x强流相对论环形电子束在低磁场中传输分析

 用理论和粒子模拟相结合的方法分析了强流薄环形相对论电子束在低磁场导引下，在均匀波导，无箔二极管，以及锥形波导和渐减磁场位形条件下的传输过程，研究了束包络的波动和如何减少波动的问题。分析表明：在无箔二极管中一个适当渐增的磁场位形可以有效地抑制束电子的径向运动，从而减少电子在波导中的波动幅度；电子束在锥形波导和渐减磁场位形中运动，不会增加束电子的波动。因此适当的磁场位形可以降低微波器件对导引磁场的要求，有利于实现永磁包装微波器件。     

基于FPGA的PLC并行执行定时器/计数器的设计

针对ARM+FPGA构建的PLC系统,分析PLC对定时器/计数器的功能需求,设计了可以并行执行的定时器/计数器,构建的定时器/计数器共用一个端口读写控制器与FPGA中央控制器进行数据通信,定时器/计数器内部工作是相互独立的,能够并行的工作,并通过使用地址映射存储器使得定时器/计数器的指令执行更加高效。对中央控制器与定时器/计数器的通信时序和通信格式进行了设计,方便了中央控制器对定时器/计数器的控制与测试。通过仿真测试,该定时器/计数器能够满足PLC定时器/计数器的基本功能,并且达到了稳定的定时/计数的设计要求。     

Relative locations of subwords in free operated semigroups and Motzkin words

Bracketed words are basic structures both in mathematics (such as Rota-Baxter algebras) and mathematical physics (such as rooted trees) where the locations of the substructures are important. In this paper, we give the classification of the relative locations of two bracketed subwords of a bracketed word in an operated semigroup into the separated, nested, and intersecting cases. We achieve this by establishing a correspondence between relative locations of bracketed words and those of words by applying the concept of Motzkin words which are the algebraic forms of Motzkin paths.     

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给出了EAST极向场磁体电源失超保护系统的设计方案,描述了两种失超保护开关——直流快速开关和爆炸开关采用的两级换流结构的设计和工作原理,分析了这种结构在换流过程中的规律,该结构有效地解决了开关开断直流大电流的难点。通过模拟实验证明了该失超保护系统满足设计要求。     

In-situ gasification chemical looping combustion of plastic waste in a semi-continuously operated fluidized bed reactor

Conventional air incineration of plastic waste has been considered as one of important sources of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) through de novo synthesis and precursor conversion. Chemical looping combustion (CLC) is an attractive technology for the conversion of plastic wastes to energy with the potential to drastically suppress the formation of PCDD/Fs. In this paper, the iG-CLC (in-situ gasification CLC) experiments of plastic waste were implemented in a semi-continuously operated fluidized bed reactor, which actually simulates the fuel reactor of a continuously-operated interconnected fluidized bed reactor. A kind of low-cost material, natural iron ore without/with 5 wt% CaO adsorbent through the ultrasonic impregnation method, was used as oxygen carrier (OC). Firstly, some key performances of the reactor system, such as the relevance of the bed inventory to the flow rate of fluidizing agent as well as the relationship between the feeding rate and overflow rate of OC, were calibrated. Then, 90 min of single experiment was conducted for each experimental case and an accumulative operation of more than 10 h was attained. Typically, the combustion efficiency can reach at about 98%, and both the carbon conversion and CO₂ yield can approach to 95% at 900 °C and input thermal power of 150 W with a mixture of 5 vol% H₂O and 95 vol% N₂ as the fluidizing agent (U_FR/U_mf = 3). Moreover, the results obtained in the semi-continuously operated fluidized bed reactor demonstrated that CaO decoration to iron ore is conductive to suppressing the formation of chlorobenzene (as a toxic matter and precursor/intermediate of PCDD/Fs) and does not obviously deteriorate the OC performance.     

代数的算子的Rota纲领、重写系统和Grobner-Shirshov基

许多年前,Rota提出了Rota纲领:找出所有能被(结合)代数上的线性算子满足的代数恒等式.经过一段时间的沉寂之后,近些年来在带算子代数和Grobner-Shirshov基的观点下,Rota纲领有了快速的进展,发表在一系列从特殊情形到一般情形的论文中.这也表明,Rota的远见卓识可以非常广泛地应用到其他代数结构上,比如李代数和更为广泛的operad.本文介绍了Rota纲领的动机、早期发展及最近在结合代数和李代数上的进展,主要用到了重写系统和Grobner-Shirshov基的方法.本文回顾了一些老问题,也提出了一些新问题,以推动Rota纲领的进一步发展.     

Flow injection analysis as a tool for enhancing oceanographic nutrient measurements—A review

Macronutrient elements (C, N and P) and micronutrient elements (Fe, Co, Cu, Zn and Mn) are widely measured in their various physico-chemical forms in open ocean, shelf sea, coastal and estuarine waters. These measurements help to elucidate the biogeochemical cycling of these elements in marine waters and highlight the ecological and socio-economic importance of the oceans. Due to the dynamic nature of marine waters in terms of chemical, biological and physical processes, it is advantageous to make these measurements in situ and in this regard flow injection analysis (FIA) provides a suitable shipboard platform. This review, therefore, discusses the role of FIA in the determination of macro- and micro-nutrient elements, with an emphasis on manifold design and detection strategies for the reliable shipboard determination of specific nutrient species. The application of various FIA manifolds to oceanographic nutrient determinations is discussed, with an emphasis on sensitivity, selectivity, high throughput analysis and suitability for underway analysis and depth profiles. Strategies for enhancing sensitivity and minimizing matrix effects, e.g. refractive index (schlieren) effects and the important role of uncertainty budgets in underpinning method validation and data quality are discussed in some detail.     

硅紫外光伏探测器件响应度的研究

分析了硅紫外光伏探测器件的响应度与器件使用模式之间的关系．研究了包括网格结构在内的３种版图设计及所对应的响应度．结果表明，网格结构对改善紫外响应度的实际作用只是减小了串联电阻．细致讨论了光伏器件串联电阻的主要来源，给出了串联电阻对紫外响应度发生显著影响时所对应的估算数值．     

水下机器人抗波浪扰动动力定位研究

针对水下机器人近水面运动受到波浪干扰而产生的不确定性问题,结合所研制的新型海洋工程模态切换机器人MC-ROV,文章基于CFD法建立动力学模型,进行6DOF动力定位分析。根据定位误差设计力和力矩分配策略,采用非奇异终端滑膜控制(NTSM)对推力予以补偿,以减小由波浪等随机带来的影响,并采用无味卡尔曼(UKF)实时估计水下机器人的状态。仿真结果表明,该方法具有良好的动力定位效果,并且在受扰动后可以迅速调整动力分配策略,减小其带来的负面影响。     

A Novel Production Route for Nylon-6:. Aspects of Catalysis and Process Development

Summary: A novel production route for nylon-6 out of 6-aminocapronitrile has been investigated. Hydrolysis of 6-aminocapronitrile using a solid porous ZrO₂ catalyst is the key step in this novel route. Nylon-6 with a number average molecular weight of 10 · 10³ g · mol⁻¹ can be produced from the hydrolyzed 6-aminocapronitrile. The reactor set up for the polycondensation can in broad outline be the same as the continuously operated reactor used for the ε-caprolactam based production of nylon-6. For the hydrolysis of 6-aminocapronitrile a number of parallel batchwise operated loop reactors is recommended. A fixed bed of catalyst particles is part of each recirculation loop. Intraparticle mass transport limitation can be avoided by using catalyst particles made of a shell of active ZrO₂ and a massive inert core. An annual production of 50 · 10⁶ kg nylon-6 demands for 5.3 m³ zirconia.