超声波检测仪对承压设备厚度测量方法研究

在承压设备检验过程中,超声波测厚多数采用的是数字式超声测厚仪,当测量区域存在声速面小于缺陷面积或者因内部不均匀而产生散射等情况时,就会有反射信号触动数字式超声测厚仪计算电路,进而出现测厚数据异常、或无数据显示等现象发生。本文主要研究利用超声波探伤仪对其承压设备厚度进行测量,依靠反射回波的判断和校准曲线的修正,从而避免数据异常或无数据现象,有效的保证承压设备的安全运行。     

超声波检测仪对承压设备厚度测量方法研究

在承压设备检验过程中,超声波测厚多数采用的是数字式超声测厚仪,当测量区域存在声速面小于缺陷面积或者因内部不均匀而产生散射等情况时,就会有反射信号触动数字式超声测厚仪计算电路,进而出现测厚数据异常、或无数据显示等现象发生。文章主要研究利用超声波探伤仪对其承压设备厚度进行测量,依靠反射回波的判断和校准曲线的修正,从而避免数据异常或无数据现象,有效的保证承压设备的安全运行。     

掀开贷款支持证券的黑匣子——对招行信贷资产证券化产品的分析

这种信贷资产证券化产品通过产品分层设计和承担损失的先后序列，实现了低信用等级证券持有人对高信用等级证券持有人的内部信用增级。     

海底石油管线使用中的维护和检测技术探讨

目前海洋石油已经是我国的主要开采石油基地,海底石油的开采已经成为了人们关注的课题。海底管线是海洋油气的运输与储存系统的重要组成部分。我国目前所铺设的海底管线长达数千公里,然而随着使用时间的不断推移,有些海底管道出现了不同程度的老化。针对海底石油管线在使用过程中出现的一些问题,本文介绍了在使用过程中的一些维护方法,以及对其进行检测的技术作了一些探讨,希望能对海底石油管道的维护与检测工作有所帮助。     

Ni-Mo_2C一维纳米线的制备及吸波性能研究

通过水热法合成了NiMoO_4一维线,许多纳米线聚在一起形成微米级的花状结构。通过在纳米线外层包覆盐酸多巴胺形成核壳结构来改变材料介电和磁导率参数,NiMoO_4@PDA经烧结成为具有介电损耗和磁损耗介质吸波材料Ni-Mo2C,研究其吸波性能。3.0 mm时25 wt%Ni-Mo_2C/wax显示出最大反射损耗,其值可达-54.4 dB,最大反射损耗出现在频率8.1 GHz。反射损耗小于-10 dB的频率带宽最大为3.4 GHz(11.4～14.8 GHz)。     

海底管道失效原因分析及其对策

海底管道的失效会出现管道的断裂,石油的泄露,一方面造成了能源的浪费,另一方面带来了严重的海洋污染。因此本文对海底管道失效的原因进行了较为全面的分析,并提出了可行的控制措施。     

浅谈海洋管道铺设方法

随着国内外对于海洋油气资源的日益重视，海底管道日益蓬勃发展，对管道施工方法的选择和铺设技术也越来越高。本文通过对中缅油气海底管道铺设的实例，综合介绍并比较了海底管道的各种施工方法，具有一定的参考价值。     

夏季循环冷却水监督调整探索

因为夏季气温高,循环冷却水蒸发损失大,循环冷却水中的盐类浓缩程度大,循环冷却水系统结垢的倾向更大.本文针对出现结垢现象,分析原因,采取有效处理措施,加强循环水加药调整,防止循环冷却水系统结垢现象的再次发生.     

锅炉引风机增大出力改造

黑龙江省赵光糖厂自备电站一台SHL35-2.45/400型锅炉的Y4-73-11№12D引风机,由于锅炉所燃用原煤质量不一,遇到发热量低且燃点高的煤质,引风量相对不足,导致炉膛正压、跑火,灰渣含炭量高,锅炉产汽量降低,热效率下降,给生产造成损失.     

如何克服直接混纺染料染牛仔布缸样与实样不符?

在采用直接混纺染料染全棉牛仔布时,经常会出现缸样与实样不符的现象,且主要发生在水洗工序中。这主要因为直接染料是一类水溶性很大的染料,如果水洗温度过高,虽有利于充分洗除织物上的浮色,但也会使已经上染纤维的染料被溶解下来,以致出现缸样(染好后在缸上剪1块小样,马上用冷水冲洗一下)与实样(待缸样与标样对准后,再进行清洗,出缸,到成品)不符。夏季,染色车间里的气温通常要比外面高3-5℃左右,加之许多高温高压喷射溢流染色机体上还包覆着厚厚的防护材料,经过染色后的机体很难声速冷却。因此,实际上布样的水洗温度在60℃左右,水洗时间约…     

纸张性能对喷墨印刷品光泽度的影响

本文采用EPSON Stylus C88＋喷墨打印系统,对5种不同性能的纸张进行印刷品光泽度研究。结果发现：成纸性能、纸张涂层结构以及油墨在纸张上的转移过程对喷墨印刷品光泽度均有较大影响,如喷墨墨水中溶剂在纸张表面渗透过多,颜料颗粒浮于印刷品表面形成漫反射,导致印刷品光泽度降低。本文根据实验给出纸张性能对印刷品光泽度的影响权重,按相关系数从大到小排列为：光泽度、定量、粗糙度、表面润湿性能。纸张光泽度、定量与印刷品光泽度正相关,纸张粗糙度、表面润湿性能与印刷品光泽度负相关,且纸张光泽度与印刷品光泽度高度相关。因此,要得到光泽度高的喷墨印刷品,必须根据纸张性能对印刷品光泽度的影响权重选择适合的纸张。     

气相流化床反应器内聚合物结块的检测

对某聚乙烯装置气相流化床反应器的声波信号进行的监测表明,流化床内产生颗粒结块时,声波信号的频率由高频向低频转移,声波能量检测值显著降低。根据这一特点,利用声检测技术,结合对声波信号的分析,建立了一种简单、快捷的检测方法,实现了对流化床中结块的实时监控。     

Interaction of acoustic waves with flame front propagation

The mechanisms of laminar premixed flame propagation have been intensively studied over the last century. Numerous authors have highlighted intrinsic phenomena in flame propagation such as Darrieus-Landau instability and Rayleigh-Taylor instability. Rayleigh-Taylor instability is often linked to the interaction between the flame front and an acoustic wave. To better characterize the interaction between a flame and aerodynamic conditions, we designed a special vertical closed tube apparatus. Our analysis focused on the behavior of a flame that propagates in a uniform stoichiometric mixture of H₂ and O₂ diluted with nitrogen. The experimental investigation revealed that acoustic waves emitted as the flame formed near the ignition point could increase the flame front surface by a factor of 10. An acoustic node with an amplitude of 1.3 m was identified and seemed to be responsible for the disappearance of one of the acoustic modes and for a reduction in the average flame surface. This could explain why the flame trajectory had two distinct parts: one corresponding to propagation at a high speed in the lower part of the tube, and the other with a slower speed in the upper part of the tube. The flame surface seemed to depend primarily on the frequencies of vibration and marginally on the nature of the reactive components. Propagation velocities, obtained by multiplying these flame surfaces by the fundamental burning velocity, strongly depended on the mixture reactivity. © 2009 American Institute of Chemical Engineers Process Saf Prog, 2009     

前景理论框架下基于期望的损失厌恶报童博弈

本文运用前景理论,考虑了损失厌恶报童期望水平对其损失厌恶程度的影响,扩展了损失厌恶报童模型,分析了多个基于期望的损失厌恶报童向一个风险中性供应商竞争订货的情形,研究了报童相关参数对报童均衡总订货量的影响。在随机需求情形下引入期望参考利润水平,首先基于前景理论建立单个基于期望的损失厌恶报童效用函数,其次推导出多个基于期望的损失厌恶报童博弈模型,然后证明了该博弈模型对称纯策略纳什均衡的存在性和唯一性,推导出均衡总订货量的表达式并分析了均衡总订货量与报童数量、损失厌恶系数、期望水平的关系,最后通过算例论证了均衡总订货量与报童数量、损失厌恶系数和期望水平之间关系的正确性,进而比较分析了风险中性报童最优订货量、单个基于期望的损失厌恶报童最优订货量以及均衡总订货量之间的关系。结果表明,均衡总订货量随着报童数量的增多而增加,随着损失厌恶系数的增大而减少,随着期望水平的增大而减少;单个基于期望的损失厌恶报童最优订货量要小于风险中性报童最优订货量以及均衡总订货量。     

一种小水电厂T接入配电网分摊线损的方法

分析了小水电厂T接入配电网后存在的线损分摊问题，提出一种能反映使用者利用电网线路程度的容量利用小时系数法。该方法容易理解，计算所需数据简单易得，便于小水电厂自我验算，所得线损分摊结果能反映小水电厂利用线路的程度，能较好地解决线损分摊问题。     

Third‐Degree Price Discrimination and Consumer Surplus

This paper considers the effects of monopoly third‐degree price discrimination on aggregate consumer surplus. Discrimination is likely to reduce surplus (relative to that obtained with a uniform price), but surplus can rise under reasonable conditions. If the ratio of the pass‐through coefficient to the price elasticity at the uniform price is higher in the market with the higher price elasticity then surplus is larger with discrimination (for a large set of demand functions). The relatively high pass‐through coefficient implies a large price reduction in this market. With logit demand functions surplus is higher with discrimination if pass‐through is above 0.5.     

Managing uncertain,complex product development in high‐tech firms: in search of controlled flexibility

This paper investigates ways of managing complexity and uncertainty in R&D simultaneously. Previous research on the subject indicates that these dimensions require different approaches, but these studies tend to provide suggestions either on managing complexity in stable industries or on handling uncertainty in less complex projects. In this paper, the two dimensions are studied simultaneously in three commercial product development projects at a firm that may be viewed as an extreme case of complexity and with multiple dimensions of uncertainty. The paper illustrates that a critical issue in this kind of high‐tech development is the search for and development of approaches that integrate and balance needs for formal organizational control with high levels of project flexibility. Four key elements of such integrated approaches are identified: hybrid formal systems, structured interaction in public arenas, transparent visual communication tools, and a system of participative reflection.     

Action, reflection, and learning – coaching in order to enhance the performance of drug development project management teams

High-performing project teams are crucial for effective research and development (R&D). To become high performing, teams need to make use of their different skills and reflect upon their collective actions, thereby combining knowledge that could lead to value-adding activities for the company. This article describes the use of team coaching in supporting team reflection and learning in global R&D project teams. A collaborative research approach was used during the 8 months of coaching, with several inquiry methods being employed. The results indicate that coaching interventions have a positive effect on team performance, both from an efficiency perspective as well as from a creativity and climate perspective. Practical and theoretical implications are discussed, as is future research.     

Service guarantee and optimal payout models

This paper evaluates both the optimal service level and optimal economic payout in service payout models. A service guarantee level is explicitly taken into consideration to obtain the optimal payout. In this study, we consider a generic model to provide insights into the dynamic interaction between the service guarantee and optimal payout levels. Parametric analyses show that when the demand payout coefficient is high, the impact of the payout is positive only if the payout rate is high enough.     

用MC145152-2实现具有四模数分频器的锁相环

对MC145152-2常规的几种使用方法进行了总结,提出了一种用MC145152-2实现四模数分频器的PLL的新方法。此方法采用两块MC145152-2和两块双模数前置分频器,由两块双模数前置分频器构成四个分频模式,因而称其为四模数方案。四模数分频器保证了PLL的分频系统连续变化。降低了分频系数下限值,增大了分频系数连续变化的范围,解决了PLL中的高频与低分频系数之间的矛盾。按此方法设计的电路已成功应用于某工程。