Development of All-Weather and Real-Time Bottom-Mounted Monitor of Bed Load Quantity

Quantity of bed load is an important physical parameter in sediment transport research. Aiming at the difficulties in the bed load measurement, this paper develops a bottom-mounted monitor to measure the bed load transport rate by adopting the sedimentation pit method and resolving such key problems as weighing and desilting, which can achieve long-time, all-weather and real-time telemeasurement of the bed load transport rate of plain rivers, estuaries and coasts. Both laboratory and field tests show that this monitor is reasonable in design, stable in properties and convenient in measurement, and it can be used to monitor the bed load transport rate in practical projects.

Real-time forward modeling and inversion of logging-while-drilling electromagnetic measurements in horizontal wells

Based on the pseudo-analytical equation of electromagnetic log for layered formation,an optimal boundary match method is proposed to adaptively truncate the encountered formation structures.An efficient integral method is put forward to significantly accelerate the convergence of Sommerfeld integral.By asymptotically approximating and subtracting the first reflection/transmission waves from the scattered field,the new Sommerfeld integral method has addressed difficulties encountered by the traditional digital filtering method,such as low computational precision and limited operating range,and realized the acceleration of the computation speed of logging-while-drilling electromagnetic measurements(LWD EM).By making use of the priori information from the offset/pilot wells and interactively adjusting the formation model,the optimum initial guesses of the inversion model is determined in order to predict the nearby formation boundaries.The gradient optimization algorithm is developed and an interactive inversion system for the LWD EM data from the horizontal wells is established.The inverted results of field data demonstrated that the real-time interactive inversion method is capable of providing the accurate boundaries of layers around the wellbore from the LWD EM,and it will benefit the wellbore trajectory optimization and reservoir interpretation.

UML statechart based rigorous modeling of real-time system

Rigorous modeling could ensure correctness and could verify a reduced cost in embedded real-time system development for models. Software methods are needed for rigorous modeling of embedded real-time systems. PVS is a formal method with precise syntax and semantics defined. System modeled by PVS specification could be verified by tools. Combining the widely used UML with PVS, this paper provides a novel modeling and verification approach for embedded real-time systems. In this approach, we provide 1) a time-extended UML statechart for modeling dynamic behavior of an embedded real-time system; 2) an approach to capture timed automata based semantics from a timed statechart; and 3) an algorithm to generate a finite state model expressed in PVS specification for model checking. The benefits of our approach include flexibility and user friendliness in modeling, extendability in formalization and verification content, and better performance. Time constraints are modeled and verified and is a highlight of this paper.

Rigorous Modeling of Real-time System Based on UML and PVS

Rigorous modeling could improve the correctness and reduce cost in embedded real-time system development for models could be verified. Tools are needed for rigorous modeling of embedded real-time system. UML is an industrial standard modeling language which provides a powerful expressi-veness, intuitive and easy to use interface to model. UML is widely accepted by software developer. However, for lack of precisely defined semantics, especially on the dynamic diagrams, UML model is hard to be verified. PVS is a general formal method which provides a high-order logic specification language and integrated with model checking and theorem proving tools. Combining the widely used UML with PVS, this paper provides a novel modeling and verification approach for embedded real-time system. In this approach, we provide 1) a timed extended UML statechart for modeling dynamic behavior of an embedded real-time system; 2) an approach to capture timed automata based semantics from timed statechart; and 3) an algorithm to generate a finite state model expressed in PVS specification for model checking. The benefits of our approach include flexible and friendly in modeling, extendable in forma-lization and verification content, and better performance. Time constraints are modeled and verified and it’s a highlight of this paper.

Verification of Real-Time Pricing Systems Based on Probabilistic Boolean Networks

In this paper, verification of real-time pricing systems of electricity is considered using a probabilistic Boolean network (PBN). In real-time pricing systems, electricity conservation is achieved by manipulating the electricity price at each time. A PBN is widely used as a model of complex systems, and is appropriate as a model of real-time pricing systems. Using the PBN-based model, real-time pricing systems can be quantitatively analyzed. In this paper, we propose a verification method of real-time pricing systems using the PBN-based model and the probabilistic model checker PRISM. First, the PBN-based model is derived. Next, the reachability problem, which is one of the typical verification problems, is formulated, and a solution method is derived. Finally, the effectiveness of the proposed method is presented by a numerical example.

翻身床安全核查表在特重度创面烧伤患者实施翻身床治疗中的应用效果

目的探讨翻身床安全核查表在特重度创面烧伤患者实施翻身床治疗中的临床应用效果。方法将2019年1月至2022年12月在浙江省金华市中心医院烧伤科就诊的50例特重度创面烧伤患者,按照非同期列队研究方法分为两组,其中2019年1月至2020年7月就诊的20例患者为对照组,2020年8月至2022年12月就诊的30例患者作为观察组。两组患者均采用翻身床治疗,观察组在对照组的基础上运用了自制的翻身床安全核查表。治疗后,比较两组安全隐患发生率、不良事件总发生率和疼痛程度评分[视觉模拟评分法(VAS)]。结果观察组安全隐患总发生率低于对照组,差异有统计学意义(P<0.05)。观察组不良事件总发生率低于对照组,差异有统计学意义(P<0.05)。治疗前,两组VAS评分比较,差异无统计学意义(P>0.05);治疗后,两组VAS评分较治疗前降低,且观察组低于对照组,差异有统计学意义(P<0.05)。结论翻身床安全核查表能够降低特重度创面烧伤患者实施翻身床治疗过程中的不良事件发生率,提高翻身床治疗的安全性,改善患者的疼痛情况,值得推广。

钢箱梁大节段整孔吊装线形控制技术

某跨海大桥部分连续钢箱梁采用大节段整孔吊装。钢箱梁大节段由小节段接长而成,在制造阶段考虑钢箱梁预拱度设置;为确保接长后钢箱梁制造误差满足要求,钢箱梁小节段出胎前进行预拼装,检查几何尺寸,并设置线形控制点;大节段组拼时通过线形控制点定位,并对焊接完成后的几何尺寸及线形进行复核。在架设阶段,建立大节段线形调整流程,将大节段调整到指定位置确定环切量;针对大节段架设存在梁端夹角的问题,利用墩顶千斤顶顶落大节段做刚体旋转调整其夹角,使得钢梁顺接。钢箱梁大节段安装成联后,高程和平面线形偏差总体均在10 mm以内,线形控制效果总体良好。

Model Checking Real-Time Value-Passing Systems

In this paper, to model check real-time value-passing systems, a formallanguage Timed Symbolic Transition Graph and a logic system named Timed Predicate μ-Calculus areproposed. An algorithm is presented which is local in that it generates and investigates thereachable state space in top-down fashion and maintains the partition for time evaluations as coarseas possible while on-the-fly instantiating data variables. It can deal with not only data variableswith finite value domain, but also the so called data independent variables with infinite valuedomain. To authors knowledge, this is the first algorithm for model checking timed systemscontaining value-passing features.

地震反演中储层表征的对策和思路

从储层预测实际出发,通过研究实例对储层反演的对象、研究内容、工作流程、技术思路和质量控制等几个方面进行了阐述,强调反演前的岩石物理特征分析是做好反演工作的基础,提出储层反演必须依据地震资料和研究目的,开展可行性研究与先导性试验,选择确定适用的工作流程,在反演过程中应尽量保持各类数据的一致性。另外对反演中需要注意的问题进行了探讨,期望能够对提高地震反演工作水平,改善储层预测效果有所裨益。

重力式码头抛石基床内部滑移破坏研究

现行规范要求对抛石基床的顶面和底面进行水平抗滑稳定性验算,而不考虑抛石基床的内部滑移破坏情况,当基床较薄时,这样的规定可以保证抛石基床的安全性;当抛石基床比较厚时,基床后侧水平土压力作用不能忽略,基床内部可能会存在水平滑移面。通过模型实验和有限元软件PLAXIS的数值分析,证明了厚基床内部存在滑移面,建议在验算基床抗滑稳定性时要考虑基床前后土压力作用。

滚筒式前轮侧滑调整台的研究

论述了汽车前轮侧滑对汽车使用性能的影响，分析了影响前轮定位的因素及目前常用侧滑检测调整方法，在此基础上提出一种新的前轮侧滑检测调整法，即动态检测调整法。介绍了根据此方法研制的滚筒式前轮侧滑调整台的基本构造和工作原理。

汽车车速试验台实现原理分析

汽车车速检测系统由滚筒式车速试验台架、磁电式传感器、检测系统等组成。检测系统由8031单片机、74LS373锁存器、2764EPROM存储器、8155扩展I/O芯片等组成,应用MCS-51汇编语言,按模块化的要求编写采样计数程序。该系统能够满足汽车车速的检测要求,具有较高的自动化水平和可靠性。

循环流化床锅炉耐磨耐火材料的检验及其施工

随着循环流化床锅炉的广泛应用,关于循环流化床锅炉的施工工艺的探讨越发深入,特别是耐磨耐火材料的施工好坏直接影响到锅炉的经济安全运行,就此本文对耐磨耐火材料以及现场施工进行系统的描述。

软弱下卧层地基承载力验算中常见的几个问题分析

根据《建筑地基基础设计规范》(GB 50007-2002)的规定,结合各种工程实践,文章分析了在软弱下卧层地基承载力验算中遇到的几个常见问题,针对常见的问题,分别提出了相应的计算方法,并举例进行说明。

一种超声检查床的制作

目的介绍一种超声检查床,可根据具体检查部位随意移动病人位置,并在任意位置固定。方法采用两层床面,分别受控横向移动装置和纵向移动装置。利用齿轮与锥尖的分开和接触来控制床面的移动和固定。结论本制作采用纯机械传动,避免漏电对患者的潜在危险。横向和纵向自由移动床面,并在任意位置固定,极大地减轻操作人员的工作强度,具有较高的实用价值。

低温真空吸附床矩形法兰设计与强度校核

针对低温、真空的工况特点,本文对吸附床矩形法兰进行了初步设计。分别采用当量圆法和有限元法,对矩形法兰强度进行了校核,并对两种计算方法进行了比较。计算结果表明:采用当量圆法与有限元法相结合的方式,可提高矩形法兰设计的可靠性和精确性,在工程设计中具有重要的指导意义。

硬点可调式独立悬架综合性能试验台的设计

设计了硬点可调式独立悬架综合性能试验台,应用于轮边电驱动系统进行垂向动力学和悬架运动学试验。在该试验台中引入了Stewart并联机构以实现车身硬点的位姿可调。在ADAMS软件里进行某悬架的垂向动力学仿真试验,得到了方位调整机构的动载,并利用该结果对方位调整机构进行强度校核,验证了六自由度平台及试验台整体设计的合理性。

浅谈德玛吉机床床身铸件生产中的注意事项

详细阐述了德玛吉2551089床身铸件的制芯、造型及装配等工序的操作过程和注意事项。德玛吉2551089床身铸件的制芯工序有21个检查项目,造型工序有29个检查项目,装配工序有9个检查项目。把好每一关,可确保德玛吉2551089床身铸件的质量。

先张法槽式张拉台座承力杆设计分析

本文介绍了先张法槽式张拉台座的力杆的设计分析。分别从承受的张拉力、结构稳定分析、强度验算、确定横向联系梁间距和纵向变形方面对工程实际进行验算。解决了梁板加宽后张拉力增加而张拉台座承力杆截面不需要增大的实际问题。

粘性泥石流坝后回淤比降的实验

拦挡坝坝后回淤比降是泥石流防治工程设计中的一个重要参数。本实验选取粘性泥石流,开展了沟床纵比降为9.5%～26.2%共8组和重度17～22 kN/m3共6组的坝后回淤比降的模拟实验。实验发现:1.在沟床纵坡为9.5%、12.1%、14.4%、16.7%、18.9%、21.3%、23.8%和26.2%时,其回淤比降分别为8.08%、9.8%、11.38%、12.69%、14.55%、16.61%、18.56%和20.96%;2.回淤比降比值在0.76至0.85间,平均0.80;3.回淤比降随沟槽纵比降的增大而增大,二者呈线性正相关,相关系数在0.95以上;回淤比降随重度的增大,总体呈缓慢增大的趋势,关系为二次函数关系。由此建立了回淤比降与重度和沟床纵比降的关系式:i=0.6014×γ0.0526×i0.94700,据此可以初步确定回淤比降的设计值。