排序方式: 共有47条查询结果,搜索用时 203 毫秒
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对18名河南省现役优秀女子空手道运动员体能特征进行分组研究.河南省优秀女子空手道运动员的体能特征主要表现为:运动员上肢较长、上臂围度表现突出;优秀组运动员的心肺功能、有氧和无氧代谢水平都高于一般组;优秀组运动员在爆发力、速度力量、专项速度、无氧耐力、专项柔韧和灵敏素质优于一般组.研究认为,优秀女子空手道运动员身体素质中... 相似文献
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针对一类特殊的多目标优化问题,其每个目标函数为一个二阶连续可微凸函数与一个真凸但不必可微函数之和,提出了邻近牛顿法.我们引入了带线搜索的邻近牛顿法和不带线搜索的邻近牛顿法.在适当的条件下,我们证明了由这两类算法产生的序列的每个聚点是多目标优化问题的Pareto平稳点.此外,我们给出了它们在约束多目标优化和鲁棒多目标优化... 相似文献
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研究Sn-9Zn中添加微量稀土元素Nd对合金显微组织和铺展性能的影响,对比分析Sn-9Zn-xNd(x=0,0.1,0.5)钎料/Cu焊点界面微观特征及力学性能。结果表明:微量Nd元素在Sn-9Zn合金中能够显著细化组织,但添加量为0.5%时合金中形成了"十字状"NdSn3金属间化合物(IMC)。钎焊温度较低或时间较短时,微量Nd添加能够改善Sn-9Zn合金在Cu基板上的铺展性能;但是在温度较高或时间较长的钎焊工艺条件下,由于Nd元素的严重氧化导致钎料铺展性能明显下降。在Sn-9Zn中添加0.1%Nd,在界面处形成了均匀细密分布的"毛绒状"共晶组织,能够提高焊点结合性能;Nd添加量为0.5%时,成分偏聚引起的组织不均匀导致焊点力学性能下降。 相似文献
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We report the ~(87)Sr optical lattice clock developed at the National Time Service Center. We achieved a closed-loop operation of the optical lattice clock based on ~(87)Sr atoms. The linewidth of the spin-polarized clock peak is 3.9 Hz with a clock laser pulse length of 300 ms, which corresponds to a Fourier-limited linewidth of 3 Hz. The fitting of the in-loop error signal data shows that the instability is approximately 5 × 10~(-15)τ~(-1/2), affected primarily by the white noise. The fractional frequency difference averages down to 5.7 × 10~(-17) for an averaging time of 3000 s. 相似文献
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Ruo-Ting Yang 《中国物理 B》2022,31(9):98501-098501
Rapid single flux quantum (RSFQ) circuits are a kind of superconducting digital circuits, having properties of a natural gate-level pipelining synchronous sequential circuit, which demonstrates high energy efficiency and high throughput advantage. We find that the high-throughput and high-speed performance of RSFQ circuits can take the advantage of a hardware implementation of the encryption algorithm, whereas these are rarely applied to this field. Among the available encryption algorithms, the advanced encryption standard (AES) algorithm is an advanced encryption standard algorithm. It is currently the most widely used symmetric cryptography algorithm. In this work, we aim to demonstrate the SubByte operation of an AES-128 algorithm using RSFQ circuits based on the SIMIT Nb03 process. We design an AES S-bbox circuit in the RSFQ logic, and compare its operational frequency, power dissipation, and throughput with those of the CMOS-based circuit post-simulated in the same structure. The complete RSFQ S-bbox circuit costs a total of 42237 Josephson junctions with nearly 130 Gbps throughput under the maximum simulated frequency of 16.28 GHz. Our analysis shows that the frequency and throughput of the RSFQ-based S-bbox are about four times higher than those of the CMOS-based S-bbox. Further, we design and fabricate a few typical modules of the S-box. Subsequent measurements demonstrate the correct functioning of the modules in both low and high frequencies up to 28.8 GHz. 相似文献
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Photon number resolvability of multi-pixel superconducting nanowire single photon detectors using a single flux quantum circuit 下载免费PDF全文
Hou-Rong Zhou 《中国物理 B》2022,31(5):57401-057401
Superconducting nanowire single-photon detectors (SNSPDs) are typical switching devices capable of detecting single photons with almost 100% detection efficiency. However, they cannot determine the exact number of incident photons during a detection event. Multi-pixel SNSPDs employing multiple read-out channels can provide photon number resolvability (PNR), but they require increased cooling power and costly multi-channel electronic systems. In this work, a single-flux quantum (SFQ) circuit is employed, and PNR based on multi-pixel SNSPDs is successfully demonstrated. A multi-input magnetically coupled DC/SFQ converter (MMD2Q) circuit with a mutual inductance M is used to combine and record signals from a multi-pixel SNSPD device. The designed circuit is capable of discriminating the amplitude of the combined signals in accuracy of Φ0/M with Φ0 being a single magnetic flux quantum. By employing the MMD2Q circuit, the discrimination of up to 40 photons can be simulated. A 4-parallel-input MMD2Q circuit is fabricated, and a PNR of 3 is successfully demonstrated for an SNSPD array with one channel reserved for the functional verification. The results confirm that an MMD2Q circuit is an effective tool for implementing PNR with multi-pixel SNSPDs. 相似文献
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用透射电镜及电子探针X-射线显微分析法研究了丁丙诺啡(Buprenorphine,BN)引起镇痛期间小鼠中脑导水管周围灰质区钙离子分布的改变.按照改进的Komnick方法,脑组织用含有2%焦锑酸钾的1%锇酸固定.实验结果表明,动物经腹腔注射BN(0.8mg/kg)30分钟后,在髓鞘、轴突、线粒体和细胞核中均可见到电子致密的沉淀颗粒,尤其在髓鞘的环状片层中形成大量的、密集的颗粒状沉淀.电子探针X-射线显微分析证实髓鞘中的沉淀颗粒含有元素钙,提示BN镇痛时髓鞘结合大量的钙离子,并且可能经过髓鞘的转运,钙离子进入轴突,贮存于线粒体中.本文讨论了在中枢神经系统中的钙离子转运的可能途径. 相似文献