Enhancing the deep-red/near-infrared fluorescence of higher rylene diimides via the chalcogen-annulation strategy

Deep-red/near-infrared fluorescence is highly suitable for bioimaging owing to its ability to deeply penetrate tissues,organs,and live animals.However,developing organic fluorophores with high deep-red/near-infrared fluorescence quantum yield(Φ_(FL))and fluorescent brightness remain a significant challenge owing to the energy gap law.Herein,we developed a straightforward and effective chalcogen-annulation strategy by introducing O,S and Se into the bay region of TDI and QDI fluorophores,realizing the increase ofΦFLand fluorescent brightness up to 10 times.To our best knowledge,this study potentially stands as the pioneering instance showcasing the anti-heavy-atom effect of chalcogens,and the absoluteΦFL(93%)and fluorescent brightness(128,200 cm^(-1)mol^(-1)L)of Se-TDI is among top deep-red/near-infrared organic fluorophores currently available.The femtosecond transient absorption(fs-TA)measurements show the absence of obvious changes of the excited state lifetime after the introduction of chalcogens in TDI and QDI fluorophores,indicating that intersystem crossing(ISC)can be neglected in TDI and QDI fluorophores.Theoretical calculations further reveal the chalcogen-annulation strategy increase the radiative rates and reduce the reorganization energy of several accepting modes at the ground state in TDI fluorophores,leading to the suppression of internal conversion(IC)processes.Our chalcogen-annulation strategy,which effectively increases the Φ_(FL)and restricts the IC processes,while remaining unaffected by the heavy-atom effect,offers novel insights and theoretical support for the design and synthesis of deep-red/near-infrared organic fluorophores with high Φ_(FL)and fluorescent brightness.

Delayed Fluorescence and Amplified Chirality via Modified Substitution Position for Deep-red Circularly Polarized Organic Light Emitting-diodes

Developing easily accessible deep-red/near-infrared circularly polarized emitters for practical organic light-emitting diodes remains a significant challenge.Here,a practical strategy has been proposed for developing deep-red circularly polarized delayed fluorescent emitters based on a novel chiral acceptor platform.By changing triphenylamine(TPA)substitution position from para to meta,R/S-M-TBBTCN demonstrated thermally activated delayed fluorescence(TADF)properties with a delayed lifetime of 6.6µs that R/S-P-TBBTCN doesn’t have.Furthermore,R/S-M-TBBTCN showed a 65 nm red-shift in emission and a 10-fold enhancement in asymmetry factor(glum),compared with R/S-P-TBBTCN.The solution-processed nondoped circularly polarized organic light-emitting diodes(CP-OLEDs)based on R-M-TBBTCN display deep-red emission and 2.2%external quantum efficiency.

Highly stable metal halides Cs_(2)ZnX_(4)(X = Cl, Br) with Sn2+ as dopants for efficient deep-red photoluminescence

The development of deep-red emitting lead-free metal-halide perovskites with high photoluminescence quantum yields (PLQYs) and outstanding stability remains a major challenge for displays and deep-tissue bioimaging.In this work,we report a facile and convenient solvothermal method to synthesize metal halides Cs_(2)Zn X_(4)(X=Cl,Br) that however is PL innert at room temperature.Upon composition engineering utilizing Sn^(2+) as the dopant,the resulting Cs_(2)Zn Cl_(4):Sn not only emits strong deep-red PL peaked at700 nm with the highest 99.4%PLQY among the similar materials so far,but also exhibits excellent structure stability in air (PLQY remains 96%after one year exposure to the atmosphere).Detailed experimental characterizations and theoretical calculations reveal that the deep-red emission stems from self-trapped excitons induced by the Sn^(2+) dopant.Particularly,triplet emission (^(3)P_(2)→^(1)S_(0)) from Sn-5s^(2) orbitals has been observed at low temperature due to the break of parity-forbidden transition.This work provides an important guidance for the development of deep-red light-emitting materials with low price,high efficiency and excellent stability.

Confining carbon dots in amino-functionalized mesoporous silica:n→π^(*) interaction triggered deep-red solid-state fluorescence

Deep-red and near-infrared emissive carbon dots(CDs)are highly desired for bioimaging,especially in deep tissue imaging,but they are extremely rare and the known ones usually suffer from low-efficient fluorescence in water and aggregation-induced fluorescence quenching in solid state.In this work,CDs with intriguing solvent-dependent and two-photon fluorescence emissions have been prepared by a facile solvothermal method.Detailed characterizations reveal that there is an n→π*interaction between the carboxyl functional groups on CDs and the electron donor groups in solvent,which leads to the increase of energy density of CDs and the decrease of energy level,resulting in the red shift of luminescence with enhanced electron donating ability of solvent.Inspired by this finding,mesoporous silica nanoparticles(MSNs)with suitable pore size and low biological toxicity are modified by amino groups to confine CDs,thus the deep-red fluorescence emission is achieved both in solid state and in water facilitated by the n→π*interaction of host-guest.The as-prepared CDs@EDA-MSN composite exhibits high-efficient fluorescence with 650 nm wavelength,low toxicity,and good biocompatibility,which endow them a promising application in bio-imaging.

Enhanced deep-red emission in donor-acceptor molecular architecture:The role of ancillary acceptor of cyanophenyl

Organic solid-state luminescent materials with high-efficiency deep-red emission have attracted considerable interest in recent years.Constructing donor-acceptor(D-A)type molecules has been one of most commonly used strategies to achieve deep-red emission,but it is always difficult to achieve high photoluminescence(PL)quantum yield(ηPL)due to forbidden charge-transfer state.Herein,we report a new D-A type molecule 4-(7-(4-(diphenylamino)phenyl)-9-oxo-9H-fluoren-2-yl)benzonitrile(TPAFOCN),deriving from donor-acceptor-donor(D-A-D)type 2,7-bis(4-(diphenylamino)phenyl)-9H-fluoren-9-one(DTPA-FO)with a fluorescence maximum of 627 nm in solids.This molecular design enables a transformation of acceptor from fluorenone(FO)itself to 4-(9-oxo-9H-fluoren-2-yl)benzonitrile(FOCN).Compared with DTPA-FO,the introduction of cyanophenyl not only shifts the emission of TPA-FOCN to deep red with a fluorescence maximum of 668 nm in solids,but also maintains the highηPL of 10%.Additionally,a solution-processed non-doped organic light-emitting diode(OLED)was fabricated with TPA-FOCN as emitter.TPA-FOCN device showed a maximum luminous efficiency of 0.13 cd/A and a maximum external quantum efficiency(EQE)of 0.22%with CIE coordinates of(0.64,0.35).This work provides a valuable strategy for the rational design of high-efficiency deep-red emission materials using cyanophenyl as an ancillary acceptor.

供水工程新近系红层区斜坡深层变形破坏模式分析

针对新近系红层区斜坡变形破坏模式认识不足的问题,通过对以往工程区斜坡破坏现象的调查分析,寻找已有深层破坏形成的滑坡体,反分析滑坡体破坏前原始斜坡地质结构模型,并建立典型斜坡深层破坏模式,根据变形体主要工程地质条件,建立红层斜坡变形体的三维数值模型,分析其在天然、地震及降雨等条件下的稳定性。结果表明,通过建立的新近系地层不同岩段区斜坡深层破坏模式,识别出新近系地层区供水工程20#支线沿线有一个大型深层破坏斜坡变形体。该斜坡变形体在降雨条件下的稳定性较差。

大学生思政教育与意识形态深度耦合的研究——基于辽宁红色文化视域下的探讨

本文围绕辽宁红色文化视域下大学生思想政治教育与意识形态教育的深度耦合展开研究,探讨了当前红色文化视域下大学生思想政治教育与意识形态教育面临的多元文化冲击、大学生自身认知偏差及资源整合困难等挑战,深度挖掘了二者与辽宁红色文化在价值理念、教育资源及文化传承等方面的耦合点,最后提出了课程革新、实践拓展、氛围营造和师资强化等实现深度耦合的策略与途径。

赤泥深度脱水探索

以某企业国内矿和国外矿赤泥为研究对象,通过研究7种物理助滤剂和5种化学助滤剂对赤泥抽滤滤饼含水率的影响,筛选出固废XS和表面活性剂PL50作为赤泥脱水调理的物理和化学助滤剂,并研究确定了最佳添加量;在固废XS和表面活性剂PL50共同调理下,某企业国内矿和国外矿赤泥在室温、二次压榨压力1.32 MPa下压榨20 min,压滤滤饼含水率降低比例分别达3.18%和6.11%。

橡胶红根病生防深海真菌的筛选、鉴定及拮抗效果评价

橡胶树红根病是我国热带地区橡胶产业的毁灭性病害之一,严重影响我国橡胶产业的发展和热带人工林生态系统恢复。为克服实际生产中物理防治和化学防治的弊端,亟需寻找一种相对高效、安全的防治措施。随着科技发展和环境保护的需求日益扩增,生物防治成为病虫害防治最具发展潜力的研究方向。为了获得对橡胶树红根病病原菌具有较高拮抗活性的生防真菌,以橡胶树红根病的病原菌为靶标,以深海沉积物可培养真菌为指示菌,采用平板对峙法进行初筛,对有活性菌株进一步分别采用平板对峙法、对扣平板法与圆盘滤膜法测定发酵液、易挥发产物与难挥发产物等各自的抑菌率,全面评估其拮抗效果。结果表明,供试的56株深海真菌中,有9株具有平板对峙活性。复筛结果表明,9株真菌菌株发酵液、易挥发性代谢产物与难挥发性代谢产物对病原菌的的抑制率分别为–29.55%~48.45%、–3.56%~51.46%与–10.00%~50.00%。其中,菌株DSF034的发酵液、易挥发性代谢产物与难挥发性代谢产物对病原菌的抑制率分别为21.69%、32.04%与33.33%;菌株DSF073的发酵液、易挥发性代谢产物与难挥发性代谢产物对病原菌的抑制率则分别为48.45%、51.46%与50.00%,明显高于其他菌株。结合形态学观察与rDNA-ITS序列分析,分别将菌株DSF034与DSF073鉴定为青霉属(Penicillin sp.)和曲霉属(Aspergillus sp.),其生防潜力较好,可为橡胶树红根病生防菌剂的选择提供新的菌种资源。

拖木沟深厚覆盖层形成机理分析

在典型红层地区内,深厚覆盖层成因往往成为水利工程选址、选线的制约因素。在四川省亭子口灌区勘察阶段,发现拖木沟两岸覆盖层厚度大、分布广。为查明该区域深厚覆盖层成因,进行了地质测绘与钻探,并对岩体、土体取样试验。区内无泥石流发育,上部岸坡无覆盖层,该处为覆盖层滑坡堆积可能性不大;结合试验成果与工程类比计算,边坡垂向破碎带内地下水可能瞬时达hcr(13.7 m),岸坡岩体被推至河床内堆积,形成基岩平推式滑坡;临河岸坡差异风化明显,表面风化强烈,随着河床下切,岸坡多次崩塌堆积,可形成现有覆盖层结构。结果表明,该处物理地质现象发育,进行水利工程勘察工作时应充分考虑其不利因素。

结构之妙成就了《红楼梦》的“无限”

小说的结构重在营造内部情感、思想乃至意念的“无限”,深层结构决定表层结构,表层声息总是受到内部的制约而形于外,即形体跟着大脑走,外部运动依赖于心灵运动,一句话,动态来自于静态,外部花红柳绿与否,完全取决于内部结构是否精妙。《红楼梦》就妙在深层结构的草蛇灰线,远远超越了字面以及文本本身乃至无数读者的想象力,才成就了《红楼梦》的“无限”,从而构成了红学研究的长盛不衰。

红色文化资源在开放教育中的融合与应用研究

文章通过探讨红色文化资源在开放教育体系中的深度融合与创新应用,旨在实现红色文化的传承与弘扬。通过资源整合、内容融合及教学方法的创新,提出红色文化资源与开放教育的深度融合路径,具体实施路径涵盖线上平台的网络课程与虚拟仿真实践,线下活动中的实地考察与红色故事讲述,以及加强师资培训。以期进一步推动红色教育资源的研究,培育具有红色基因与文化自信的时代新人。

基于多光谱技术对原儿茶酸抑制低密度脂蛋白氧化及其与牛血清白蛋白相互作用的研究

植物多酚被称作人类健康的“第7类营养素”,在医药、食品和营养保健等多个领域受到广泛关注。红心猕猴桃果皮(RKP)中多酚含量丰富,是提取植物多酚的优良原料,但常被视为加工废料遭弃用。该研究拟通过脉冲超声(PU)辅助天然深共晶溶剂(NADES)提取RKP多酚,并通过荧光光谱和紫外-可见光谱探究RKP中重点多酚—原儿茶酸(PCA)抑制低密度脂蛋白(LDL)氧化功效及其与牛血清白蛋白(BSA)的相互作用机制。结果表明,NADES对RKP多酚的提取率显著高于常规溶剂(如水或乙醇)。在超声功率400 W、料液比1﹕40(g·mL^(-1))、温度70℃、提取20 min及含水率20%(ω/ω)条件下,所筛选的6种NADES溶剂中,氯化胆碱-乙二醇组合提取率最高(29.84 mg GAE/g DW)。光谱实验结果表明,PCA具有较强的DPPH自由基清除能力,清除率最高可达94.39%。PCA能够显著延长LDL氧化过程中共轭二烯(CD)生成的延滞时间及达到峰值时间,有效抑制脂质氧化过程中脂褐素及总荧光产物生成,减少LDL氧化过程中色氨酸(Trp)及赖氨酸(Lys)残基的氧化修饰,显示出对LDL氧化极强的抑制效果。多光谱法对PCA与BSA相互作用研究发现,两者之间存在相互作用,具有较强的亲和力,且只有一个结合位点,疏水作用力在相互作用过程中起主要作用;相互作用后酪氨酸(Tyr)周围微环境几乎不发生改变,而Trp周围微环境极性降低、疏水性增加;三维荧光光谱进一步证明二者之间存在相互作用,并由此引起蛋白质结构发生变化;综合荧光光谱和紫外-可见光谱的实验结果,PCA与BSA相互作用猝灭机理为静态猝灭。该研究为开发RKP及PCA提供参考。

地域红色文化深度融入高校思政课教学体系的实践探索

地域红色文化是一种具有极高历史价值和育人价值的文化形态,是新时代高校落实立德树人根本任务、强化育人使命的重要依托。在高校思政课教学体系中深度融入地域红色文化,可以丰富思政课教学内容,优化思政课教学方式,深化思政课教学效果。高校可以通过加强队伍建设、深化课程改革和加快教法创新等多种路径,积极推动地域红色文化深度融入思政课教学体系,显著提升思政课教育教学效果。

基于深度学习的经典红玫瑰图像分类研究

经典红玫瑰的分级一直由人工分拣完成,分拣的效率较低。近年来,机器视觉以及深度学习越来越多地被应用于农产品的分拣及工业制造领域的分类与缺陷检测。通过引入深度学习与机器视觉,开展经典红玫瑰分类研究。深度学习网络模型能够自动提取图像中的特征,大幅度减少工作量。通过实验得出,分类准确率为87.22%,基本完成既定的实验目标。

拜耳法赤泥沉降工序工艺指标对生产的影响

对影响赤泥沉降工序的混合效率、沉降槽底流固含、洗水量、滤饼含水率、赤泥压滤液及细种子苛化液加入点等工艺指标分别进行计算,分析识别影响沉降工序处理能力因素。研究发现,分离及洗涤沉降槽底液液固比降低、混合效率提高、滤饼含水率降低、洗水量增加,都能够使赤泥的碱附损量降低。因此,可通过改进沉降槽、静态混合器、压滤机等来进一步优化生产指标;同时,赤泥压滤液及细种子苛化液的最佳加入点应为矿浆碱浓度高于且最接近洗水浓度的那一级沉降槽。

基于深度学习的红色经典美术作品教学的原则与实践策略

近年来,红色经典美术作品作为展现中国共产党领导下的党史、新中国史、改革开放史、社会主义发展史的精神文化结晶,以其独特的艺术魅力和美育作用融入基础教育课程改革的方方面面。以红色经典美术作品开展深度学习要坚持情境性、探究性、理解性、内化与迁移原则,进行红色经典单元化教学设计,提升教师的价值认同和自觉实践意识,重视教材开发,建立校内外全域式深度学习体验。

Artificial Intelligence Technique in Hydrological Forecasts Supporting for Water Resources Management of a Large River Basin in Vietnam

Hydrological forecasting plays an important role in water resource management, supporting socio-economic development and managing water-related risks in river basins. There are many flow forecasting techniques that have been developed several centuries ago, ranging from physical models, physics-based models, conceptual models, and data-driven models. Recently, Artificial Intelligence (AI) has become an advanced technique applied as an effective data-driven model in hydrological forecasting. The main advantage of these models is that they give results with compatible accuracy, and require short computation time, thus increasing forecasting time and reducing human and financial effort. This study evaluates the applicability of machine learning and deep learning in Hanoi water level forecasting where it is controlled for flood management and water supply in the Red River Delta, Vietnam. Accordingly, SANN (machine learning algorithm) and LSTM (deep learning algorithm) were tested and compared with a Physics-Based Model (PBM) for the Red River Delta. The results show that SANN and LSTM give high accuracy. The R-squared coefficient is greater than 0.8, the mean squared error (MSE) is less than 20 cm, the correlation coefficient of the forecast hydrology is greater than 0.9 and the level of assurance of the forecast plan ranges from 80% to 90% in both cases. In addition, the calculation time is much reduced compared to the requirement of PBM, which is its limitation in hydrological forecasting for large river basins such as the Red River in Vietnam. Therefore, SANN and LSTM are expected to help increase lead time, thereby supporting water resource management for sustainable development and management of water-related risks in the Red River Delta.

红色基因与高校思想政治教育的深度融合研究

红色基因作为中国共产党人宝贵的精神资源。应在高校思政教育方面发挥其重要引导作用。本文将以红色基因与思政教育深度融合必要性为基础,分析红色基因与高校思政教育深度融合面临的困境与问题,并提出部分问题解决建议,以期通过探究红色基因在高校思政教育方面发挥的重要作用,为后续阶段实现红色基因与高校思政教育深度融合提供部分教育参考。

基于声景观智能识别的生态保护红线日常监测与侵扰因素分析

生态保护红线的划定是中国践行生态文明建设的重要举措,已有较多成熟的相关研究和工作利用遥感、人工调查方法对其进行划定。然而,传统生态评估方法忽略了动态要素对生态环境的影响,目前仍缺乏一套生态保护红线的日常监测体系。文章从生态声景观视角出发,先制定一份面向日常监测的声景观要素分类标准,并构建深度学习模型进行训练,得到基于声景观智能识别的分类模型;再利用该模型在共成水库保护区结合传统GIS方法对生态保护红线进行评估,并分析影响生态声景观的主要因素。结果表明:1)参考“三生空间”制定了一份面向日常监测的声景观要素分类标准,并构建深度学习模型进行训练,得到分类模型的训练精度为89.88%;2)利用训练好的深度学习模型对案例地收集的声景观进行智能识别,利用生态声景观要素占比作为衡量生态受侵扰程度的指标,实现了生态保护红线的日常监测评估;3)利用回归模型分析生态易受侵扰的影响因素,模型结果表明夜间灯光强度对生态受侵扰的影响最大,随后依次是距离居民点的距离、空间中心性、距道路距离。