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Objective Since the post-rinsing time is inconsistently recommended, this study aims to investigate the effect of post-rinsing time on the flexural strength and cytotoxicity of an stereolithographically (SLA) printed orthodontic splint material. Methods SLA-printed specimens were ultrasonically rinsed with isopropanol (IPA) for 5 min, 12 min, 20 min, 30 min, 1 h, and 12 h, respectively. Surface characterization was conducted by scanning electron microscopy and roughness measurements. Flexural strength was evaluated using a three-point bending test. Cytotoxicity was determined by direct contact test and extract test. For both tests, cell viability (live/dead staining) and cell metabolic activity (CCK-8 assay) were evaluated. Additionally, water sorption and water solubility were tested to analyze the mass loss from immersion. Results No apparent surface alterations could be detected on the samples post-rinsed for less than 1 h. In contrast, when the post-rinsing time was prolonged to 12 h, surface fissures could be observed. Flexural strength linearly decreased with increasing post-rinsing time. All post-processed specimens did not show an obvious cytotoxic effect. Significance The removal of cytotoxic methacrylate monomers by post-rinsing with IPA could be achieved in 5 min. Extending post-rinsing time could not improve the cytocompatibility of the SLA-printed orthodontic splint material, and may result in a decrease in flexural strength.

Magnetic nano- and microparticles (MNMPs) belong to a highly versatile class of colloids with actuator and sensor properties that have been broadly studied for their application in theranostics such as molecular imaging and drug delivery. The use of advanced biocompatible, biodegradable polymers and polyelectrolytes as MNMP coating materials is essential to ensure the stability of MNMPs and enable efficient drug release while at the same time preventing cytotoxic effects. In the past years, huge progress has been made in terms of the design of MNMPs. Especially, the understanding of coating formation with respect to control of drug loading and release kinetics on the molecular level has significantly advanced. In this review, recent advancements in the field of MNMP surface engineering and the applicability of MNMPs in research fields of medical imaging, diagnosis, and nanotherapeutics are presented and discussed. Furthermore, in this review the main emphasis is put on the manipulation of biological specimens and cell trafficking, for which MNMPs represent a favorable tool enabling transport processes of drugs through cell membranes. Finally, challenges and future perspectives for applications of MNMPs as theranostic nanomaterials are discussed.

The present study aimed to evaluate the bonding between three 3D printed custom tray materials and three elastomeric impression/adhesive systems using the peel test.Test blocks were 3D printed by three different technologies using Dental LT, FREEPRINT tray, and polylactide (PLA) tray materials. The reference test blocks were conventionally fabricated with Zeta Tray LC, a light-curing resin. The surface topographies of the four tray materials were investigated by scanning electron microscopy (SEM) analyses and roughness measurements. The peel bond strength between the four tray materials and three impression/adhesive systems, vinylsiloxanether (VSXE), vinyl polysiloxane (VPS), and polyether (PE), was measured (n=12 per group). The peeling failure modes and rupture sites were identified microscopically.The four tray materials featured different surface topographies. The peel bond strength was not significantly different with VSXE and PE, but PLA and the reference showed higher peel bond strength with VPS than the Dental LT and FREEPRINT tray (p0.05). The rupture site of adhesive failure in all groups was partly at the adhesive-impression material interface and partly within the adhesive but never at the adhesive-tray material interface.The 3D printed tray materials can achieve satisfactory chemical compatibility with the adhesives of VSXE, VPS, and PE. Surface topographies generated by the 3D printing technologies may affect bonding. Generally, 3D printed tray materials can provide clinically adequate bond strength with the elastomeric impression/adhesive systems. PLA is recommended for bonding with VPS when severe impression removal resistance is detected.

In this paper, a newly shunted-line stepped-impedance resonator (SLSIR) is studied and applied to realize high-order balanced filter design for radio astronomy application. The proposed SLSIR not only has more flexible control of the internal coupling between adjacent units but also provides more design freedom for the cascade connection of high-order filter. Then, the operating theory of three kinds of electrically, magnetically, and electromagnetically coupled SLSIR pairs has been discussed and utilized to high-performance filter design. Hence, fourth-order balanced filter using electromagnetically coupled SLSIR pairs is investigated and designed, which exhibits an excellent filtering performance under differential-mode (DM) operation as well as a high common-mode (CM) suppression level. In addition, the production mechanism of DM transmission zero is modeled and analyzed. Based on the analysis above, two dissimilar types of coupled SLSIR pairs with the same fundamental frequency but different harmonics are adopted to design an eighth-order balanced filter. Finally, the high-order balanced filter is fabricated on 0.5-mm-thick MgO wafer with double-sided YBCO thin films. Measured results show that the eighth-order balanced filter operates at 2.53 GHz with the corresponding in-band insertion loss of 0.1 dB. Results well verify the proposed structure with high selectivity, low insertion loss, and wide stopband performances.

Numerous factors can influence the force exerted by clear aligners teeth. This study aimed to investigate the stability of the force delivered by two different material appliances. 90 clear aligners with 2 materials and three different activations were designed and fabricated. Then, a device was employed to measure the force generated by the two types of PET-G material appliances immersed in artificial saliva for 0, 3, 7, 10, 14 days. Scanning electron microscopy was applied to observe the morphologic alterations on the aligner surfaces, respectively. The forces generated by different activation appliance exhibited differently, 0.0 mm < 0.1 mm < 0.2 mm. In addition, increasing the immersion times and the orthodontic force also decreased , but the forces decreased differently. Compared with the forces of conventional PETG appliances with 0.20 mm activation, the modified PETG appliances with the same activation exhibited significantly higher mean force. When comparing the mean force for modified PETG appliances after 10 and 14 days with conventional PETG appliances, the delivery forces exhibited significant differences (P

Recently, contrastive learning (CL) has emerged as a successful method for unsupervised graph representation learning. Most graph CL methods first perform stochastic augmentation on the input graph to obtain two graph views and maximize the agreement of representations in the two views. Despite the prosperous development of graph CL methods, the design of graph augmentation schemes -- a crucial component in CL -- remains rarely explored. We argue that the data augmentation schemes should preserve intrinsic structures and attributes of graphs, which will force the model to learn representations that are insensitive to perturbation on unimportant nodes and edges. However, most existing methods adopt uniform data augmentation schemes, like uniformly dropping edges and uniformly shuffling features, leading to suboptimal performance. In this paper, we propose a novel graph contrastive representation learning method with adaptive augmentation that incorporates various priors for topological and semantic aspects of the graph. Specifically, on the topology level, we design augmentation schemes based on node centrality measures to highlight important connective structures. On the node attribute level, we corrupt node features by adding more noise to unimportant node features, to enforce the model to recognize underlying semantic information. We perform extensive experiments of node classification on a variety of real-world datasets. Experimental results demonstrate that our proposed method consistently outperforms existing state-of-the-art baselines and even surpasses some supervised counterparts, which validates the effectiveness of the proposed contrastive framework with adaptive augmentation., Comment: Accepted to WWW 2021, authors' version. 12 pages, 3 figures, 5 tables. arXiv admin note: substantial text overlap with arXiv:2006.04131

We discuss physical constructions, and the boundary properties of various symmetry protected topological phases that involve 1-form symmetries, from one spatial dimension (1d) to four spatial dimensions (4d). For example, the prototype 3d boundary state of 4d SPT states involving 1-form symmetries can be either a gapless photon phase (quantum electrodynamics) or gapped topological order enriched by 1-form symmetries, namely the loop excitations of these topological orders carry nontrivial 1-form symmetry charges. This study also serves the purpose of diagnosing anomaly of 3d states of matter. Connection between SPT states with 1-form symmetries and condensed matter systems such as quantum dimer models at one lower dimension will also be discussed. Whether a quantum dimer model can have a trivial gapped phase or not depends on the nature of its corresponding bulk state in one higher dimension., 10 pages, 1 figure

The non-isolated HE-Boost topology has been widely used in the area of voltage boost due to the advantages of continuous input and output current, high efficiency and easy control. The freewheeling modes caused by leakage inductance of transformer are ignored by conventional small signal modeling method, and the model accuracy is low, which is not conducive to the analysis of control stability and design of compensation network. Using the switching element averaging method to model the He-Boost converter considering leakage inductance of transformer, forward voltage of diode, parasitic resistance of input inductor and output capacitor. The modified model and simulated results are basically the same, which is consistent with experimental results; the maximum amplitude and phase error at low frequency band do not exceed 1dB and 3° respectively. Using the modified model to design compensating network, the results show that the modified model has higher accuracy, and the theoretical design of controller is in good agreement with experimental result.

The present study aimed to evaluate the repairability of a 3D printed denture base material. The effects of surface treatments and artificial aging on the shear bond strength (SBS) were investigated.A total of 224 specimens were printed by digital light processing technology (Rapid Shape D30II) using a 3D printing denture base material (FREEPRINT denture). To evaluate the repairability, the SBS and failure modes were measured after surface treatment and artificial aging. Specifically, half of the specimens were further performed with thermocycling (5-55 °C, 5000 cycles) for artificial aging. The aged and non-aged specimens were further divided into four subgroups (n = 28) to simulate a denture base repair with one of the following treatments: control (without surface treatment), monomer (applying methylmethacrylate for 120 s), P600 (grinding with P600 silicon carbide paper) and sandblasting (blasted with 125 μm aluminum oxide with 2 bar), respectively. Surface roughness was measured (n = 6) and surface topography was observed by scanning electron microscopy (n = 2). A test rod was built on the sample surface using the same 3D printing material. Afterward, all specimens further underwent thermocycling (5-55 °C, 10,000 cycles).For non-aged groups, no significant differences in SBS could be found (p 0.05), and bondings failed cohesively in the denture base material. Regarding the aged control and monomer group, adhesive failures at the interface were primarily observed, and SBS values were statistically lower than those of the other groups (p 0.05).The 3D printed denture base material exhibited favorable repairability. For the realignment surface, the SBS at the bonding interface is satisfying and additional surface treatments could be not necessary. In contrast, the aged surface could significantly decrease the SBS; hence subtractive surface treatments are highly recommended.

Motivated by recent observation of nematicity in Moire systems, we study three different orbital orders that potentially can happen in Moire systems: (1) the nematic order; (2) the valley polarization; and (3) the "compass order". Each order parameter spontaneously breaks part of the spatial symmetries of the system. We explore physics caused by the quantum fluctuations close to the order-disorder transition of these order parameters. Especially, we recognize that the symmetry of the Moire systems leads to a crucial difference of the effective theory describing the nematic order from the standard Hertz-Millis formalism. We demonstrate that this key difference may lead to a special non-Fermi liquid behavior near the order-disorder nematic transition, different from the standard non-Fermi liquid behavior usually expected when a Fermi surface is coupled to the critical fluctuations of orbital orders. We also discuss the interplay of the three order parameters and the possible rich phase diagram at finite temperature. Within the three orbital orders, the valley polarization and the "compass order" likely strongly compete with the superconductor.

We discuss the boundary critical behaviors of two dimensional quantum phase transitions with fractionalized degrees of freedom in the bulk, motivated by the fact that usually it is the $1d$ boundary that is exposed and can be conveniently probed in many experimental platforms. In particular, we mainly discuss boundary criticality of two examples: i. the quantum phase transition between a $2d$ $Z_2$ topological order and an ordered phase with spontaneous symmetry breaking; ii. the continuous quantum phase transition between metal and a particular type of Mott insulator (U(1) spin liquid). This theoretical study could be relevant to many purely $2d$ systems, where recent experiments have found correlated insulator, superconductor, and metal in the same phase diagram.

Li7La3Zr2O12 (LLZO) garnet is one of the most promising Lithium-ion solid electrolytes in all-solid-state Lithium-ion batteries, due to its higher chemical stability to Li metal and relatively higher lithium-ion conductivity. To further increase the electrical conductivity of LLZO, Sm3+ is doped into the Zr4+ site of LLZO so that excess Li occupies the position of the octahedral. Thereby lithium ion transport and increasing ionic conductivity are promoted. The optimal addition of Sm3+ is 0.06. Li7+xLa3Zr2-xSmxO12 (LLZSO, x = 0.06) electrolyte with cubic phase is obtained with sintering at 1200 °C for only 3 h. It has higher relative density and better ionic conductivity than the pristine LLZO. Its bulk and total ionic conductivity are ∼6.4 × 10−4 S·cm−1 and 2.46 × 10−4 S·cm−1 at 20 °C, respectively.

The advent of metasurface gives a great push to the realization of extremely thin cloak. However, narrow bandwidth remains an unsolved problem. To solve this problem, we propose a broadband metasurface carpet cloak which can work well in the near-infrared band with circularly-polarized incidence. A novel phase compensation method is presented in this letter to show that a single metasurface can meet the phase requirements for cloaking in a broad spectrum. Through finite-difference time-domain simulations, we demonstrate that the cloak conceals a bump well in the broad spectrum from 1200 to 1680 nm.

To protect user privacy, many smartphone systems adopt the permission-based mechanism in which a user can evaluate the risk of requests for private information from a mobile app before installing it. However, recent studies show that the permission based mechanism is vulnerable to application collusion attacks because two apps, which appear to be harmless individually, can establish a covert channel and use it to leak confidential information. Consequently, people have designed some covert channel detection schemes, by checking abnormal status of the phone. In this paper, we point out that existing covert channel detection schemes may fail to detect a new type of collusion attacks referred as user-behavior-based covert channels. We implement three covert channels on Android smartphones. Our work sets a new alarm for the security issue of using smartphones. We then study the countermeasures to this new type of covert channels. Instead of trying to directly detect the proposed new type of covert channels, we propose two mitigation solutions to reduce the effectiveness of such covert channels. The mitigation solutions are also valid to other existing sensor-based side channels and/or covert channels on the phone.

The fundamental origin of giant magnetostriction in dual-phase nanostructured systems is still under debate in recent years. Previous studies have revealed that the formation of tetragonal nanoinclusions induced the enlargement in local magnetocrystalline anisotropy, leading to a strengthened magneto–elastic coupling coefficient, which was considered to promote magnetostriction. Another key factor of magnetostriction, the influence of the nanoinclusions on the elastic constants of the lattices is, however, still not clear. In this work, we propose a mechanism based on the experimental and theoretical results of binary and rare-earth (RE) doped FeGa single-crystals. Doping traces of RE atoms effectively increase the density of nanoinclusions in the A2 matrix, due to the high selectivity of RE atoms they possess stronger bonding interaction with Fe atoms rather than Ga atoms. As a consequence, the elastic constant c 12 significantly increases with the rising density of tetragonal nanoinclusions as opposed to the constant c 11 , resulting in a remarkable enhancement in magnetostriction due to the immediate relevance between magnetostriction ( λ 001 ) and c 11 − c 12 . A superior magnetostriction of 390 ppm is obtained in the RE-doped single-crystal due to lattice softening induced by the nanoinclusions. This uncovered mechanism sheds light onto the contribution of RE atoms on the magnetostriction in FeGa single-crystals, and establishes a foundation for developing new-generation dual-phase magnetostrictive materials with unprecedented levels of magnetostriction.

Wave-plate mist eliminator with porous foam layers as enhanced structures on vanes to improve separation efficiency for tiny droplets was proposed in this paper. Overall separation efficiency, grade separation efficiency and pressure drop of the mist eliminators were systematically studied by using Computational Fluid Dynamics (CFD) method. The Shear Stress Transport (SST) k-ω turbulence model and Discrete Phase Model (DPM) were adopted to describe the motion of gas phase and liquid phase, respectively. The computational field was simplified by introducing an assumption that the real 3D structure of porous foam can be equivalent to 2D layout with randomly arranged circles. The CFD results showed that the separation efficiency was enhanced by increasing the foam layer thickness. Moreover, a gradual increase in the foam porosity at fixed PPI (pores per inch) value made the separation efficiency increased to a maximum value, then fall to a lower level, while by decreasing the PPI value of the foam at fixed porosity, the separation efficiency increased. Pressure drop was increased both with the increase in the foam layer thickness and PPI value as well as the decrease of the porosity. Furthermore, the flow field and the droplet trajectories were also analyzed.

In this paper, a new kind of wave-plate mist eliminator using open-celled porous silicon carbide foam layers as enhanced structure has been firstly proposed. The effects of foam layer geometry parameters (foam layer thickness, porosity, PPI) on droplet performance (separation efficiency and pressure drop) were experimentally investigated. Re-entrainment mechanism influenced by flooding state in the foam layer was also discussed. Downstream droplet diameter distribution under the re-entrainment conditions were also investigated by color-developing method. The results show that the sample with smaller foam pore size has larger volume mean diameter of secondary droplets in the outflow, due to its weaker liquid drainage ability. Comparisons between the experiment and our earlier numerical simulation demonstrate the average relative errors of the separation efficiency and the pressure drop are within 10%, meanwhile trends relating demister performance to foam geometry parameters are the same between the two sets of results, indicating the validity of the simulation method. In addition, two empirical correlations were obtained by fitting the experimental data, which can be used for predicting separation efficiency and pressure drop in the selected experiment conditions.

This paper presents a compact wideband bandpass filter (BPF) integrating with two narrow-band notch resonators, for preventing the wideband communication system from interfering. The wideband filter adopts an asymmetric stub-loaded multimode resonator to obtain a bandwidth of 66.7%, with excellent passband fluctuation. In addition, two multiloop resonators are used to implement a 0.56% narrow-band. To illustrate its usefulness, a high-temperature superconducting wideband BPF with built-in narrow-band notch resonators is designed. It is fabricated on 20.8 mm × 16.15 mm YBCO films deposited on a 0.5-mm-thick MgO substrate with a relative permittivity ϵr of 9.78. The proposed wideband filter works at L-band, i.e., 1–2 GHz, and the return loss is greater than 19 dB. The notch-band resonator centered at 1.805 GHz provides more than 25 dB maximum attenuation for avoiding interferences from the global system for mobile communication. Finally, the circuit is measured, and the results agree well with the simulations.

In this Letter, a novel vertical bipolar junction transistor (BJT) triggered silicon-controlled rectifier (VBTSCR) is proposed for advanced nanoscale electrostatic discharge (ESD) protection applications. With the help of a vertical NPN transistor in floating base configuration, the new silicon-controlled rectifier (SCR) structure achieves lower trigger voltage and better clamping capacity than the prior enhanced modified lateral SCR (EMLSCR) under the same layout footprint. The ESD characteristics are measured using the transmission line pulsing tester. Compared with that of EMLSCR, the trigger voltage of VBTSCR drops by 1 V, and the effective ESD robustness of VBTSCR has been doubled significantly. Based on these advantages, the proposed VBTSCR can provide ESD protection for the advanced 1.8/2.5 V input/output circuits more efficiently.

One salient feature of systems with Moir\'{e} superlattice is that, Chern number of "minibands" originating from each valley of the original graphene Brillouin zone becomes a well-defined quantized number because the miniband from each valley can be isolated from the rest of the spectrum due to the Moir\'{e} potential. Then a Moir\'{e} system with a well-defined valley Chern number can become a nonchiral topological insulator with $U(1) \times Z_3 $ symmetry and a $\mathbb{Z}$ classification at the free fermion level. Here we demonstrate that the strongly interacting nature of the Moir\'{e} system reduces the classification of the valley Chern insulator from $\mathbb{Z}$ to $\mathbb{Z}_3$, and it is topologically equivalent to a bosonic symmetry protected topological state made of local boson operators. We also demonstrate that, even if the system becomes a superconductor when doped away from the valley Chern insulator, the valley Chern insulator still leaves a topological imprint as the localized Majorana fermion zero mode in certain geometric configuration., Comment: 6 pages, 4 figures

Mn-Al alloys are promising candidates to fill the performance gap between rare-earth permanent magnets and ferrites, but improving the intrinsic magnetic properties of Mn-Al alloys in the ordered $L{1}_{0}$ phase is not easy. Doping seems to be essential. This work investigates the influence of substitutional atoms on the alloy's intrinsic magnetic properties. The occupation rules for substituents with different valence-electron structures are analyzed, and a strategy to boost the alloy's magnetic properties is developed. This insight should help to promote the engineering of devices that do not rely on rare-earth-bearing magnets, which is of keen interest.

With the rapid development of intelligent electrical technologies and power demand response (DR), the power consumption scale of industrial users has expanded dramatically. Aiming at satisfying the diverse demands of industrial customers, the paper proposes three typical power optimization schemes for industrial users, which are all based on improved genetic algorithm (GA). Firstly, representative industrial load types and their corresponding demand response modes are put forward. Secondly, according to the respective demands of industrial users, a variety of power consumption models under time-of-use pricing are constructed and solved by improved genetic algorithm. Finally, the power optimization schemes proposed in the paper are verified by Matlab simulations. The results indicate that schemes designed by improved GA significantly outperform traditional GA schemes in terms of satisfying the industrial power demands over economy, efficiency and accuracy separately.

The building damage status is vital to plan rescue and reconstruction after a disaster and is also hard to detect and judge its level. Most existing studies focus on binary classification, and the attention of the model is distracted. In this study, we proposed a Siamese neural network that can localize and classify damaged buildings at one time. The main parts of this network are a variety of attention U-Nets using different backbones. The attention mechanism enables the network to pay more attention to the effective features and channels, so as to reduce the impact of useless features. We train them using the xBD dataset, which is a large-scale dataset for the advancement of building damage assessment, and compare their result balanced F (F1) scores. The score demonstrates that the performance of SEresNeXt with an attention mechanism gives the best performance among single models, with the F1 score reaching 0.787. To improve the accuracy, we fused the results and got the best overall F1 score of 0.792. To verify the transferability and robustness of the model, we selected the dataset on the Maxar Open Data Program of two recent disasters to investigate the performance. By visual comparison, the results show that our model is robust and transferable.

In this paper, a compact, high-selectivity and wideband high-temperature superconducting (HTS) bandpass filter (BPF) with a narrow notched-band is reported. This wideband BPF is realized using a multi-mode resonator (MMR) with two different T-shaped stubs. For improving the filter selectivity, multiple transmission zeros, which are located close to either side of the wide passband, were created by loaded stubs and source-load coupling technique. Moreover, two identical λ/2 spiral resonators are inserted into the filter to create a narrow notched-band. Finally, simulation results of the proposed filter show good performances and compact size.

A compact high-selectivity microstrip tri-band bandpass filter (BPF) using a multimode short stub-loaded symmetric loop resonator (SLSLR) with a feed structure is proposed in this paper. Distinct mode splitting characteristics of the quadruple-mode SLSLR are investigated and explained by using even-and odd-mode theory. The dual-band BPF is realized using the quadruple-mode SLSLR. Then, the high-impedance feeding lines of SLSLR dual-band BPF is modified to produce a new passband. To validate the approach, a tri-band BPF centered at 1.4/2.7/3.57 GHz has been implemented. Good agreement is obtained between simulated and measured results.

A microstrip triple band filter using dissimilar quarter-wavelength stepped impedance resonator (SIR) with a source-load coupling feedlines structure is proposed in this paper. Multiple transmission zeros are generated by using source-load coupling structure. Then, multipath coupling diagrams are constructed and the relative phase shifts of each path are studied to explain the responses of the triple-band filter. The bands of the designed tri-band BPF are operated at 1.9 GHz and 2.6 GHz for TD-LTE application and 3.6 GHz (Wi-MAX band) was designed. Also, the circuit size occupies only 0.29λ g ×0.20λ g , where λ g is the guided wavelength at the center frequency of the first passband.