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The coupled relationship between carrier and phonon scattering severely limits the thermoelectric performance of n-type GeTe materials. Here, we provide an efficient strategy to enlarge grains and induce vacancy clusters for decoupling carrier-phonon scattering through the annealing optimization of n-type GeTe-based materials. Specifically, boundary migration is used to enlarge grains by optimizing the annealing time, while vacancy clusters are induced through the aggregation of Ge vacancies during annealing. Such enlarged grains can weaken carrier scattering, while vacancy clusters can strengthen phonon scattering, leading to decoupled carrier-phonon scattering. As a result, a ratio between carrier mobility and lattice thermal conductivity of ∼492.8 cm3V–1s–1W–1K and a peak ZTof ∼0.4 at 473 K are achieved in Ge0.67Pb0.13Bi0.2Te. This work reveals the critical roles of enlarged grains and induced vacancy clusters in decoupling carrier-phonon scattering and demonstrates the viability of fabricating high-performance n-type GeTe materials via annealing optimization.

Cr(vi) reduction to Cr(iii) with electrochemical technique has been regarded as an effective method for the treatment of toxic Cr(vi) contaminated wastewater. Herein, to promote the reactive sites and electron transfer for improving Cr(vi) reduction, we compositely modified the carbon-fiber felt (CFF) with a tree-like branched structure of polypyrrole (PPy) microwires as the first branch and polyaniline (PANI) nanorods as the secondary branch, which increased the BET surface area from 1.2 m2per each CFF substrate to 89.8 m2per each CFF-PPy–PANI cathode. The flow-through electrochemical reduction device with the CFF-PPy–PANI cathode exhibited 20–70% larger Cr(vi) removal and 20–55% lower energy consumption than that with original CFF, PPy-modified CFF, and PANI-modified CFF cathodes. Electrochemical analyses revealed that the tree-like branched structure of the CFF-PPy–PANI cathode promoted the reactive sites, electron transfer, and interfacial ion diffusion for enhancing Cr(vi) reduction. According to the in situsampling experiments, the Cr(vi) reduction to Cr(iii) on cathode was the major removal mechanism with minor Cr(vi) adsorption on the anode. The CFF-PPy–PANI cathode at 1.4 V and 500 L h−1m−2exhibited excellent durability and stability for almost Cr(vi) reduction and 98.8 ± 0.98% energy efficiency within 5-day continuous operation. These results suggested that the micro-nano PPy/PANI composite modification can be a promising strategy for efficient Cr(vi) reduction.

l Se-alloying induces dense point defects scatter high-frequency phonons. l Se-alloying induce resonant states strengthen Umklapp phonon scattering. l Approaching low lattice thermal conductivity of ∼0.65 W m−1K−1 at 723 K. l Approaching a peak figure of merit value of ∼1.6 at 723 K. High lattice thermal conductivity of intrinsic GeTe limits the wide application of GeTe-based thermoelectrics. Recently, the optimization of GeTe-based thermoelectric materials has been focusing on reducing lattice thermal conductivity via strengthening phonon scattering. In this study, we systematically studied thermoelectric properties of Se-alloyed Ge 0.95 Bi 0.05 Te via theoretical calculations, structural characterizations, and performance evaluations. Our results indicate that Se-alloying can induce dense point defects with mass/strain-field fluctuations and correspondingly enhance point defect phonon scattering of the Ge 0.95 Bi 0.05 Te matrix. Se-alloying might also change chemical bonding strength to introduce resonant states in the base frequency of Ge 0.95 Bi 0.05 Te matrix, which can strengthen Umklapp phonon scattering. Finally, a decreased lattice thermal conductivity from ∼1.02 W m−1 K−1 to ∼0.65 W m−1 K−1 at 723 K is obtained in Ge 0.95 Bi 0.05 Te 1- x Se x pellets with increasing the Se content from 0 to 0.3. A peak figure of merit of ∼1.6 at 723 K is achieved in Ge 0.95 Bi 0.05 Te 0.7 Se 0.3 pellet, which is ∼77% higher than that of pristine GeTe. This study extends the understanding on the thermoelectric performance of GeTe. [ABSTRACT FROM AUTHOR]

Objective: To observe the clinical efficacy of moxibustion therapy plus Liu’s pediatric massage (tuina) for children with recurrent respiratory tract infections due to qi deficiency of spleen and lung. Methods: A total of 60 children who met the inclusion criteria were divided into an observation group and a control group according to the visiting sequence, with 30 cases in each group. Children in the observation group were treated with moxibustion therapy plus Liu’s pediatric massage, and those in the control group were treated with Liu’s pediatric massage alone. The incidence of respiratory tract infections and traditional Chinese medicine (TCM) symptoms score were observed and recorded in both groups before and after treatment. And the clinical efficacy was compared between the two groups. Results: The total effective rate of the observation group was 93.3%, and that of the control group was 83.3%. The difference between the two groups was statistically significant (P<0.05). After treatment, the TCM symptoms score and total times of infections in both groups were all statistically different from those before treatment (all P<0.05). The differences in TCM symptoms score and infection frequency before and after treatment in the observation group were statistically different from those in the control group (both P<0.05). Conclusion: Moxibustion therapy plus Liu’s pediatric massage has a better effect in improving the clinical symptoms and reducing the frequency of respiratory tract infections for children with recurrent respiratory tract infections due to qi deficiency of spleen and lung than the pediatric massage alone.

With the development of China's economy, large-scale engineering and complex engineering are emerging. The Engineering Procurement Construction (EPC) project general contracting model is widely used in civil engineering, water conservancy, railway, water treatment, waste incineration plants and other large engineering area. The increasing complexity of construction technology and the risks are facing overwhelming and fragile supply chain. Based on the deep analysis of supply chain operation reference (SCOR) model, which is widely used in various fields of industry, this article puts forward the preliminary index system of supply chain risk of EPC project by analytic hierarchy process (AHP). The risk index system of waste incineration project including 5 first-level risk indicators and 27 second-level risk indicators has been established and determined. The multi-level grey model is used to evaluate the risk index, calculate the grey evaluation coefficient and the grey evaluation weight vector as well as the weight matrix, draw the specific risk evaluation value of the project, and sort the first level index. Finally, an EPC example of a waste incineration in Hubei Province is used to verify the feasibility and reliability of the method.

Differential Evolution Algorithm (DE) is fast and stable, but it’s easy to fall into the local optimal solution and the population diversity reduces fast in the later period. In order to improve the algorithm optimization and convergence capability, this paper proposes an improved DE algorithm based on the new crossover strategy (CMDE). As to the Crossover-factor is decided by the proportion of the variance and the evolution process in each generation, so it can follow the process of evolution and constantly change; the added operation of Second Mutation can improve the capacity of solving problem, which algorithm falls into the local solution easily. With four standard test functions, the results show that the CMDE algorithm is superior to DE in convergence speed, precise and stability of algorithm.

Unsteady cavitation flows in a centrifugal pump operating under off-design conditions are investigated by using a numerical framework combining the re-normalization group k–ɛ turbulence model and the transport equation-based cavitation model. The reliability and accuracy of the numerical model are demonstrated by the satisfactory agreement between the experimental and numerical values of the pump performance. Under partial discharge, the frequency spectra of the pressure fluctuation at the impeller inlet become more complex as the pump inlet pressure decreases. The maximum amplitude of pressure fluctuation at the blade leading edge for cavitation flow is 2.54 times larger than that for non-cavitation flow because of the violent disturbances caused by cavitation shedding and explosion. Under large discharge, the magnification on the maximum pressure amplitude is 1.6. This finding indicates that cavitation has less influence on pressure fluctuations in the impeller under large discharge than under partial discharge. This numerical simulation demonstrates the evolution of cavitation structure inside the impeller.

Nitric-oxide synthase (NOS; EC 1.14.13.39) catalyzes the oxidation of L-arginine to nitric oxide (NO(.)) and L-citrulline via the intermediate N(omega)-hydroxy-L-arginine. Of the three distinct isoforms of NOS that have been characterized, the constitutive neuronal NOS (NOS I) generates NO(.) associated with long-term potentiation (LTP) and early brain development. All of the NOS isoforms contain an N-terminal oxidase and a C-terminal reductase domain connected by a Ca(2+)/calmodulin binding region. To activate NOS I, Ca(2+) has to bind to calmodulin, allowing electron transport through both domains. Calcium ions are tightly regulated in cells. However, a number of other metal ions that bind and activate calmodulin may also activate NOS I. One such metal ion may be Pb(2+), which is associated with neurobehavioral and psychological alterations, including the inhibition of LTP. The effect of various divalent cations on NOS I activity was tested, and the results presented herein demonstrate that Pb(2+) and Sr(2+) can activate NOS I to a level similar to that found for Ca(2+). Finally, there is a synergy between Pb(2+) and Ca(2+) resulting in maximal activation of NOS I using minimal concentrations of both metal ions.

In order to solve the problem of poor robustness of the traditional method of calculating torque in the mechanical model of 7-DOF picking manipulator, this paper proposes a control strategy of calculating torque plus fuzzy compensation by using adaptive fuzzy logic system to compensate the uncertain part of the mechanical model of 7-DOF picking manipulator. By using Lagrange method, the dynamic model of 7-DOF manipulator is established, and the relationship between joint motion and applied torque (force) is obtained. Using ADAMS and MATLAB to establish a co-simulation platform, the manipulator and trajectory tracking control system are simulated. The results show that the trajectory tracking error of each joint in the algorithm is obviously reduced and the convergence trend is obvious. The average trajectory tracking accuracy of joint 1 to joint 7 was improved by 70.22%, 94.78%, 0.62%, 74.23%, 89.78%, 86.45%, and 67.15%, respectively. In this control scheme, the control force (moment) of each joint changes regularly, and the output force (moment) does not appear chattering and mutation when the disturbance signal is added. The research results can provide support for the further study of picking manipulator trajectory tracking control system.

Two qubits in pure entangled states going through separate paths and interacting with their own individual environments will gradually lose their entanglement. Here we show that the entanglement change of a two-qubit state due to amplitude damping noises can be recovered by entanglement swapping. Some initial states can be asymptotically purified into maximally entangled states by iteratively using our protocol. [ABSTRACT FROM AUTHOR]

Two known nonorthogonal quantum states can be cloned either deterministically or probabilistically. In this paper, we investigate quantum cloning by combining these two extreme cases, i.e., a trade-off between the copy fidelity and the success probability. For a special set of two known nonorthogonal quantum states, we start with an explicit unitary transformation and derive the copy fidelity as a function of the success probability. The result shows that the higher is the copy fidelity, the less is the success probability. This quantum cloning may have important applications in quantum cryptography. [ABSTRACT FROM AUTHOR]

We present a proposal for storing and retrieving a continuous-variable quadripartite polarization-entangled cluster state, using macroscopic atomic ensembles in a magnetic field. The Larmor precession of the atomic spins leads to a symmetry between the atomic canonical operators. In this scheme, each of the four spatially separated pulses passes twice through the respective ensemble in order to map the polarization-entangled cluster state onto the long-lived atomic ensembles. The stored state can then be retrieved by another four read-out pulses, each crossing the respective ensemble twice. By calculating the variances, we analyzed the fidelities of the storage and retrieval, and our scheme is feasible under realistic experimental conditions. [ABSTRACT FROM AUTHOR]

Remote entanglement will inevitably decrease due to the interactions between quantum systems and their environments. Therefore protecting remote entanglement against decoherence is of great importance in realizing quantum communication and quantum comp utation. In this paper, we demonstrate that decoherence caused by weak-measurement-induced damping can be effectively suppressed by adding local unitary operation series on each qubit. The results show that the entanglement of the output state can approach that of the state before amplitude damping. The most distinct advantage of this entanglement protection scheme is that any unitary operation (except the identity operation) has this entanglement reversal effect on the amplitude-damped states. Furthermore, in each local unitary operation series, all the operations can be different from one other, and all the time intervals between any two adjacent operations can be different too. In addition, there is no need for the two remote users to synchronize their operations. Unlike most of the previous schemes, we do not assume the instantaneous local unitary operation, and each operation has a duration. All these advantages suggest that this remote entanglement protection scheme is much simpler and feasible than the previous ones, and we hope it can be implemented in the near future. Recently, Y. S. Kim et al. [Nat. Phys. 8, 117 (2012)] pointed out that "pre-weak measurement + amplitude damping + bit-flipping operation + post-weak measurement" can actively combat specific decoherence. By combing our proposal with Kim et al.'s scheme, the protection performance can be greatly improved by replacing the bit-flipping operation with an arbitrary rotational operation around the x axis, the number of the operations as well as the interval between any two adjacent operations all can be different, and the application range of the scheme can be greatly broadened. [ABSTRACT FROM AUTHOR]

In this work, we study how to distill two typical multipartite entangled noisy states, the amplitude-damped W state and the amplitude-damped Greenberger-Horne-Zeilinger state. Unlike the currently existing multipartite entanglement purification schemes, our scheme is a single-copy-based scheme, i.e., only one noisy state is needed in each distillation round, and the complicated multilateral controlled-NOT (CNOT) operations are replaced by measurements of local positive-operator-valued measures (POVMs). The results show that local POVM measurements on one copy of the noisy state can project the initial state onto a new state with higher entanglement and nonlocality. In this scheme, although the final state can violate the multipartite Bell inequality, the corresponding initial noisy state does not violate it, which means that this distillation scheme can reveal the hidden genuine multipartite nonlocality of these initial states. For the case of the amplitude-damped W state, if the POVM parameters are appropriately chosen, the fidelity of the output state can approach 1.0 for all the initial states with fidelity bigger than zero. So this single-copy-based multipartite entanglement distillation scheme has a wide range of distillable fidelities, and it is much simpler than the two-copy- or multiple-copy-based schemes. Furthermore, if the POVM measurement is carried out only on some member qubits rather than all of them, the distillation scheme can succeed too, which will greatly decrease the implementation complexity of the scheme. So this multipartite entanglement distillation scheme may be implementable in some physical system. [ABSTRACT FROM AUTHOR]

We present three protocols for directly measuring the concurrence of two-photon polarization-entangled states, including pure states and mixed states. Two signal photon pairs in the same polarization-entangled states are needed in each detection round, and the signal photons will pass through polarization-independent beam splitters simultaneously. The concurrence of the photon pairs will be encoded in the total probability of picking up the balanced states in the two output modes of the beam splitter, which can be directly measured by single-photon detectors. The photon detection efficiency can be further enhanced with the help of the weak cross-Kerr nonlinearity, and the signal photons will not be absorbed. The third scheme using the bilateral nondemolition measurements can measure the concurrence of both pure and mixed states with high efficiency and high fidelity and is robust against the copy error of the state to be measured. The sophisticated controlled-NOT operation of the previous schemes is not required here, so our protocols are more feasible within the current experimental technology. [ABSTRACT FROM AUTHOR]

Fusion technique plays a key role in the preparation of large-scale W states, but the currently existing fusion schemes are suffering from the qubit loss problem, i.e., the number of the output entangled qubits is smaller than the sum of numbers of the input entangled qubits, which will inevitably decrease the fusion efficiency and increase the number of fusion steps as well as the requirement of quantum memories. In this paper, we design a fusion mechanism to fuse two small-size W states into a large-scale W state without qubit loss, and thus we call it qubit-loss-free (QLF) fusion mechanism. This QLF fusion mechanism is based on a two-outcome positive-operator valued measurement on two qubits extracting from two small-size W states, and works for both pure and mixed W states. The QLF nature of this fusion mechanism clearly increases the final size of the obtained W state, and greatly reduces the number of fusion steps as well as the requirement of quantum memories required to achieve a W state of a target size, so it is more efficient and feasible than the currently existing fusion schemes. There is no complete failure output in our QLF fusion scheme, and all the garbage states are recyclable. Two example schemes are proposed to realize this QLF fusion mechanism in a cavity quantum electrodynamics system and three-qubit Heisenberg XYZ model, respectively, which demonstrates the possibility of the physical realization of this QLF fusion mechanism. [ABSTRACT FROM AUTHOR]

We prove that the squared Rényi-α entanglement (SRαE), which is the generalization of entanglement of formation, obeys a general monogamy inequality in an arbitrary N-qubit mixed state. Furthermore, for a class of Rényi-α entanglement, we prove that the monogamy relations of the SRαE have a hierarchical structure when the N-qubit system is divided into k parties. As a by-product, the analytical relation between the Rényi-α entanglement and the squared concurrence is derived for bipartite 2⊗d systems. Based on the monogamy properties of SRαE, we can construct the corresponding multipartite entanglement indicators, which still work well even when the indicators based on the squared concurrence and EOF lose their efficacy. In addition, the monogamy property of the μth power of Rényi-α entanglement is analyzed. [ABSTRACT FROM AUTHOR]