由单片机AT89C51构成的定时控制系统

介绍了单片机ＡＴ８９Ｃ５１,给出了由ＡＴ８９Ｃ５１构成的定时控制系统,并将此系统与ＣＰＵ８０３１构成的单片机系统比较,具有结构简单、可靠性高的特点．     

斗轮挖掘机水平切削参数分析

本文针对斗轮挖掘机经常采用的水平切削方式作了较为详细的分析,在此基础上推导了水平切割时切削厚度、切削高度和切削宽度的较为精确的计算公式,为斗轮挖掘机水平切削时的受力分析和功率计算提供了较为可靠的理论依据。     

基于COM技术的工业CT控制软件I／O组件分析

为实现工业CT控制系统中软件的复用性，便于维护和升级，对基于COM技术的工业CT控制软件进行了研究．结合COM技术的可扩充性、语言无关性以及基于二进制级代码可重用性等特点，根据工业CT机的控制功能对控制软件进行了组件划分，并开发了其中的I／O组件．该组件顺利实现了与客户端程序的通信，具有良好的开放性，取得了较好的效果．     

工程边坡的稳定性分析及抗滑桩的应用研究

文章在采用传递系数法对边坡进行稳定性分析的基础上。对抗滑桩在边坡治理中的作用原理及其设计参数进行了研究。     

一种确定三维锥束CT精确重建域的方法

三维锥束CT精确重建是近几年图像重建领域的研究热点,完全条件、源点轨迹和重建方法是精确重建的主要研究内容。在已知源点轨迹形状和尺寸的情况下,确定物体精确重建的区域,是一个在实际应用中需要解决的重要问题。基于3D Radon变换的性质和三维锥束CT精确图像重建的一般公式,提出了一种在锥束源点轨迹给出之后确定物体精确重建域(ERR)的方法——“Radon壳图解法”。该方法使原有分析复杂轨迹ERR的工作大大简化,且更加直观、有效,使精确重建方法向实际应用又前进了一步。     

基于胸部CT图像的肺部自动分割

肺区自动分割是肺部肿瘤计算机辅助诊断系统的关键之一。文章采用多阈值和区域生长方法,先去掉背景,再去掉气管／支气管,最后对提取出来的肺区使用滚球的方法进行修补。该方法速度快、人工干预少、准确。     

一种新的MPEG-2 VBR视频场景切换判别法

提出了一种新的ＭＰＥＧ－２ＶＢＲ视频场景切换判别法,此判别法表明,相邻编码帧宏块条码率的频域互相关能够有效反映图像活动性及变化的特点,以此为判决准则,将频域互相关的结果与自适应门限进行比较,可以准确地判断出活动图像场景发生切换的位置及其帧类型,具有实现简单,计算量少的优点,可以满足实时应用。     

3D virtual reconstruction of the Pleistocene cheetah skull from the Tangshan, Nanjing, China

The development of computer tomography and image processing has made it possible to establish virtual 3D reconstruction and non-invasive dissection of fossil specimens. We used these methods to reconstruct a virtual 3D skull of a Pleistocene cheetah skull from the Tuozi cave, Tangshan, Nanjing, and virtually dissected it for anatomic studies, and measured the volumes of different parts of the endocranium. The endocranium of the cheetah skull has showed that its frontal sinus is beehive-like, the frontal lobe of cerebra is relatively large but the temporal lobe is relatively small, its cerebral sulcus and gyrus are more complicated than those of the domestic cat, similar to those of the domestic dog, but simpler than those of giant panda, pig, cattle and horse. The technology of virtual 3D reconstruction and non-invasive dissection of fossil specimens can extend the morphological study from the exterior to the interior, and it can also help to study fragile specimens and virtually backup rare and precious specimens.     

Modulation of presynaptic nAChRs on postsynaptic GABA receptor in optic tectum of juvenile<Emphasis Type="Italic">Xenopus</Emphasis>

Using the blind patch-clamp technique with the whole-cell mode,we have studied the modulation presynaptic receptor on postsynaptic γ-raminobutyric acid (GABA) receptor measuring miniature inhibitory postsynaptic currents (mIPSCs)in optic tectum of Xenopus during critical peroid.It was demonstrated that compared with mature neurons,mIPSCs recorded from immature neurons had smaller amplitude and longer decay time.mIPSCs are mediated by GABAa receptor.The nicotinic acetylcholine receptor agonists(carbachol,cytisine,nicotine,DMPP and so on) could increase the frequency of mIPSCs.The enhancement of mIPSCs frequency induced by nAChR agonists was calcium-dependent.However,the choline,a product of hydrolyzed acetylcholine,could not increase the frequency of mIPSCs.DH-β-E,a competitive antagonist of nAChR,blocked the increase of mIPSCs frequency induced by carbachol.Mecamyllamine,an α3β4 subtype of nAChR antagonist,also blocked the carbachol-induced enhancement of mIPSCs.On the other hand,MLA,α7 subtype of nAChR antagonist,had no effect on it .Thus,it seems that nAChR could presynaptically modulate the mIPSCs and α3β4 subtype of nAChR might be involved.But α7 nAChR subtype of nAChR would not be involved.The modulation is calcium-dependent.Meanwhile,we found that Ca^2 -free solution could elicit giant PSCs.The frequency of mIPSCs also is related with the level of HP.     

多任务深度卷积网络的CT图像方向校正

针对医学电子计算机断层扫描(CT)图像方向校正问题,提出一种并行卷积回归(PCRN)多任务深度学习网络.通过侧旋角度正回归和翻转概率逻辑回归,求得校正参数来精准地校正图像.进一步,针对医学图像训练样本稀缺的情况,提出一种串行回归(SCRN)的深度学习架构,弥补并行卷积回归网络在小样本情况下校正精度不足的问题.实验结果表明:在样本充分,并行卷积回归网络和样本稀缺情况下,串行卷积回归网络对小角度偏转、大角度偏转和翻转的腹部CT图像校正结果都优于传统的配准方法.