Preparation and Performance of Short Carbon Fiber and Flake Graphene Reinforced Polycarbonate Composites: Effects of Different Tougheners

Different tougheners including methyl methacrylate-butadiene-styrene terpolymer (MBS, core-shell type), maleic anhydride (MAH) grafted ethylene-octene copolymer (EOM), and MAH grafted polyethylene wax (PEM) were investigated for toughening the polycarbonate (PC) composites reinforced by short carbon fiber (SCF) and flake graphene (FG). The effects of tougheners on the preparation, thermal conductivity and mechanical properties of PC composites were studied. Scanning electron microscopy was used for characterizing the impact fracture surfaces of the composites. The results showed that introducing tougheners into the carbon reinforced PC composites was beneficial to improving the processability, and PEM was more effective than EOM and MBS. Meanwhile, the through-thickness and the in-plan thermal conductivity decreased to some degree due to the isolated island effects of tougheners. Moreover, the brittle PC composites with high flexural stress could be easily toughened by tougheners. In contrast, PEM had better toughening function than EOM and MBS, and correspondingly, the stiffness of the composites was the lowest for the PEM toughened systems. The fractography revealed that dense and uniformly distributed carbon fillers dispersed in matrix PC and circular cavities coexisted in the composites. The naked fiber length gradually increased as the ductility of composite materials improved.

General Structure Physics of an Aerial Remote Sensing Platform and Its Systemic Accuracy Criterion

Accuracy is a key factor in high-resolution remote sensing and photogrammetry. The factors that affect accuracy are imaging system errors and data processing errors. Due to the complexity of aerial camera errors, this paper focuses on the design of digital aerial camera systems and the means to reduce system error and data processing inefficiencies. There are many kinds of digital aerial camera systems at present;however, these systems lack a unified physical model, which ultimately leads to more complicated designs and multi-camera modes. Such a system is complex and costly, as it is easily affected by factors such as vibration and temperature. Thus, the installed accuracy can only reach the millimeter level. Here, we describe a unified physical structure for a digital aerial camera that imitates an out-of-field multi-charge-coupled device (CCD), an in-field multi-CCD, and once-imaging and twice-imaging digital camera systems. This model is referred to as the variable baseline-height ratio spatiotemporal model. The variable ratio allows the opto-mechanical spatial parameters to be linked with height accuracy, thus providing a connection to the surface elevation. The twice-imaging digital camera prototype system and the wideband limb imaging spectrometer provide a transformation prototype from the current multi-rigid once-imaging aerial camera to a single rigid structure. Thus, our research lays a theoretical foundation and prototype references for the construction and industrialization of digital aerial systems.

Quantum control for time-dependent noise by inverse geometric optimization

Quantum systems are exceedingly difficult to engineer because they are sensitive to various types of noises.In particular,timedependent noises are frequently encountered in experiments but how to overcome them remains a challenging problem.In this work,we propose a flexible robust control technique to resist time-dependent noises based on inverse geometric optimization working in the filter-function formalism.The basic idea is to parameterize the control filter function geometrically and minimize its overlap with the noise spectral density.This then effectively reduces the noise susceptibility of the controlled system evolution.We show that the proposed method can produce high-quality robust pulses for realizing desired quantum evolutions under realistic noise models.Also,we demonstrate this method in examples including dynamical decoupling and quantum sensing protocols to enhance their performances.

Dynamical-invariant-based holonomic quantum gates:Theory and experiment

Among existing approaches to holonomic quantum computing,the adiabatic holonomic quantum gates(HQGs)suffer errors due to decoherence,while the non-adiabatic HQGs either require additional Hilbert spaces or are difficult to scale.Here,we report a systematic,scalable approach based on dynamical invariants to realize HQGs without using additional Hilbert spaces.While presenting the theoretical framework of our approach,we design and experimentally evaluate single-qubit and two-qubits HQGs for the nuclear magnetic resonance system.The single-qubit gates acquire average fidelity 0.9972 by randomized benchmarking,and the controlled-NOT gate acquires fidelity 0.9782 by quantum process tomography.Our approach is also platform-independent,and thus may open a way to large-scale holonomic quantum computation.

Pilot test of polymer microsphere alternate surfactant flood(PMAS)with mixtures of anionic-cationic surfactants under harsh conditions in a sandstone reservoir

The first pilot test of polyacrylamide microsphere alternate surfactant flood(PMAS)with mixtures of anionic-cationic surfactants(Sa/c)was carried out for a high-temperature,high-salinity,and highhardness sandstone reservoir to demonstrate the potential of this novel technique to improve oil recovery.A critical micelle concentration(CMC)of 4.82 mg/L,an ultralow interfacial tension(IFT)of 8104 mN/m,and a high oil solubilization of 22 were obtained.Static and dynamic adsorptions of Sa/c on natural core containing 15 wt%clay were reduced to about 2.20 and 0.30 mg/g-core,respectively,with the addition of adsorption inhibitor(AI).Since June 2014,the pilot test of PMAS was carried out in a Sinopec reservoir with a temperature of 87C,a salinity of 260,393 mg/L,and a hardness of 6,401 mg/L.Twelve cycles of alternative injection of 0.0125 PV Sa/c with a concentration of 0.1%and 0.0125 PV polyacrylamide microsphere with a concentration of 0.2%were conducted at an injection rate of 0.1 PV/yr,for a total of 0.3 PV chemical injection.As a result,the net daily oil production increased from 0 t to 6.5 t,and the water cut decreased from 96.3%to 93.8%,leading to an ultimate improved oil recovery of 6.3%original oil-in-place.

Experimental quantum simulation of a topologically protected Hadamard gate via braiding Fibonacci anyons

Topological quantum computation(TQC)is one of the most striking architectures that can realize fault-tolerant quantum computers.In TQC,the logical space and the quantum gates are topologically protected,i.e.,robust against local disturbances.The topological protection,however,requires complicated lattice models and hard-to-manipulate dynamics;even the simplest system that can realize universal TQC-the Fibonacci anyon system—lacks a physical realization,let alone braiding the non-Abelian anyons.Here,we propose a disk model that can simulate the Fibonacci anyon system and construct the topologically protected logical spaces with the Fibonacci anyons.Via braiding the Fibonacci anyons,we can implement universal quantum gates on the logical space.Our disk model merely requires two physical qubits to realize three Fibonacci anyons at the boundary.By 15 sequential braiding operations,we construct a topologically protected Hadamard gate,which is to date the least-resource requirement for TQC.To showcase,we implement a topological Hadamard gate with two nuclear spin qubits,which reaches 97.18%fidelity by randomized benchmarking.We further prove by experiment that the logical space and Hadamard gate are topologically protected:local disturbances due to thermal fluctuations result in a global phase only.As a platform-independent proposal,our work is a proof of principle of TQC and paves the way toward fault-tolerant quantum computation.