Colorless to black switching with high contrast ratio via the electrochemical process of a hybrid organic-inorganic perovskite

Colorless‐to‐black switching has attracted widespread attention for smart windows and multifunctional displays because they are more useful to control solar energy.However,it still remains a challenge owing to the tremendous difficulties in the design of completely reverse absorptions in transmissive and colored states.Herein,we report on an electrochemical device that can switch between colorless and black by using the electrochemical process of hybrid organic–inorganic perovskite MAPbBr_(3),which shows a high integrated contrast ratio of up to 73%from 400 to 800 nm.The perovskite solution can be used as the active layer to assemble the device,showing superior transmittance over the entire visible region in neutral states.By applying an appropriate voltage,the device undergoes reversible switching between colorless and black,which is attributed to the formation of lead and Br_(2)in the redox reaction induced by the electron transfer process in MAPbBr_(3).In addition,the contrast ratio can be modulated over the entire visible region by changing the concentration and the applied voltage.These results contribute toward gaining an insightful understanding of the electrochemical process of perovskites and greatly promoting the development of switchable devices.

High contrast atomic magnetometer based on coherent population trapping

We present an experimental and theoretical investigation of the coherent population trapping （CPT） resonance excited on the D1 line of 87Rb atoms by bichromatic linearly polarized laser light. The experimental results show that a lin｜｜lin tran- sition scheme is a promising alternative to the conventional circular-circular transition scheme for an atomic magnetometer. Compared with the circular light transition scheme, linear light accounts for high-contrast transmission resonances, which makes this excitation scheme promising for high-sensitivity magnetometers. We also use linear light and circular light to detect changes of a standard magnetic field, separately.

Generating Proton Beams Exceeding 10 MeV Using High Contrast 60TW Laser

A prototype of a laser driven proton accelerator is built at Peking University. Protons exceeding IOMeV are accelerated from micrometer-thick aluminum targets irradiated by tightly focused laser pulse with 1.8 J energy and 30fs duration. The beam energy spectrum and charge distribution are measured by a Thomson parabola spectrometer and radiochromic fihn stacks. The sensitivity of proton cut-off energy to the focusing of the laser beam, the pulse duration, and the foil thickness are systematically investigated in the experiments. Stable proton beams have been produced with an optimized parameter set, providing a cornerstone for the future applications of laser accelerated protons.

Dual-function beam splitter of high contrast gratings

we preset the design and rabrication of a novel auai-iunction hign contrast gratings that can De usea as a polarizationselective beam splitter with transverse magnetic polarization,which performs two independent functions,i.e.,reflection focusing and power equalization at a wavelength of 1550 nm.This dual-function grating profile is optimized by the rigorous coupled-wave analysis and the finite-element method.Simple analytical expressions of phase and modal guideline for the beam splitter design are given.The beam splitter based on the grating structure is experimentally studied at a distance of 160 μm from the reflection plane,the results are consistent with the theoretical results basically.

Spectral-Phase-Modulated Cross-Polarized Wave for Chirped Pulse Amplifier with High Contrast Ratio

We demonstrate a high-quality cross-polarized-wave filter based on spectral phase modulation. Driven by Well- eompressed spectral-phase fully-compensated fundamental laser lmlses, the filter stretches the pulse bandwidth from 35 nm to 7Ohm with a conversion efficeiency of 20%.

pH-responsive metal nanoparticles as high contrast theranostic agents for selective imaging and synergistic cancer therapy

The low signal-to-noise ratio(S/N)and single functionality of fluorescence imaging agents have limited their practical applications.Bright two-photon excitation(2PE)imaging probes are highly desirable in vivo with larger imaging depth,minor autofluorescence background,and less photodamage.Herein,we developed responsive aggregated gold nanoparticles(Au NPs)as high contrast 2PE imaging agents,capable of emitting red fluorescence upon excitation of near-infrared(NIR)laser and possessing a high signal-to-noise ratio(S/N of 2,475).By forming aggregates in situ inside tumor tissue,doxorubicin hydrochloride(DOX)-loaded mix-charged gold nanoparticles(DOX-MC-Au NPs)were utilized to act as selective fluorescence imaging probes and precise therapy agents.These high-contrast theranostic agents offer a promising potential for precise cancer imaging and therapy,which might open a new venue to multifunctional and noninvasive theranostics.

Dual microenvironmental parameter-responsive lysosome-targeting carbon dots for the high contrast discrimination of a broad spectrum of cancer cells

The development of new carbon dots(CDs)for fluorescence-based cancer diagnosis has recently attracted extensive attention.Diagnosis methods based on ligand-receptor fluorescence suffer from the heterogeneity of receptor expression.Changes in the microenvironments of cancer cells provide opportunities for accurate and broad-spectrum cancer diagnosis.The lysosomes in cancer cells have lower polarity and higher viscosity than normal cells.Based on these two key microenvironmental parameters,dual-responsive CDs with inherent lysosome-targeting ability were synthesized via one-step hydrothermal treatment.The CDs exhibit many advantageous properties including facile synthesis,good water solubility,pH-independent emission,excellent photostability,good biocompatibility,and wash-free imaging ability.The CDs were successfully employed in the fluorescence-based discrimination of a broad spectrum of cancer cells from normal cells with high contrast.The CDs are promising candidates for use in the field of cancer diagnosis.

Improving seismic interpretation: a high-contrast approximation to the reflection coefficient of a plane longitudinal wave

Linearized approximations of reflection and transmission coefficients set a foundation for amplitude versus offset（AVO） analysis and inversion in exploration geophysics.However,the weak properties contrast hypothesis of those linearized approximate equations leads to big errors when the two media across the interface vary dramatically.To extend the application of AVO analysis and inversion to high contrast between the properties of the two layers,we derive a novel nonlinearized high-contrast approximation of the PP-wave reflection coefficient,which establishes the direct relationship between PPwave reflection coefficient and P-wave velocities,S-wave velocities and densities across the interface.（A PP wave is a reflected compressional wave from an incident compressional wave（P-wave）.） This novel approximation is derived from the exact reflection coefficient equation with Taylor expansion for the incident angle.Model tests demonstrate that,compared with the reflection coefficients of the linearized approximations,the reflection coefficients of the novel nonlinearized approximate equation agree with those of the exact PP equation better for a high contrast interface with a moderate incident angle.Furthermore,we introduce a nonlinear direct inversion method utilizing the novel reflection coefficient equation as forward solver,to implement the direct inversion for the six parameters including P-wave velocities,S-wave velocities,and densities in the upper and lower layers across the interface.This nonlinear inversion algorithm is able to estimate the inverse of the nonlinear function in terms of model parameters directly rather than in a conventional optimization way.Three examples verified the feasibility and suitability of this novel approximation for a high contrast interface,and we still could estimate the six parameters across the interface reasonably when the parameters in both media across the interface vary about 50%.

Application Value of High-Frequency Ultrasound and Contrast-Enhanced Ultrasound in Patients with Knee Osteoarthritis with Different TCM Syndromes

Objective: To explore the application value of high-frequency ultrasound and contrast-enhanced ultrasound in different syndrome types of knee osteoarthritis, and to provide more imaging evidence for clinical diagnosis and treatment. Method: Sixty patients with KOA were selected according to TCM classification, which were mainly divided into Qi stagnation and blood stasis type and cold-dampness blockage type. All knee joints were routinely examined by high frequency ultrasound, and those with synovial hyperplasia were examined by contrast-enhanced ultrasound. High frequency ultrasound is the examination of synovium, cartilage and collateral ligament of knee joint based on two-dimensional ultrasound. Contrast-enhanced ultrasound (CEUS) refers to the contrast examination of synovium in knee joint patients with synovial hyperplasia. Result: Among them, the suprapatellar sac effusion and synovial thickening of Qi stagnation and blood stasis type were more obvious than those of cold-dampness arthralgia type (P < 0.05), and the degree of wear of the intercondylar cartilage of cold-dampness arthralgia type was more obvious than that of Qi stagnation. The blood stasis type is heavier and the meniscus bulge is higher (P < 0.05). The radiography of synovial hyperplasia showed that the area under the curve of Qi stagnation and blood stasis type was higher than that of cold dampness arthralgia type (P < 0.05), and the peak time was significantly shorter than that of cold dampness arthralgia type. There was no statistical difference in effective peak gradient and onset time of type (P > 0.05). Conclusion: To a certain extent, the high-frequency ultrasound and contrast-enhanced ultrasound performance of knee osteoarthritis can be used as a dialectical reference for different TCM syndrome types.

High-contrast imaging based on wavefront shaping to improve low signal-to-noise ratio photoacoustic signals using superpixel method

Photoacoustic(PA) imaging has drawn tremendous research interest for various applications in biomedicine and experienced exponential growth over the past decade. Since the scattering effect of biological tissue on ultrasound is two-to three-orders magnitude weaker than that of light, photoacoustic imaging can effectively improve the imaging depth.However, as the depth of imaging further increases, the incident light is seriously affected by scattering that the generated photoacoustic signal is very weak and the signal-to-noise ratio(SNR) is quite low. Low SNR signals can reduce imaging quality and even cause imaging failure. In this paper, we proposed a new wavefront shaping and imaging method of low SNR photoacoustic signal using digital micromirror device(DMD) based superpixel method. We combined the superpixel method with DMD to modulate the phase and amplitude of the incident light, and the genetic algorithm(GA) was used as the wavefront shaping algorithm. The enhancement of the photoacoustic signal reached 10.46. Then we performed scanning imaging by moving the absorber with the translation stage. A clear image with contrast of 8.57 was obtained while imaging with original photoacoustic signals could not be achieved. The proposed method opens new perspectives for imaging with weak photoacoustic signals.

A differential-imaging polarimeterforhigh-contrast exoplanet imaging

Starlight is generally unpolarized,but the light reflected from the planet is linearly polarized as the result of the Rayleigh scattering.For ground-based exoplanet imaging,atmospheres turbulence is changing from time to time,which induces speckle noise and hampers the high-contrast imaging of the faint exoplanets.In this paper,we propose a differential-imaging polarimeter dedicated for exoplanet high-contrast imaging.The system contains a zero-order half-wave plate(HWP)located on the optical pupil plane,which can rotate to modulate the incoming light,and a Wollaston prism(WP)is used to generate two polarized images,which is used for simultaneously polarization differential imaging and thus our system is fundamentally immune to the atmospheric turbulence induced temporally-variable wavefront aberration.Our polarimeter can be inserted near the telescope image focal plane,and provide an extra contrast for the exoplanet high-contrast imaging.To achieve best differential-imaging performance,dedicated algorithm is developed,which can effectively correct the distortion and the intensity unbalance between the two differential images.The system successfully achieves an extra contrast of^30~50 times,which can be used with current adaptive optics and coronagraph system for directly imaging of giant Jupiter-like exoplanets.

Correlation of Enhancement Degree on Contrast-enhanced Ultrasound with Histopathology of Carotid Plaques and Serum High Sensitive C-Reactive Protein Levels in Patients Undergoing Carotid Endarterectomy

This study was undertaken to investigate the correlation of the enhancement degree on contrast-enhanced ultrasound(CEUS) with the histopathology of carotid plaques and the serum high sensitive C-reactive protein(hs-CRP) levels in patients undergoing carotid endarterectomy(CEA). Carotid CEUS was performed preoperatively in 115 patients who would undergo CEA, and the enhancement degree of the carotid plaques was evaluated by both the visual semiquantitative analysis and the quantitative time-intensity curve analysis. Serum hs-CRP levels were detected using the particle-enhanced immunoturbidimetric assay also before the operation. Additionally, the carotid plaque samples were subjected to histopathological examination postoperatively. The density of neovessels and the number of macrophages in the plaques were assessed by immunohistochemistry. The results showed that among the 115 patients, grade 0 plaque contrast enhancement was noted in 35 patients, grade 1 in 48 patients and grade 2 in 32 patients. The degree of plaque enhancement, the density of neovessels, the number of macrophages, and the hs-CRP levels were highest in the grade 2 patients. Correlation analysis showed that the enhancement degree of the carotid plaques was closely related to the immunohistochemical parameters of the plaques and the serum hs-CRP levels. It was suggested that the carotid plaque enhancement on CEUS can be used to evaluate the vulnerability of carotid plaques.

化疗患者行个体化低流率腹部增强CT:双源CT低管电压高管电流的可行性分析

目的 探讨在癌症患者中使用双源CT结合低流速和低管电压方案的可行性。方法 共纳入90名进行上腹部增强CT扫描的患者,并随机分为A组、B组和C组(每组30人)。在A组中,患者使用120kVp和448mgl/kg对比剂量进行扫描。B组患者以100kVp和336 mgl/kg对比剂量进行扫描。C组患者以70kVp和224mgI/kg对比剂量进行扫描。对CT值、标准差、信噪比、对比噪声比、主观评分、对比剂剂量和流速进行测量。结果 在三组中,除了肾脏外,主观图像评分无统计学差异(均P>0.05)。与其他组相比,C组在大多数感兴趣区域(ROIs)中显示出显著更高的CT值、更低的噪声水平以及更高的SNR和CNR值(P<0.05)。与A组相比,C组所用对比剂剂量减少了47.3%(79.2±13.7 vs.41.7±8.9,P<0.01),对比剂注射速率降低了19.2%(2.6±0.5 vs.2.1±0.4,P<0.01)。结论 在化疗后血管受损的患者中使用70kVp管电压结合高管电流的方法,在保证图像质量和诊断信心的同时降低流速是可行的。

高频超声联合超声造影对阴囊肿块良恶性的鉴别价值

目的探究高频超声联合超声造影对阴囊肿块良恶性的鉴别价值,为临床诊治提供参考。方法选取2020年1月至2023年12月郑州大学第一附属医院收治的94例阴囊肿块患者作为研究对象,经病理检查结果分为恶性病变组54例和良性病变组40例,以病理检查结果为金标准,分析高频超声联合超声造影对阴囊肿块良恶性的鉴别价值。结果恶性病变组患者的阴囊肿块长径、短径分别为(5.67±2.85)cm、(3.73±2.04)cm,明显长于良性病变组的(3.84±2.56)cm、(2.31±1.45)cm,恶性病变组患者阴囊肿块位于睾丸位置的比例为96.30%,明显高于良性病变组的35.00%,差异均有统计学意义(P<0.05);高频超声、超声造影诊断阴囊肿块良恶性的准确率分别为75.53%(71/94)、77.66%(73/94),两种诊断方式联合的准确率为94.68%(89/94),明显高于两者单独诊断,差异有统计学意义(P<0.05);良、恶性阴囊肿块的形态、钙化、内部回声、血流比较,差异均有统计学意义(P<0.05),但边界和回声分布比较差异均无统计学意义(P>0.05);良、恶性阴囊肿块的增强强度、增强均匀度、造影剂进入与消退方式、增强形式比较,差异均有统计学意义(P<0.05);阴囊肿块良性病变平均渡越时间为(28.04±8.65)s,明显短于恶性病变的(49.21±15.29)s,开始增强时间为(20.53±7.17)s,明显晚于恶性病变的(17.14±4.91)s,差异均有统计学意义(P<0.05);阴囊肿块良性病变的峰值强度为(50.17±8.64)dB,明显高于恶性病变的(45.41±4.31)dB,AUC值、上升支斜率分别为(1043.82±304.25)mm^(2)、(0.21±0.17)dB/s,明显低于恶性病变的(1400.59±340.08)mm^(2)、(0.90±0.20)dB/s,差异均有统计学意义(P<0.05)。结论高频超声联合超声造影应用于阴囊肿块良恶性鉴别的准确率较高,不同病变性质阴囊肿块的高频超声、超声造影表现有明显差异。

高对比度有机刺激响应发光材料研究进展(综述)

【目的】信息技术的不断发展对经济、政治、文化和军事等领域产生了深远影响,信息安全问题也变得愈发突出。将信息深度隐藏是提高信息安全的重要途径之一,开发具有信息深度隐藏功能的材料是研究的热点之一。刺激响应发光材料能够对机械力、光、温度、pH值等外部刺激产生响应性荧光信号,而具备信号开关转换功能、高对比度以及高信噪比的发光启亮型材料在信息深度隐藏领域展现出明显的优势和巨大的应用潜力。【方法】按照从分子结构改变到聚集态结构转变的顺序,总结了近五年不同类型的刺激响应发光启亮型材料,并对该材料体系进行了系统归纳。【结论】从发光机制、动力学调控、多相态转换等角度,总结了高性能刺激响应发光材料仍存在的问题,并提出了解决思路,旨在为新型高性能刺激响应发光材料的设计、制备和应用提供可借鉴的理论和实践经验。

指夹式亚高速玉米播种不同导种管种子运移轨迹对比

为了解决玉米亚高速播种机作业速度为8~12km/h条件下,指夹排种器导种管选型问题,以14°和16°两种角度的导种管为研究对象,通过自制试验台架并利用高速摄像技术对玉米种子在不同导种管中的运动过程进行追踪拍摄,描述了指夹排种器分别在作业速度8~12km/h、倾斜角度0°~30°、离地高度2~4cm 3种因素下,种子落入不同导种管的位移轨迹,结果表明:种子在16°导种管比在14°导种管中弹跳剧烈。

基于TiO_(2)的近红外大数值孔径、高聚焦效率、高透射率会聚透镜

利用相位调控原理设计了一种基于TiO_(2)材料的具有非周期同心圆环形高折射率差亚波长光栅结构的会聚透镜,可实现大数值孔径、高聚焦效率、高透射率、低损耗特性,同时具有体积小、易集成的优点。采用时域有限差分法对提出的透镜结构进行仿真和分析,工作波长为850 nm时,该透镜透射率为90.5%,焦距约为10.4μm,焦斑的半高全宽为0.61μm。通过对仿真得到的数据进行分析,可得数值孔径为0.92,聚焦效率高达91.07%,损耗为0.41 dB,平衡了高数值孔径与高聚焦效率之间的矛盾,可在小器件直径下接近衍射极限实现点会聚效果。

高频超声造影在浅表肝脏局灶性病变检出及诊断中的临床价值

目的探讨高频超声造影(CEUS)在浅表肝脏局灶性病变(FLLs)检出及诊断中的临床价值。方法选取我院浅表FLLs患者38例,共63个病变,分别使用低频凸阵探头和高频线阵探头对患者进行CEUS检查,比较低频CEUS与高频CEUS在病变可见度评分、检出率和良恶性鉴别诊断中的差异。结果浅表FLLs在高频CEUS下平均可见度评分和检出率分别为(3.62±0.79)分、93.7%(59/63),均显著高于低频CEUS[(2.44±1.04)分、57.1%(36/63)],差异均有统计学意义(均P<0.05)。高频CEUS对最大径≤1 cm FLLs、最大径1~2 cm FLLs和肝转移瘤的检出率均显著高于低频CEUS[96.7%(29/30)vs.46.7%(14/30)、92.6%(25/27)vs.66.7%(18/27)、100%(26/26)vs.57.7%(15/26)],差异均有统计学意义(均P<0.001)。高频CEUS鉴别诊断浅表FLLs良恶性的灵敏度、准确率分别为92.9%、91.7%,均高于低频CEUS(78.6%、77.8%),差异均有统计学意义(均P<0.05)。结论高频CEUS在提高浅表FLLs的检出率和定性诊断方面均有明显优势,具有重要的临床价值。

高频超声联合超声造影对RA患者腕关节病变的诊断价值

目的:探讨高频超声联合超声造影对RA患者腕关节病变的诊断价值。方法:回顾性分析2018年4月~2019年6月简阳市人民医院收治的83例RA患者的资料,分析高频超声、超声造影、高联合诊断对RA患者腕关节病变的诊断价值。结果:高频超声联合超声造影对RA病变总检出率、滑膜炎检出率均高于高频超声(P<0.05),腱鞘炎检出率、关节腔积液检出率、骨侵蚀检出率与高频超声对比差异无统计学意义(P>0.05);高频超声联合超声造影诊断RA患者腕关节病变的灵敏度、准确度、阴性预测值均明显高于高频超声(P<0.05)。结论:高频超声联合超声造影可诊断RA患者腕关节病变,联合诊断价值高于单纯高频超声。

高阶结构增强的跨视图无负样本对比的图异常检测算法

图异常检测在网络安全、金融评估和医疗保健等多个领域都有广泛的实际应用。近年来,基于对比学习和基于生成重构的图异常检测算法框架取得了显著的性能提升。然而,大多数基于图神经网络的范式忽略了一个内在的缺点,即可能会无意识地将异常节点与其邻域正常节点聚合在一起。此外,现有的检测算法缺乏对高阶结构信息的关注,导致正常节点与异常节点之间的判别性下降。为了改善以上缺点,提出了一种高阶结构增强的跨视图无负样本对比的图异常检测算法(CNCL-GAD)。与现有的单视图对比范式不同,提出了以高阶结构信息作为增强视图,通过多视图对比学习方法为图异常检测任务(GAD)引入更多、更丰富的判别信息。为了缓解图异常检测任务中正常样本与异常样本类别不平衡导致的对比负样本对大多数是同一类别的现象,提出了跨视图无负样本对比策略,即只将两个视图之间的正样本子图对拉近。将视图内节点-子图对比模块、属性重构模块和跨视图子图-子图对比模块联合训练,以获得更好的检测性能。在现有的公开数据集上进行了大量实验,与其他竞争算法相比,所提出的算法实现了有竞争力甚至更优越的性能。