摘要：The duck circovirus （DuCV） infection in sick ducks from Fujian Province was investigated. The liver samples of 43 sick Muscovy ducks with infectious serositis were collected from 12 duck farms in Fujian Province Based on the published sequences of DuCV, two primers were designed for the detection of DuCV and four pairs of primers were designed to amplify four overlapping fragments that cover the complete genome of DuCV. The specific PCR products were amplified from positive samples. The fragments were then cloned into pMD18-T vector and sequenced, and the full length genomic sequence of the FJ0601 isolate of DuCV was obtained. PCR analysis showed that the proportion of ducks which were positive for circovirus was 79% and 10 out of the 12 farms were positive. Sequence analysis showed that the complete genome of DuCV-FJ0601 was 1988 bp and possessed features common to the family Circoviridae which included a stem-loop structure and the Rep protein motifs. Homology analysis showed that FJ0601 isolate of DuCV had 97.3%-97.5% nucleotide sequence identity to all the four Taiwan isolates （TC1/2002, TC2/2002, TC3/2002, TC4/2002）, 82.9% identity to the America （33753-52） isolate and 82.3% identity to the Germany isolate. Phylogenetic analysis with Clustal W, however, showed that FJ0601 isolate of DuCV was on a common branch with Taiwan isolates, and Germany and America isolates belonged to the other branch.

摘要：研究了一类含有状态时滞的离散不确定性系统的鲁棒H∞滤波器设计问题,其中,系统的参数不确定性是时变和模有界的.为了设计使得滤波过程渐近稳定,且满足H∞扰动抑制水平的滤波器,给出了时滞系统满足H∞扰动抑制的鲁棒稳定性引理,利用修正的Riccati型方程推导了滤波器存在的充分条件.仿真试验表明了该设计方法的有效性和可行性.

摘要：涵道风扇无人机可以实现起降与悬停,结构简单可靠且安全系数高。针对常规水空两栖无人机起降环境受限、折叠翼机构冗余与气动效率较低等问题,设计一种新型双涵道风扇水空两栖跨介质无人机。借鉴水下无人潜航器和无人驾驶飞机对机身进行优化设计,并采用倾转双涵道风扇动力系统。基于改进叶素动量理论,得出小型涵道风扇升力计算理论公式。分析力学物理场下无人机整体的结构振型,并通过流场有限元仿真验证整机的气动性能。分析结果表明:改进的小型涵道风扇升力计算公式计算结果与风洞试验结果基本一致,两者最大误差为4.5%,设计出的小型涵道风扇可提供20%的附加升力,气动效率高;通过模态分析发现该无人机机体结构较为稳定,振型合理;完成了风洞试验与新型涵道风扇水空两栖无人机在不同介质下的试飞验证,证明了无人机设计方案的可行性。

摘要：研究含有状态时滞的非线性不确定性系统的鲁棒H∞ 滤波器设计问题。利用修正的Riccati型不等式分析了使滤波系统渐近稳定、且从噪声输入到误差输出的传递函数的H∞ 范数小于指定上界的充分条件,通过两个代数Riccati方程的正定解参数化表示了该滤波器。滤波器的设计过程和结构均是与状态时滞的大小、非线性扰动以及不确定性的参数无关的。仿真试验进一步表明了设计方法的有效性和可行性。

摘要：对于网络信息体系的构建,目前国际上主要采用企业体系结构分析方法,这种框架从业务、系统和技术的角度来描述系统结构.此类方法仍然停留在如何定义开发体系结构的领域,并没有考虑到体系的动态演化以及系统在决策和交互过程中的涌现行为.对于某一单独系统的参与与否对体系全局能力造成的影响缺乏掌控,缺乏这些能力就难以实现体系设计的最优化.提出一套网络信息体系能力演化分析框架,指出体系能力演化的要素及要素之间的关系和属性,并给出体系能力演化机理分析,从而为研究网络信息体系演化规律提供手段方法.

摘要：为研究弹丸章动对引信无返回力矩钟表机构延迟解锁时间的影响,依据多刚体动力学理论,建立弹丸章动运动下无返回力矩钟表机构延迟解锁时间的数学模型。采用ADAMS虚拟样机技术并设置驱动、摩擦等参数对延迟解锁过程进行动力学仿真分析。结果表明:建立的无返回力矩钟表机构延迟解锁时间的数学模型准确性较高;弹丸最大章动角出现在炮口处,当炮口速度为358 m/s,最大章动角为0.153 rad;章动角与延迟解锁时间呈反比关系。该研究方法可为引信设计提供理论依据,对缩短生产周期、调试模型参数、降低研制成本具有重要意义。

摘要：As an emerging technology to promote the combination of medicine and industry,the three-dimensional(3D)printing has developed rapidly in the fields of orthopedics,while its unique advantages in improving precise treatment still need to be further *** this report,our team have exhibited several classic cases of integrating 3D printing into orthopedic clinical application,thereby further elaborating thoughts and opinions on the significance of 3D printing in the orthopedic clinical application,technical advantages,existing main problems and coping strategies.

摘要：随着农机智能化的发展,现有农机向智能化方向升级,机械换挡则是优化之路的瓶颈。针对此问题设计一种传统变速箱电动换挡机构,该机构由电动推杆作为主要换挡的执行部件,传感器为检测部件,通过继电器等电器元件组成控制机构。通过对该机构执行部件的设计及电动换挡的可靠性试验,验证该电动换挡机构可以完成挡位的自由切换,为传统机械向智能方向发展、远程控制奠定基础。

摘要：连续-离散耦合方法同时集成了有限元和离散元的优点,在非连续介质边坡的破坏模式和机理研究中已得到一定应用,但是该方法不能定量分析边坡的稳定性。为了解决此问题,首先开发出一种连续-离散耦合强度折减法,提出了宏、细观强度折减系数关系的建立方法,然后基于某经典边坡算例验证了方法的可行性,并从细观角度上研究了边坡破坏机理和失稳判据,最后讨论了耦合强度折减法最优离散域的选取原则和方法。结果表明:宏、细观折减系数之间满足指数增长关系;从耦合计算位移连续性、边坡安全系数、潜在滑动面多个角度验证了连续-离散耦合强度折减法是可行的,安全系数较其他方法差距最大为5.39%;边坡临界破坏时拉力链数量和颗粒间黏结破坏数量会出现明显的突变,由此提出可将这2种细观上的突变作为新的边坡失稳判据;最优离散域的安全系数较标准值差距仅为0.02%;选取离散域时,应遵循充分发挥离散元优势、权衡数值计算效率、简化数值计算模型等原则,即尽可能穿过边坡潜在滑动面、减少离散域的大小、采用规则和简单的矩形。

摘要：On the basis of the analysis of solidification interval and temperature distribution of components manufactured by the squeeze casting method, formulas for calculating the solidification interval and compaction pressure were deduced according to the principal request that the compaction pressure should be equal to or greater than the plastic deformation resistance of the forming component when solidification ended. The solidification interval was proven to be associated with many factors, such as weight of the component, specific heat of the alloy, latent heat, pouring temperature, component temperature at the end of solidification and heat-transfer coefficients. The compaction pressure was related to the strain rate, deformation temperature, and dimension of the de- forming component. The solidification interval and compaction pressure calculated by the formulas deduced in this article were adopted in the production of 45 steel bidirectional chapiter valves, and components with excellent oerformance were manufactured.