采用影子价格法的公众气象服务效益定量评估--以京沪穗为例

公众气象服务效益资料获取主要是通过社会抽样调查.影子价格法是公众气象服务效益评估最常用的方法之一.采用中国气象局公共气象服务中心在全国范围内搜集的10 430份有效问卷,运用影子价格法比较分析北京市、上海市和广州市的公众气象服务效益评估结果.通过比较分析发现在公众气象服务方面产生的效益对经济社会发展的良性影响最大的是北...     

一种集成电路老化测试设备的嵌入式系统设计

针对传统集成电路老化过程耗时长,老化成本高的问题,提出了老化中测试的研制方案。老化测试将器件的测试与老化过程同时进行,从而节约时间与成本。为了提高老化测试设备的通用性和性能指标,将嵌入式系统引用到老化测试设备领域,通过移植嵌入式Linux系统,开发驱动实现通信接口协议,编写老化测试代码,实现了芯片老化过程中的流程控制及数据通信功能。经实际电路仿真验证,能够实现64路数字信号通道芯片的老化测试。     

关注过程学会思考

一个优秀的建筑作品必然依赖于一个合理的设计过程,如果设计行为漫无计划又无可循之法,势必无法期待高品质的作品出现。建筑创作过程虽并不具有程式化、确定性的可操作模式,但仍有一些规律可循。经过较长时期创作与教学实践的积累,对建筑创作过程所具有的阶段性、分叉选择性和循环性等过程规律进行了系统的研究。在研究生教育期间通过相关课程的设置使学生从理论上对这些过程规律有所认识,可以大大减少学生创作过程中的盲目性和随意性,系统地掌握合理的设计过程方法,养成良好的思维习惯,为今后的创作实践奠定必要的方法论基础。     

二段真空长效运行的探讨

分析影响二段真空的各种因素，采取相关措施来维持二段真空的长效运行，以确保尿素产品的优等品率。     

纵扭超声磨削ZrO2陶瓷表面形貌及粗糙度特征研究

ZrO2陶瓷作为典型硬脆材料,采用普通的磨削方法难以获得良好表面质量,而超声振动磨削可显著改善其加工效果.本文将纵扭超声振动应用于磨削加工,运用单因素法,设计普通磨削(OG)及纵扭超声磨削(LTUG)对比试验,以加工后材料表面粗糙度Ra值和微观形貌作为评价指标,分析并得到各工艺参数对表面质量的影响规律.结果 表明:整体上LTUG表面Ra值始终低于OG,且磨削表面平整,磨痕形貌更加均匀、顺畅;相比于OG,随超声能量增大,LTUG表面Ra值呈先减小后增大趋势,同时均随磨削深度加深先减小后增大,随主轴转速提高均逐渐降低;另外,OG表面Ra值随进给速度提升先增大后减小,而LTUG为持续增大并逐渐趋向OG.     

某电厂化水系统运行问题分析研究

某电厂以城市中水作为化水系统水源,运行不到半年,出现保安过滤器滤芯污堵严重、管道内壁粘附大量杂质以及膜系统化学清洗频繁、清洗效果下降等问题。通过系统性诊断,查明了原因,对采用城市中水的电厂具有借鉴和指导意义。     

Monte Carlo simulation of single beam dose profile

The single beam dose profiles of Leksell Gamma Unit are simulated and the rsults are compared with the experimental results of ELEKTA.The effect of diameter of cylinder souce on the dose profile is also studied and the yielded results show that there are not much difference of the dose profiles between a point source and cylinder source when diameter is less than 1mm.     

对执行氯化锌新标准的体会

本文简述了氯化锌新标准:HG2323—92《工业氯化锌》,并就如何贯彻执行这一标准谈了一些体会和看法。     

Conformation‐Tuning Effect of Asymmetric Small Molecule Acceptors on Molecular Packing,Interaction, and Photovoltaic Performance

Understanding the conformation effect on molecular packing, miscibility, and photovoltaic performance is important to open a new avenue for small‐molecule acceptor (SMA) design. Herein, two novel acceptor–(donor‐acceptor1‐donor)–acceptor (A‐DA1D‐A)‐type asymmetric SMAs are developed, namely C‐shaped BDTP‐4F and S‐shaped BTDTP‐4F . The BDTP‐4F ‐based polymer solar cells (PSCs) with PM6 as donor, yields a power conversion efficiency (PCE) of 15.24%, significantly higher than that of the BTDTP‐4F ‐based device (13.12%). The better PCE for BDTP‐4F ‐based device is mainly attributed to more balanced charge transport, weaker bimolecular recombination, and more favorable morphology. Additionally, two traditional A‐D‐A‐type SMAs ( IDTP‐4F and IDTTP‐4F ) are also synthesized to investigate the conformation effect on morphology and device performance. Different from the device result above, here, IDTP‐4F with S‐shape conformation outperforms than IDTTP‐4F with C‐shape conformation. Importantly, it is found that for these two different types of SMA, the better performing binary blend has similar morphological characteristics. Specifically, both PM6:BDTP‐4F and PM6:IDTP‐4F blend exhibit perfect nanofibril network structure with proper domain size, obvious face‐on orientation and enhance donor‐acceptor interactions, thereby better device performance. This work indicates tuning molecular conformation plays pivotal role in morphology and device effciciency, shining a light on the molecular design of the SMAs.     

Printing Semiconductor–Insulator Polymer Bilayers for High‐Performance Coplanar Field‐Effect Transistors

Source–semiconductor–drain coplanar transistors with an organic semiconductor layer located within the same plane of source/drain electrodes are attractive for next‐generation electronics, because they could be used to reduce material consumption, minimize parasitic leakage current, avoid cross‐talk among different devices, and simplify the fabrication process of circuits. Here, a one‐step, drop‐casting‐like printing method to realize a coplanar transistor using a model semiconductor/insulator [poly(3‐hexylthiophene) (P3HT)/polystyrene (PS)] blend is developed. By manipulating the solution dewetting dynamics on the metal electrode and SiO₂ dielectric, the solution within the channel region is selectively confined, and thus make the top surface of source/drain electrodes completely free of polymers. Subsequently, during solvent evaporation, vertical phase separation between P3HT and PS leads to a semiconductor–insulator bilayer structure, contributing to an improved transistor performance. Moreover, this coplanar transistor with semiconductor–insulator bilayer structure is an ideal system for injecting charges into the insulator via gate‐stress, and the thus‐formed PS electret layer acts as a “nonuniform floating gate” to tune the threshold voltage and effective mobility of the transistors. Effective field‐effect mobility higher than 1 cm² V^?1 s^?1 with an on/off ratio > 10⁷ is realized, and the performances are comparable to those of commercial amorphous silicon transistors. This coplanar transistor simplifies the fabrication process of corresponding circuits.