Working condition recognition of sucker rod pumping system based on 4-segment time-frequency signature matrix and deep learning

High-precision and real-time diagnosis of sucker rod pumping system(SRPS)is important for quickly mastering oil well operations.Deep learning-based method for classifying the dynamometer card(DC)of oil wells is an efficient diagnosis method.However,the input of the DC as a two-dimensional image into the deep learning framework suffers from low feature utilization and high computational effort.Additionally,different SRPSs in an oil field have various system parameters,and the same SRPS generates different DCs at different moments.Thus,there is heterogeneity in field data,which can dramatically impair the diagnostic accuracy.To solve the above problems,a working condition recognition method based on 4-segment time-frequency signature matrix(4S-TFSM)and deep learning is presented in this paper.First,the 4-segment time-frequency signature(4S-TFS)method that can reduce the computing power requirements is proposed for feature extraction of DC data.Subsequently,the 4S-TFSM is constructed by relative normalization and matrix calculation to synthesize the features of multiple data and solve the problem of data heterogeneity.Finally,a convolutional neural network(CNN),one of the deep learning frameworks,is used to determine the functioning conditions based on the 4S-TFSM.Experiments on field data verify that the proposed diagnostic method based on 4S-TFSM and CNN(4S-TFSM-CNN)can significantly improve the accuracy of working condition recognition with lower computational cost.To the best of our knowledge,this is the first work to discuss the effect of data heterogeneity on the working condition recognition performance of SRPS.

Constructing low-dimensional perovskite network to assist efficient and stable perovskite solar cells

The use of low-dimensional(LD)perovskite materials is crucial for achieving high-performance perovskite solar cells(PSCs).However,LD perovskite films fabricated by conventional approaches give rise to full coverage of the underlying 3D perovskite films,which inevitably hinders the transport of charge carriers at the interface of PSCs.Here,we designed and fabricated LD perovskite structure that forms net-like morphology on top of the underlying three-dimensional(3D)perovskite bulk film.The net-like LD perovskite not only reduced the surface defects of 3D perovskite film,but also provided channels for the vertical transport of charge carriers,effectively enhancing the interfacial charge transfer at the LD/3D hetero-interface.The net-like morphological design comprising LD perovskite effectively resolves the contradiction between interfacial defect passivation and carrier extraction across the hetero-interfaces.Furthermore,the net-like LD perovskite morphology can enhance the stability of the underlying 3D perovskite film,which is attributed to the hydrophobic nature of LD perovskite.As a result,the net-like LD perovskite film morphology assists PSCs in achieving an excellent power conversion efficiency of up to 24.6%with over 1000 h long-term operational stability.

Ground settlement and tunnel response due to twin-curved shield tunnelling in soft ground with small clear distance

Twin curved tunnels are often encountered in shield tunnelling,where significant complexities in densely exploited underground space are observed.In this study,the ground settlement and tunnel deformation due to twin-curved shield tunnelling in soft ground were investigated using numerical simulation and field monitoring.Different curvature radii of twin curved tunnels and subsequent effects of tunnel construction were considered to reveal the tunnelling effect on ground surface settlement and tunnel deformation.The results show that the settlement trough yields one offset towards inside of curved shield tunnelling.The location of settlement trough and maximum settlement were affected by curvature radius but except for the shape and width of settlement trough.Adjacent parallel twin-curved shield tunnelling could increase the offset of existing settlement trough and maximum settlement.Then,an empirical prediction of surface settlement trough due to twin-curved shield tunnelling with same tunnel diameters in soft clay was proposed,which was applicable to curvature radius less than 800 m.Finally,a minimum radius of 600 m of curvature tunnel was proposed in terms of allowable convergence deformation of tunnel.The result could provide guidance on safety evaluation for twin curved shield tunnelling construction.

Author Correction:Recent Progress in Interfacial Dipole Engineering for Perovskite Solar Cells

In the version of this Article originally published online,there was an error in the schematics of Figures 2b and 2c.These errors have now been corrected in the original article.

On the Preparation of Low-Temperature-Rise and Low-Shrinkage Concrete Based on Phosphorus Slag

The effects of different contents of a MgO expansive agent and phosphorus slag on the mechanical properties,shrinkage behavior,and the heat of hydration of concrete were studied.The slump flow,setting time,dry shrinkage,and hydration heat were used as sensitive parameters to assess the response of the considered specimens.As shown by the results,in general,with an increase in the phosphorus slag content,the hydration heat of concrete decreases for all ages,but the early strength displays a downward trend and the dry shrinkage rate increases.The 90-d strength and dry shrinkage of concrete could be improved with a phosphorus residue content between 0%-20%,with the best performances in terms of mechanical properties and shrinkage characteristics being achieved for a content of 20 kg/m^(3).On the basis of these results,it can be concluded that appropriate amounts of phosphorus slag and MgO expansive agent can be used to improve the compressive strength of concrete in the later stage by reducing the hydration heat and dry shrinkage rate,respectively.

Few-shot working condition recognition of a sucker-rod pumping system based on a 4-dimensional time-frequency signature and meta-learning convolutional shrinkage neural network

The accurate and intelligent identification of the working conditions of a sucker-rod pumping system is necessary. As onshore oil extraction gradually enters its mid-to late-stage, the cost required to train a deep learning working condition recognition model for pumping wells by obtaining enough new working condition samples is expensive. For the few-shot problem and large calculation issues of new working conditions of oil wells, a working condition recognition method for pumping unit wells based on a 4-dimensional time-frequency signature (4D-TFS) and meta-learning convolutional shrinkage neural network (ML-CSNN) is proposed. First, the measured pumping unit well workup data are converted into 4D-TFS data, and the initial feature extraction task is performed while compressing the data. Subsequently, a convolutional shrinkage neural network (CSNN) with a specific structure that can ablate low-frequency features is designed to extract working conditions features. Finally, a meta-learning fine-tuning framework for learning the network parameters that are susceptible to task changes is merged into the CSNN to solve the few-shot issue. The results of the experiments demonstrate that the trained ML-CSNN has good recognition accuracy and generalization ability for few-shot working condition recognition. More specifically, in the case of lower computational complexity, only few-shot samples are needed to fine-tune the network parameters, and the model can be quickly adapted to new classes of well conditions.

Recent Progress in Interfacial Dipole Engineering for Perovskite Solar Cells

Design and modification of interfaces have been the main strategies in developing perovskite solar cells(PSCs). Among the interfacial treatments, dipole molecules have emerged as a practical approach to improve the efficiency and stability of PSCs due to their unique and versatile abilities to control the interfacial properties. Despite extensive applications in conventional semiconductors, working principles and design of interfacial dipoles in the performance/stability enhancement of PSCs are lacking an insightful elucidation. In this review, we first discuss the fundamental properties of electric dipoles and the specific roles of interfacial dipoles in PSCs. Then we systematically summarize the recent progress of dipole materials in several key interfaces to achieve efficient and stable PSCs. In addition to such discussions, we also dive into reliable analytical techniques to support the characterization of interfacial dipoles in PSCs. Finally, we highlight future directions and potential avenues for research in the development of dipolar materials through tailored molecular designs. Our review sheds light on the importance of continued efforts in this exciting emerging field, which holds great potential for the development of high-performance and stable PSCs as commercially demanded.

Ocular manifestations and quality of life in patients after hematopoietic stem cell transplantation

AIM:To explore the relationship between ocular and systemic conditions and the impact of ocular complications on the quality of life(QOL)in patients after allogeneic hematopoietic stem cell transplantation(ALLO-HSCT).METHODS:Forty-four patients with severe hematopoietic disease were enrolled after ALLO-HSCT at our center from July 2018 to October 2020.They completed two questionnaires:the Ocular Surface Disease Index(OSDI)and the quality-of-life scale for Chinese patients with visual impairment(SQOL-DV1).Ocular conditions and systemic conditions were also assessed.RESULTS:Eye damage was correlated with total bilirubin(P=0.005),and gamma-glutamyl transferase(GGT)(P=0.021).There was no significant correlation between the overall QOL score and OSDI(P=0.8226)or SQOLDV1(P=0.9526)scores.The OSDI and the overall QOL score were not correlated with ocular conditions,including best-corrected visual acuity(BCVA),intraocular pressure,Schirmer tear test II,sodium fluorescein staining,tear film breakup time,and tear meniscus height.SQOLDV1 was correlated with BCVA(P=0.0007),sodium fluorescein staining(P=0.007),and tear film breakup time(P=0.0146).CONCLUSION:In some patients,early ocular symptoms are not evident after ALLO-HSCT,while ocular surface complications can be observed after a comprehensive ophthalmological examination.Especially for those with elevated total bilirubin or GGT,regular ophthalmic follow-up visits are essential to diagnose and treat ocular graft versus host disease(o GVHD),especially for patients with elevated total bilirubin or GGT.

An RFI Mitigation Pipeline for CRAFTS Multi-beam Data Based on Signal Cross-Correlation Function and SumThreshold Algorithm

The increasing radio frequency interference(RFI)is a well-recognized problem in radio astronomy research.Pulsars and Fast Radio Bursts(FRBs)are high-priority science targets of the ongoing Commercial Radio Astronomy FAST Survey(CRAFTS).To improve the quality of RFI removal in searches of pulsars and FRBs based on CRAFTS multi-beam data,we here propose an intuitive but powerful RFI mitigation pipeline(CCF-ST).The“CCF-ST”is a spatial filter constructed by signal cross-correlation function(CCF)and Sum-Threshold(ST)algorithm.The RFI marking result is saved in a“mask”file,a binary format for RFI masks in PRESTO.Three known pulsars,PSR B0525-21,PSR B0621-04,and PSR J0943+2252 from CRAFTS L-band 19 beams data are used for evaluation of the performance of CCF-ST in comparison with other methods,such as PRESTO’s“rfifind”,ArPLS-ST and ArPLS-SF.The result shows that CCF-ST can reduce effective data loss rate and improves the detected signal-to-noise ratio of the pulsations by~26%and~18%respectively compared with PRESTO’s“rfifind”and ArPLS-ST.The CCF-ST also has the advantage of low computational cost,e.g.,reducing the time consumption by~40%and memory consumption by~90%compared with ArPLS-SF.We expect that the new RFI mitigation and analysis toolkit(CCF-ST)demonstrated in this paper can be applied to CRAFTS and other multi-beam telescope observations to improve the data quality and efficiency of pulsar and FRB searches.

赤铁矿法除铁过程中硫酸亚铁的转化行为（英文）

针对湿法炼锌赤铁矿法除铁过程中硫酸亚铁的转化行为,研究供氧方式(硫酸亚铁的预结晶或预氧化)和反应温度(170~190℃)对硫酸亚铁晶体再溶解-氧化水解的影响,考察赤铁矿产物的析出特性和物相组成。结果表明:硫酸亚铁在高温溶液中的溶解度明显降低;硫酸亚铁晶体的溶解行为受两个因素的控制:游离酸与硫酸锌浓度的变化和硫酸亚铁离子的氧化水解;亚铁离子的快速氧化是硫酸亚铁结晶重溶解的驱动力;赤铁矿的析出经历硫酸亚铁的结晶、再溶解、氧化和沉淀过程;硫酸亚铁的缓慢溶解有助于保持较低的过饱和度,有利于生产高品质的赤铁矿。

高效钼基催化剂上正丁烯自歧化生成乙烯和己烯（英文）

烯烃歧化反应(又称烯烃复分解反应)是两分子烯烃通过碳-碳键断裂重排生成新烯烃分子的反应,自1964年Phillips公司的Banks等发现以来,引起了研究者的广泛关注,且在均相催化体系的发展尤为迅速;与此同时,多相烯烃歧化催化剂因其在分离简单、可循环再生利用方面的优势而在工业界崭露锋芒.多相烯烃歧化催化剂通常由活性金属组分(Re,Mo,W)分散到大比表面积的多孔载体制备而成.多相催化剂上烯烃歧化反应主要集中在乙烯和2-丁烯反歧化制丙烯反应,其中WO_3/SiO_2催化剂先后应用于Phillips公司的Triolefin Process和ABB Lummus公司的OCT工艺,低温Re系催化剂被法国石油研究院应用到Meta-4歧化工艺.同时丙烯歧化也是研究最多的反应,多数情况下被用作探针反应来研究催化剂的性能.烯烃歧化反应可以根据市场需求灵活调变产物分布,为碳四烃类的高效转化利用提供很好的途径.受国内拉动内需的政策及下游应用行业强劲需求的影响,中国液化石油气的产量逐年递增.2014年我国液化气产量约为2550万吨,其中仅有39%左右用于碳四深加工,大部分当做燃料直接烧掉.从组成来看,液化气中烯烃含量在40%-50%,可以转化为高附加值的乙烯和丙烯进一步利用.本文重点开发了一条从1-丁烯出发生产乙烯/己烯的反应路线及对应的催化剂.首先从热力学角度分析了碳四歧化反应网络中各反应路径发生的难易程度.在此基础上,以Mo/Al_2O_3为催化剂考察了Mo负载量和反应条件对产物分布的影响-.在优化的6Mo/Al_2O_3催化剂上,80°C,1.0 MPa和丁烯空速3 h1的条件下,产物中乙烯和己烯的摩尔选择性超过85%,并且在48 h内保持良好的反应稳定性.为了进一步探究催化剂结构与反应性能的关系,系统考察了催化剂载体差异对Mo物种状态和反应性能的影响.借助N2吸附,NH_3-TPD,Py-IR,H_2-TPR,UV-Vis和HRTEM等表征手段,发现催化剂反应活性与其酸密度直接相关.催化剂酸量越大,丁烯转化率越高,但副反应越多;载体适宜的酸量和较大的比表面积更有利于钼物种的分散和四配位钼物种的形成,促进目标1-丁烯自歧化制乙烯/己烯反应的发生.

正常人外层视网膜厚度随年龄增长的相关性分析（英文）

目的:研究正常人外层视网膜厚度和年龄的关系。方法:回顾分析100例100眼健康人的频域光学相干断层扫描的图像,测量黄斑区及四个象限下列项目的距离:内界膜到内外节连接体(ELM-IS/OS),内外节连接体到视锥细胞外节段(IS/OS-COST),视锥细胞外节段到色素上皮复合体(COST-RPE)和视网膜外层全层(RT)。分析各层厚度和年龄、性别的关系。结果:女性RT比男性薄(男:234.47±16.79μm;女:223.13±15.43μm)。鼻侧视网膜外层全层、中心凹及四个象限处ELM-IS/OS的厚度与年龄呈显著负相关。中心凹及四个象限处IS/OS-COST和COST-RPE厚度与年龄、性别均无显著相关性。中心凹处RT厚度比其余象限显著变薄;ELM-IS/OS、IS/OS-COST和COST-RPE中心凹处相比其余四象限厚度增厚。结论:在正常眼中,鼻侧RT厚度和ELM-IS/OS厚度随年龄增长显著变薄,IS/OS-COST和COST-RPE厚度不随年龄及性别变化而变化。

热处理温度对选择性激光熔化TC4钛合金板不同成形面组织和性能的影响

通过热处理试验、金相检验、扫描电镜观察、X射线衍射分析和硬度测试,分析了热处理温度对选择性激光熔化TC4钛合金板不同成形面的相组成、显微组织和硬度的影响。结果表明:随热处理温度由750℃升高至950℃,选择性激光熔化TC4钛合金板顶面和侧面的针状马氏体α'相不断减少;当热处理温度为850℃时,针状α'相完全转变为α+β相,当热处理温度(950℃)超过α相转变温度时,β相含量升高;钛合金板顶面基本没有柱状β相,形成了等轴状β相,其侧面仍存在柱状β相;钛合金板顶面和侧面的硬度随着温度的升高呈先减小后增大的趋势。

电子束选区熔化成形Ti-6Al-4V合金不同沉积高度上的组织与性能

采用电子束选区熔化技术制备了厚度10 mm的Ti-6A1-4V合金板,研究了沿沉积方向合金的显微组织、拉伸性能和显微硬度的变化。结果表明:合金组织以α集束和α片层交织的网篮组织为主,底部由于经历多次热循环作用,α片层较顶部的略粗大,初生β晶的宽度随沉积高度增加而略有增大;合金底部、中部和顶部的屈服强度和抗拉强度呈逐渐升高趋势,但差异不大;不同沉积高度处的拉伸试样均表现为韧性断裂,断口处存在孔洞和未熔化的球形粉末;合金顶部的平均硬度(约315 HV)略高于底部(约295 HV),拉伸后由于应变硬化效应硬度略有提高。

Deep cleaning of a metallurgical zinc leaching residue and recovery of valuable metals

Huge quantities of zinc leaching residues(ZLRs) generated from zinc production are dumped continuously around the world and pose a potential environmental threat because of their considerable amounts of entrained heavy metals(mainly lead). Most ZLRs have not been properly treated and the valuable metals in them have not yet been effectively recovered. Herein, the deep cleaning of a ZLR and recovery of valuable metals via a hydrometallurgical route were investigated. The cleaning process consists of two essential stages: acid leaching followed by calcium chloride leaching. The optimum conditions for extracting zinc, copper, and indium by acid leaching were a sulfuric acid concentration of 200 g·L^(-1), a liquid/solid ratio of 4:1(m L/g), a leaching time of 2 h, and a temperature of 90°C. For lead and silver extractions, the optimum conditions were a calcium chloride concentration of 400 g·L^(-1), a pH value of 1.0, a leaching time of 1 h, and a temperature of 30°C. After calcium chloride leaching, silver and lead were extracted out and the lead was finally recovered as electrolytic lead by electrowinning. The anglesite phase, which poses the greatest potential environmental hazard, was removed from the ZLR after deep cleaning, thus reducing the cost of environmental management of ZLRs. The treatment of chlorine and spent electrolyte generated in the process was discussed.

Highly selective ethylbenzene production through alkylation of dilute ethylene with gas phase-liquid phase benzene and transalkylation feed

A novel industrial process was designed for the highly selective production of ethylbenzene. It comprised of a reactor vessel, vapor phase ethylene feed stream, benzene and transalkylation feed stream. Especially the product stream containing ethylbenzene was used to heat the reactor vessel, which consisted of an alkylation section, an upper heat exchange section, and a bottom heat exchange section. In such a novel reactor, vapor phase benzene and liquid phase benzene were coexisted due to the heat produced by isothermal reaction between the upper heat exchange section and the bottom heat exchange section. The process was demonstrated by the thermodynamic analysis and experimental results. In fact, during the 1010 hour-life-test of gas phase ethene with gas phase-liquid phase benzene alkylation reaction, the ethene conversion was above 95%, and the ethylbenzene selectivity was above 83% （only benzene feed） and even higher than 99% （benzene plus transalkylation feed）. At the same time, the xylene content in the ethylbenzene was less than 100 ppm when the reaction was carried out under the reaction conditions of 140-185℃ of temperature, 1.6-2.1 MPa of pressure, 3.0-5.5 of benzene/ethylene mole ratio, 4-6 v% of transalkylation feed/（benzene＋transalkylation feed）, 0.19-0.27 h^-1 of ethene space velocity, and 1000 g of 3998 catalyst loaded. Thus, compared with the conventional ethylbenzene synthesis route, the transalkylation reactor could be omitted in this novel industrial process.

YAP promotes osteogenesis and suppresses adipogenic differentiation by regulatingβ-catenin signaling

YAP（yes-associated protein） is a transcriptional factor that is negatively regulated by Hippo pathway, a conserved pathway for the development and size control of multiple organs. The exact function of YAP in bone homeostasis remains controversial. Here we provide evidence for YAP＇s function in promoting osteogenesis, suppressing adipogenesis, and thus maintaining bone homeostasis.YAP is selectively expressed in osteoblast（OB）-lineage cells. Conditionally knocking out Yap in the OB lineage in mice reduces cell proliferation and OB differentiation and increases adipocyte formation, resulting in a trabecular bone loss. Mechanistically, YAP interacts with β-catenin and is necessary for maintenance of nuclear β-catenin level and Wnt/β-catenin signaling. Expression of β-catenin in YAP-deficient BMSCs（bone marrow stromal cells） diminishes the osteogenesis deficit. These results thus identify YAP-β-catenin as an important pathway for osteogenesis during adult bone remodeling and uncover a mechanism underlying YAP regulation of bone homeostasis.

光纤表面等离子体共振生物传感器检测植物激素脱落酸的研究

设计了一种基于纳米颗粒的光纤表面等离子体共振传感器,该传感器由包裹金膜的光纤和金纳米颗粒组成,纳米耦联金膜后形成纳米量级的局域结构,位于纳米颗粒极化方向的电场强度明显增强,并对外界环境折射率的变化敏感。论文以塑料包层光纤为基底对传感器结构进行了验证,通过将去包层的光纤表面巯基化,游离态的金纳米粒子很容易自组装在光纤表面上,形成表面等离子共振传感器纳米涂层,粒径为10 nm的金颗粒在0~5 mmol·L-1浓度变化中,传感器光谱共振峰移动10 nm,传感器对折射率变化的平均灵敏度在2000 nm·RIU-1。将传感器用于植物激素脱落酸的浓度检测,试验结果表明,使用核酸适配体功能化的金纳米粒子后,低浓度的植物激素脱落酸分子可以特异性地结合核酸适配体,共振峰位置在0.1~1.6μmol·L-1的浓度变化中移动了3nm,分辨率为0.535μmol·nm-1。这种纳米颗粒光纤表面等离子共振传感方式具有制备方法简单和灵敏度高的特点,可以在其他生物小分子的微量检测中发挥作用。

A Stochastic Programming Strategy in Microgrid Cyber Physical Energy System for Energy Optimal Operation

This paper focuses on the energy optimal operation problem of microgrids(MGs) under stochastic environment.The deterministic method of MGs operation is often uneconomical because it fails to consider the high randomness of unconventional energy resources.Therefore,it is necessary to develop a novel operation approach combining the uncertainty in the physical world with modeling strategy in the cyber system.This paper proposes an energy scheduling optimization strategy based on stochastic programming model by considering the uncertainty in MGs.The goal is to minimize the expected operation cost of MGs.The uncertainties are modeled based on autoregressive moving average(ARMA) model to expose the effects of physical world on cyber world.Through the comparison of the simulation results with deterministic method,it is shown that the effectiveness and robustness of proposed stochastic energy scheduling optimization strategy for MGs are valid.

MAS Based Distributed Automatic Generation Control for Cyber-Physical Microgrid System

The microgrid is a typical cyber-physical microgrid system(CPMS). The physical unconventional distributed generators(DGs) are intermittent and inverter-interfaced which makes them very different to control. The cyber components,such as the embedded computer and communication network,are equipped with DGs, to process and transmit the necessary information for the controllers. In order to ensure system-wide observability, controllability and stabilization for the microgrid,the cyber and physical component need to be integrated. For the physical component of CPMS, the droop-control method is popular as it can be applied in both modes of operation to improve the grid transient performance. Traditional droop control methods have the drawback of the inherent trade-off between power sharing and voltage and frequency regulation. In this paper, the global information(such as the average voltage and the output active power of the microgrid and so on) are acquired distributedly based on multi-agent system(MAS). Based on the global information from cyber components of CPMS, automatic generation control(AGC) and automatic voltage control(AVC)are proposed to deal with the drawback of traditional droop control. Simulation studies in PSCAD demonstrate the effectiveness of the proposed control methods.