Fast phase switching within the bunch train of the PHIN photo-injector at CERN using fiber-optic modulators on the drive laser

The future Compact Linear Collider (CLIC) e⁻/e⁺ collider is based on the two-beam acceleration concept, whereby interleaving electron bunches of the drive beam through a delay loop and combiner rings as well as high peak RF power at 12 GHz are created locally to accelerate a second beam, the main beam. One of the main objectives of the currently operational CLIC Test Facility (CTF3) is to demonstrate beam combination from 1.5 GHz to 12 GHz, which requires satellite-free fast phase-switching of the drive beam with sub-ns speed. The PHIN photo-injector, with the photo-injector laser, provides flexibility in the time structure of the electron bunches produced, by direct manipulation of the laser pulses. A novel fiber modulator-based phase-switching technique allows clean and fast phase-switch at 1.5 GHz. This paper describes the switching system based on fiber-optic modulators, and the measurements carried out on both the laser and the electron beam to verify the scheme.     

Defocus estimation from stroboscopic cryo-electron microscopy data

Defocus estimation is an important step for improving the resolution of single particle reconstructions. It can be troublesome to estimate the defocus from low-dose cryo-electron microscopy (cryo-EM) data, particularly if there is not sufficient contrast present in the Fourier transform of the micrograph. Most existing approaches estimate the defocus from the presence of Thon rings within the power spectrum, employing image enhancement techniques to highlight these rings. In this paper, an approach to estimating the defocus from a stroboscopic image series is described. The image series is used to obtain two statistical metrics: figure of merit (FOM) and Q-factor. These metrics have been used to estimate the defoci from low-dose stroboscopic cryo-EM data consisting of a variable number of images.     

两种机炉协调控制系统特性的分析比较

根据两种机炉协调控制策略——CBF和CTF的实际应用情况,从单元机组控制对象的动态特性出发,对其特点进行分析、比较,阐述了两种协调控制策略的控制品质特性,可为机炉协调控制系统的完善提供参考。     

Thickness dependence of high-k materials on the characteristics of MAHONOS structured charge trap flash memory

The electrical characteristics of tunnel barrier engineered charge trap flash (TBE-CTF) memory of MAHONOS (Metal/Al₂O₃/HfO₂/SiO₂/Si₃N₄/SiO₂/Si) structure were investigated. The stack of SiO₂/Si₃N₄/SiO₂ films were used as engineered tunnel barrier, HfO₂ and Al₂O₃ films were used as charge trap layer and blocking oxide layer, respectively. For comparison, the electrical characteristics of MONOS (Metal/SiO₂/Si₃N₄/SiO₂/Si), MONONOS (Metal/SiO₂/Si₃N₄/SiO₂/Si₃N₄/SiO₂/Si), and MAHOS (Metal/Al₂O₃/HfO₂/SiO₂/Si) were also evaluated. The energy band diagram was designed by using the quantum-mechanical tunnel model (QM) and then the CTF memory devices were fabricated. As a result, the optimized thickness combination of MAHONOS structure was confirmed. The tunnel barrier engineered MAHONOS CTF memory showed a considerable enhancement of program/erase (P/E) speeds, retention time and endurance characteristics.     

Short time step heat flow calculation of building constructions based on frequency-domain regression method

Short time step heat flow calculation of building constructions is often needed for practical applications. Conventional methods such as state-space method and root-finding method may produce unstable conduction transfer function (CTF) coefficients at short time steps, and thus result in unstable heat flow calculation through building constructions. Frequency-domain regression (FDR) method is a newly developed method for computing CTF coefficients efficiently by representing the real building construction system with equivalent polynomial s-transfer functions. Previous studies on this method mainly addressed CTF coefficients at the conventional time step of 3600 s and the performance of heat flow calculation using these coefficients. This paper presents the investigation on the performance of CTF coefficients at various short time steps based on FDR method, and the performance of the heat flow calculation using these coefficients. The results show that FDR method can produce stable CTF coefficients at various time steps for most building constructions, and the calculated heat flows using these coefficients are of high accuracy.     

CTP应用CTF电子文件输出时的补偿曲线测算

分别使用CTF和CTP系统印刷四色网点梯尺,对印版和印刷得到的网点梯尺进行测量,根据测量数据,采用最小二乘法拟合CTP和CTF的印刷复制曲线方程,并计算出相应的数据,从而拟合出CTP匹配CTF的补偿曲线方程。根据拟合的CTP补偿曲线,可以用CTF的数据出CTP版。     

CTF增效剂在高强混凝土中的应用研究

本文介绍了掺入CTF增效剂与未掺入CTF增效剂的混凝土在拌合物性能、力学性能、耐久性能和成本控制四个方面进行对比试验。由试验得出结论：在混凝土中掺用CTF增效剂后,可以明显的改善高强度等级混凝土和易性等工作性能,对抗压强度、混凝土脱模强度和耐久性能也有积极作用,同时能够降低成本,具有十分可观的经济效益和环保效益。     

基于CTcP和CTF工艺的网点复制特性研究

CTcP技术采用普通预涂感光版,在国内印刷市场中的应用正逐渐增加。为了更好地控制网点的复制过程,提高印刷质量,通过实验和对比方法,采用6套不同方案,对测试版进行了输出,探讨了印版网点的复制特性,分析了印版网点的微观结构。结果表明：制版工艺、加网线数、成像分辨率均对网点复制有一定的影响。与传统的CTF工艺相比,CTcP制版工艺的网点复制性能更佳,表现为成像更精确,均匀性更好,阶调复制曲线更平滑,制版过程的可控性更佳。     

A criterion for the assessment of the reliability of ASHRAE conduction transfer function coefficients

This paper presents a new mathematical approach, which, when applied to conduction transfer functions (CTFs) of a multi-layered wall, is able to predict the reliability of building simulations. This new procedure can be used to identify the best set of CTF coefficients, which are a critical point at the core of the ASHRAE calculation methodology founded on the transfer function method. To evaluate the performance of different CTF coefficient sets, the authors performed a large number of thermal simulations on the multi-layered walls included in the ASHRAE Handbook, volume fundamentals, and on other walls typical of Mediterranean building heritage. Those data were employed to test an algorithm able to assess the reliability of the simulations. The numerical results show that it is possible to select the optimal number of coefficients on the basis of the size of the poles of a CTF. The proposed criterion, which employs a pole threshold value, is highly accurate, fast and easy to integrate in the most diffuse building simulation tools.     

与自然对话，以巧搏力——2008奥运会北京射击馆、飞碟靶场建筑设计

2008奥运会北京射击馆和飞碟靶场的建筑设计是以射击比赛的基本要求为出发点,以功能为先导,追求建筑空间与自然的对话。运用适宜的生态建筑技术,将阳光，绿树，风作为设计的自然元素，结合生态呼吸式幕墙，预制清水混凝土外挂板，绿色中庭等，在较低的建筑造价控制下，最大限度地创造合理，人性，舒适的比赛，观赛条件，遵循“林中狩狺“的设计理念，彰显场信中射击运动的人文色彩。