Exploring plasmons weakly coupling to perovskite excitons with tunable emission by energy transfer

Localized surface plasmon resonance(LSPR) has caused extensive concern and achieved widespread applications in optoelectronics. However, the weak coupling of plasmons and excitons in a nanometal/semiconductor system remains to be investigated via energy transfer. Herein, bandgap tunable perovskite films were synthesized to adjust the emission peaks,for further coupling with stable localized surface plasmons from gold nanoparticles. The degree of mismatch, using steadystate and transient photoluminescence(PL), was investigated systematically in two different cases of gold nanoparticles that were in direct contacting and insulated. The results demonstrated the process of tuning emission coupled to LSPR via wavelength-dependent photoluminescence intensity in the samples with an insulating spacer. In the direct contact case,the decreased radiative decay rate involves rapid plasmon resonance energy transfer to the perovskite semiconductor and non-radiative energy transfer to metal nanoparticles in the near-field range.

Effects of electron temperature on the ion extraction characteristics in a decaying plasma confined between two parallel plates

In this paper,a one-dimension particle-in-cell(PIC)code(EDIPIC)is employed to simulate the parallel-plate ion extraction process under an externally applied electrostatic field,focusing on the analysis of the influe nee of the initial electron temperature on the extracted ion fluxes to the metal plates during the ion extraction process.Compared with previously published results,the plasma oscillations on a timescale of the electron plasma period,and the excitation of the ion acoustic rarefaction waves resulting from the plasma oscillations originating from both the negative and positive electrodes,are studied for the first time.The modeling results show that both the negative and positive extractors can collect ions due to the plasma oscillations and the propagation of the ion acoustic rarefaction waves.With the in crease of the initial electron temperature achieved by keeping other parameters unchanged,on the one hand,both the ion speed and flux to the negative and positive plates increase,which leads to a significant decrease of the ion extraction time,while on the other hand,the ion flux to the positive plate after the formation of a Child-Langmuir sheath is much more sensitive to an increase of the initial electron temperature than that to the negative plate.The PIC simulation results provide a deeper physical understanding of the influence of the initial electron temperature on the characteristics of the entire ion extraction process in a decaying plasma.

Co-registered photoacoustic and ultrasound imaging for tongue cancer detection

Tongue cancer is an increasingly common disease with high morbidity,Besides clinical obser-vation,biomedical imaging techniques have been investigated for early detection of tonguecancer.In this paper,we proposed a co-registered dual-modality photoacoustic(PA)and ul.trasound imaging technique to simultaneously map the functional and structural information ofhuman tongue,which has the potential to detect and diagnose tongue cancer in early stage,Theimaging probe comprises a 20-MHz side-view focused transducer for ultrasound imaging and PAdetection,a light path constructed by a multimode optical fiber,and a prism for PA illumination.Phantom experiments were conducted to evaluate the performance of the system includingpenetration depth,spatial resolution and signal-to-noise ratio.In vivo imaging of animaltumor and human tongue was carried out to show the feasibility of the proposed technique todetect tumor lesions in human tongue.The results of phantom and in vivo experiments suggestthat the proposed technique has the potential to detect the early-stage cancer lesions in humantongue.

High-performance self-powered ultraviolet to near-infrared photodetector based on WS_(2)/InSe van der Waals heterostructure

van der Waals heterostructures(vdWHs)based on two-dimensional(2D)materials without the crystal lattice matching constraint have great potential for high-performance optoelectronic devices.Herein,a WS_(2)/InSe vdWH photodiode is proposed and fabricated by precisely stacking InSe and WS_(2)flakes through an all-dry transfer method.The WS_(2)/InSe vdWH forms an n–n heterojunction with strong built-in electric field due to their intrinsic n-type semiconductor characteristics and energy-band alignments with a large Fermi level offset between WS_(2)and InSe.As a result,the device displays excellent photovoltaic behavior with a large open voltage of 0.47 V and a short-circuit current of 11.7 nA under 520 nm light illumination.Significantly,a fast rising/decay time of 63/76μs,a large light on/off ratio of 105,a responsivity of 61 mA/W,a high detectivity of 2.5×10^(11) Jones,and a broadband photoresponse ranging from ultraviolet to near-infrared(325–980 nm)are achieved at zero bias.This study provides a strategy for developing high-performance self-powered broadband photodetectors based on 2D materials.

Nanoscale multi-beam lithography of photonic crystals with ultrafast laser

Photonic crystals are utilized in many noteworthy applications like optical communications,light flow control,and quantum optics.Photonic crystal with nanoscale structure is important for the manipulation of light propagation in visible and near-infrared range.Herein,we propose a novel multi beam lithography method to fabricate photonic crystal with nanoscale structure without cracking.Using multi-beam ultrafast laser processing and etching,parallel channels with subwavelength gap are obtained in yttrium aluminum garnet crystal.Combining optical simulation based on Debye diffraction,we experimentally show the gap width of parallel channels can be controlled at nanoscale by changing phase holograms.With the superimposed phase hologram designing,functional structures of complicated channel arrays distribution can be created in crystal.Optical gratings of different periods are fabricated,which can diffract incident light in particular ways.This approach can efficiently manufacture nanostructures with controllable gap,and offer an alternative to the fabrication of complex photonic crystal for integrated photonics applications.

三维/一维CsPbBr_(3)@PbBrOH分子矩阵高性能闪烁体

无机卤化铅钙钛矿纳米晶体(NCs)因其优异的固有电子和光学性能成为X射线探测和成像的热门材料.然而,由于钙钛矿材料的高离子晶体结构,其存在严重的水分、热、光不稳定性问题,阻碍了其商业化.为了解决这一问题,本文从分子结构的角度设计了3D/1D CsPbBr_(3)@PbBrOH复合结构,将高度发光的3D CsPbBr_(3)NCs纳入1D PbBrOH基体中,形成“基体中的发射器”.制备的CsPbBr_(3)@PbBrOH在不牺牲光致发光量子产率的同时表现出优异的稳定性.同时,1D PbBrOH可以被认为是一个完美的宿主,其基体中重原子Pb的存在增强了X射线的吸收.最终,将嵌入惰性PbBrOH宿主中的发光CsPbBr_(3)NCs应用于X射线探测.CsPbBr_(3)@PbBrOH闪烁体显示出明亮的辐射发光和对X射线信号的敏感响应.此外,将闪烁体制成薄膜屏进行成像,获得了隐藏在胶囊内部的TEM网格的清晰图像且CsPbBr_(3)@PbBrOH薄膜的分辨率计算高达50 lp mm^(-1).因此,CsPbBr_(3)@PbBrOH闪烁体在电离辐射探测特别是X射线成像方面具有广阔的应用前景.

Portable multi-amplified temperature sensing for tumor exosomes based on MnO_(2)/IR780 nanozyme with high photothermal effect and oxidase-like activity

Efficient determination of tumor exosomes using portable devices is crucial for the establishment of facile and convenient early cancer diagnostic methods. However, it is still challenging to effectively amplify the detection signal to achieve tumor exosomes detection with high sensitivity by portable devices. To address this issue, we developed a portable multi-amplified temperature sensing strategy for highly sensitive detecting tumor exosomes based on multifunctional manganese dioxide/IR780 nanosheets(MnO_(2)/IR780 NSs) nanozyme with high oxidase-like activity and enhanced photothermal performance.Inspiringly, MnO_(2)/IR780 NSs were synthesized via a facile one-step method with mild experimental conditions, which not only exhibited a stronger photothermal effect than that of MnO_(2) but also showed excellent oxidase-like activity that can catalyze the oxidation of 3',3',5',5'-tetramethylbenzidine(TMB) to generate TMB oxide(oxTMB) with a robust photothermal property, thus conjoining with MnO_(2)/IR780 NSs to further enhance the temperature signal. The present assay enables highly sensitive determination of tumor exosomes with the detection limit down to 5.1×10~3 particles/mL, which was comparable or superior to those of the most previously reported sensors. Furthermore, detection of tumor exosomes spiked in biological samples was successfully realized. More importantly, our method showed the recommendable portability, robust applicability, and easy manipulation. By taking advantages of these features,this high-performance photothermal sensor offered a promising alternative means for nondestructive early cancer diagnosis and treatment efficacy evaluation.

Scalability and efficiency challenges for the exascale supercomputing system:practice of a parallel supporting environment on the Sunway exascale prototype system

With the continuous improvement of supercomputer performance and the integration of artificial intelligence with traditional scientific computing,the scale of applications is gradually increasing,from millions to tens of millions of computing cores,which raises great challenges to achieve high scalability and efficiency of parallel applications on super-large-scale systems.Taking the Sunway exascale prototype system as an example,in this paper we first analyze the challenges of high scalability and high efficiency for parallel applications in the exascale era.To overcome these challenges,the optimization technologies used in the parallel supporting environment software on the Sunway exascale prototype system are highlighted,including the parallel operating system,input/output(I/O)optimization technology,ultra-large-scale parallel debugging technology,10-million-core parallel algorithm,and mixed-precision method.Parallel operating systems and I/O optimization technology mainly support largescale system scaling,while the ultra-large-scale parallel debugging technology,10-million-core parallel algorithm,and mixed-precision method mainly enhance the efficiency of large-scale applications.Finally,the contributions to various applications running on the Sunway exascale prototype system are introduced,verifying the effectiveness of the parallel supporting environment design.

In Situ Super-Hindrance-Triggered Multilayer Cracks for Random Lasing inπ-Functional Nanopolymer Films

In situ self-assembly of semiconducting emitters into multilayer cracks is a significant solution-processing method to fabricate organic high-Q lasers.However,it is still difficult to realize from conventional conjugated polymers.Herein,we create the molecular super-hindrance-etching technology,based on theπ-functional nanopolymer PG-Cz,to modulate multilayer cracks applied in organic single-component random lasers.Massive interface cracks are formed by promoting interchain disentanglement with the super-steric hindrance effect ofπ-interrupted main chains,and multilayer morphologies with photonic-crystal-like ordering are also generated simultaneously during the drop-casting method.Meanwhile,the enhancement of quantum yields on micrometer-thick films(Φ=40%to 50%)ensures high-efficient and ultrastable deep-blue emission.Furthermore,a deep-blue random lasing is achieved with narrow linewidths~0.08 nm and high-quality factors Q≈5,500 to 6,200.These findings will offer promising pathways of organicπ-nanopolymers for the simplification of solution processes applied in lasing devices and wearable photonics.

电催化合成氨反应原位表征技术

常温常压下电催化氮气-水合成氨反应主要受限于氮气吸附与活化、反应路径以及析氢竞争反应.为了解析合成氨催化反应中N–N键活化和N–H键形成的作用机理,用于开发具有更高活性与更好稳定性的催化剂以提高氮气还原反应的催化选择性和氨合成效率,研究与发展实时监测催化反应过程中催化剂的结构变化和反应物种动态演变过程的原位表征技术显得至关重要.本文简介了X射线衍射、光电子能谱、吸收谱、红外光谱、拉曼光谱等多种原位表征技术在合成氨催化剂和催化反应研究的具体应用,指出用于氮气-水体系原位表征技术发展亟待解决的关键问题,并探讨了原位技术联用及时空分辨率提升所面临的挑战.

Defect passivation strategy for inorganic CsPbI2Br perovskite solar cell with a high-efficiency of 16.77%

All-inorganic halide perovskite solar cells(PSCs)have acquired great progress,especially CsPbI2Br.However,their photoelectric conversion efficiency(PCE)remains far below the theoretical predictions.Non-radiative recombination is one of the important issues affecting the photoelectric performance of the PSCs,and the defective lead ions derived from the evaporation of halide ions in the inorganic perovskite are the principal non-radiative recombination centers.Herein,the non-radiative recombination is effectively suppressed by introducing the N-methyl-2-pyrrolidone(NMP)as a Lewis base molecule to passivate the defective lead ions.Therefore,by adjusting the dosage of NMP,the smooth and pinhole-free CsPbI_(2)Br perovskite film is obtained and the optimized device exhibits a champion PCE of 16.77%with an excellent fill factor(FF)of 0.80.This work proves the effectiveness of passivation using Lewis base molecules to prevent non-radiative recombination defects in inorganic perovskite.

Lithocarpinols A and B,a pair of diastereomeric antineoplastic tenellone derivatives from the deep-sea derived fungus Phomopsis lithocarpus FS508

Lithocarpinols A(1) and B(2), a pair of tenellone diastereoisomers with novel fused skeleton were isolated from the deep-sea derived fungus Phomopsis lithocarpus FS508. Their structures were elucidated by comprehensive spectroscopic analyses, X-ray diffraction and quantum molecular calculation. Their plausible biogenetic pathway featured an intriguing carbonyl-ene cyclization. Lithocarpinol A exhibited moderate inhibitory effect against HepG-2 and A549 tumor cell lines with IC_(50) values of 9.4 μmol/L and10.9 μmol/L,respectively.

Biosynthesis of the Central Piperidine Nitrogen Heterocycle in Series a Thiopeptides

Summary of main observation and conclusion Thiopeptides,arising from complex posttranslational modifications of a genetically encoded precursor peptide,are of great interest due to their structural complexity and important biological activities.All of these antibiotics share a macrocyclic peptidyl core that contains a central,six-membered nitrogen heterocycle and are classified into five series a-e based on the oxidation state of the central nitrogenous ring.Here,we report that the biosynthesis of the central piperidine heterocycle of series a thiopeptides relies on the activity of homologues of an F420H2-dependent reductase TppX4 by exploiting and characterizing the piperidine-containing thiopeptin biosynthetic gene (tpp)cluster in Streptomyces tateyamensis.In vitro reconstruction of TppX4 activity demonstrated that the piperidine heterocycle of thiopeptins was transformed from a dehydropiperidine heterocycle,and TppX4 tolerated the changes in the C-termini and macrocyclic peptidyl core of substrate and also tolerated dehyropiperidine-containing monocyclic or bicyclic thiopeptides.The identification of TppX4 and its substrate tolerance enriches the biosynthetic toolbox for development of additional thiopeptide analogs for clinical drug screening.

Donor strategy for promoting nonradiative decay to achieve an efficient photothermal therapy for treating cancer

Photothermal therapy(PTT)is emerging as an effective treatment for superficial carcinoma.A key challenge to the effectiveness of PTT is to develop photosensitizers with high photothermal conversion efficiency.Aiming to address this challenge,we develop a series of multi-arylpyrrole derivatives with different donors that contain different multi-rotor structures to explore highly efficient PTT photosensitizers.Among these multi-arylpyrrole derivatives,MAP4-FE nanoparticles with a small size of their donor groups and better-donating ability exhibit a high photothermal conversion efficiency(up to 72%)when they are encapsulated by an amphiphilic polymer.As a result,the MAP4-FE nanoparticles have shown satisfactory PTTeffects on in vivo tumor eradication under the guidance of photoacoustic signals.The findings of this study provide significant insights for the development of high-efficiency PTT photosensitizers for cancer treatment by making full use of the nonradiative decay of small size donors as rotors.

Amphichoterpenoids A-C,unprecedented picoline-derived meroterpenoids from the ascidian-derived fungus Amphichorda felina SYSU-MS7908

Amphichoterpenoids A-C(1-3),unprecedented picoline-derived meroterpenoids possessing a pyrano[3,2-c]pyridinyl-g-pyranone scaffold,were characterized from the ascidian-derived fungus Amphichorda felina SYSU-MS7908.Their structures were elucidated by spectroscopic methods,X-ray diffraction and electronic circular dichroism(ECD)calculations.A plausible biosynthetic pathway was proposed.The isolated compounds displayed moderate inhibitory activity against acetylcholinesterase with 50%inhibiting concentration(IC_(50))values of 18.8-53.2 mmol/L.

Spatiotemporal sectioning of two-photon fluorescence ellipsoid with a CsPbBr_(3) nanosheet

Two-photon fluorescence (TPF) ellipsoid formed by a focused femtosecond laser into luminescent media serves as a fundamental pixel for TPF spatiotemporal imaging. Visualizing spatiotemporal evolution of the TPF ellipsoid itself in a selected luminescent medium is important for correctly reconstructing and interpreting spatiotemporal information of imaged targets. Here, we report a new spatiotemporal sectioning technique with a luminescent CsPbBr_(3) nanosheet and visualize the spatiotemporal evolution of TPF ellipsoid along the axial direction. Time-resolved axial lengths of TPF ellipsoids turn out to broaden nonlinearly with a turning point at about 600 ps. By comparison experiments, observed phenomena are attributed to photocarrier trapping and TPF photon recycling processes within CsPbBr_(3) nanosheets. The spatiotemporal sectioning technique is expected to be widely applicable, which will ignite a plethora of investigations and applications utilizing TPF ellipsoid.

Cross and joint ordinal partition transition networks for multivariate time series analysis

We propose the construction of cross and joint ordinal pattern transition networks from multivariate time series for two coupled systems, where synchronizations are often present. In particular, we focus on phase synchronization, which is a prototypical scenario in dynamical systems. We systematically show that cross and joint ordinal pattern transition networks are sensitive to phase synchronization. Furthermore, we find that some particular missing ordinal patterns play crucial roles in forming the detailed structures in the parameter space, whereas the calculations of permutation entropy measures often do not. We conclude that cross and joint ordinal partition transition network approaches provide complementary insights into the traditional symbolic analysis of synchronization transitions.

Moldable and transferrable conductive nanocomposites for epidermal electronics

Skin-inspired soft and stretchable electronic devices based on functional nanomaterials have broad applications such as health monitoring,human-machine interface,and the Internet of things.Solution-processed conductive nanocomposites have shown great promise as a building block of soft and stretchable electronic devices.However,realizing conductive nanocomposites with high conductivity,electromechanical stability,and low modulus over a large area at sub-100μm resolution remains challenging.Here,we report a moldable,transferrable,high-performance conductive nanocomposite comprised of an interpenetrating network of silver nanowires and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate).The stacked structure of the nanocomposite synergistically integrates the complementary electrical and mechanical properties of the individual components.We patterned the nanocomposite via a simple,low-cost micromolding process and then transferred the patterned large-area electrodes onto various substrates to realize soft,skin-interfaced electrophysiological sensors.Electrophysiological signals measured using the nanocomposite electrodes exhibit a higher signal-to-noise ratio than standard gel electrodes.The nanocomposite design and fabrication approach presented here can be broadly employed for soft and stretchable electronic devices.

Roussoelins A and B:two phenols with antioxidant capacity from ascidian-derived fungus Roussoella siamensis SYSU-MS4723

Ascidian-derived microorganisms are a signifcant source of pharmacologically active metabolites with interesting structural properties.When discovering bioactive molecules from ascidian-derived fungi,two new phenols,roussoelins A(1)and B(2),and ten known polyketides(3–12)were isolated from the ascidian-derived fungus Roussoella siamensis SYSU-MS4723.The planar structure of compounds 1 and 2 was established by analysis of HR-ESIMS and NMR data.The conformational analysis of the new compounds was assigned according to coupling constants and selective gradient NOESY experiments,and absolute confgurations were completed by the modifed Mosher’s method.Among the isolated compounds,1,2,and 9 showed moderate antioxidant capacity.

PFNa结合钢丝环扎治疗小转子移位的不稳定型股骨转子间骨折疗效分析

目的:对本院伴有小转子移位的不稳定型股骨转子间骨折进行PFNa结合钢丝环扎手术的病人资料进行分析观察其治疗效果.方法:采用回顾性分析的研究方法,对本院骨科收治的2015年6月-2017年10月因外伤致伴有小转子移位的不稳定型转子间骨折行PFNa结合钢丝环扎手术治疗的24 例病人进行疗效分析并随访,对手术时间、术中出血量、骨折愈合时间、术后并发症进行分析;并对病人术前、术后及末次随访时的 Harris 评分、VAS 疼痛评分进行分析.结果:所有病人均顺利完成手术治疗.所有随访病人术后均获骨性愈合,愈合时间14-22 周,中位数18周, 未出现感染、内固定物失效、下肢深静脉血栓等并发症.手术时间平均(63. 50 ± 11. 50) 分钟、术中出血量平均(260. 00 ± 60) ml,按 Harris 评分、VAS 疼痛评分进行近期效果评估.术前、术后及随访末次 Harris评分为(30. 60 ± 4. 15)分(23-52分);(65. 30 ± 5. 25)分 (58-79 分);(79. 50 ± 8. 65)分(75-92分),术前、术后及末次随访 VAS 平均分(8. 26 ±0. 70)分(7-10 分);(4. 18 ± 1. 55)分(3-6 分);(1. 65 ± 2. 15)分(0-3分).术前与末次随访时 Harris评分及 VAS 评分均较前明显转优.差异有统计学意义( < 0. 05).结论:PFNa结合钢丝环扎治疗伴有小转子移位不稳定型转子间骨折力学结构合理,钢丝环扎利于维持内侧柱骨块的固定.具有可早期进行功能锻炼,保持骨折对位持久,骨折愈合好,并发症少等优点,对疼痛缓解及髋关节功能均明显改善,有利于病人尽早回归伤前生活方式.