An efficient design-for-testability （DFT） technique is proposed to achieve low overhead for scan-based delay fault testing. Existing techniques for delay test such as skewed-load or broadside make the test generatio...An efficient design-for-testability （DFT） technique is proposed to achieve low overhead for scan-based delay fault testing. Existing techniques for delay test such as skewed-load or broadside make the test generation process complex and produce lower coverage for scan-based designs as compared with non-scan designs, whereas techniques such as enhanced-scan test can make the test easy but need an extra holding latch to add substantial hardware overhead. A new tri-state holding logic is presented to replace the common holding latch in enhanced-scan test to get a substantial low hardware overhead. This scheme can achieve low delay overhead by avoiding the holding latch on the critical timing scan path. What＇s more, this method can also keep the state and signal activity in the combinational circuit from the scan during data scan-in operation to reduce the power dissipation. Experiment results on a set of ISCAS89 benchmarks show the efficiency of the proposed scheme.展开更多
The microstructure of(CrFe)_7C_3 has been studied with scanning tunneling microscopy.It shows that a carbide consists of colonies which are full of stacking faults. The stacking faults in one colony are parallel while...The microstructure of(CrFe)_7C_3 has been studied with scanning tunneling microscopy.It shows that a carbide consists of colonies which are full of stacking faults. The stacking faults in one colony are parallel while those in different colonies lie at angle with each other.展开更多
南口-孙河断裂是北京地区重要的全新世活动断裂之一,也是张家口-渤海地震带的重要组成部分。该断裂总体走向310°,全长约80 km。前人通过大量的活动构造研究揭示,其全新世以来存在明显活动,发生了3次古地震事件,单次地震事件的垂直...南口-孙河断裂是北京地区重要的全新世活动断裂之一,也是张家口-渤海地震带的重要组成部分。该断裂总体走向310°,全长约80 km。前人通过大量的活动构造研究揭示,其全新世以来存在明显活动,发生了3次古地震事件,单次地震事件的垂直位错约为1.3 m,断裂的垂直滑动速率约为0.3 mm/a。但由于直接观察证据和测年精度限制,前人对南口-孙河断裂最近一次强震事件离逝时间的约束相对薄弱。同时,针对南口-孙河断裂可能存在的最新走滑变形特征,缺乏相对可靠的地表变形证据支撑。为此,本研究在南口-孙河断裂全新世活动段东南端进行了古地震研究,系统分析了强震事件造成的沉积地层和构造变形,采集了探槽内主断层面构造定向样品,并开展了扫描电镜分析。通过古地震探槽研究揭示,南口-孙河断裂的活动造成了沉积地层显著构造变形,表现为标志地层的错断、地层厚度的变化以及崩积楔的发育等。对探槽内沉积地层的对比分析表明,南口-孙河断裂的活动错断了探槽内1.3 m以下的沉积地层。14C测年结果揭示,南口-孙河断裂最新一次地震事件的离逝时间为2820~3700 a BP。依据古地震探槽内崩积楔、错断层位分布、地层厚度变化以及地层的倾斜变形等古地震事件识别标志分析,南口-孙河断裂在本探槽内共揭示了4次古地震事件,10020 a BP以来发生了3次古地震事件。依据显微构造分析揭示,断裂主断层面存在平行于断层走向的黏土矿物的定向排列,揭示断层可能存在左旋水平运动,这也被探槽内揭示的主断裂约75°的陡倾角和显著的花状构造所验证。因此,南口-孙河断裂全新世以来表现为显著的走滑运动特征,启示北京地区发震构造分析需要考虑华北地区的走滑构造变形。展开更多
基金This project was supported by the National Natural Science Foundation of China (90407007).
文摘An efficient design-for-testability （DFT） technique is proposed to achieve low overhead for scan-based delay fault testing. Existing techniques for delay test such as skewed-load or broadside make the test generation process complex and produce lower coverage for scan-based designs as compared with non-scan designs, whereas techniques such as enhanced-scan test can make the test easy but need an extra holding latch to add substantial hardware overhead. A new tri-state holding logic is presented to replace the common holding latch in enhanced-scan test to get a substantial low hardware overhead. This scheme can achieve low delay overhead by avoiding the holding latch on the critical timing scan path. What＇s more, this method can also keep the state and signal activity in the combinational circuit from the scan during data scan-in operation to reduce the power dissipation. Experiment results on a set of ISCAS89 benchmarks show the efficiency of the proposed scheme.
文摘The microstructure of(CrFe)_7C_3 has been studied with scanning tunneling microscopy.It shows that a carbide consists of colonies which are full of stacking faults. The stacking faults in one colony are parallel while those in different colonies lie at angle with each other.
文摘南口-孙河断裂是北京地区重要的全新世活动断裂之一,也是张家口-渤海地震带的重要组成部分。该断裂总体走向310°,全长约80 km。前人通过大量的活动构造研究揭示,其全新世以来存在明显活动,发生了3次古地震事件,单次地震事件的垂直位错约为1.3 m,断裂的垂直滑动速率约为0.3 mm/a。但由于直接观察证据和测年精度限制,前人对南口-孙河断裂最近一次强震事件离逝时间的约束相对薄弱。同时,针对南口-孙河断裂可能存在的最新走滑变形特征,缺乏相对可靠的地表变形证据支撑。为此,本研究在南口-孙河断裂全新世活动段东南端进行了古地震研究,系统分析了强震事件造成的沉积地层和构造变形,采集了探槽内主断层面构造定向样品,并开展了扫描电镜分析。通过古地震探槽研究揭示,南口-孙河断裂的活动造成了沉积地层显著构造变形,表现为标志地层的错断、地层厚度的变化以及崩积楔的发育等。对探槽内沉积地层的对比分析表明,南口-孙河断裂的活动错断了探槽内1.3 m以下的沉积地层。14C测年结果揭示,南口-孙河断裂最新一次地震事件的离逝时间为2820~3700 a BP。依据古地震探槽内崩积楔、错断层位分布、地层厚度变化以及地层的倾斜变形等古地震事件识别标志分析,南口-孙河断裂在本探槽内共揭示了4次古地震事件,10020 a BP以来发生了3次古地震事件。依据显微构造分析揭示,断裂主断层面存在平行于断层走向的黏土矿物的定向排列,揭示断层可能存在左旋水平运动,这也被探槽内揭示的主断裂约75°的陡倾角和显著的花状构造所验证。因此,南口-孙河断裂全新世以来表现为显著的走滑运动特征,启示北京地区发震构造分析需要考虑华北地区的走滑构造变形。
