Effect of TS-1 Treatment by Mixed Alkaline on Propylene Epoxidation

Titanium silicate-1(TS-1) was treated with a mixed alkaline of tetrapropyl ammonium hydroxide(TPAOH) and NaOH. It was characterized by XRD, nitrogen physical adsorption, SEM, FT-IR, UV-Vis and ICPOES, and studied in propylene epoxidation. The mixed alkaline treatment with TPAOH/NaOH solution did not destroy the MFI structure of TS-1. With increasing NaOH concentrations, the relative crystallinity and the framework titanium decreased to some extent while the mesopore volume, mesopore diameter, and extra-framework titanium increased appreciably. When NaOH concentration was 0.0333 mol L^(-1), the best catalytic performance was obtained.

Iterative Receiver for Orthogonal Time Frequency Space with Index Modulation via Structured Prior-Based Hybrid Belief and Expectation Propagation

Orthogonal Time Frequency Space(OTFS)signaling with index modulation(IM)is a promising transmission scheme characterized by high transmission efficiency for high mobility scenarios.In this paper,we study the receiver for coded OTFS-IM system.First,we construct the corresponding factor graph,on which the structured prior incorporating activation pattern constraint and channel coding is devised.Then we develop a iterative receiver via structured prior-based hybrid belief propagation(BP)and expectation propagation(EP)algorithm,named as StrBP-EP,for the coded OTFS-IM system.To reduce the computational complexity of discrete distribution introduced by structured prior,Gaussian approximation conducted by EP is adopted.To further reduce the complexity,we derive two variations of the proposed algorithm by using some approximations.Simulation results validate the superior performance of the proposed algorithm.

A rescaling algorithm for multi-relaxation-time lattice Boltzmann method towards turbulent flows with complex configurations

Understanding and modeling flows over porous layers are of great industrial significance.To accurately solve the turbulent multi-scale flows on complex configurations,a rescaling algorithm designed for turbulent flows with the Chapman-Enskog analysis is proposed.The mesh layout and the detailed rescaling procedure are also introduced.Direct numerical simulations(DNSs)for a turbulent channel flow and a porous walled turbulent channel flow are performed with the three-dimensional nineteen-velocity(D3Q19)multiple-relaxation-time(MRT)lattice Boltzmann method(LBM)to validate the accuracy,adaptability,and computational performance of the present rescaling algorithm.The results,which are consistent with the previous DNS studies based on the finite difference method and the LBM,demonstrate that the present method can maintain the continuity of the macro values across the grid interface and is able to adapt to complex geometries.The reasonable time consumption of the rescaling procedure shows that the present method can accurately calculate various turbulent flows with multi-scale and complex configurations while maintaining high computational efficiency.

EGFR突变晚期非小细胞肺癌患者后线接受免疫治疗的疗效分析

背景与目的免疫检查点抑制剂单药治疗在驱动基因阳性的晚期非小细胞肺癌(non-small cell lung cancer, NSCLC)患者中疗效甚微。研究表明,部分驱动基因阳性患者靶向治疗耐药后对免疫联合治疗仍有效。国内研究甚少。本研究旨在分析人表皮生长因子(epidermal growth factor receptor, EGFR)敏感突变NSCLC患者后线接受免疫治疗的疗效,评价真实世界免疫联合化疗在EGFR突变晚期患者后线治疗中的价值。方法收集2018年6月-2020年11月在首都医科大学附属北京胸科医院确诊的EGFR突变的初治晚期肺腺癌患者共27例,均在靶向治疗进展后接受了程序性死亡受体1(programmed cell death protein 1, PD-1)检查点抑制剂联合化疗以及抗血管生成药物治疗。结果27例晚期NSCLC患者中,未合并T790M突变的有19例(70.4%),合并T790M点突变的有8例(29.6%)。总客观缓解率为40.7%。Kaplan-Meier生存分析显示,不同EGFR突变类型之间接受含PD-1单抗治疗的无进展生存期(progression-free survival, PFS)均无统计学差异(χ^(2)=4.15, P=0.23)。未合并T790M突变的患者PFS较合并T790M突变的患者显著延长(9.2个月vs 3.3个月,χ^(2)=2.81,P=0.041),两者总生存时间未见统计学差异(12.2个月vs 7.3个月,χ^(2)=3.22,P=0.062)。未合并T790M的客观缓解率明显优于合并T790M的患者(52.63%vs 12.5%, P=0.045)。结论 EGFR突变患者人群能从后线免疫联合治疗中获益,但合并T790M突变的患者后线接受免疫联合治疗疗效差。因此,这部分患者的后续治疗和全程化管理需要探索更优的治疗策略来提高获益。

PD-L1高表达晚期非小细胞肺癌患者单纯免疫治疗与免疫联合化疗疗效比较

背景与目的以免疫检查点抑制剂(immune checkpoint inhibitors,ICIs)为代表的免疫治疗越来越广泛地应用于肺癌治疗。然而,对于程序性死亡受体配体1(programmed cell death-ligand 1,PD-L1)高表达,即肿瘤比例评分(tumor proportion score,TPS)≥50%的晚期非小细胞肺癌(non-small cell lung cancer,NSCLC)患者,采用单纯免疫治疗还是免疫联合化疗在临床上仍存争议。本研究旨在评估PD-L1高表达的晚期NSCLC患者接受单纯免疫治疗与免疫联合化疗的疗效。方法本研究回顾性分析了49例PD-L1高表达晚期NSCLC患者的临床资料。PD-L1表达采用22C3抗体行免疫组化染色,按TPS判读PD-L1表达水平。比较不同临床特征分组患者的客观缓解率(objective response rate,ORR)和无进展生存时间(progression free survival,PFS)。结果免疫单药与免疫联合化疗组的ORR分别为47.1%(8/17)和43.8%(14/32),差异无统计学意义(P=0.825)。免疫单药与免疫联合化疗组的中位PFS分别为8.0个月和6.8个月,差异无统计学意义(P=0.502)。并对本组PD-L1高表达患者免疫治疗的预测因素进行了分析,结果显示,一线免疫治疗OR R(12/19,63.2%)显著优于二线及以上免疫治疗(10/30,33.3%),差异有统计学意义(P=0.041),二者间PFS无差异。年龄、性别、吸烟史、功能状态评分(performance status,PS)、病理类型、肿瘤大小、肿瘤淋巴结转移(tumor node metastasis,TNM)分期与OR R和PFS不相关。结论PD-L1高表达的晚期NSCLC患者接受免疫单药和免疫联合化疗的疗效相近。PD-L1高表达患者一线免疫治疗的ORR更佳。对此类人群的最佳治疗方案有待于前瞻性临床研究进一步探索。

CD45RO^(+)记忆T细胞作为非小细胞肺癌患者预后标志物的研究

背景与目的肺癌是世界范围内最常见的恶性肿瘤之一。肿瘤微环境中多种多样的免疫浸润细胞,是肿瘤免疫的重要组成,对患者预后具有临床意义。CD45RO^(+)肿瘤浸润淋巴细胞(tumor infiltrating lymphocytes,TILs),即记忆T细胞,其表达与多种肿瘤预后相关。本研究旨在探讨非小细胞肺癌(non-small cell lung cancer,NSCLC)中评估肿瘤和基质区CD45RO^(+)TILs密度与患者临床特征和预后的关系,及其联合程序性死亡受体配体1(programmed cell deathligand 1,PD-L1)作为预后标志物的临床价值。方法对167例NSCLC患者的组织微阵列进行多重荧光免疫组织化学染色,标记CD45RO、细胞角蛋白(cytokeratin,CK)和PD-L1。利用人工智能图像识别技术和肿瘤细胞特异性CK染色,划分组织中的肿瘤区和基质区,评估肿瘤区和基质区CD45RO^(+)TILs的密度以及肿瘤细胞的PD-L1表达水平。采用非参检验分析CD45RO^(+)TILs与患者临床特征的关系,使用Kaplan-Meier方法和Cox风险比例模型分析CD45RO^(+)TILs独立或与PD-L1联合与肿瘤预后的关系。结果CD45RO^(+)TILs的密度与患者年龄、吸烟、肿瘤分期和病理类型显著相关。在NSCLC和肺腺癌(lung adenocarcinoma,LUAD)患者中,基质区高密度CD45RO^(+)TILs具有更长的总生存期(overall survival,OS)(NSCLC:P=0.007;LUAD:P<0.001),并且是OS的独立预后因素(NSCLC:HR=0.559,95%CI:0.377-0.829,P=0.004;LUAD:HR=0.352,95%CI:0.193-0.641,P=0.001)。联合肿瘤细胞的PD-L1评分以及所有区域CD45RO^(+)TILs的浸润评分将患者分为四组:其中PD-L1^(+)/CD45RO^(+)患者无病生存期(disease-free survival,DFS)最长,PD-L1^(+)/CD45RO-的患者DFS时间最短,并可作为DFS预后的独立因素(HR=2.221,95%CI:1.258-3.919,P=0.006)。结论肿瘤组织中CD45RO^(+)TILs密度以及CD45RO^(+)TILs联合肿瘤区PD-L1,与NSCLC的临床病理特征及预后显著相关,可作为新的生存预后标志物。

晚期非小细胞肺癌免疫治疗进展

近年来,以免疫检查点抑制剂为代表的免疫治疗显著改善了晚期肺癌患者的生存,改变了肺癌的治疗模式。本文围绕免疫治疗的机制、免疫治疗的重要临床试验、关键生物标志物以及免疫相关不良反应进行综述,介绍了近年来晚期非小细胞肺癌免疫治疗发展过程中取得的成就和面临的挑战,展望了晚期非小细胞肺癌免疫治疗的未来前景。

多肽Trp-Pro_(n)-Tyr中色氨酸和酪氨酸之间的超快质子耦合电子转移

本文使用稳态吸收与荧光光谱、纳秒时间分辨荧光光谱和飞秒时间分辨瞬态吸收光谱技术,在pH=3、7和10的三种条件下,全面研究了一系列模型多肽(Trp-Pro_(n)-Tyr,WPnY,n=0、1、2、3、5)中色氨酸(Trp,W)和酪氨酸(Tyr,Y)之间的超快质子耦合电子转移特性:研究发现多肽中色氨酸的荧光猝灭程度与肽链的长度呈负相关.在WPY中,色氨酸的荧光被强烈猝灭,并且这种猝灭效应与pH值高度相关.稳态吸收光谱表明,WPY中存在与其他模型多肽明显不同的缺色性;瞬态吸收光谱也展现出其激发态衰减比其他模型多肽更快,尤其是在pH=10时,这可能归因于色氨酸和酪氨酸之间高效的质子耦合电子转移效应.由于WPY中色氨酸和酪氨酸之间的距离极短,两个氨基酸之间发生了偶极相互作用,从而实现了酪氨酸向色氨酸“直接式”的质子和电子转移过程。其他模型多肽中,两个氨基酸之间的距离较远,只能发生缓慢和长程的“间接式”质子和电子转移.此外,本文对WY和WP二肽的研究结果进一步表明,色氨酸可能与多肽的肽骨架或脯氨酸之间还存在更复杂的相互作用:该研究为色氨酸-酪氨酸“二联体”中的电子和质子转移机制提供了实验证据,可以帮助人们了解蛋白质中色氨酸自由基的清除机制,也为进一步研究蛋白质的抗氧化自我保护功能提供了指导意义。

Nano-additive manufacturing of multilevel strengthened aluminum matrix composites

Nanostructured materials are being actively developed,while it remains an open question how to rapidly scale them up to bulk engineering materials for broad industrial applications.This study propose an industrial approach to rapidly fabricate high-strength large-size nanostructured metal matrix composites and attempts to investigate and optimize the deposition process and strengthening mechanism.Here,advanced nanocrystalline aluminum matrix composites(nanoAMCs)were assembled for the first time by a novel nano-additive manufacturing method that was guided by numerical simulations(i.e.the in-flight particle model and the porefree deposition model).The present nanoAMC with a mean grain size<50 nm in matrix exhibited hardness eight times higher than the bulk aluminum and shows the highest hardness among all Al–Al2O3 composites reported to date in the literature,which are the outcome of controlling multiscale strengthening mechanisms from tailoring solution atoms,dislocations,grain boundaries,precipitates,and externally introduced reinforcing particles.The present high-throughput strategy and method can be extended to design and architect advanced coatings or bulk materials in a highly efficient(synthesizing a nanostructured bulk with dimensions of 50×20×4 mm^(3) in 9 min)and highly flexible(regulating the gradient microstructures in bulk)way,which is conducive to industrial production and application.

Performance of Methanol-to-Olefins Catalytic Reactions by the Addition of PEG in the Synthesis of SAPO-34

SAPO-34, a silicoaluminophosphate zeolite, has been synthesized by the hydrothermal method with the addition of different molecular weights of polyethylene glycol (PEG), and has been characterized with XRD, SEM, N2adsorption–desorption, FT-IR, and NH3temperature-programmed desorption (NH3-TPD). We studied SAPO-34 as a catalyst in the methanol-to-olefins (MTO) reaction, in a fixed-bed reactor. The results show that the chain length of PEG has a great influence on the particle size and morphology of SAPO-34. PEG acts as inhibitor in the crystallization process. With the increase of the chain length of PEG used in the synthesis, from a relative molecular weight of 400–6000, the morphology of SAPO-34 changes gradually from cubic to nanoplate-like and then changes to cubic again. The particle size decreases markedly at first and then increases to some extent. The catalytic stability in the MTO reaction also increases first and then decreases, with all the catalysts having almost the same selectivity to olefins. When the sample is synthesized with PEG800, the particles become nanoplate-like with a thickness of 46 nm on average, and the catalytic stability is appreciably prolonged, which is attributed to the shorter diffusion paths of the reactants in the zeolite. © 2017 The Author(s)

Post-treatment of TS-1 with Mixtures of TPAOH and Ammonium Salts and the Catalytic Properties in Propylene Epoxidation

TS-1/SiO_2 extrudate was post-treated with mixed solution of tetrapropyl ammonium hydroxide(TPAOH)and various ammonium salts solution(NH_4F,(NH_4)_3PO_4,(NH_4)_2CO_3,(NH_4)_2SO_4,NH_4CH_3CO_2,NH_4NO_3,NH_4Cl and(NH_4)_2TiF_6).The obtained hierarchical TS-1 catalysts were characterized by many techniques and tested for propylene epoxidation using hydrogen peroxide as an oxidant in a fixed-bed reactor.It was shown that the physicochemical and catalytic properties of the treated TS-1/SiO_2 extrudate depended on the types of ammonium salts added.Compared to the treatment with TPAOH alone,the treatment with a mixed solution of TPAOH and some ammonium salts can greatly improve the catalytic properties of the treated TS-1/SiO_2 extrudate.Some of these ammonium salts were favorable for the incorporation of titanium in the framework,and the beneficial effect depended on the types of ammonium salt.TS-1/SiO_2 extrudate treated with a mixed solution of TPAOH and(NH_4)_3PO_4 exhibited the highest catalyst stability in propylene epoxidation.Such catalytic property can be correlated to high crystallinity,more framework titanium,large specific surface area and large external surface area.

Electrical characteristics of new three-phase traction power supply system for rail transit

A novel three-phase traction power supply system is proposed to eliminate the adverse effects caused by electric phase separation in catenary and accomplish a unifying manner of traction power supply for rail transit.With the application of two-stage three-phase continuous power supply structure,the electrical characteristics exhibit new features differing from the existing traction system.In this work,the principle for voltage levels determining two-stage network is dissected in accordance with the requirements of traction network and electric locomotive.The equivalent model of three-phase traction system is built for deducing the formula of current distribution and voltage losses.Based on the chain network model of the traction network,a simulation model is established to analyze the electrical characteristics such as traction current distribution,voltage losses,system equivalent impedance,voltage distribution,voltage unbalance and regenerative energy utilization.In a few words,quite a lot traction current of about 99%is undertaken by long-section cable network.The proportion of system voltage losses is small attributed to the two-stage three-phase power supply structure,and the voltage unbal-ance caused by impedance asymmetry of traction network is less than 1‰.In addition,the utilization rate of regenerative energy for locomotive achieves a significant promotion of over 97%.

Extreme ultraviolet spectral characteristic analysis of highly charged ions in laserproduced Cu plasmas

This paper reports the results of spectral measurements and a theoretical analysis of the temporal and spatial evolution of laser-produced Cu plasma in vacuum in the range of 8–14 nm.The time dependence of the extreme ultraviolet band spectrum at different positions near the target surface was obtained and found to be dominated by three broad-band features.The 3p and 3d excitations of Cu5+–Cu9+ions were calculated using the Hartree–Fock theory with configuration interactions.The characteristics of the spectral line distribution for the 3p–nd and 3d–nf transition arrays were analyzed.Based on the steady-state collisional radiation model and the normalized Boltzmann distribution,the complex spectral structure in the band of 13–14 nm is accurately explained through consistency comparisons and benchmarking between the experimental and theoretical simulation spectra,demonstrating that the structure mainly stems from the overlapping contribution of the 3d–4f and 3p–3d transition arrays for the Cu5+–Cu9+ions.These results may help in studying the radiation characteristics of isoelectronic series highly-charged ions involving the 3d excitation process.

Spectral‐spatial sequence characteristics‐based convolutional transformer for hyperspectral change detection

Recently,ground coverings change detection(CD)driven by bitemporal hyperspectral images(HSIs)has become a hot topic in the remote sensing community.There are two challenges in the HSI‐CD task:(1)attribute feature representation of pixel pairs and(2)feature extraction of attribute patterns of pixel pairs.To solve the above problems,a novel spectral‐spatial sequence characteristics‐based convolutional transformer(S3C‐CT)method is proposed for the HSI‐CD task.In the designed method,firstly,an eigenvalue extrema‐based band selection strategy is introduced to pick up spectral information with salient attribute patterns.Then,a 3D tensor with spectral‐spatial sequence characteristics is proposed to represent the attribute features of pixel pairs in the bitemporal HSIs.Next,a fusion framework of the convolutional neural network(CNN)and Transformer encoder(TE)is designed to extract high‐order sequence semantic features,taking into account both local context information and global sequence dependencies.Specifically,a spatial‐spectral attention mechanism is employed to prevent information reduction and enhance dimensional interactivity between the CNN and TE.Finally,the binary change map is determined according to the fully‐connected layer.Experimental results on real HSI datasets indicated that the proposed S3C‐CT method outperforms other well‐known and state‐of‐the‐art detection approaches in terms of detection performance.

A muon high-resolution pseudorange measurement method: Application to muon navigation in confined spaces

Confined spaces such as polar regions, deep earth and deep ocean are crucial navigation scenarios where traditional navigation techniques have difficulty in obtaining external signals for positioning. The cosmic ray muons, which carry the spatial and energetic information, are easy to penetrate these confined spaces. Therefore, the unique muon characteristic provides a new perspective to estimate detector position, which can be considered using in confined spaces navigation.In this paper, a well-developed theory of muon navigation is established by combining a muon pseudorange measurement method. Moreover, an Equivalent Velocity Calculation Model(EVCM)and a Muon Sequence Matching Technology(MSMT) are proposed. The first model corrects flight pseudorange error caused by the relativistic energy loss and the second technology compensates the random error in pseudorange measurement. Further, a series of simulations are performed to analyze the muon events number which can be received by detector in different scenarios with the variations of zenith angle, detector area, varied detector plates gap, and muon flight distance.Meanwhile, the simulation results demonstrate that the muon navigation update rate every 10 minutes can reach 5.989 in confined spaces at 100 m, and further pseudorange error analysis indicates that the meter-level positioning accuracy can be acquired. Finally, we construct a muon coincidence measurement scheme and verify that the laws of the muon positioning system for high-energy muons are consistent with the simulation results.

Intelligent metasurface imager and recognizer

There is an increasing need to remotely monitor people in daily life using radio-frequency probe signals.However,conventional systems can hardly be deployed in real-world settings since they typically require objects to either deliberately cooperate or carry a wireless active device or identification tag.To accomplish complicated successive tasks using a single device in real time,we propose the simultaneous use of a smart metasurface imager and recognizer,empowered by a network of artificial neural networks(ANNs)for adaptively controlling data flow.Here,three ANNs are employed in an integrated hierarchy,transforming measured microwave data into images of the whole human body,classifying specifically designated spots(hand and chest)within the whole image,and recognizing human hand signs instantly at a Wi-Fi frequency of 2.4 GHz.Instantaneous in situ full-scene imaging and adaptive recognition of hand signs and vital signs of multiple non-cooperative people were experimentally demonstrated.We also show that the proposed intelligent metasurface system works well even when it is passively excited by stray Wi-Fi signals that ubiquitously exist in our daily lives.The reported strategy could open up a new avenue for future smart cities,smart homes,human-device interaction interfaces,health monitoring,and safety screening free of visual privacy issues.

Initiation characteristics of oblique detonation waves from a finite wedge under argon dilution

In this paper,the flow field characteristics of Oblique Detonation Waves(ODWs)induced by a finite wedge under argon dilution are studied by solving the Euler equations with a detailed chemical model of hydrogen and air.First,the effects of the expansion waves,argon concentration,geometric parameters,and Mach number on the ODW are discussed.The results show that the changes of these parameters may make the oblique detonation not be initiated.Then,the ODW initiation criterion of the finite wedge is summarized,as the characteristic length of the induction zone LCand the characteristic length of the oblique wedge LWmeet the condition LC/LW<1,the initiation of the ODW occurs;otherwise,it does not occur.What’s more,the Constant Volume Combustion(CVC)theory is applied to study the characteristic length of induction zone.It is found that CVC theory is more suitable for the“smooth transition”type of ODW flow field,the theoretical and numerical characteristic length in induction regions are in good agreement.This work is of great significance for the design of oblique detonation engines for hypersonic vehicles.

Stability Mechanism of Laser-induced Fluorinated Super-hydrophobic Coating in Alkaline Solution

Great attention has been focused on super-hydrophobic surfaces due to their fantastic applications.Fluoride chemicals are widely used to fabricate super-hydrophobic surfaces due to their convenience,simplicity,and high efficiency.Previous research has made extensively efforts on corrosion resistance of fluorinated super-hydrophobic surfaces in corrosive media.Nevertheless,rare papers focused on the underlying reasons of anticorrosion property and stability mechanism on the fluorinated super-hydrophobic coatings in alkaline solution.Therefore,this work aims to reveal these mechanisms of fluorinated super-hydrophobic copper samples in strong alkaline solution(pH 13).Through the characterization of surface wettability and surface morphology,the laser-induced super-hydrophobic surface retained excellent stability after soaking in alkaline solution for 4 h.Through measurement of chemical compositions,the anticorrosion mechanism and stability mechanism of the fluorinated super-hydrophobic surface were proposed.Importantly,the hydroxyl ion(OH−)can further promote the hydrolysis reaction to improve the density and bonding strength of the fluoride molecules.Finally,the electrochemical experiments(PDP and EIS tests)were conducted to validate the rationality of our proposed conclusions.

Erratum to: Stability Mechanism of Laser-induced Fluorinated Super-hydrophobic Coating in Alkaline Solution

The article“Stability Mechanism of Laser-induced Fluorinated Super-hydrophobic Coating in Alkaline Solution”,written by Haoyang Li,Yanling Tian,Zhen Yang,was originally published electronically on the publisher’s internet portal on 26 November 2021 without open access.With the author(s)’decision to opt for Open Choice the copyright of the article changed on 29 of December 2021 to The Author(s)2021 and the article is forthwith distributed under a Creative Commons Attribution 4.0 International License,which permits use,sharing,adaptation,distribution and reproduction in any medium or format,as long as you give appropriate credit to the original author(s)and the source,provide a link to the Creative Commons licence,and indicate if changes were made.The images or other third party material in this article are included in the article’s Creative Commons licence,unless indicated otherwise in a credit line to the material.

A novel videogrammetry-based full-field dynamic deformation monitoring method for variable-sweep wings

The measurement of wing dynamic deformation in morphing aircraft is crucial for achieving closed-loop control and evaluating structural safety.For variable-sweep wings with active large deformation,this paper proposes a novel videogrammetric method for full-field dynamic deformation measurement.A stereo matching method based on epipolar geometry constraint and topological constraint is presented to find the corresponding targets between stereo images.In addition,a new method based on affine transformation combined with adjacent closest point matching is developed,aiming to achieve fast and automatic tracking of targets in time-series images with large deformation.A calculation model for dynamic deformation parameters is established to obtain the displacement,sweep variable angle,and span variation.To verify the proposed method,a dynamic deformation measurement experiment is conducted on a variable-sweep wing model.The results indicate that the actual accuracy of the proposed method is approximately 0.02%of the measured area(e.g.,0.32 mm in a 1.6 m scale).During one morphing course,the sweep variable angle,the span variation and the displacement increase gradually,and then decrease.The maximum sweep variable angle is 36.6°,and the span variation is up to 101.13 mm.The overall configuration of the wing surface is effectively reconstructed under different morphing states.