Recommendation Method for Contrastive Enhancement of Neighborhood Information

Knowledge graph can assist in improving recommendation performance and is widely applied in various person-alized recommendation domains.However,existing knowledge-aware recommendation methods face challenges such as weak user-item interaction supervisory signals and noise in the knowledge graph.To tackle these issues,this paper proposes a neighbor information contrast-enhanced recommendation method by adding subtle noise to construct contrast views and employing contrastive learning to strengthen supervisory signals and reduce knowledge noise.Specifically,first,this paper adopts heterogeneous propagation and knowledge-aware attention networks to obtain multi-order neighbor embedding of users and items,mining the high-order neighbor informa-tion of users and items.Next,in the neighbor information,this paper introduces weak noise following a uniform distribution to construct neighbor contrast views,effectively reducing the time overhead of view construction.This paper then performs contrastive learning between neighbor views to promote the uniformity of view information,adjusting the neighbor structure,and achieving the goal of reducing the knowledge noise in the knowledge graph.Finally,this paper introduces multi-task learning to mitigate the problem of weak supervisory signals.To validate the effectiveness of our method,experiments are conducted on theMovieLens-1M,MovieLens-20M,Book-Crossing,and Last-FM datasets.The results showthat compared to the best baselines,our method shows significant improvements in AUC and F1.

Monte Carlo study of the magnetic properties and magnetocaloric effect of an AFM/FM BiFeO_(3)/Co bilayer

The magnetic properties and magnetocaloric effect of an antiferromagnetic/ferromagnetic(AFM/FM)BiFeO_(3)/Co bilayer with mixed-spin(5/2,3/2)have been studied based on Monte Carlo simulation.The magnetization,susceptibility,and critical temperature are investigated under various exchange couplings and an external magnetic field.In particular,the influence of exchange couplings and an external magnetic field on the magnetic entropy change,adiabatic temperature change,and the relative cooling power(RCP)are studied.The simulation results indicated that the decrease of the exchange coupling and the increase of external magnetic fields can cause an increase of magnetic entropy change,adiabatic temperature change,and RCP.In addition,the hysteresis loops of the system are presented for different exchange couplings and temperatures.

High-humidity tolerance of porous TiO2(B)microspheres in photo thermal catalytic removal of NOx

Semiconductor oxides are widely used to achieve photocatalytic removal of NOx(NO and NO2) species. These materials also exhibit enhanced oxidation ability in thermally assisted photocatalysis;however, many of them tend to be deactivated at high relative humidity(RH) levels. In the case of the benchmark P25 TiO2 photocatalyst, we observe a significant decrease in non-NO2 selectivity from 95.02% to 58.33% when RH increases from 20% to 80%. Interestingly, the porous TiO2(B) microspheres synthesized in this work exhibit 99% selectivity at 20% RH;the selectivity remains as high as 96.18% at 80% RH. The high humidity tolerance of the TiO2(B) sample can be ascribed to its strong water desorption capacity and easy O2 adsorption at elevated temperatures, which reflects the fact that the superoxide radical is the main active species for the deep oxidation of NOx. This work may inspire the design of efficient photothermal catalysts with application in NOx removal in hot and humid environments.

Growth, characterization, and Raman spectra of the 1T phases of TiTe_(2), TiSe_(2), and TiS_(2)

High-quality large 1T phase of TiX_(2)(X = Te, Se, and S) single crystals have been grown by chemical vapor transport using iodine as a transport agent. The samples are characterized by compositional and structural analyses, and their properties are investigated by Raman spectroscopy. Several phonon modes have been observed, including the widely reported A_(1g) and E_(8) modes, the rarely reported E_(u) mode(-83 cm^(-1) for TiTe_(2), and -185 cm^(-1)for TiS_(2)), and even the unexpected K mode(-85 cm^(-1)) of TiTe_(2). Most phonons harden with the decrease of temperature, except that the K mode of TiTe_(2) and the E_(u) and “A_(2u)/Sh” modes of TiS_(2) soften with the decrease of temperature. In addition, we also found phonon changes in TiSe_(2) that may be related to charge density wave phase transition. Our results on TiX_(2) phonons will help to understand their charge density wave and superconductivity.

The effect of cold-light-activated bleaching treatment on enamel surfaces in vitro

This in vitrostudy aims to evaluate the crystal and surface microstructure of dental enamel after cold-light bleaching treatment. Twelve sound human premolars were cross-split into four specimens, namely, mesio-buccal （Group LP）, disto-buccal （Group P）, mesio-lingual （Group NP） and disto-lingual （Group L） specimens. These four groups were treated using the standard cold-light bleaching procedure, a bleaching agent, a peroxide-free bleaching agent and cold-light, respectively. Before and after treatment, all specimens were analyzed by high-resolution, micro-area X-ray diffraction and scanning electron microscopy. Using a spectrometer, tooth color of all specimens was measured before and after treatment. The phase of the enamel crystals was identified as hydroxyapatite and carbonated hydroxyapatite. After treatment, specimens in Groups LP and P showed significantly weaker X-ray diffraction peaks, significant reduction in crystal size and crystallinity, significant increase in L~ but decrease in a＊ and b＊, and obvious alterations in the surface morphology. However, specimens in Groups NP and L did not show any significant changes. The cold-light bleaching treatment leads to demineralization in the enamel surface. The acidic peroxide-containing bleaching agent was the major cause of demineralization, whereas cold-light did not exhibit significant increase or decrease effect on this demineralization.

Microzoning Study for Seismic Risk Reduction in the Areas Covered Soft Soil Deposit, Japan

Kanagawa Prefecture, Japan, is just located on the tectonic plate boundary between the Philippines Sea Plate and the North American Plate. This tectonic plate boundary is called Sagami Trough and located in Sagami Bay. The 1923 Great Kanto Earthquake （Mj7.9） occurred on this plate boundary sub-ducting from Sagami Trough, the damage due to this earthquake was so huge in Kanaawa Pref., especially, along the big river, called Sagami River, located at the middle part of Kanagawa Pref. which was mostly seriously damaged. It is caused by the soft soil deposit along the Sagami River. So, in this study, we first confirmed the results of single point microtrcemor observation of about 980 points in the target area, and at this time, we tried to investigate the surface soil structure by using the miniature array microtrcemor observation, and aimed to estimate the overall ground structure of Sagami Plain. The ground structure of Sagami plains is complex, but the northern part of the plain is relatively simple and soft soil layer is shallow and stable. But the plains of the southern part, especially the west side of the Sagami River were found to be fairly soft ground. Following above, the surface soil structure in north-south direction is very clearly changed depending on the distance from the sea coast. A changing gap on the basement is very quickly appeared about 10 km far from the coast. And also, we calculated the average Vs of the surface ground and confirmed the consistency with the current ground state while confirming the historical change and the topography situation.

Analysis of Engine Exhaust Pressure Wave Performance

By analyzing the form of pressure wave within automotive exhaust system and relationship between propagation process and working condition of engine, simulate a work cycle for purpose of timely diagnosing troubles, thus presenting exhaust stroke of four cylinders through pressure wave;modifying of the speed of engine will affect the amplitude of pressure wave, harmonic components, phase position and other parameters;at the end of the exhaust stroke, exhaust pressure wave generates interference, superposition and negative effect, which is of great importance for analysis and diagnosis of engine troubles by using exhaust pressure wave.

Real-time Control Oriented HCCI Engine Cycle-to-cycle Dynamic Modelling

For homogeneous charge compression ignition （HCCI） combustion, the auto-ignition process is very sensitive to in-cylinder conditions, including in-cylinder temperature, in-cylinder components and concentrations. Therefore, accurate control is required for reliable and efficient HCCI combustion. This paper outlines a simplified gasoline-fueled HCCI engine model implemented in Simulink environment. The model is able to run in real-time and with fixed simulation steps with the aim of cycle-to-cycle control and hardware- in-the-loop simulation. With the aim of controlling the desired amount of the trapped exhaust gas recirculation （EGR） from the previous cycle, the phase of the intake and exhaust valves and the respective profiles are designed to vary in this model. The model is able to anticipate the auto-ignition timing and the in-cylinder pressure and temperature. The validation has been conducted using a comparison of the experimental results on Ricardo Hydro engine published in a research by Tianjin University and a JAGUAR V6 HCCI test engine at the University of Birmingham. The comparison shows the typical HCCI combustion and a fair agreement between the simulation and experimental results.

Pseudoaneurysm with Median Nerve Injury Caused by Right Radial Artery Puncture:A Case Report

Background:Pseudoaneurysm with median nerve injury is a serious complication of radial artery puncture.It is very important to summarize the prevention and treatment experience of this complication through case discussion.Case report:A 66-year-old woman was admitted to the hospital because of‘‘paroxysmal chest tightness and suffocation for 5 days.”Coronary angiography was performed.During insertion of the arterial sheath,the patient experienced severe pain in the right forearm,which radiated to the palm.The puncture sheath did not return blood after the sheath core was withdrawn.The sheath was removed and local compression was used to stop bleeding.There was no obvious bleeding at the puncture point,and the compression was removed 6 hours after the procedure.Local swelling and increased tension were seen in the right forearm.At the 1-week follow-up she exhibited swelling,high local tension,small blisters,and bluish-purple skin of the right forearm,with an acceptable right radial artery pulsation.She had severe pain in the affected limb,which radiated to the thumb,index fi nger,and middle fi nger.Case discussion:We discuss the causes of and treatment measures for pseudoaneurysm with median nerve injury caused by radial artery puncture.

Supramolecular systems for bioapplications:recent research progress in China

Supramolecular systems feature dynamic,reversible and stimuli-responsive characteristics,which are not easily achieved by molecular entities.The last decade has witnessed tremendous advances in the investigations of supramolecular systems for various bioapplications,which include drug delivery,anticancer therapy,antibacterial therapy,photodynamic therapy,photothermal therapy,combination therapy,antidotes for residual drugs or toxins,and bioimaging and biosensing.Host-guest chemistry has played a key role in the development of such bioactive supramolecular systems,and natural macrocycles(such as cyclodextrins),synthetic macrocycles(such as calixarenes,cucurbit[n]urils,and pillararenes),and porous framework polymers(such as supramolecular organic frameworks and flexible organic frameworks)have been most successfully used as hosts to build different kinds of host-guest systems for attaining designed biofunctions.The self-assembly of rationally designed amphiphilic molecules,macromolecules and polymers represent another important approach for the construction of supramolecular architectures with advanced biofunctions.In this review,we summarize the important contributions made by Chinese researchers in this field,with emphasis on those reported in the past five years.

Microstructures and mechanical properties of a commercial Mg-Al-Zn-Mn alloy with various hot-extrusion processes

Mg-Al-Zn-Mn(AZ)system alloys have become widely used due to their good castability,excellent formability and outstanding corrosion resistance[1-6].However,their strength is still much lower than that of traditional Mg-RE(rare earth)based alloys or even some new Mg-Li basedalloys[7-19].

Quantum simulations of materials on near-term quantum computers

Quantum computers hold promise to enable efficient simulations of the properties of molecules and materials;however,at present they only permit ab initio calculations of a few atoms,due to a limited number of qubits.In order to harness the power of near-term quantum computers for simulations of larger systems,it is desirable to develop hybrid quantum-classical methods where the quantum computation is restricted to a small portion of the system.This is of particular relevance for molecules and solids where an active region requires a higher level of theoretical accuracy than its environment.Here,we present a quantum embedding theory for the calculation of strongly-correlated electronic states of active regions,with the rest of the system described within density functional theory.We demonstrate the accuracy and effectiveness of the approach by investigating several defect quantum bits in semiconductors that are of great interest for quantum information technologies.We perform calculations on quantum computers and show that they yield results in agreement with those obtained with exact diagonalization on classical architectures,paving the way to simulations of realistic materials on near-term quantum computers.

SEM imaging of insulating specimen through a transparent conducting veil of carbon nanotube

Observing the morphology of insulating specimen in scanning electron microscope(SEM)is of great significance for the nanoscale semiconductor devices and biological tissues.However,the charging effect will cause image distortion and abnormal contrast when observing insulating specimen in SEM.A typical solution to this problem is using metal coating or water-removable conductive coating.Unfortunately,in both cases the surface of the specimen is covered by a thin layer of conductive material which hides the real surface morphology and is very difficult to be completely removed after imaging.Here we show a convenient,residue-free,and versatile method to observe real surface morphology of insulating specimen without charging effect in SEM with the help of a nanometer-thick film of super-aligned carbon nanotube(SACNT).This thin layer of SACNT film,like metal,can conduct the surface charge on insulating specimen through the sample stage to the ground,thus eliminating the charging effect.SACNT film can also be used as the conductive tape to carry and immobilize insulating powder or particles during SEM imaging.Different from the metal coating,SACNT film is transparent,so that the real microstructure of the insulating specimen surface can be observed.In addition,SACNT film can be easily attached to and peeled off from the surface of specimen without any residue.This convenient,residue-free,and versatile method can open up new possibilities in nondestructive SEM imaging of a wide variety of insulating materials,semiconductor devices,and biological tissues.

A site-oriented nanosystem for active transcellular chemo-immunotherapy to prevent tumor growth and metastasis

Immunotherapy has shown promising potential in cancer therapy;however, poor delivery by nanocarriers and insufficient immune response in tumors have severely impeded its clinical application. To overcome these disadvantages, a site-specific and active transcellular drug delivery system was developed herein for chemotherapyenhanced immunotherapy. When arriving at the tumor site,the matrix metallopeptidase 2(MMP2)-responsive shell detached from the nanosystem, releasing positively charged cores. The cationic surface of the inner cores induced adsorption-meditated transcytosis, which facilitated transendothelial transportation and transcellular drug delivery into distal tumor cells. PD-L1 antibody and chemotherapeutic drugs were loaded in the outer layer and inner cores of the nanosystem, respectively, to be precisely delivered to target sites, thereby achieving synchronized delivery and siteoriented release of different anticancer agents. PD-L1 antibody released in the tumor microenvironment effectively blocked the binding of PD-L1 to its receptors on the T cell surface. Oxaliplatin and indoximod co-delivered in the cationic cores can induce immunogenic cell death and attenuate the immunosuppressive effect throughout the tumor tissues,recruiting a large amount of T cells and further enhancing the immunotherapy. The resulting synergistic antitumor response could not only efficiently inhibit the growth of primary tumors, but also help prevent metastasis of primary tumor to distant sites. This study offers a novel nano-enabled strategy for chemo-immunotherapy in immunosuppressive tumors.

CD44-Specific Targeting Nanoreactors with Glutathione Depletion for Magnifying Photodynamic Tumor Eradication

Photodynamic therapy(PDT)is an efficacious noninvasive therapeutic modality that utilizes nontoxic photosensitizers(PSs)to transform oxygen into highly cytotoxic reactive oxygen species(ROS)under specific light irradiation.However,low intratumoral accumulation capacity and the reduced ROS production caused by excessive glutathione(GSH,a scavenger of ROS)in the tumor microenvironment(TME)immensely limit PDT therapeutic efficacy.

Research on GGT-responsive drug carrier with active transport effect

Although a great quantity research has been done on cancer nano-drug carriers,how to deliver more cancer nano-drugs to tumor sites accurately and then endocytosis by cells is still a key problem in the process of cancer treatment.Since the concentration ofγ-glutamyl transpeptidase(GGT)in the microenvironment will be greatly increased when the liver,kidney,other organs become cancerous,we have designed a polymer nanomicelle as drug carrier that can respond to the GGT in the tumor microenvironment.When the drug delivery system participates in blood circulation through the vascular wall cells to the tumor tissue,the overexpressed GGT on the surface of the cancer cells will recognize and cut theγ-glutamyl group on the carrier,the primary amines will be released to make the system with weak positive charge,which not only improves the carrier’s active transport ability for nanodrugs,but also improves the cell’s endocytosis ability for nano-drugs,so as to realize the release of nano-drugs in cancer cells.What’s more,the positive charge on the surface of the carrier also improves the permeability of the carrier in the tumor tissue,so that the cancer cells in the hypoxic area can also endocytosis drugs.

Bidirectional micro-actuators based on eccentric coaxial composite oxide nanofiber

It is of great importance to develop new micro-actuators with high performance by optimizing the structures and materials.Here we develop a VO2/AI2O3/CNT eccentric coaxial nanofiber,which can be potentially applied as a micro-actuator.The specific eccentric coaxial structure was efficiently fabricated by conventional thin film deposition methodology with individual CNT templet.Activated by thermal and photothermal stimuli,the as-developed actuator delivers a bidirectional actuation behavior with large amplitudes and an ultra-fast response,〜2.5 mS.A tweezer can be further made by assembling two such nanofibers symmetrically onto a tungsten probe.Clamping and unclamping can be realized by laser stimulus.More experimental and simulation investigations indicated that the actuation behaviors could be attributed to the nanostructured eccentric coaxial geometry,the thermal coefficient mismatch between layers and the fast phase transition of V02.The micro-actuators will have potentials in micro manipulators,nanoscaled switches,remote controls and other autonomous systems.Furthermore,a large variety of coaxial and eccentric coaxial nanofibers with various functions can also be developed,giving the as-developed methodology more opportunities.

Bioinspired nanochannels based on polymeric membranes

Bio-nanochannels in living organisms participate in the physiological activities by selectively transporting ions through cell membranes.The structure and function of biological ion channels inspire the development of artificial ion nanochannels with practical applications.The bioinspired nanochannels based on polymer materials present good mechanical stability,high-performance ion transport and designability,which have attracted much attention.In this review,we mainly focus on the fabrication and application of polymer-based biomimetic nanochannels especially in environmentally responsive biosensor and energy conversion.We firstly introduce the basic understanding of nanochannels in ion regulation and osmotic energy conversion.Then,we discuss the fabrication methods of polymer-based nanochannels and highlight their advantages compared with other materials.The practical applications of polymer-based biomimetic nanochannels,especially in energy conversion and environmentally responsive biosensor,are detailedly discussed.Finally,we summarize the unsolved problems in bioinspired nanochannels and overview the further developing direction in this field.

Giant pattern evolution in third-harmonic generation of strained monolayer WS2 at two-photon excitonic resonance

Strong geometrical confinement and reduced dielectric screening of two-dimensional(2D)materials leads to strong Coulomb interaction and eventually give rise to extraordinary excitonic effects,which dominates the optical and optoelectronic properties.For nonlinear 2D photonic or optoelectronic applications,excitonic effects have been proved effective to tune the light-matter interaction strength.However,the modulation of excitonic effects on the other aspect of nonlinear response,i.e.,polarization dependence,has not been fully explored yet.Here we report the first systemic study on the modulation of excitonic effects on the polarization dependence of second and third harmonic generation(SHG and THG)in strained monolayer WS2 by varying excitation wavelength.We demonstrated that polarization-dependent THG patterns undergo a giant evolution near two-photon excitonic resonance,where the long-axis of the parallel component(originally parallel to the strain direction)has a 90°flip when the excitation wavelength increases.In striking contrast,no apparent variation of polarization-dependent SHG patterns occurs at either two-or three-photon excitonic resonance conditions.Our results open a new avenue to modulate the anisotropic nonlinear optical response of 2D materials through effective control of excitonic resonance states,and thus open opportunity for new designs and applications in nonlinear optoelectronic 2D devices.

Author Correction:Spin–spin interactions in defects in solids from mixed all-electron and pseudopotential first-principles calculations

The original version of this Article contained an error in Fig.2,in which the colour coding of the legend,depicting the data for‘PWPAW’and‘FE-AE’,is interchanged.This has been corrected in both the PDF and HTML versions of the Article.