)beam propagating through anisotropic ocean turbulence based on the Huygens–Fresnel principle.Under the Rytov approximation theory,we derive the analytical formula of the channel capacity of the focused LG beam in the anisotropic ocean turbulence,and analyze the relationship between the capacity and the light source parameters as well as the turbulent ocean parameters.It is found that the focusing mirror can greatly enhance the channel capacity of the system at the geometric focal plane in oceanic turbulence.The results also demonstrate that the communication link can obtain high channel capacity by adopting longer beam wavelength,greater initial beam waist radius,and larger number of transmission channels.Further,the capacity of the system increases with the decrease of the mean squared temperature dissipation rate,temperature-salinity contribution ratio and turbulence outer scale factor,and with the increase of the kinetic energy dissipation rate per unit mass of fluid,turbulence inner scale factor and anisotropy factor.Compared to a Hankel–Bessel beam with diffraction-free characteristics and unfocused LG beam,the focused LG beam shows superior anti-turbulence interference properties,which provide a theoretical reference for research and development of underwater optical communication links using focused LG beams.

Propagation and focusing characteristics of the Bessel-Gaussian beam with the spiral phase term of new power-exponent-phase

A new type of beam called the NPEP-BG(a Bessel-Gaussian(BG)beam with a spiral phase term of a new powerexponent-phase(NPEP))is theoretically studied in this paper.The results show that the number of singularities of the phase and side lobes of the intensity of this beam were equal to the topological charges(TCs)and the beam has the characteristics of self-healing during propagation.The NPEP-BG beam combined the partial characteristics of the new power-exponentphase vortex(NPEPV)and the Bessel-Gaussian beam.At the focus of the beam,the characteristic like a perfect vortex beam was present,in which the focal radius is stable and independent of the topological charge.There are multi-focal spots around a ring in the focal plane,meaning that the NPEP-BG beam has a potential for application in multi-particle manipulation.

Spectra-assisted laser focusing in quantitative analysis of laser-induced breakdown spectroscopy for copper alloys

Laser-induced breakdown spectroscopy(LIBS)is a capable technique for elementary analysis,while LIBS quantitation is still under development.In quantitation,precise laser focusing plays an important role because it ensures the distance between the laser and samples.In the present work,we employed spectral intensity as a direct way to assist laser focusing in LIBS quantitation for copper alloys.It is found that both the air emission and the copper line could be used to determine the position of the sample surface by referencing the intensity maximum.Nevertheless,the fine quantitation was only realized at the position where the air emission(e.g.O(I)777.4 nm)reached intensity maximum,and also in this way,a repeatable quantitation was successfully achieved even after 120 days.The results suggested that the LIBS quantitation was highly dependent on the focusing position of the laser,and spectra-assisted focusing could be a simple way to find the identical condition for different samples’detection.In the future,this method might be applicable in field measurements for LIBS analysis of solids.

Generation of Higher Terahertz Harmonics in Nonlinear Paraelectrics under Focusing in a Wide Temperature Range

It is theoretically investigated the generation of higher harmonics of two-dimensional and three-dimensional terahertz electromagnetic beams in nonlinear crystals. The attention is paid to crystalline paraelectrics like SrTiO3 under the temperatures 60 - 200 K, these crystals possess the cubic nonlinearity. The bias electric field is applied to provide the dominating quadratic nonlinearity. The initial focusing of the beams not only increases the efficiency of generation of higher harmonics, but alto makes possible to select maxima of different higher harmonics at some distances from the input. At lower temperatures the nonlinearity behaves at smaller input amplitudes, whereas at higher temperatures the harmonic generation can be observed at higher frequencies up to 1.5 THz. In three-dimensional beams the peak amplitudes of higher harmonics can be bigger than in two-dimensional beams, but the ratios of these peak values to the maximum values of the focused first harmonic are smaller than in two-dimensional beams.

Co-doped BaFe_(2)As_(2) Josephson junction fabricated with a focused helium ion beam

Josephson junction plays a key role not only in studying the basic physics of unconventional iron-based superconductors but also in realizing practical application of thin-film based devices,therefore the preparation of high-quality iron pnictide Josephson junctions is of great importance.In this work,we have successfully fabricated Josephson junctions from Co-doped BaFe_(2)As_(2)thin films using a direct junction fabrication technique which utilizes high energy focused helium ion beam(FHIB).The electrical transport properties were investigated for junctions fabricated with various He^(+)irradiation doses.The junctions show sharp superconducting transition around 24 K with a narrow transition width of 2.5 K,and a dose correlated foot-structure resistance which corresponds to the effective tuning of junction properties by He^(+)irradiation.Significant J_c suppression by more than two orders of magnitude can be achieved by increasing the He^(+)irradiation dose,which is advantageous for the realization of low noise ion pnictide thin film devices.Clear Shapiro steps are observed under 10 GHz microwave irradiation.The above results demonstrate the successful fabrication of high quality and controllable Co-doped BaFe_(2)As_(2)Josephson junction with high reproducibility using the FHIB technique,laying the foundation for future investigating the mechanism of iron-based superconductors,and also the further implementation in various superconducting electronic devices.

参仙升脉口服液化学成分的UHPLC-Q Exactive Focus MS/MS快速分析

目的探究参仙升脉口服液的化学物质基础。方法利用超高效液相色谱-四极杆/静电场轨道阱高分辨质谱(UHPLC-Q Exactive Focus MS/MS)对参仙升脉口服液的化学成分进行整体、系统辨识。采用Thermo Accucore aQ C_(18)色谱柱(150 mm×2.1 mm,2.6μm),流动相0.1%甲酸水溶液(A)-甲醇(B)梯度洗脱,洗脱程序为0-13 min,5%-60%B;13-27 min,60%-95%B;27-30 min,95%B,流速0.3 mL·min^(-1),柱温30°C;质谱分析离子化方式为加热电喷雾离子化(H-ESI),扫描模式为正、负离子切换,扫描范围m/z 120-1800,碰撞能量30 eV、50 eV、70 eV。结果共鉴定出160个化学成分,包括29个黄酮类成分,24个有机酸类成分,21个生物碱类成分,19个萜类成分,15个苯丙素类成分,12个皂苷类成分和40个其他类成分;其中6个化学成分(芦丁、补骨脂苷、异补骨脂苷、补骨脂素、异补骨脂素和补骨脂酚)经对照品比对确认。结论该研究借助UHPLC-Q Exactive Focus MS/MS技术实现了参仙升脉口服液化学成分准确、快速、系统的分析和鉴定,为其化学物质基础的阐明和质量控制提供了重要依据。

A historical overview of nano-optics:From near-field optics to plasmonics

Nano-optics is an emergent research field in physics that appeared in the 1980s,which deals with light–matter optical interactions at the nanometer scale.In early studies of nano-optics,the main concern focus is to obtain higher optical resolution over the diffraction limit.The researches of near-field imaging and spectroscopy based on scanning near-field optical microscopy(SNOM)are developed.The exploration of improving SNOM probe for near-field detection leads to the emergence of surface plasmons.In the sense of resolution and wider application,there has been a significant transition from seeking higher resolution microscopy to plasmonic near-field modulations in the nano-optics community during the nano-optic development.Nowadays,studies of nano-optics prefer the investigation of plasmonics in different material systems.In this article,the history of the development of near-field optics is briefly reviewed.The difficulties of conventional SNOM to achieve higher resolution are discussed.As an alternative solution,surface plasmons have shown the advantages of higher resolution,wider application,and flexible nano-optical modulation for new devices.The typical studies in different periods are introduced and characteristics of nano-optics in each stage are analyzed.In this way,the evolution progress from near-field optics to plasmonics of nano-optics research is presented.The future development of nano-optics is discussed then.

Modeling Near-Field Impulsive Waves Generated by Deformable Landslide Using the HBP Model Based on the SPH Method

Landslide-generated impulsive waves(LGWs)in reservoir areas can seriously threaten waterway safety as well as hu-man life and properties around the two side slopes.The risk reduction and mitigation of such a hazard require the accurate prediction of near-field wave characteristics,such as wave amplitude and run-up.However,near-field LGW involves complicated fluid-solid interactions.Furthermore,the wave characteristics are closely related to various aspects,including the geometry and physical features of the slide,river,and body of water.However,the empirical or analytical methods used for rough estimation cannot derive accurate results,especially for deformable landslides,due to their significant geometry changes during the sliding process.In this study,the near-field waves generated by deformable landslides were simulated by smoothed particle hydrodynamics(SPH)based on multi-phase flow.The deformable landslides were generalized as a kind of viscous flow by adopting the Herschel-Bulkley-Papanastasiou(HBP)-based nonNewtonian rheology model.The HBP model is capable of producing deformable landslide dynamics even though the high-speed sliding process is involved.In this study,an idealized experiment case originating from Lituya LGW and a practical case of Gongjiafang LGW were reproduced for verification and demonstration.The simulation results of both cases show satisfactory consistency with the experiment/investigation data in terms of landslide movement and near-field impulsive wave characteristics,thus indicating the applicability and accuracy of the proposed method.Finally,the effects of the HBP model’s rheological parameters on the landslide dynamics and near-field wave characteristics are discussed,providing a parameter calibration method along with sug-gestions for further applications.

FOCUS-PDCA模式对老年肌少症病人日常生活能力和生活质量影响的Meta分析

目的:系统评价FOCUS-PDCA模式对老年肌少症病人日常生活能力和生活质量的影响。方法:检索PubMed、Web of Science、the Cochrane Library、中国知网、万方数据库、维普数据库、中国生物医学文献数据库中关于FOCUS-PDCA模式对老年肌少症病人日常生活能力和生活质量影响的随机对照试验,检索时限从建库至2022年12月31日。采用RevMan 5.4软件进行Meta分析。结果:共纳入5篇文献,涉及534例病人。Meta分析结果显示,使用FOCUS-PDCA模式干预可有效改善病人的生活质量[SMD=2.52,95%CI(1.50,3.54),P<0.000 01],提高日常活动能力[MD=23.94,95%CI(14.96,32.96),P<0.000 01]。结论:现有证据表明,FOCUS-PDCA模式可提高老年肌少症病人的日常生活能力,改善其生活质量。

Influence of substrate effect on near-field radiative modulator based on biaxial hyperbolic materials

Relative rotation between the emitter and receiver could effectively modulate the near-field radiative heat transfer(NFRHT)in anisotropic media.Due to the strong in-plane anisotropy,natural hyperbolic materials can be used to construct near-field radiative modulators with excellent modulation effects.However,in practical applications,natural hyperbolic materials need to be deposited on the substrate,and the influence of substrate on modulation effect has not been studied yet.In this work,we investigate the influence of substrate effect on near-field radiative modulator based onα-MoO_(3).The results show that compared to the situation without a substrate,the presence of both lossless and lossy substrate will reduce the modulation contrast(MC)for different film thicknesses.When the real or imaginary component of the substrate permittivity increases,the mismatch of hyperbolic phonon polaritons(HPPs)weakens,resulting in a reduction in MC.By reducing the real and imaginary components of substrate permittivity,the MC can be significantly improved,reaching 4.64 forε_(s)=3 at t=10 nm.This work indicates that choosing a substrate with a smaller permittivity helps to achieve a better modulation effect,and provides guidance for the application of natural hyperbolic materials in the near-field radiative modulator.

Focus on pet diseases

Pets become vital companions in human life.Tey ofer companionship and emotional support,and contribute signifcantly to physical and mental health,as well as social activities.Living with pets can stimulate human bodies to release more“afnity hormones”such as serotonin,dopamine,and oxytocin,which helps alleviate negative emotions.Te human-animal bond can enhance the human body’s ability to eliminate toxins,reduce the risk of illnesses,strengthen the immune system,and alleviate depressive symptoms.Moreover,pet-related social activities can facilitate the making of new friends and the establishment of social connections,serving as a bridge for those who struggle with social interactions.

Near-field radiative heat transfer between nanoporous GaN films

Photon tunneling effects give rise to surface waves,amplifying radiative heat transfer in the near-field regime.Recent research has highlighted that the introduction of nanopores into materials creates additional pathways for heat transfer,leading to a substantial enhancement of near-field radiative heat transfer(NFRHT).Being a direct bandgap semiconductor,GaN has high thermal conductivity and stable resistance at high temperatures,and holds significant potential for applications in optoelectronic devices.Indeed,study of NFRHT between nanoporous GaN films is currently lacking,hence the physical mechanism for adding nanopores to GaN films remains to be discussed in the field of NFRHT.In this work,we delve into the NFRHT of GaN nanoporous films in terms of gap distance,GaN film thickness and the vacuum filling ratio.The results demonstrate a 27.2%increase in heat flux for a 10 nm gap when the nanoporous filling ratio is 0.5.Moreover,the spectral heat flux exhibits redshift with increase in the vacuum filling ratio.To be more precise,the peak of spectral heat flux moves fromω=1.31×10^(14)rad·s^(-1)toω=1.23×10^(14)rad·s^(-1)when the vacuum filling ratio changes from f=0.1 to f=0.5;this can be attributed to the excitation of surface phonon polaritons.The introduction of graphene into these configurations can highly enhance the NFRHT,and the spectral heat flux exhibits a blueshift with increase in the vacuum filling ratio,which can be explained by the excitation of surface plasmon polaritons.These findings offer theoretical insights that can guide the extensive utilization of porous structures in thermal control,management and thermal modulation.