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排序方式: 共有220条查询结果,搜索用时 15 毫秒
1.
随着供热计量系统的普及,系统可以根据负荷的变化进行调整,管网的阻力系数随即发生变化。对变动阻力系数进行优化辨识是了解供热管网实时运行状况的有效手段。提出一种基于流量监测数据的供热管网变动阻力系数优化辨识方法,并利用遗传算法进行求解。对洛阳市某小区供暖季管网实际运行数据进行验证,辨识结果的相对误差在5%以内。结果表明:该方法可以在只有流量观测数据时得到精度较高的供热管网变动阻力系数,为供热系统的运行调节提供指导。  相似文献   
2.
Yao-Yao Jiang 《中国物理 B》2022,31(4):40307-040307
Shenvi et al. have proposed a quantum algorithm based on quantum walking called Shenvi-Kempe-Whaley (SKW) algorithm, but this search algorithm can only search one target state and use a specific search target state vector. Therefore, when there are more than two target nodes in the search space, the algorithm has certain limitations. Even though a multi-objective SKW search algorithm was proposed later, when the number of target nodes is more than two, the SKW search algorithm cannot be mapped to the same quotient graph. In addition, the calculation of the optimal target state depends on the number of target states m. In previous studies, quantum computing and testing algorithms were used to solve this problem. But these solutions require more Oracle calls and cannot get a high accuracy rate. Therefore, to solve the above problems, we improve the multi-target quantum walk search algorithm, and construct a controllable quantum walk search algorithm under the condition of unknown number of target states. By dividing the Hilbert space into multiple subspaces, the accuracy of the search algorithm is improved from pc=(1/2)-O(1/n) to pc=1-O(1/n). And by adding detection gate phase, the algorithm can stop when the amplitude of the target state becomes the maximum for the first time, and the algorithm can always maintain the optimal number of iterations, so as to reduce the number of unnecessary iterations in the algorithm process and make the number of iterations reach $ t_{\rm f}=(\pi /2)\sqrt{2^{n-2}} $.  相似文献   
3.
In this study, vanadium nanoparticles (VNPs) were green synthesized using Foeniculum vulgare extract. VNPs were characterized using chemical analysis techniques including FT-IR, XRD, FE-SEM, TEM and EDS. The microscopy techniques revealed a spherical morphology for the particles with size less than 50 nm. According to XRD data V2O5 was confirmed for VNPs. Maybe significant anti-human acute leukemia potentials of the synthesized nanoparticles against common human acute leukemia cell lines are linked to their antioxidant activities. MTT assay was used on common acute leukemia cell lines i.e., 32D-FLT3-ITD, MOLT-3 and Jurkat, Clone E6-1 to survey the cytotoxicity and anti-acute leukemia effects of the synthesized nanoparticles. The synthesized nanoparticles had very low cell viability and high anti-acute leukemia activities dose-dependently against 32D-FLT3-ITD, MOLT-3 and Jurkat, Clone E6-1 cell lines without cytotoxicity on the normal cell line (HUVEC). To determine the antioxidant properties of the synthesized nanoparticles, the DPPH test was used in the presence of butylated hydroxytoluene as the positive control. The IC50 of VNPs were 25, 33 and 26 µg/mL against 32D-FLT3-ITD, MOLT-3 and Jurkat, Clone E6-1 cell lines, respectively. The synthesized nanoparticles inhibited half of the DPPH molecules in the concentration of 28 µg/mL.  相似文献   
4.
5.
于波  郭峰 《高分子科学》2015,33(1):163-172
We directly monitor the absolute separation profiles that function as film thickness between a single glass disk and the charged polyelectrolyte brushes decorated steel slider in water using a home-made slider-on-disk apparatus, which reflects the structural conformation variations and interactions of polymer brushes under externally applied pressure, in addition to probing the relative variation of friction forces under different applied loads and sliding velocities. We find that the polyelectrolyte brushes modified surfaces can sustain high pressure and have extremely low friction coefficients(around 0.006 at pressures of 0.13 MPa; 0.5-0.6 without brushes). The water-lubrication characteristics are correlated to the structural conformation changes of the polyelectrolyte brushes that are mainly governed by electrostatic interactions and the osmotic pressure of counterions inside the polymer chains, which can be used to support and distribute the normal pressure. The apparent thickness of the brush decreases with the increase of loading forces, an increase in the ionic strength causes the polymer chains collapse, and the friction forces increase. This fundamental research is of great importance to understand the mechanical and structural properties of polyelectrolyte brushes and their influences on the tribological behaviors, and helps to design friction/lubrication-controlled surface/interface by taking advantage of polyelectrolyte brushes.  相似文献   
6.
This study represents the first example of a bidentate phosphine-free manganese(I)-NN complex catalyst for the synthesis of quinolines (pyridines) through acceptorless dehydrogenative condensation of various secondary alcohols with amino alcohols. The coupling reactions occurred at 3 mol% catalyst loading and 110°C, and tolerated diverse functional groups. Moderate to excellent yields ranging from 45% to 89% were achieved after 12 hr of reaction. The present protocol provides a concise and environmentally friendly method for the construction of heterocyclic compounds.  相似文献   
7.
Zhen-Yu Chen 《中国物理 B》2021,30(8):80303-080303
We investigate the correlations between two qubits in the Grover search algorithm with arbitrary initial states by numerical simulation. Using a set of suitable bases, we construct the reduced density matrix and give the numerical expression of correlations relating to the iterations. For different initial states, we obtain the concurrence and quantum discord compared with the success probability in the algorithm. The results show that the initial states affect the correlations and the limit point of the correlations in the searching process. However, the initial states do not influence the whole cyclical trend.  相似文献   
8.
本文中研究了不同固溶处理后7055铝合金在3.5%NaCl溶液中的耐腐蚀行为,在3.5%NaCl溶液下进行了静态腐蚀试验及腐蚀磨损试验,并通过扫描电子显微镜对磨痕形貌进行分析. 结果表明:固溶处理后试样的耐腐蚀性能均有不同程度的提高,其中以双级固溶处理试样的耐腐蚀性能最好. 在动极化、开路电位以及阴极保护和阳极加速腐蚀试验中,固溶处理后材料自腐蚀电位正移,腐蚀电流密度减小,耐腐蚀磨损性能提高. 在不同加载电位下,腐蚀电流密度和磨损率随着电位的增加而增大,在?1.2 V时摩擦系数最小. 同时随着电位的升高,腐蚀作用促进了合金的磨损. 在较低电位时,合金的腐蚀磨损机制主要是磨粒磨损;而较高电位下,合金的腐蚀磨损机制主要是黏着磨损和腐蚀磨损.   相似文献   
9.
The contents of topological classification of matter are enriched by non-Hermiticity, such as exceptional points, bulk-edge correspondence, and skin effects. Physically, gain and loss can be introduced by imaginary on-site potentials of lattice Hamiltonians, and the topological phase transition for a cross-linked chain in the presence of such non-Hermiticity is investigated. The topological phase diagram in terms of a winding number is obtained analytically with phase boundaries coinciding with the surfaces of exceptional points. The topologically original edge states with distribution mainly at the joints between domains of different phases are protected even for long chains. The non-Hermitian topological feature can also be reflected by vortex structures in the vector fields of complex eigenenergies, expected values of Pauli matrices, and trajectories of these quantities. This model may be implemented in coupled photonic crystals, fermions trapped in optical lattice, or non-Hermitian electrical-circuit lattices, and the edge states are immune to various kinds of disorders until topological phase transition occurs. This work gives insight into the influence of non-Hermiticity on topological phase of matter.  相似文献   
10.
马鸿洋  秦国卿  范兴奎  初鹏程 《物理学报》2015,64(16):160306-160306
提出和研究了噪声情况下的量子网络直接通信. 通信过程中所有量子节点共享多粒子Greenberger-Horne-Zeilinger (GHZ)量子纠缠态; 发送节点将手中共享的GHZ态的粒子作为控制比特、传输秘密信息的粒子作为目标比特, 应用控制非门(CNOT)操作; 每个接收节点将手中共享GHZ 态的粒子作为控制比特、接收到的秘密信息粒子作为目标比特, 再次应用CNOT门操作从而获得含误码的秘密信息. 每个接收节点从秘密信息中提取部分作为检测比特串, 并将剩余的秘密信息应用奇偶校验矩阵纠正其中存在的比特翻转错误, 所有接收节点获得纠正后的秘密信息. 对协议安全、吞吐效率、通信效率等进行了分析和讨论.  相似文献   
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