FP-DSN三效助剂在催化裂化装置上的工业应用

为降低催化裂化烟气中SO_2和NOx排放量,中国石化济南分公司800 kt·a-1的FDFCC-Ⅲ重油催化裂化装置试用了FP-DSN三效助剂。工业应用结果表明,首先按反再系统催化剂藏量的2%加入三效助剂,然后每天按催化剂单耗的2%加入FP-DSN三效助剂,可使再生烟气SO2脱除率达到75.5%,NOx脱除率达到65.5%,同时具有较好的助燃效果,可停止加入铂基助燃剂。加入FP-DSN三效助剂后,液化气中丙烷和丙烯体积分数分别升高0.52个百分点和0.97个百分点,丁烷和丁烯体积分数分别下降1.11个百分点和0.35个百分点;干气、汽油和柴油等产品质量没有明显变化,同时FP-DSN三效助剂对产品分布无不良影响。     

基于机会约束规划的储能日前优化调度

为了最大程度地使风光储联合发电系统的出力与计划出力相匹配,采用提前一天对储能装置进行优化控制的方法。因风光出力具有随机性,提出了基于机会约束规划的储能优化控制方法。该方法考虑了储能装置的功率出力和电量约束条件,以风光储总出力曲线与给定的计划出力曲线的相似度最大为目标函数,使用基于随机模拟的粒子群算法求解,得到两条曲线最接近时对应的储能充放电功率。算例分析结果表明,所提出的储能优化控制策略能够使风光储联合发电系统总出力最大程度地跟踪计划出力曲线。     

Plasma tailoring in WTe2 nanosheets for efficiently boosting hydrogen evolution reaction

2D transition metal dichalcogenides(TMDs)have been considered as promising non-precious electro-catalysts for the hydrogen evolution reaction(HER).However,their limited active sites and poor electric conductivity pose a significant hurdle to their HER performance,resulting in a large overpotential.Here,we report the defect engineering in ultrathin tungsten telluride(WTe2)nanosheets with semimetal nature to improve hydrogen evolution effectively.We find that the oxygen plasma etching imposes a cutting effect on WTe2 nanosheets,resulting in a large number of tungsten vacancies.Particularly,the sample after plasma treatment for 10 min shows a feather-like structure with an overpotential of 251 mV at 10 mA/cm2 and a Tafel slope of 94 mV/dec,which is 4 times lower than the Tafel slope of pris-tine nanosheets.Further first-principles calculations shed light on the evolution of defect-rich WTe2 nanosheets and offer rational explanation to their superiority in efficient hydrogen evolution.     

电动自行车20GNY5.0蓄电池组的研制

本文采用由新型泡沫式镍正极和拉浆式镐负极制成标称容量为5Ah的D型镐镍电池,并按特定的分选原则和组合方式,制备了性能优良的电动自行车用24V,5Ah镉镍电池组。     

Efficient Synergism of Chemisorption and Wackenroder Reaction via Heterostructured La2O3-Ti3C2Tx -Embedded Carbon Nanofiber for High-Energy Lithium-Sulfur Pouch Cells

Lithium-sulfur (Li-S) batteries have been regarded as promising next-generation energy storage systems due to their high energy density and low cost, but their practical application is hindered by inferior long-cycle stability caused by the severe shuttle effect of lithium polysulfides (LiPSs) and sluggish reaction kinetics. This study reports a La₂O₃-MXene heterostructure embedded in carbon nanofiber (CNF) (denoted as La₂O₃-MXene@CNF) as a sulfur (S) host to address the above issues. The unique features of this heterostructure endow the sulfur host with synergistic catalysis during the charging and discharging processes. The strong adsorption ability provided by the La₂O₃ domain can capture sufficient LiPSs for the subsequent catalytic conversion, and the insoluble thiosulfate intermediate produced by hydroxyl terminal groups on the surface of MXene greatly promotes the rapid conversion of LiPSs to Li₂S via a “Wackenroder reaction.” Therefore, the S cathode with La₂O₃-MXene@CNF (La₂O₃-MXene@CNF/S) exhibits excellent cycling stability with a low capacity fading rate of 0.031% over 1000 cycles and a high capacity of 857.9 mAh g⁻¹ under extremely high sulfur loadings. Furthermore, a 5 Ah-level pouch cell is successfully assembled for stable cycling, which delivers a high specific energy of 341.6 Wh kg⁻¹ with a low electrolyte/sulfur ratio (E/S ratio).     

Adaptive dynamic surface control for MIMO nonlinear time-varying systems with prescribed tracking performance

In this paper, an adaptive dynamic surface control scheme is proposed for a class of multi-input multi-output (MIMO) nonlinear time-varying systems. By fusing a bound estimation approach, a smooth function and a time-varying matrix factorisation, the obstacle caused by unknown time-varying parameters is circumvented. The proposed scheme is free of the problem of explosion of complexity and needs only one updated parameter at each design step. Moreover, all tracking errors can converge to predefined arbitrarily small residual sets with a prescribed convergence rate and maximum overshoot. Such features result in a simple adaptive controller which can be easily implemented in applications with less computational burden and satisfactory tracking performance. Simulation results are presented to illustrate the effectiveness of the proposed scheme.     

基于文本注意力的推荐系统可解释性研究

可解释性能够提高用户对推荐系统的信任度并且提升推荐系统的说服力和透明性,因此有许多工作都致力于实现推荐系统的可解释性。由于评论中包含了丰富的信息,能够体现用户偏好与情感信息,同时包含了对应商品所具有的特性,最近的一些基于评论的深度推荐系统有效地提高了推荐系统的可解释性。这些基于评论的深度推荐系统中内置的注意力机制能够从对应的评论中识别出有用的语义单元（例如词、属性或者评论）,而推荐系统通过这些高权重的语义单元做出决策,从而增强推荐系统的可解释性。但可解释性在很多工作中仅作为一个辅助性的子任务,只在一些案例研究中来做出一些定性的比较,来说明推荐系统是具有可解释性的,到目前为止并没有一个能够综合地评估基于评论推荐系统可解释性的方法。本文首先根据在注意力权重计算机制的不同,将这些具有可解释性的基于评论的推荐系统分为三类：基于注意力的推荐系统,基于交互的推荐系统,基于属性的推荐系统,随后选取了五个最先进的基于评论的深度推荐系统,通过推荐系统内置的注意力机制获得的评论权重文档,在三个真实数据集上进行了人工标注,分别量化地评价推荐系统的可解释性。标注的结果表明不同的基于评论的深度推荐系统的可解释性是具有优劣之分的,但当前的基于评论的深度推荐系统都有超过一半的可能性能够捕捉到用户对目标评论的偏好信息。在评估的五个推荐系统中,并没有哪个推荐系统在所有的数据中具有绝对的优势。也就是说,这些推荐系统在推荐可解释性方面是相互补充的。通过进一步的数据分析发现,如果推荐系统具有更精确的分数预测结果,那推荐系统通过注意力机制获得的高权重的信息确实更能够体现用户的偏好或者商品特征,说明推荐系统内置的注意力机制在提高可解释性的同时也能够提高预测精度;并且发现相较于长评论,推荐系统更容易捕捉到较短的评论中的特征信息;而可解释性评分高的推荐系统会更可能地为形容词赋予较高的权重。本文也为推荐系统可解释性评估进一步研究和探索更好的基于评论的推荐系统解决方案提供了一些启示。     

A Fast Preconditioned Iterative Algorithm for the Electromagnetic Scattering from a Large Cavity

In this paper, a fast preconditioned Krylov subspace iterative algorithm is proposed for the electromagnetic scattering from a rectangular large open cavity embedded in an infinite ground plane. The scattering problem is described by the Helmholtz equation with a nonlocal artificial boundary condition on the aperture of the cavity and Dirichlet boundary conditions on the walls of the cavity. Compact fourth order finite difference schemes are employed to discretize the bounded domain problem. A much smaller interface discrete system is reduced by introducing the discrete Fourier transformation in the horizontal and a Gaussian elimination in the vertical direction, presented in Bao and Sun (SIAM J. Sci. Comput. 27:553, 2005). An effective preconditioner is developed for the Krylov subspace iterative solver to solve this interface system. Numerical results demonstrate the remarkable efficiency and accuracy of the proposed method.     

各种因素对煤加压热解影响的试验研究

在新研制的双炉膛加压热重分析仪上进行了韩桥烟煤和阳泉无烟煤的加压热解试验,研究了各种因素（如温度,粒径,加热速率等）在压力下对煤热解行为的影响,并对此作出新的合理的解释。     

舰船涂料电化学行为研究

应用电化学技术研究舰船涂料电化学行为,得出不同类型舰船涂料电化学阻抗变化特征,对各类舰船涂料防腐蚀性能作出评价,为舰船长效涂料配套的选用提供技术数据.