Understanding the synergistic effect of mixed solvent annealing on perovskite film formation

Morphology control of perovskite films is of critical importance for high-performance photovoltaic devices. Although solvent vapor annealing(SVA) treatment has been widely used to improve the film quality efficiently, the detailed mechanism of film growth is still under construction, and there is still no consensus on the selection of solvents and volume for further optimization. Here, a series of solvents(DMF, DMSO, mixed DMF/DMSO) were opted for exploring their impact on fundamental structural and physical properties of perovskite films and the performance of corresponding devices. Mixed solvent SVA treatment resulted in unique benefits that integrated the advantages of each solvent, generating a champion device efficiency of 19.76% with improved humidity and thermal stability. The crystallization mechanism was constructed by conducting grazing-incidence wide-angle x-ray diffraction(GIWAXS) characterizations, showing that dissolution and recrystallization dominated the film formation. A proper choice of solvent and its volume balancing the two processes thus afforded the desired perovskite film. This study reveals the underlying process of film formation, paving the way to producing energy-harvesting materials in a controlled manner towards energy-efficient and stable perovskite-based devices.

Nomogram based on liver stiffness and spleen area with ultrasound for posthepatectomy liver failure:A multicenter study

BACKGROUND Liver stiffness(LS)measurement with two-dimensional shear wave elastography(2D-SWE)correlates with the degree of liver fibrosis and thus indirectly reflects liver function reserve.The size of the spleen increases due to tissue proliferation,fibrosis,and portal vein congestion,which can indirectly reflect the situation of liver fibrosis/cirrhosis.It was reported that the size of the spleen was related to posthepatectomy liver failure(PHLF).So far,there has been no study combining 2D-SWE measurements of LS with spleen size to predict PHLF.This prospective study aimed to investigate the utility of 2D-SWE assessing LS and spleen area(SPA)for the prediction of PHLF in hepatocellular carcinoma(HCC)patients and to develop a risk prediction model.AIM To investigate the utility of 2D-SWE assessing LS and SPA for the prediction of PHLF in HCC patients and to develop a risk prediction model.METHODS This was a multicenter observational study prospectively analyzing patients who underwent hepatectomy from October 2020 to March 2022.Within 1 wk before partial hepatectomy,ultrasound examination was performed to measure LS and SPA,and blood was drawn to evaluate the patient’s liver function and other conditions.Least absolute shrinkage and selection operator logistic regression and multivariate logistic regression analysis was applied to identify independent predictors of PHLF and develop a nomogram.Nomogram performance was validated further.The diagnostic performance of the nomogram was evaluated with receiver operating charac-teristic curve compared with the conventional models,including the model for end-stage liver disease(MELD)score and the albumin-bilirubin(ALBI)score.RESULTS A total of 562 HCC patients undergoing hepatectomy(500 in the training cohort and 62 in the validation cohort)were enrolled in this study.The independent predictors of PHLF were LS,SPA,range of resection,blood loss,international normalized ratio,and total bilirubin.Better diagnostic performance of the nomogram was obtained in the training[area under receiver operating characteristic curve(AUC):0.833;95%confidence interval(95%CI):0.792-0.873;sensitivity:83.1%;specificity:73.5%]and validation(AUC:0.802;95%CI:0.684-0.920;sensitivity:95.5%;specificity:52.5%)cohorts compared with the MELD score and the ALBI score.CONCLUSION This PHLF nomogram,mainly based on LS by 2D-SWE and SPA,was useful in predicting PHLF in HCC patients and presented better than MELD score and ALBI score.

金线莲发酵液的抗氧化和美白功效研究

为开发金线莲发酵提取物在化妆品领域的应用,筛选合适的乳酸菌与酵母菌,对金线莲水提液与水提后滤渣酶解液分别进行发酵,结果表明:在采用Gb-12、Mls-34与CC-1三种菌株进行不同的单菌、复合菌发酵方式中,金线莲水提液经Mls-34与CC-1联合发酵后,其多酚含量、抗氧化活性与美白活性提升最高。金线莲酶解液经CC-1单菌发酵后,其多酚含量提升最高,DPPH自由基与ABTS自由基清除率分别提高了56.30%和85.58%,而羟自由基清除率和总还原力有所下降,而金线莲酶解液经Mls-34与CC-1联合发酵后,其美白活性提升最高。

Surface doping manipulation of the insulating ground states in Ta_(2)Pd_(3)Te_(5) and Ta_(2)Ni_(3)Te_(5)

Manipulating emergent quantum phenomena is a key issue for understanding the underlying physics and contributing to possible applications.Here we study the evolution of insulating ground states of Ta_(2)Pu_(3)Te_(5) and Ta_(2)Ni_(3)Te_(5) under in-situ surface potassium deposition via angle-resolved photoemission spectroscopy.Our results confirm the excitonic insulator character of Ta_(2)d_(3)Te_(5).Upon surface doping,the size of its global gap decreases obviously.After a deposition time of more than 7 min,the potassium atoms induce a metal-insulator phase transition and make the system recover to a normal state.In contrast,our results show that the isostructural compound Ta_(2)Ni_(3)Te_(5) is a conventional insulator.The size of its global gap decreases upon surface doping,but persists positive throughout the doping process.Our results not only confirm the excitonic origin of the band gap in Ta_(2)Pd_(3)Te_(5),but also offer an effective method for designing functional quantum devices in the future.

最平滑圈、六音系统和浪漫主义晚期三和弦进行分析

文章基于新黎曼理论三和弦进行提出一个理论框架,以“平行”和“导音转换”两种仅涉及半音进行的三和弦变换架构六音系统和超六音系统,并通过在这一理论框架下分析瓦格纳、弗朗克、理查·施特劳斯等作曲家作品中的半音化和声,演示晚期浪漫主义音乐中三和弦在六音空间及自然音级空间中独特的进行方式。该理论框架的完整与自洽性、其与浪漫主义晚期创作实践的紧密联系,及其对游离于传统调性理论边缘的和声进行引发的思考,使该文成为新黎曼理论最具开创性的研究之一,以及该领域迄今引用量最高的文章(据web of science及谷歌学术数据)。

Observation of Zero-Energy Modes with Possible Time-Reversal Symmetry Breaking on Step Edge of CaKFe_(4)As_(4)

Topologically nontrivial Fe-based superconductors attract extensive attentions due to their ability of hosting Majorana zero modes(MZMs)which could be used for topological quantum computation.Topological defects such as vortex lines are required to generate MZMs.Here,we observe the robust edge states along the surface steps of CaKFe_(4)As_(4).Remarkably,the tunneling spectra show a sharp zero-bias peak(ZBP)with multiple integerquantized states at the step edge under zero magnetic field.We propose that the increasing hole doping around step edges may drive the local superconductivity into a state with possible spontaneous time-reversal symmetry breaking.Consequently,the ZBP can be interpreted as an MZM in an effective vortex in the superconducting topological surface state by proximity to the center of a tri-junction with different superconducting order parameters.Our results provide new insights into the interplay between topology and unconventional superconductivity,and pave a new path to generate MZMs without magnetic field.

于节奏中交集、悖离:梅西安与布列兹的《春之祭》

1953年,在欧洲乐坛初露头角的布列兹发表了对《春之祭》的分析文章,其中盛赞斯特拉文斯基在节奏领域的创新。布列兹的分析在学术界产生了较大影响,却也因未作说明,而使分析的核心内容出自梅西安作曲课的事实长久不为人所知。回到战后最初数年间,通过考察梅西安从《春之祭》发展而来的“节奏角色”理论,并将其印证于梅西安与布列兹各自的分析与创作实践之中,结合布列兹与阿多诺由《春之祭》展开的思辨,探讨两位法国作曲家在战后的“零点时刻”,如何在刻意误读与“影响焦虑”下,找寻各自节奏写作的创新之路。

植物程序性细胞死亡检测技术

程序性细胞死亡(PCD)是细胞死亡的方式之一,在植物发育及逆境响应等方面起着重要作用。主要介绍检测植物PCD的细胞学、生物化学、分子生物学及生理学方法,以及流式细胞仪在植物PCD检测中的应用。

湿型砂旧砂再生及其在智能化制芯生产线上的实践应用

介绍了铸造粘土湿型砂的旧砂再生处理,以及再生砂应用于自动化、智能化的缸盖制芯生产线的开发与实践应用情况,并就生产线的开发及实践应用过程中出现的一些问题进行了分析探讨,实践得出湿型旧砂再生后可用于制造缸盖砂芯,降低废砂固废的排放。

Imaging in detecting sites of pulmonary fibrosis induced by paraquat

BACKGROUND： The most common cause of death from paraquat （PQ） poisoning is respiratoryfailure from pulmonary fi brosis, which develops through pathological overproduction of extracellularmatrix proteins such as collagens. In this study, a MicroCT system was used to observe dynamicchanges of pulmonary fi brosis in rats with PQ poisoning, and fi nd the characteristics of interstitial lungdiseases via density-based and texture-based analysis of CT images of the lung structure.METHODS： A total of 15 male SD rats were randomly divided into a control group （n=5） and aPQ poisoning group （n=10）. The rats in the poisoning group were intraperitoneally administered with4 mg/ mL PQ at 14 mg/kg, and the rats in the control group were administered with the same volumeof saline. The signs of pulmonary fi brosis observed by the MicroCT included ground-glass opacity,nodular pattern, subpleural interstitial thickening, consolidation honeycomb-like shadow of the lung.RESULTS： Compared with the control group, the rats with acute PQ poisoning had differentsigns of pulmonary fibrosis. Ground-glass opacity and consolidation of the lung appeared at theearly phase of pulmonary fi brosis, and subpleural interstitial thickening and honeycomb-like shadowdeveloped at the middle or later stage. MicroCT images showed that fibrotic lung tissues weredenser than normal lungs, and their density was up-regulated with pulmonary fi brosis. There was nodifference in the progress of pulmonary fi brosis between the right lung and the left lung （P〉0.05）, butthere were differences in fi brosis degree at different sites in the lung （P〈0.05 or P〈0.01）. Pulmonaryfi brosis was mainly seen in the exterior area of the middle-lower part of the lung.CONCLUSION： Imaging can show the development of pulmonary fi brosis in PQ poisoning rats,and this method may help to administer drugs more reasonably in treating pulmonary fi brosis.

Machine Learning to Instruct Single Crystal Growth by Flux Method

Growth of high-quality single crystals is of great significance for research of condensed matter physics. The exploration of suitable growing conditions for single crystals is expensive and time-consuming, especially for ternary compounds because of the lack of ternary phase diagram. Here we use machine learning(ML) trained on our experimental data to predict and instruct the growth. Four kinds of ML methods, including support vector machine(SVM), decision tree, random forest and gradient boosting decision tree, are adopted. The SVM method is relatively stable and works well, with an accuracy of 81% in predicting experimental results. By comparison,the accuracy of laboratory reaches 36%. The decision tree model is also used to reveal which features will take critical roles in growing processes.

Photophysics, morphology and device performances correlation on non-fullerene acceptor based binary and ternary solar cells

Non-fullerene acceptor(NFA) based organic solar cells(OSCs) are of high efficiency and low energy loss and low recombination features, which is owing to the advantage of non-fullerene acceptors. The photophysics investigation of non-fullerene solar cells, in comparing to fullerene based analogue as well as mixed acceptor ternary blends could help to understand the working mechanism of NFA functioning mechanism. We choose PBDB-T donor, the fullerene derivative PC71 BM acceptor, and the non-fullerene acceptor ITIC as the model system, to construct binary and ternary solar cells, which then subject to ultrafast spectroscopy investigation. The charge transfer pathway in binary and ternary blends is revealed.And it is seen that ITIC leads to a faster exciton separation and exciton diffusion. ITIC in blends suppresses the geminate recombination and shows smaller amount of charge transfer states, which is beneficial for the device performance. And the addition of ITIC enhances the crystallinity for both donor and acceptor leads to a morphology change of forming bicontinuous crystalline networks and phase separation. In a consequence, fill factor and JSC, increase dramatically for the related OSC.

High quality PdTe_2 thin films grown by molecular beam epitaxy

PdTe2, a member of layered transition metal dichalcogenides （TMDs）, has aroused significant research interest due to the coexistence of superconductivity and type-II Dirac fermions. It provides a promising platform to explore the inter- play between superconducting quasiparticles and Dirac fermions. Moreover, PdTe2 has also been used as a substrate for monolayer antimonene growth. Here in this paper, we report the epitaxial growth of high quality PdTe2 films on bilayer graphene/SiC（0001） by molecular beam epitaxy （MBE）. Atomically thin films are characterized by scanning tunneling microscopy （STM）, X-ray photoemission spectroscopy （XPS）, low-energy electron diffraction （LEED）, and Raman spec- troscopy. The band structure of 6-layer PdTe2 film is measured by angle-resolved photoemission spectroscopy （ARPES）. Moreover, our air exposure experiments show excellent chemical stability of epitaxial PdTe2 film. High-quality PdTe2 films provide opportunities to build antimonene/PdTe2 heterostructure in ultrahigh vacuum for future applications in electronic and optoelectronic nanodevices.

为什么他们都讨厌霍洛维茨?

在1980年版《新格罗夫音乐及音乐家辞典》的“霍洛维茨”词条中,美国著名乐评人迈克尔·斯坦伯格用一种对于辞典而言极不恰当的讽刺口吻,批评这位钢琴家技巧高超却对音乐缺乏理解。同样的言论也出现在蒂姆·佩奇、约瑟夫·霍洛维茨等人的评论中。塔鲁斯金文章从对一个具体演绎的分析(舒曼《梦幻曲》)开始,将这种批评与源自斯特拉文斯基的“文本字面主义审美观”联系起来,称其为现代的偏见。文章以同样犀利的语言讽刺这种偏见出自“屈尊”于巨人的侏儒;并预示了新世纪一种从文本向表演转移的学术视角。

他们是否依然讨厌弗拉基米尔·霍洛维茨?(下)——“最后的浪漫派大师”再议

很少有钢琴家像霍洛维茨那样受到几乎等同的毁谤和赞誉。斯坦伯格在《新格罗夫音乐及音乐家辞典》以及塔鲁斯金在《纽约时报》上的隔空对战即为一例。在霍洛维茨去世三十余年后,通过分析几十张霍洛维茨职业生涯后期的现场录音,文章重新评估了这位钢琴家的艺术才能、公众形象以及他在钢琴史上的地位。文章也试图阐明对于诠释的艺术而言相悖的两种美学观点;并指出,某些在演奏实践中看似纯粹的音乐问题,实则与伦理与拥有权、权威性与道德密切相关。

Hybridization Effects Revealed by Angle-Resolved Photoemission Spectroscopy in Heavy-Fermion Ce2IrIn8

We utilize high-resolution resonant angle-resolved photoemission spectroscopy(ARPES)to study the band structure and hybridization effect of the heavy-fermion compound Ce2 IrIn8.We observe a nearly flat band at the binding energy of 7 meV below the coherent temperature Tcoh^40 K,which characterizes the electrical resistance maximum and indicates the onset temperature of hybridization.However,the Fermi vector and the Fermi surface volume have little change around Tcoh,which challenges the widely believed evolution from a hightemperature small Fermi surface to a low-temperature large Fermi surface.Our experimental results of the band structure fit well with the density functional theory plus dynamic mean-field theory calculations.

Realization of low-energy type-Ⅱ Dirac fermions in(Ir_(1-x)Pt_x)Te_2 superconductors

Topological Dirac semimetals(DSMs) present a kind of topologically nontrivial quantum state of matter, which has massless Dirac fermions in the bulk and topologically protected states on certain surfaces. In superconducting DSMs, the effects of their nontrivial topology on superconducting pairing could realize topological superconductivity in the bulk or on the surface. As superconducting pairing takes place at the Fermi level E_F, to make the effects possible, the Dirac points should lie in the vicinity of E_F so that the topological electronic states can participate in the superconducting paring. Here,we show using angle-resolved photoelectron spectroscopy that in a series of(Ir_(1-x)Pt_x)Te_2 compounds, the type-Ⅱ Dirac points reside around E_F in the superconducting region, in which the bulk superconductivity has a maximum T_c of ～ 3 K.The realization of the coexistence of bulk superconductivity and low-energy Dirac fermions in(Ir_(1-x)Pt_x)Te_2 paves the way for studying the effects of the nontrivial topology in DSMs on the superconducting state.

Atomically flat surface preparation for surface-sensitive technologies

Surface-sensitive measurements are crucial to many types of researches in condensed matter physics.However,it is difficult to obtain atomically flat surfaces of many single crystals by the commonly used mechanical cleavage.We demonstrate that the grind-polish-sputter-anneal method can be used to obtain atomically flat surfaces on topological materials.Three types of surface-sensitive measurements are performed on CoSi(001)surface with dramatically improved quality of data.This method extends the research area of surface-sensitive measurements to hard-to-cleave alloys,and can be applied to irregular single crystals with selective crystalline planes.It may become a routine process of preparing atomically flat surfaces for surface-sensitive technologies.

Coexistence of Polaronic States and Superconductivity in Iron-Pnictide Compound Ba_2Ti_2Fe_2As_4O

The electronic structure of iron-pnictide compound superconductor Ba_2Ti_2Fe_2As_4O, which has metallic intermediate Ti_2O layers, is studied using angle-resolved photoemission spectroscopy. The Ti-related bands show a‘peak-dip-hump＇ line shape with two branches of dispersion associated with the polaronic states at temperatures below around 120 K. This change in the spectra occurs along with the resistivity anomaly that was not clearly understood in a previous study. Moreover, an energy gap induced by the superconducting proximity effect opens in the polaronic bands at temperatures below T_c（~21 K）. Our study provides the spectroscopic evidence that superconductivity coexists with polarons in the same bands near the Fermi level, which provides a suitable platform to study interactions between charge, lattice and spin freedoms in a correlated system.

Fabrication of honeycomb AuTe monolayer with Dirac nodal line fermions

Two-dimensional honeycomb lattices show great potential in the realization of Dirac nodal line fermions(DNLFs).Here,we successfully synthesized a gold telluride(AuTe)monolayer by direct tellurizing an Au(111)substrate.Low energy electron diffraction measurements reveal that it is(2×2)AuTe layer stacked onto(3×3)Au(111)substrate.Moreover,scanning tunneling microscopy images show that the AuTe layer has a honeycomb structure.Scanning transmission electron microscopy reveals that it is a single-atom layer.In addition,first-principles calculations demonstrate that the honeycomb AuTe monolayer exhibits Dirac nodal line features protected by mirror symmetry,which is validated by angle-resolved photoemission spectra.Our results establish that monolayer AuTe can be a good candidate to investigate 2D DNLFs and provides opportunities to realize high-speed low-dissipation devices.