曲锥前体/内转进气道一体化设计与试验研究

介绍了曲锥前体/内转进气道一体化的设计方法,针对进气道侧壁外扩角这一设计因素,设计了具有不同捕获形状的两套一体化构型,并完成了两套模型在马赫数Ma=6.0、0°迎角状态下的风洞试验及数值模拟对比。结果表明,基于该一体化设计方法,曲锥前缘产生的初始入射激波在设计状态下能够完全封闭进气道唇罩,进而起到抑制唇罩溢流和提高一体化构型流量捕获能力的效果。在设计条件下,进气道侧壁外扩角的增加有助于减少侧壁产生的溢流,从而提高一体化构型的流量捕获能力。同时,外扩角的增大将导致下游反压前传速度加快,从而恶化进气道的内部流场并降低一体化构型的反压特性。因此,设计此类一体化构型时,需要考虑外扩角对捕获流量和进气道出口性能的综合影响,选择合适的进气道侧壁外扩角度以达到设计需求。

曲锥前体/三维内转进气道一体化设计与分析

对圆锥流场在不同攻角条件下的气动特征进行分析,以流线追踪技术为基础,发展了一种曲锥前体/三维内转进气道一体化设计方法,获得了三个几何参数对一体化方案外形和性能的影响规律。研究发现,三维内转进气道侧壁外扩角对进气道流量捕获系数影响明显,而捕获形状圆心角对进气道的影响主要表现在几何特征上。此外,进气道流量捕获系数随外压缩段总长度的增大而减小。基于对捕获形状的研究,设计了一种曲锥前体/三维内转进气道,并通过数值模拟对该方案进行研究。结果表明:在设计点来流马赫数为6.0时,该方案进气道流量捕获系数能够达到0.93,且具有0.61的总压恢复系数;在非设计点来流马赫数为5.0时,流量捕获系数能够保持在0.86,总压恢复系数为0.77。

大顶子山航电枢纽工程灯泡贯流式机组管形座安装

管形座作为贯流式水轮发电机组的基准件,其安装质量与进度将直接关系到水轮机与发电机的安装质量和安装进度。大顶子山航电枢纽工程位于松花江干流,属高寒地区,离哈尔滨市46km,主机设备由哈尔滨电机厂制造,因此管形座的安装独具特色。

Contributions of distinct prefrontal neuron classes in reward processing

The prefrontal cortex(PFC)is thought to be involved in higher order cognitive functions,such as in working memory,abstract categorization,and reward processing.It has been reported that two distinct neuron classes(putative pyramidal cells and interneurons)in the PFC played different functional roles in neural circuits involved in forming working memory and abstract categories.However,it remains elusive how the two types of neurons process reward information in the PFC.To investigate this issue,the activity of single neurons was extracellularly recorded in the PFC of the monkey performing a reward predicting task.PFC neurons were classified into putative pyramidal cells and interneurons,respectively,based on the waveforms of action potentials.Both the two types of neurons encoded reward information and discriminated two reward conditions(the preferred reward condition vs.the nonpreferred reward condition).However,the putative pyramidal neurons had better and more reliable discriminability than the putative interneurons.Also,the pyramidal cells represented reward information in the preferred reward condition,but not in the nonpreferred reward condition by raising their firing rates relative to the baseline rates.In contrast,the interneurons encoded reward information in the nonpreferred reward condition,but not in the preferred reward condition by inhibiting their discharge rates relative to the baseline rates.These results suggested that the putative pyramidal cells and interneurons had complementary functions in reward processing.These findings may help to clarify individual functions of each type of neurons in PFC neuronal circuits involved in reward processing.

Design methodology of an osculating cone waverider with adjustable sweep and dihedral angles

When considering the practical engineering application of a waverider,the on-design and off-design aerodynamic characteristics of the design conditions,especially the lift-to-drag ratio and the stability,deserve attention.According to recently studies,the planform and rear sight shape of a waverider are closely related to the above aerodynamic performance.Thus,the planform leading-edge profile curve used to design the planform shape of a vehicle is applied to designing an osculating cone waverider.Two key parameters concerned in planform and rear sight shape,namely the plan view sweep angle of the leading edge and the dihedral angle of the underside are introduced to the waverider design process.Each parameter is inserted in the control curve equation.Especially,a parameterization scheme is put forward for the free adjustment of the sweep angle along the leading edge.Finally,three examples are generated for verification and investigation.After the verification process based on the inviscid flow field of one case,the influences of the sweep and dihedral angles on the lift-to-drag ratio and the lateral static stability are evaluated,and meaningful results are obtained.Based on these results,we can conclude that,considering the maximum lift-to-drag ratio,the sweep angle plays a role on the lift-to-drag ratio only at subsonic and trans/supersonic speed as a negligible effect is observed at hypersonic speeds,whereas the dihedral angle is seem to produce a relevant difference at hypersonic speeds.Considering the lateral static stability,the dihedral angles have more influence on the waverider than the sweep angles.

BDNF rescues prefrontal dysfunction elicited by pyramidal neuron-specific DTNBP1 deletion in vivo

Dystrobrevin-binding protein 1 （Dtnbp1） is one of the earliest identified schizophrenia susceptibility genes. Reduced expression of DTNBP1 is commonly found in brain areas of schizophrenic patients. Dtnbp1-nuU mutant mice exhibit abnormalities in beha- viors and impairments in neuronal activities. However, how diminished DTNBP1 expression contributes to clinical relevant fea- tures of schizophrenia remains to be illustrated. Here, using a conditional Dtnbp1 knockout mouse line, we identified an in vivo schizophrenia-relevant function of DTNBP1 in pyramidal neurons of the medial prefrontal cortex （mPFC）. We demonstrated that DTNBP1 elimination specifically in pyramidal neurons of the mPFC impaired mouse pre-pu[se inhibition （PPI） behavior and reduced perisomatic GABAergic synapses. We further revealed that loss of DTNBP1 in pyramidal neurons diminished activity- dependent secretion of brain-derived neurotrophic factor （BDNF）. Finally, we showed that chronic BDNF infusion in the mPFC fully rescued both GABAergic synaptic dysfunction and PPI behavioral deficit induced by DTNBP1 elimination from pyramidal neurons. Our findings highlight brain region- and cell type-specific functions of DTNBP1 in the pathogenesis of schizophrenia, and under- score BDNF restoration as a potential therapeutic strategy for schizophrenia.