Efficient and Stable Inverted Perovskite Solar Modules Enabled by Solid-Liquid Two-Step Film Formation

A considerable efficiency gap exists between large-area perovskite solar modules and small-area perovskite solar cells.The control of forming uniform and large-area film and perovskite crystallization is still the main obstacle restricting the efficiency of PSMs.In this work,we adopted a solid-liquid two-step film formation technique,which involved the evaporation of a lead iodide film and blade coating of an organic ammonium halide solution to prepare perovskite films.This method possesses the advantages of integrating vapor deposition and solution methods,which could apply to substrates with different roughness and avoid using toxic solvents to achieve a more uniform,large-area perovskite film.Furthermore,modification of the NiO_(x)/perovskite buried interface and introduction of Urea additives were utilized to reduce interface recombination and regulate perovskite crystallization.As a result,a large-area perovskite film possessing larger grains,fewer pinholes,and reduced defects could be achieved.The inverted PSM with an active area of 61.56 cm^(2)(10×10 cm^(2)substrate)achieved a champion power conversion efficiency of 20.56%and significantly improved stability.This method suggests an innovative approach to resolving the uniformity issue associated with large-area film fabrication.

Two-step growth of β-Ga_(2)O_(3) on c-plane sapphire using MOCVD for solar-blind photodetector

In this work,a two-step metal organic chemical vapor deposition(MOCVD)method was applied for growingβ-Ga_(2)O_(3) film on c-plane sapphire.Optimized buffer layer growth temperature(T_(B))was found at 700℃ and theβ-Ga_(2)O_(3) film with full width at half maximum(FWHM)of 0.66°was achieved.A metal−semiconductor−metal(MSM)solar-blind photodetector(PD)was fabricated based on theβ-Ga_(2)O_(3) film.Ultrahigh responsivity of 1422 A/W@254 nm and photo-to-dark current ratio(PDCR)of 10^(6) at 10 V bias were obtained.The detectivity of 2.5×10^(15) Jones proved that the photodetector has outstanding performance in detecting weak signals.Moreover,the photodetector exhibited superior wavelength selectivity with rejection ratio(R_(250 nm)/R_(400 nm))of 105.These results indicate that the two-step method is a promising approach for preparation of high-qualityβ-Ga_(2)O_(3)films for high-performance solar-blind photodetectors.

Two-step strategy—conjunctival flap covering surgery combined with secondary deep anterior lamellar keratoplasty for the treatment of high-risk fungal keratitis

AIM:To investigate whether the two-step strategy[conjunctival flap covering surgery(CFCS)combined with secondary deep anterior lamellar keratoplasty(DALK)]is effective for patients with high-risk fungal keratitis(FK).METHODS:In this noncomparative,retrospective case series,10 subjects(6 males,4 females)with a mean age of 56.5±7.1(range 47-72)y with high-risk FK undergone the two-step strategy were included.Reported outcome measures were healing of the corneal ulcer,recurrence of FK,reject reaction,improvement in best corrected visual acuity(BCVA)and relevant complications.RESULTS:The average diameter of corneal infiltrates was 7.50±0.39 mm,ranging from 6.94 to 8.13 mm.The mean depth of corneal infiltrates was 422.4±77.1μm,ranging from 350 to 535μm.The mean corneal thickness was 597.4±117.3μm,ranging from 458 to 851μm.Hypopyon and endothelial plaques were presented in all patients.The period between the two steps was 3.65±0.9(ranging from 3 to 5)mo.The graft diameter was 7.75±0.39 mm.At the last follow-up(average 9.25±3.39,ranging from 5.5 to 17mo),no fungal recurrence or graft rejection appeared,and all patients showed improvement of BCVA.One patient suffered from liver function impairment due to oral voriconazole for 4wk and recovered spontaneously after 1wk of drug withdrawal.CONCLUSION:The two-step strategy is safe and effective in the treatment of high-risk FK by transforming intentional therapeutic penetrating keratoplasty during acute infection to later optical DALK.It is a practical strategy,especially in areas lacking fresh donor corneas and eye bank services.

Intensified shape selectivity and alkylation reaction for the two-step conversion of methanol aromatization to p-xylene

Two-step conversion of methanol to aromatics via light hydrocarbons can significantly improve the conversion stability compared with direct aromatization of methanol,but it remains a challenge to achieve a high p-xylene(PX)selectivity.Herein,silica coating was firstly used to passivate external acid sites of ZSM-5 catalyst for the aromatization of light hydrocarbons by the chemical liquid deposition method.With the increase of SiO_(2) deposition,the density of the external acid sites of the catalyst was decreased from 0.1 to 0.03 mmol·g^(-1),which inhibited the surface secondary reactions and increased the PX/X from 34.6% to 60.0%.In view of the fact that the aromatization process in the second step was partly inhibited as methanol was consumed in advance in the upper methanol-to-light hydrocarbons catalyst layer,part of methanol was directly introduced into the lower aromatization catalyst layer to promote the alkylation process during the aromatization,which decreased the toluene selectivity from 34.5% to 14.3% but increased the xylene selectivity from 40.0%to 55.3%.It was also found that an appropriate external acid density was needed for aromatization catalyst to strengthen the alkylation process and improve the selectivity of xylene under the conditions of methanol introduction.

A two-step correction of a congenital alar cleft in an adult patient:A case report

This report describes a two-step surgical correction of an isolated left-sided congenital alar cleft in a 21-year-old male patient presenting with a 9×6.5 mm^(2)-sized cleft.Malformations of the alar structure and displacement of the lower lateral cartilage were observed.All flaps survived,and the patient was completely satisfied with the surgical results.This surgical treatment is simple and reliable,can greatly improve the nasal appearance of patients with alar clefts,and may be an alternative to the current surgical treatment.

复合高斯杂波下距离扩展目标的OM-GLRT

广义似然比检测(Generalized Likelihood Ratio Test,GLRT)是解决复合高斯杂波下距离扩展目标检测问题的一种有效方法,而当目标速度未知时,对于毫米波等高频雷达而言,速度估计误差将造成方向矢量(steering vector)失配,从而导致GLRT性能的严重下降。此时,如何设计最佳的GLRT检测器就成为一个优化问题。本文在分析方向矢量失配对GL- RT影响的基础上提出了一种最优匹配GLRT(Optimum Matched GLRT,OM-GLRT)方法。仿真结果表明,OM-GLRT能有效地实现对速度未知目标的检测。

部分均匀环境中训练样本不足时的贝叶斯子空间检测器

为了解决部分均匀环境中训练数据不足时的子空间信号检测难题,采用贝叶斯理论,将噪声协方差矩阵建模为逆威沙特分布,并采用广义似然比准则(generalized likelihood ratio test,GLRT)、Rao准则和Wald准则设计自适应检测器,结果表明3种准则得到相同的结果。基于仿真及实测数据验证了所提检测器的有效性,并得出了影响检测性能的关键物理量。

分布式目标的子空间双门限GLRT CFAR检测

研究了分布式目标在球不变随机变量杂波中的检测问题,提出了一种具有恒虚警特性的双门限广义似然比检测器。分布式目标建模为子空间信号,在距离维和多普勒频率维同时扩展.第一门限的作用是筛选信杂比高的待检测距离单元.将选出的距离单元进行能量积累并与第二门限进行比较做出判决.假设杂波协方差矩阵已知,构造了双门限检测器,并通过推导检测器虚警概率说明其具有恒虚警特性.将基于辅助通道数据的杂波协方差矩阵的估计值替换假设已知的杂波协方差矩阵,得到一个自适应检测器.通过Monte Carlo仿真进行性能分析,说明检测器的有效性和鲁棒性.

基于对角加载的机载MIMO雷达GLRT检测器

本文研究了基于GLRT的机载MIMO雷达自适应目标检测问题.针对参考单元数据不足对GLRT性能的影响,提出了基于对角加载的MIMO雷达GLRT(MIMO-LGLRT)检测器,并对其检测性能进行了分析,给出了虚警概率和检测概率的闭合表达式.该检测器充分利用机载MIMO雷达杂波子空间低秩的特点和对角加载技术,解决了因参考数据不足所引起的矩阵病态问题.为了减少MIMO-LGLRT检测器的运算量,在分析杂波协方差矩阵块对角化特性的基础上,给出一种简化MIMO-LGLRT检测器.理论分析和仿真结果表明,上述两种检测器相对于杂波协方差矩阵都具有恒虚警特性,检测性能优于普通GLRT检测器.

有色噪声中信号的GLRT检测算法研究

针对在高斯广义平稳(W SS)有色噪声环境中含有未知参数信号的检测问题,对于广义似然比检验(GLRT)和匹配子空间方法,提出了一种新的检测算法。通过AR(自回归)参数模型得到含有未知参数的信号加噪声渐进概率密度函数,利用参数变换的方法把一个非线性最小二乘估计问题转化为线性求解问题,然后采用最小二乘估计方法得到参数的极大似然估计(MLE),从而建立了具有恒虚警特性的GLRT检测器。最后结合匹配子空间方法得到了检测概率和虚警概率的表达式,计算机仿真实验验证了方法的有效性。

非均匀杂波背景下双基地MIMO雷达距离扩展目标的GLRT检测

利用球不变随机矢量(Spherically Invariant Random Vector,SIRV)描述非均匀杂波,建立了双基地多输入多输出(Multiple-Input Multiple-Qutput,MIMO)雷达距离扩展目标的信号检测模型,提出了距离扩展目标的两步广义似然比检测(Generalized Likelihood Ratio Test,GLRT)算法.首先,根据目标散射系数的两种假设模型,分别推导确定型目标、高斯型目标GLRT检测器的解析表达式,然后利用固定点迭代算法估计杂波协方差矩阵,获得自适应GLRT(AD-GLRT和AG-GLRT)检测器.仿真实验表明:AD-GLRT和AG-GLRT检测器的检测性能均优于非均匀杂波背景、高斯杂波背景下点目标的检测性能,且两者的检测性能相当,并且虚拟阵元数、目标分布的距离单元数,以及信杂比越大,两者的检测性能越好.

居民消费结构转型升级的碳减排效应研究

降低各地区的碳排放强度对于“双碳”目标的实现具有重要意义。近年来,我国居民消费结构发生了重大变化,居民消费结构转型升级对碳排放强度有显著影响。本文采用2000-2020年我国30个省级地区的空间面板样本数据,利用动态面板模型研究了居民消费结构转型对碳排放强度是否存在非线性影响机制;对产业结构能否充当中介变量进行分析,对东中西部地区的异质性进行了研究;研究表明居民消费结构对碳排放强度能够产生明显的抑制效果,东部地区的影响更为显著,并且产业结构能够作为中介效应影响碳排放强度。本研究结论与政策启示对于居民消费结构转型升级实现“双碳”目标具有一定的现实意义。

海杂波背景下的组合自适应GLRT-LTD

为了检测海杂波背景下的微弱运动目标,相干检测器通常需要作长时间的累积。然而,长时累积条件下的目标多普勒频率的扩散和幅度的起伏以及海杂波空间非均匀性对参考单元数目的限制导致传统的自适应检测器没法工作。注意到逆伽马(IG)纹理的复合高斯分布(CGD)可以很好地描述海杂波和目标的瞬时频率是时间的慢变函数,该文提出一种组合自适应检测器,即组合自适应广义似然比线性门限检测器(CA-GLRT-LTD),它由自适应GLRT-LTD在几个连续的短的累积间隔上的最大响应的乘积的构成。由于GLRT-LTD对IG纹理的复合高斯杂波的最优性,该检测器相比组合自适应归一化匹配滤波(CANMF)检测器具有更好的检测性能。

PPM-UWB信号的GLRT同步捕获算法研究

提出了一种适合于PPM-UWB信号的基于广义似然比检测(GLRT)的同步捕获算法,首先采用了一种新颖的本地模板信号与接收信号进行滑动相关,得到符号速率的采样信号,然后通过精心设计训练序列的图案,利用GLRT实现信号时延估计.由于该算法采用了符号速率(几百兆赫兹)的采样信号,与传统的需要极高采样率(几吉赫兹)的同步算法相比,它极大地降低了系统的复杂度和运算量,同时也提高了捕获速度.通过在密集多径信道模型下,对PPM-UWB信号的同步捕获进行计算机仿真,仿真表明该算法能够快速有效地实现同步捕获.

Socioeconomic traits and the risk of Barrett’s esophagus and gastroesophageal reflux disease: A Mendelian randomization study

BACKGROUND Previous observational studies have shown that the prevalence of gastroesophageal reflux disease(GERD)and Barrett’s esophagus(BE)is associated with socioeconomic status.However,due to the methodological limitations of traditional observational studies,it is challenging to definitively establish causality.AIM To explore the causal relationship between the prevalence of these conditions and socioeconomic status using Mendelian randomization(MR).METHODS We initially screened single nucleotide polymorphisms(SNPs)to serve as proxies for eight socioeconomic status phenotypes for univariate MR analysis.The inverse variance weighted(IVW)method was used as the primary analytical method to estimate the causal relationship between the eight socioeconomic status phenotypes and the risk of GERD and BE.We then collected combinations of SNPs as composite proxies for the eight socioeconomic phenotypes to perform multivariate MR(MVMR)analyses based on the IVW MVMR model.Furthermore,a two-step MR mediation analysis was used to examine the potential mediation of the associations by body mass index,major depressive disorder(MDD),smoking,alcohol consumption,and sleep duration.RESULTS The study identified three socioeconomic statuses that had a significant impact on GERD.These included household income[odds ratio(OR):0.46;95% confidence interval(95%CI):0.31-0.70],education attainment(OR:0.23;95%CI:0.18-0.29),and the Townsend Deprivation Index at recruitment(OR:1.57;95%CI:1.04-2.37).These factors were found to independently and predominantly influence the genetic causal effect of GERD.Furthermore,the mediating effect of educational attainment on GERD was found to be mediated by MDD(proportion mediated:10.83%).Similarly,the effect of educational attainment on BE was mediated by MDD(proportion mediated:10.58%)and the number of cigarettes smoked per day(proportion mediated:3.50%).Additionally,the mediating effect of household income on GERD was observed to be mediated by sleep duration(proportion mediated:9.75%)CONCLUSION This MR study shed light on the link between socioeconomic status and GERD or BE,providing insights for the prevention of esophageal cancer and precancerous lesions.

距离扩展目标基于GLRT的两检测器性能分析仿真报告

本文通过研究相关高斯杂波中扩展目标的两种检测器的差异,通过仿真事实,证实其与参考单元个数(此文中的K)有密切的关系。这样的结论对复合高斯杂波中的检测有特别重要的参考价值。

A two-step quantum secure direct communication protocol with hyperentanglement

We propose a two-step quantum secure direct communication （QSDC） protocol with hyperentanglement in both the spatial-mode and the polarization degrees of freedom of photon pairs which can in principle be produced with a beta barium borate crystal. The secret message can be encoded on the photon pairs with unitary operations in these two degrees of freedom independently. This QSDC protocol has a higher capacity than the original two-step QSDC protocol as each photon pair can carry 4 bits of information. Compared with the QSDC protocol based on hyperdense coding, this QSDC protocol has the immunity to Trojan horse attack strategies with the process for determining the number of the photons in each quantum signal as it is a one-way quantum communication protocol.

Effects of the two-step ageing treatment on the microstructure and properties of 7B04 alloy pre-stretched thick plates

The effects of the two-step ageing parameters （temperature and time） on the mechanical properties and electrical conductivity of 7B04 （A1-Zn-Mg-Cu） pre-stretched thick plates were studied. The results reveal that the initial T1 ageing contributes a major increase of the tensile strength, and the 0.2% proof stress value reaches 482 MPa after ageing for 7 h at 115℃. Behavioral differences in the tensile properties of the alloy after the two-step ageing treatment were less with the first-step ageing at 115~C for different time periods （7, 14, and 21 h）. The effects of the second ageing parameters on the properties and microstructure of the 7B04 alloy were remarkable. TEM analysis of the samples aged at Temper I （7 h at 115℃ ＋ 12 h at 160℃） and Temper II （7 h at 115℃ ＋ 16 h at 165℃） indicates that two kinds of phases, i.e. 11＇ and 11 phases, precipitate from the matrix and efficiently improve the tensile strength of the alloy, and the grain boundary precipitates are coarse and discrete. There are obvious precipitate free zones （PFZs） along the grain boundary in the microstructure of the alloy after the two-step ageing treatment.

Design System of the Two-step Gear Reducer on Case-based Reasoning

The design of the two-step gear reducer is a tedious and time-consuming process. For the purpose of improving the efficiency and intelligence of design process, case-based reasoning（CBR） technology was applied to the design of the two-step gear reducer. Firstly, the current design method for the two-step gear reducer was analyzed and the principle of CBR was described. Secondly, according to the characteristics of the reducer, three key technologies of CBR were studied and the corresponding methods were provided, which are as follows： （a） an object-oriented knowledge representation method, （b） a retrieval method combining the nearest neighbor with the induction indexing, and （c） a case adaptation algorithm combining the revision based on rule with artificial revision. Also, for the purpose of improving the credibility of case retrieval, a new method for determining the weights of characteristics and a similarity formula were presented, which is a combinatorial weighting method with the analytic hierarchy process（AHP） and roughness set theory. Lastly, according to the above analytic results, a design system of the two-step gear reducer on CBR was developed by VC＋＋, UG and Access 2003. A new method for the design of the two-step gear reducer is provided in this study. If the foregoing developed system is applied to design the two-step gear reducer, design efficiency is improved, which enables the designer to release from the tedious design process of the gear reducer so as to put more efforts on innovative design. The study result fully reflects the feasibility and validity of CBR technology in the process of the design of the mechanical parts.

Multi-agent controlled teleportation of multi-qubit quantum information via two-step protocol

Utilizing both the general quantum teleportation and the two-step protocol, a new method is presented by which multi-qubit quantum information can be teleported in a much easier way from a sender Alice to a receiver Bob via the control of many agents in a network than by Yang et al＇s method. In this method, only all the agents collaborate with Bob can the unknown states in Alice＇s qubits be fully reconstructed in Bob＇s qubits. Comparisons between the method and Yang et al＇s method are made. Results show that, in this method, the preparation difficulty of initial states and the identification difficulty of entangled states are considerably reduced, new method is more feasible in technique, and Hadamard operations are not needed at all.