摘要：研究目的:纳米二氧化钛已是防晒霜、化妆品和光催化剂等的常用成分。纳米二氧化钛的大量应用,已被证明具有潜在的环境负面影响与人体健康风险。如何分析环境中工程纳米二氧化钛的理化性质无疑是认识其潜在风险的关键课题。研究方法:从工程纳米颗粒可用的表征与测定方法(如电镜显微方法、色谱与质谱技术等)的优缺点出发,结合稳定同位素与稀有元素示踪技术来探讨环境中工程纳米二氧化钛颗粒的分析方法。重要结论:环境中工程纳米二氧化钛的表征与测定方法仍需深入的研究,其可靠性需要现有各种分析技术的相互验证、良好的样品预处理技术和参考物质、以及稳定同位素与稀有元素技术示踪的配合。

摘要：Total temporomandibular joint(TMJ)replacement is recommended only when there is irreversible damage to the joint and no conservative treatment can provide functional *** stock and custom-made TMJ implants have been made available;however,retrospective and comparative studies were unable to find significant differences between the two types of *** introduction of additive manufacturing(AM)techniques in medical practice allows for a greater freedom of design and a higher degree of device *** combination of AM with structural optimisation may streamline development and provide the key for fabricating biomechanic ally enhanced TMJ *** this study,structural optimis ation techniques were applied to develop and numerically validate a patient-specific TMJ *** biomechanical behaviour of each intermediate TMJ design was assessed under four different nominal and maximum biting tasks using finite element *** addition,a new set of metrics were proposed to compare each design regarding biomechanical performance and implant *** results suggest that 55-82%of the natural/intact strain patterns can be recovered with the finally selected TMJ *** represents an increase of 15%in biomechanical performance for incisor biting,15%for right molar biting,17%for left molar biting and a decrease of 2%for left group biting compared with the initial *** results also suggest that load transfer at the proximal ramus reduces the implant’s impact on the mandible’s strain ***,structural optimisation allows for a volume reduction of up to 44%with a minimum loss of implant safety and biomechanical performance.

摘要：A mathematical approach was proposed to investigate the impact of high penetration of large-scale photovoltaic park(LPP) on small-signal stability of a power network and design of hybrid controller for these units.A systematic procedure was performed to obtain the complete model of a multi-machine power network including *** damping of oscillations focusing on inter-area oscillatory modes,a hybrid controller for LPP was *** performance of the suggested controller was tested using a 16-machine 5-area *** results indicate that the proposed hybrid controller for LPP provides sufficient damping to the low-frequency modes of power system for a wide range of operating *** method presented in this work effectively indentifies the impact of increased PV penetration and its controller on dynamic performance of multi-machine power network containing *** results demonstrate that the model presented can be used in designing of essential controllers for LPP.

摘要：We present a parallel iterative algorithm to find the shortest distance projection of a given point onto the intersection of a finite number of closed convex sets in a real Hilbert space ; the number of sets used at each iteration stept corresponding to the number of available processors, may be smaller than the total number of sets. The relaxation coefficient at each iteration step is determined by a geometrical condition in an associated Hilbert space, while for the weights mild conditions are given to assure norm convergence of the resulting sequence. These mild conditions leave enough flexibility to determine the weights more specifically in order to improve the speed of convergence.

摘要：The dynamic adsorption of possible intermediates on single-atom catalysts(SACs)under working condition plays a key role in the electrocatalytic performance by the oxygen evolution reaction(OER),and therefore the performance of the dynamic adsorption should be fully considered in the theoretical screening of potential *** on density functional theory calculations,the OER performance of 27 types of C_(2)N-supported single transition metal atoms(TM@C_(2)N)is systematically investigated without and with considering the dynamic adsorption of possible *** considering dynamic adsorption,only Rh@C_(2)N and Ni@C_(2)N are screened out as good ***,by further considering the dynamic adsorption configurations of possible intermediates,more promising TM@C_(2)N SACs including Fe(Co,Ni,Ru,Rh,Ir)@C_(2)N toward the OER are screened *** presence of the intermediates(*HO,*O)on SACs could shift their d band center toward lower energy level,which makes the interaction between the adsorbate and SACs moderate and thus enhances their OER *** present work is instructive for further screening and designing of efficient single-atom catalysts for the oxygen evolution reaction.

摘要：综合介绍了比利时根特大学Magnel实验室与其他合作单位关于微生物与建筑材料（混凝土和石材）之间相互作用的研究概况。第一个研究课题是生物硫酸腐蚀，主要研究混凝土下水道系统和储肥设施的侵蚀。整个过程可用纯化学或微生物侵蚀实验来模拟。利用化学硫酸实验来模拟侵蚀过程的缺点是忽视了混凝土本身的杀菌效果。微生物实验结果表明使用具有高度中和能力的材料可限制生物腐蚀的发生。因此，生物硫酸侵蚀模型中不但需要考虑耐久性（如孔隙率），也需要把混凝土碱性列为参数之一。第二个研究课题是细菌在胶结固化和混凝土自修复中的应用。细菌诱导产生的碳酸钙用于水泥基材料和石灰石的表面防护。研究表明：沉积在表面的生物碳酸钙可有效降低混凝土吸水率、碳化和氯离子侵蚀；还能提高混凝土抗冻融性能。多孔石灰石表面固化深度可达到30mm甚至更多，固结区的强度可增加300％。与此同时，微生物碳酸钙也被应用于混凝土裂缝自修复。细菌先被固载于硅藻土或微胶囊内，然后加入到混凝土中与其一起搅拌。结果显示：加有硅藻土固载的细菌的砂浆试块上0．15～O．17mitt宽的裂缝可在40d内被细菌诱导产生的碳酸钙完全修复；而加有微胶囊固载的细菌的试块上1rnm宽的裂缝可以在3周内自修复完毕。微生物在混凝土中的另一个应用是创造绿色生态混凝土墙壁。这种混凝土墙壁经过特殊设计获得特定的微观结构和生物兼容性，从而可充当生物生长的基体。为了适于生物生长，使用低pH值的磷酸镁水泥混凝土和碳化水泥混凝土，并对其他影响生物兼容性的因素如混凝土孔隙率、表面粗糙度等进行了优化研究。

摘要：A 2 × 2 optical waveguide coupler at 850 nm based on the multimode interference （MMI） structure with the polysilsesquioxanes liquid series （PSQ-Ls） polymer material and the imprint technique is presented. The influence of the structural parameters, such as the single mode condition, the waveguide spacing of input/output ports, and the width and length of the multimode waveguide, on the optical splitting performance including the excess loss and the uniformity is simulated by the beam propagation method. By inserting a taper section of isosceles trapezoid between the single mode and multimode waveguides, the optimized structural parameters for low excess loss and high uniformity are obtained with the excess loss of -0.040 dB and the uniformity of-0.007 dB. The effect of the structure deviations induced during the imprint process on the optical splitting performance at different residual layer thicknesses is also investigated. The analysis results provide useful instructions for the waveguide device fabrication.

摘要：Photocatalytic hydrogen(H_(2))evolution using covalent organic frameworks(COFs)is an attractive and promising avenue for exploration,but one of its big challenges is low photo-induced charge *** this study,we present a straightforward and facile dipole polarization engineering strategy to enhance charge separation efficiency,achieved through atomic modulation(O,S,and Se)of the COF *** findings demonstrate that incorporating atoms with varying electronegativities into the COF matrix significantly influences the local dipole moment,thereby affecting charge separation efficiency and photostability,which in turn affects the rates of photocatalytic H_(2) *** a result,the newly developed TMT-BO-COF,which contains highly electronegative O atoms,exhibits the lowest exciton binding energy,the highest efficiency in charge separation and transportation,and the longest lifetime of the active *** leads to an impressive average H_(2) production rate of 23.7 mmol g^(−1) h^(−1),which is 2.5 and 24.5 times higher than that of TMT-BS-COF(containing S atoms)and TMT-BSe-COF(containing Se atoms),respectively.A novel photocatalytic hydrogen evolution mechanism based on proton-coupled electron transfer on N in the structure of triazine rings in vinylene-linked COFs is proposed by theoretical *** findings provide new insights into the design of highly photoactive organic framework materials for H_(2) evolution and beyond.

摘要：国际科技合作是促进科技进步和人类社会文明发展的重要举措,在环境保护和维护地球生态系统良好运行的目标下,最容易达成共识。中国国家自然科学基金委员会和欧盟委员会2018年和2019年分别发布了在环境生物技术领域合作的项目指南,共同支持环境生物修复技术和塑料降解微生物菌群相关领域的基础研究和成果转化。本专刊邀请了相关项目负责人介绍合作框架内项目的设计思想、主要内容以及获得的进展,并收录了在环境生物修复技术领域的基础研究和成果转化方面的论文23篇。

摘要：背景：黄斑转位术包括手术摘除年龄相关性黄斑变性（AMD）患者的脉络膜新生血管膜并将中心凹区神经视网膜移位至邻近的视网膜色素上皮上。目的：确定对于AMD继发的中心凹下脉络膜新生血管形成（CNV）的患者，黄斑转位联合360度视网膜切开手术是否有稳定和提高患者视力的作用。设计：本研究包括对90例患者施行标准的手术并在术后12个月内的固定时间进行随访检查。参加者：本研究中所有患者均因AMD导致的中心凹下CNV而出现视力下降。26例患者出现严重的黄斑部视网膜下出血，39例有潜伏的中心凹下CNV，25例有经典的中心凹下CNV。方法：黄斑转位术进行时间从1997年至1999年。患者于术前及术后3、6、12个月进行视力、微视野、血管造影检查和视轴评估。结果：术后12个月时，24例患者视力提高了15个字符以上，37例患者保持稳定，29例视力下降了15个字符以上。17例患者由于严重的并发症而需要做2次手术；17只眼可以观察到增殖性玻璃体视网膜病变，5只眼出现黄斑前膜，1只眼出现黄斑破孔。结论：黄斑转位术是一种技术性很强的手术。虽然术中和术后并发症的发生率较高，但对AMD继发的中心凹下CNV患者，手术在功能和解剖方面的结果都是确实有效的。