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Sketch-based method has emerged as a promising direction for per-flow measurement in data center networks. Usually in such a measurement system, a sketch data structure is placed as a whole at one switch for counting all passing packets, but when summarizing measurement results from multiple switches, the overall accuracy is generally constrained by a few individual switches with small-sized sketches due to their limited memory resources. To address this problem, in this paper, we present Distributed Sketch, a new method for per-flow network measurement in data center networks. In Distributed Sketch, each network path is associated with a logical sketch, whose data structure is collectively maintained by all the switches along the path; meanwhile, each switch multiplexes its physical sketch to the constructions of the logical sketches of all the paths it belongs to. With Distributed Sketch, switches collaborate to measure network flows, and the network-wide measurement workload is fairly distributed among all the switches in the network. We implement Distributed Sketch with P4 on commodity hardware programmable switch, and in particular, to overcome the limitation that hardware switches do not support float-point computation, we present an optimal approximation method that involves only integer operations. We also propose an In-band Network Telemetry (INT) based method for addressing the challenges in deploying Distributed Sketch in large-scale data centers. Experiment results and theoretical analysis show that our proposed method is lightweight regarding measurement overhead, and by aggregating and making fair uses of resources from all the switches in the network, Distributed Sketch achieves a higher measurement accuracy compared with the state-of-the-art solutions.

The deposition time was controlled to prepare Mn nanowires of different lengths and diameters on templates of anodic aluminum oxide (AAO) with different pore sizes. The surface of as-prepared Mn nanowires was modified with SiO2using the sol–gel method to improve their dispersion in aqueous solution. The effects of the diameter and length of the as-prepared Mn nanowires coated with SiO2on the relaxivity were investigated. It was found that the Mn@SiO2nanowires have smaller diameters and a higher longitudinal relaxivity (r1) with an increased length. Mn3@SiO2nanowires had the highest r1value of 5.8 mM–1s–1among the Mn@SiO2nanowires (Mn3 nanowires have a diameter of about 30 nm and a length of about 0.5 μm length). Additionally, the biocompatibility and in vivo imaging ability of the Mn3@SiO2nanowires were evaluated. The Mn3@SiO2nanowires had good cytotoxicity and biocompatibility, and the kidney of SD rats showed a positive enhancement effect during small animal imaging at 1.5 T. This study showed that the Mn3@SiO2nanowires could potentially become contrast agents (CAs) of longitudinal relaxation time (T1).

Highly-ordered Fe nanowires (NWs) were successfully electrodeposited in a laboratory made anodic aluminum oxide template with a diameter of 30 nm. The as prepared Fe NWs were used as a substrate to prepare core–shell Fe@Fe3O4NWs after annealing and hydrogen reduction at high temperature. The phase transformation of the oxide shell of electrodeposited Fe NWs took the form Fe2O3→ α-Fe2O3→ Fe3O4. Transmission electron microscopy images revealed that the surface of Fe@Fex−1OxNWs was smooth and orderly, and the oxide layer was dense and uniform. The magnetic analysis of Fe@Fex−1Oxnanowires was carried out using a vibrating sample magnetometer. It was found that Fe@Fe3O4nanowires manifested the characteristics of super-paramagnetism in the direction perpendicular to the nanowires due to smaller coercive force, and they can be suitable material for future biomedical applications.

We demonstrate a versatile nanoparticle with imaging-guided chemo–photothermal synergistic therapy and EpCAM-targeted delivery of liver tumor cells. EpCAM antibody (anti-EpCAM) and Pt(IV) were grafted onto the polydopamine carbon dots (PDA-CDs) by the amidation reaction. The EpCAM antibody of particles enables the targeted interaction with liver progenitor cells due to their overexpressed EpCAM protein. The tetravalent platinum prodrug [Pt(IV)] induces apoptosis with minimum toxic side effects through the interaction between cisplatin and tumor cell DNA. The nanoparticles displayed stable photothermal property and considerable anti-tumor therapeutic effect in vivo. Coupling with cellular imaging due to their fluorescence property, anti-EpCAM@PDA-CDs@Pt(IV) offers a convenient and effective platform for imaging-guided chemo–photothermal synergistic therapy toward liver cancers in the near future.

Modeling the mechanical stress birefringence and slow-axis distributions of optical plates is critical for optical lithography systems. In this paper, the distributions of mechanical stress birefringence and the slow axes of optical plates were modeled by the finite element (FE) model, stress optic relations, and the ray-traced Jones matrices method. To validate this model, the load incremental approach was utilized to reduce the disturbance of residual birefringence in mechanical stress birefringence measurement. The measured distributions of birefringence and the slow axis of the optical plate show a good agreement with our numerical simulation results. This model provides a better understanding of simulation of mechanical stress birefringence and provides a reference for optical design and polarization analysis of other optical elements.

A setup for surface-plasmon-resonance- (SPR) based imaging ellipsometry was developed, which gains from the sensitivities of both SPR and ellipsometry to ultrathin film parameters. It is based on Otto’s configuration for prism–sample coupling and a wide-beam imaging ellipsometry. A set of ultrathin gold and silver films was measured to determine their optical constants and thicknesses. Coupling the sample using a prism with a convex surface enables us to capture images of generated SPR elliptical fringes, which correspond to different SPR amplitude values at different air gap thicknesses. Analysis of the images acquired at different polarizer and analyzer angles provides the ellipsometric functions Ψ and Δ versus thickness of air gap and hence the extraction of the optical constants of ultrathin metal films. The measured film thickness is in agreement with the results of x-ray reflectivity measurements.

Single layer lattice graphene deposited on the metal substrate can hardly be imaged by the optical microscope. In this Letter, a large field-of-view imaging ellipsometer is introduced to image single layer graphene which is deposited on a metal substrate. By adjusting the polarizer and the analyzer of imaging ellipsometer, the light reflected from surfaces of either single layer graphene or a Au film substrate can be extinguished, respectively. Thus, single layer graphene can be imaged correspondingly under brightfield or darkfield imaging modes. The method can be applied to imaging large-area graphene on a metal substrate.