摘要：Due to the complex high-temperature characteristics of hydrocarbon fuel,the research on the long-term working process of parallel channel structure under variable working conditions,especially under high heat-mass ratio,has not been systematically carried *** this paper,the heat transfer and flow characteristics of related high temperature fuels are studied by using typical engine parallel channel *** numeri⁃cal simulation and systematic experimental verification,the flow and heat transfer characteristics of parallel chan⁃nels under typical working conditions are obtained,and the effectiveness of high-precision calculation method is preliminarily *** is known that the stable time required for hot start of regenerative cooling engine is about 50 s,and the flow resistance of parallel channel structure first increases and then decreases with the in⁃crease of equivalence ratio(The following equivalence ratio is expressed byΦ),and there is a flow resistance peak in the range ofΦ=0.5~*** is mainly caused by the coupling effect of high temperature physical proper⁃ties,flow rate and pressure of fuel in parallel *** the same time,the cooling and heat transfer character⁃istics of parallel channels under some conditions of high heat-mass ratio are obtained,and the main factors affect⁃ing the heat transfer of parallel channels such as improving surface roughness and strengthening heat transfer are *** the experiment,whenΦis less than 0.9,the phenomenon of local heat transfer enhancement and deterioration can be obviously observed,and the temperature rise of local structures exceeds 200℃,which is the risk of structural ***,the reliability of long-term parallel channel structure under the condition of high heat-mass ratio should be fully considered in structural design.

摘要：针对传统的双差分载波相位实时定位平台精度低的特点,本文设计了一种新型的基于单周期多基线组合的实时定位平台。该平台采用单周期整周模糊度算法进行模糊度解算,有效避免了周跳和初始化问题,并组合多基线测量观测值,有效地减少了单基线长度增加带来的影响,通过对平台进行建模仿真,表明其与传统平台相比具有更好的稳定性和精度。最后,本文将GPS多基线测姿算法引入,将该平台应用到空中对准技术中,进行对准仿真,取得了更高的速度和精度。

摘要：针对微型无人机用小功率航空活塞发动机电容放电点火系统快速高效充电进行了优化设计与试验研究.分析了传统充电升压变换采用恒频脉宽调制PWM(pulse width modulation)方式的缺点,提出了一种开关频率可变、输出电压检测无需电阻分压实现的充电方式,推导给出了关断时间和充电时间的计算公式,设计实现了该充电电路并进行了试验.结果表明:该充电方式充电时间短,效率高;充电时间估算方法准确可靠,误差小,计算量少.

摘要：采用实验的方法对中心进气开式转静系转盘的风阻扭矩特性进行了研究,利用特殊的测量装置设计,实现利用静止扭矩仪测量转盘受到的风阻扭矩。结合流动参数以及转静间隙比等变量,对比研究了有无封严结构的转静系两种模型,并总结出开式转静系转盘的扭矩系数经验关系式。结果表明,转盘的风阻扭矩主要受到腔内的流动结构影响,腔内流体的流动形式,旋转主导或者通流主导对转盘扭矩系数有着不同的影响。对比自由盘,开式转静系中静盘对扭矩系数的影响与间隙比的大小有关。分析实验数据发现最小临界间隙比以及最大临界间隙比的范围,分别为G=0.02-0.04以及G=0.06-0.08,当间隙比较小且腔内旋转主导,转盘扭矩会比对应参数自由盘模型小5%-15%,而出口封严环罩会使得转盘扭矩系数增大20%。

摘要：针对矩形芯片提出了Y形构形微通道的芯片内部冷却结构,通过三维数值计算比较了Y形构形微通道与传统直微通道中的流体层流流动和换热特性,并对Y形构形微通道的重要结构参数进行了优化.研究表明:在相同对流换热面积和水利直径的条件下,Y形构形微通道具有比直微通道更高的传热效率和更低的进出口压降,可以满足高热负荷需求.在研究范围内通道级数为3级、分叉角度为60°、分支个数为2时,散热器的综合换热性能最好.以上结论为Y形构形微通道的结构设计提供了重要依据.

摘要：本文针对2016年6月山西、山东地区一次强对流活动,通过GRAPES(Global/Regional Assimilation and PredictionEnhancedSystem)云分析系统融合了多普勒雷达反射率三维组网拼图资料和ADTD(ActiveDirectory Topology Diagrammer)闪电定位资料,对模式初始场的云水、云冰等云微物理变量进行了调整和分析,并对这次强对流过程设计了3组数值试验。结果表明:(1)云分析系统在加入雷达反射率资料以后,能在模式初始场中较准确的计算模式的初始水物质;(2)闪电定位资料转换成的替代雷达反射率对原有的雷达反射率有一定的补充作用,使模式的初始场与真实状况更接近;(3)从模式降水的角度看,在加入雷达资料以后,GRAPES云分析可以显著提高6小时以内降水的模拟效果,而闪电定位资料的加入,对中雨以上量级的降水模拟有进一步的改进作用。

摘要：The famous late-Qing statesman Weng Tonghe, acclaimed by Kang Youwei as "the first guiding master of China’s reform," left a precious spiritual legacy for later generations. Weng imbibed the rich cultural nourishment of Changshu, his home town, both as a young student and when he returned in his later years. His experience offers a mirror for consideration of Changshu’s cultural development today.

摘要：为研究壁面不同粗糙程度以及带有螺栓等表面凸起的转盘风阻扭矩特性,建立了一个转盘扭矩测量实验台.自由盘测量结果与经典经验关系式较好的符合度验证了测量方法的准确性.分析研究了在不同粗糙度以及附有6种凸起结构的转盘风阻扭矩规律.结果表明,壁面的粗糙会增大转盘受到的扭矩,在所测量旋转雷诺数范围内,从气动光滑一直到粗糙高度0.2mm,扭矩系数增大1倍.基于气动光滑自由盘经验关系式进一步总结出相对粗糙度对于风阻扭矩的影响系数.对比6种凸起引起的风阻扭矩特性发现,叶型凸起会大幅降低风阻扭矩.凸起安装迎风角度的改变会带来10%的风阻扭矩差别.结合自由光滑盘扭矩系数经验关系式,总结出不同凸起形状对于扭矩系数的影响因数.

摘要：为进一步提高骨修复材料的骨诱导性能,引入了BaTiO_3压电涂层。首先,通过等离子喷涂法在Ti基体上制备羟基磷灰石(HA)、Ti-HA和Ti-HA-BaTiO_3这3种生物涂层;然后,采用正交试验设计优化了喷涂工艺参数,用SEM/EDS对涂层的形貌和成分进行了表征,并通过划痕试验测试了涂层与基体的结合强度;最后,进行了细胞培养试验,用CCK-8法对细胞毒性进行了评价,并在SEM下观察了细胞的粘附形态。结果显示:细胞带有伪足,呈梭形和不规则多边形,且粘附在Ti-HA-BaTiO_3复合涂层表面;细胞伸展形态良好,涂层的细胞毒性等级不高于1级。可见,Ti-HA-BaTiO_3复合材料可以作为临床植入材料应用。

摘要：将PIV(particle image velocimetry,粒子图像测速仪)技术应用于多功能旋转换热实验台,测量了不同工作状态下径向进气旋转盘腔间的速度场.介绍了实验装置、实验方法和误差分析方法;给出了旋转盘腔间速度场的瞬时值和平均值,测量结果表明了PIV技术能够测量复杂旋转盘腔间的流场,并定量分析影响因素(旋转雷诺数和流量系数)对速度场的影响;同时,分析得出激光反光的控制和示踪粒子的均匀稳定散播是实验成功的关键因素.