Zinc battery goes to anode-free

The zinc (Zn) batteries have challenges include uncontrollable dendritic growth, unreasonable negative to positive ratio and limited areal capacity. This highlight presents the latest development to resolve the uncontrollable Zn dendrite formation at high areal capacities of 200 mAh·cm–2 through a two-dimensional metal/metal-Zn alloy heterostructured interface. The anode-free Zn batteries with an attractive and practical pouch cell energy density of 62 Wh·kg–1 enlighten an arena towards their commercialization

Interface engineering of inverted wide-bandgap perovskite solar cells for tandem photovoltaics

Wide-bandgap perovskite solar cells (WBG PSCs) have garnered significant research attention for their potential in tandem solar cells. However, they face challenges such as high open-circuit voltage losses and severe phase instability. These issues are primarily owing to the formation of defects, ion migration, and energy level mismatches at the interface of WBG perovskite devices. Meanwhile, inverted PSCs demonstrate superior stability potential and compatibility with tandem devices, making them the most promising application for WBG perovskite materials. Consequently, interface modulation for such devices has become imperative. In this review, from the perspective of applicability in tandem devices, we first provided a concise overview of WBG perovskite research and its efficiency progress in inverted devices. We further discussed interface carrier dynamics and the potential impact of interfaces on such device performance. Afterward, we presented a comprehensive summary of interface engineering in inverted WBG perovskite (1.60 eV–1.80 eV) solar cells. The research particularly explored both the upper and buried interfaces of WBG absorbers in the inverted PSCs, thoroughly investigating interface design strategies and outlining promising research directions. Finally, this review provides insight into the future development of interface engineering for high-performance and large-area WBG PSCs

Cross-plane transport in a single-molecule two-dimensional van der Waals heterojunction

Two-dimensional van der Waals heterostructures (2D-vdWHs) stacked from atomically thick 2D materials are predicted to be a diverse class of electronic materials with unique electronic properties. These properties can be further tuned by sandwiching monolayers of planar organic molecules between 2D materials to form molecular 2D-vdW heterojunctions (M-2D-vdWHs), in which electricity flows in a cross-plane way from one 2D layer to the other via a single molecular layer. Using a newly developed cross-plane break junction (XPBJ) technique, combined with density functional theory calculations, we show that M-2D-vdWHs can be created, and that cross-plane charge transport can be tuned by incorporating guest molecules. More importantly, the M-2D-vdWHs exhibit distinct cross-plane charge transport signatures, which differ from those of molecules undergoing in-plane charge transport

Heteroatom-Induced Molecular Asymmetry Tunes Quantum Interference in Charge Transport through Single-Molecule Junctions

We studied the interplay between quantum interference (QI) and molecular asymmetry in charge transport through a single molecule. Eight compounds with five-membered core rings were synthesized, and their single-molecule conductances were characterized using the mechanically controllable break junction technique. It is found that the symmetric molecules are more conductive than their asymmetric isomers and that there is no statistically significant dependence on the aromaticity of the core. In contrast, we find experimental evidence of destructive QI in five-membered rings, which can be tuned by implanting different heteroatoms into the core ring. Our findings are rationalized by the presence of antiresonance features in the transmission curves calculated using nonequilibrium Green’s functions. This novel mechanism for modulating QI effects in charge transport via tuning of molecular asymmetry will lead to promising applications in the design of single-molecule devices

Electric-field-induced selective catalysis of single-molecule reaction

随着单分子电学检测技术的迅速发展，分子电子学的研究不再局限于分子电子学器件的构筑及其电学性质的测量，而且扩展到单分子尺度化学反应过程的探索。然而目前相关的研究仍然局限于理论计算方面，在单分子尺度上实时监测和调控化学反应的活性和选择性是化学领域的长期目标和挑战。针对这一挑战，洪文晶教授课题组与程俊教授课题组合作，自主研发了精密科学仪器，将单个有机分子定向连接在两个末端尺寸为原子级的电极之间，解决了化学反应中分子取向控制的问题.理论计算结果证实了定向电场可以有效地稳定化学反应的过渡态，从而降低反应能垒。该研究工作在化学化工学院洪文晶教授、程俊教授、能源材料化学协同创新中心（iChEM）刘俊扬副研究员的共同指导下完成，由硕士研究生黄晓艳、iChEM博士研究生唐淳、博士研究生李洁琼以及兰州大学的陈力川博士作为共同第一作者，化学化工学院师佳副教授、陈招斌高级工程师、夏海平教授和田中群教授，萨本栋微纳研究院杨扬副教授、环境与生态学院白敏冬教授以及兰州大学张浩力教授参与了研究工作的讨论并给予指导，博士后乐家波、博士研究生郑珏婷、张佩（已毕业）、李瑞豪、李晓慧也参与了研究工作。Oriented external electric fields (OEEFs) offer a unique chance to tune catalytic selectivity by orienting the alignment of the electric field along the axis of the activated bond for a specific chemical reaction; however, they remain a key experimental challenge. Here, we experimentally and theoretically investigated the OEEF-induced selective catalysis in a two-step cascade reaction of the Diels-Alder addition followed by an aromatization process. Characterized by the mechanically controllable break junction (MCBJ) technique in the nanogap and confirmed by nuclear magnetic resonance (NMR) in bottles, OEEFs are found to selectively catalyze the aromatization reaction by one order of magnitude owing to the alignment of the electric field on the reaction axis. Meanwhile, the Diels-Alder reaction remained unchanged since its reaction axis is orthogonal to the electric fields. This orientation-selective catalytic effect of OEEFs reveals that chemical reactions can be selectively manipulated through the elegant alignment between the electric fields and the reaction axis.This work was supported by the National Key R&D Program of China (2017YFA0204902), the National Natural Science Foundation of China (21722305, 21703188, 21673195, 21621091, 51733004, 51525303, and 91745103), the China Postdoctoral Science Foundation (2017M622060), and the Young Thousand Talents Project of China. 该工作得到国家自然科学基金委（21722305、21703188、21673195、51733004、51525303、91745103），国家重点研发计划课题（2017YFA0204902），中国博士后面上基金（2017M622060）的资助，以及固体表面物理化学国家重点实验室、醇醚酯化工清洁生产国家工程实验室、能源材料化学协同创新中心的支持

Promoting Effect of Layered Titanium Phosphate on the Electrochemical and Photovoltaic Performance of Dye-Sensitized Solar Cells

We reported a composite electrolyte prepared by incorporating layered α-titanium phosphate (α-TiP) into an iodide-based electrolyte using 1-ethyl-3-methylimidazolium tetrafluoroborate(EmimBF4) ionic liquid as solvent. The obtained composite electrolyte exhibited excellent electrochemical and photovoltaic properties compared to pure ionic liquid electrolyte. Both the diffusion coefficient of triiodide (I3−) in the electrolyte and the charge-transfer reaction at the electrode/electrolyte interface were improved markedly. The mechanism for the enhanced electrochemical properties of the composite electrolyte was discussed. The highest conversion efficiency of dye-sensitized solar cell (DSSC) was obtained for the composite electrolyte containing 1wt% α-TiP, with an improvement of 58% in the conversion efficiency than the blank one, which offered a broad prospect for the fabrication of stable DSSCs with a high conversion efficiency

Abnormal sleep duration is associated with sarcopenia in older Chinese people: A large retrospective cross-sectional study

Abnormalities in sleep patterns are a common health problem for the older adults. The relationship between sarcopenia and sleep duration in older people is controversial. This research is to examine the association between sleep duration and sarcopenia

Assessment of Earthquake Destructive Power to Structures Based on Machine Learning Methods

This study presents a machine learning-based method for the destructive power assessment of earthquake to structures. First, the analysis procedure of the method is presented, and the backpropagation neural network (BPNN) and convolutional neural network (CNN) are used as the machine learning algorithms. Second, the optimized BPNN architecture is obtained by discussing the influence of a different number of hidden layers and nodes. Third, the CNN architecture is proposed based on several classical deep learning networks. To build the machine learning models, 50,570 time-history analysis results of a structural system subjected to different ground motions are used as training, validation, and test samples. The results of the BPNN indicate that the features extraction method based on the short-time Fourier transform (STFT) can well reflect the frequency-/time-domain characteristics of ground motions. The results of the CNN indicate that the CNN exhibits better accuracy (R2 = 0.8737) compared with that of the BPNN (R2 = 0.6784). Furthermore, the CNN model exhibits remarkable computational efficiency, the prediction of 1000 structures based on the CNN model takes 0.762 s, while 507.81 s are required for the conventional time-history analysis (THA)-based simulation. Feature visualization of different layers of the CNN reveals that the shallow to deep layers of the CNN can extract the high to low-frequency features of ground motions. The proposed method can assist in the fast prediction of engineering demand parameters of large-number structures, which facilitates the damage or loss assessments of regional structures for timely emergency response and disaster relief after earthquake

Modified anterior approach versus traditional posterior approach for ultrasound-guided superior laryngeal nerve block in awake endotracheal intubation: a randomized non-inferiority clinical trial

AbstractStudy objective This study was undertaken to compare the effect of the modified ultrasound-guided anterior superior laryngeal nerve block (SLNB) with the traditional ultrasound-guided posterior SLNB in providing intubation conditions during awake tracheal intubation (ATI) in patients without difficult airway.Design Randomized, assessor-blind. Registration number: ChiCTR2200058086.Setting West China Hospital of Sichuan University, Chengdu, China.Patients 104 patients aged 18–65 years, of American Society of Anesthesiologists status I-III, posted for elective general surgery with general endotracheal anesthesia.Interventions The patients were randomized into two groups (modified group, n = 52; traditional group, n = 52). Modified anterior SLNB or traditional posterior SLNB was performed under ultrasound guidance.Measurements The primary outcome was the proportion of acceptable intubation condition (AIC), which was analyzed in both per-protocol (PP) and intention-to-treat (ITT) populations. The prespecified non-inferiority margin was −4.8%. Secondary outcomes included intubation success rate on the first attempt, hemodynamic parameters during ATI, time taken for airway anesthesia and intubation, recall of intubation, patient perception of comfort, and incidence and severity of postoperative complications.Main results In the PP population, the proportion of AIC in the modified group was 49/49 (100%) and that in the traditional group was 49/49 (100%), absolute difference 0, lower limit of 1-sided 95% CI, −0.3%. In the ITT population, the primary outcomes in the modified and traditional group were 52/52 (100%) and 51/52 (98.1%), respectively, with an absolute difference of 1.9% and a lower limit of 1-sided 95% CI of −1.2%. The non-inferiority of modified ultrasound-guided anterior SLNB was confirmed in both populations.Conclusions Among adults without difficult airways during videolaryngoscope-assisted ATI, the modified ultrasound-guided anterior SLNB, compared to the traditional posterior approach, showed a statistically non-inferior effect in terms of providing AIC