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Hypoxia-inducible factors (HIFs) are highly conserved transcription factors that are crucial for adaptation of metazoans to limited oxygen availability. Recently, HIF activation and inhibition have emerged as therapeutic targets in various human diseases. Pharmacologically desirable effects of HIF activation include erythropoiesis stimulation, cellular metabolism optimization during hypoxia and adaptive responses during ischaemia and inflammation. By contrast, HIF inhibition has been explored as a therapy for various cancers, retinal neovascularization and pulmonary hypertension. This Review discusses the biochemical mechanisms that control HIF stabilization and the molecular strategies that can be exploited pharmacologically to activate or inhibit HIFs. In addition, we examine medical conditions that benefit from targeting HIFs, the potential side effects of HIF activation or inhibition and future challenges in this field.

Factor graph optimization (FGO) provides a new means for asynchronous data fusion of integrated underwater vehicle navigation in a plug-and-play unified framework. However, in complex underwater environments, FGO suffers from observation anomalies, leading to deteriorated navigation solutions. This article proposes an improved factor graph with anomaly detection using Mahalanobis distance to overcome the above issue for inertial navigation system/Doppler velocity log/ultra-short baseline (INS/DVL/USBL) integrated underwater vehicle navigation. This method constructs a new factor graph model embedded with the node of anomaly detection for INS/DVL/USBL integration. Since the standard FGO computational load is increased with the number of the factor nodes, a sliding window technique is established to restrict the factor node number to improve the FGO computational efficiency. Based on above, a scheme of anomaly detection and regulation is presented for handling the disturbance of observation anomaly on system state estimation via the concept of Mahalanobis distance. Results of simulation and ground test experimentation show that the proposed methodology not only has the real-time performance but also has a strong robustness against observation anomaly for INS/DVL/USBL integrated navigation of underwater vehicles.

Two-dimensional materials have emerged as an important research frontier for overcoming the challenges in nanoelectronics and for exploring new physics. Among them, black phosphorus, with a combination of a tunable bandgap and high mobility, is one of the most promising systems. In particular, black phosphorus nanoribbons show excellent electrostatic gate control, which can mitigate short-channel effects in nanoscale transistors. Controlled synthesis of black phosphorus nanoribbons, however, has remained an outstanding problem. Here we report large-area growth of black phosphorus nanoribbons directly on insulating substrates. We seed the chemical vapour transport growth with black phosphorus nanoparticles and obtain uniform, single-crystal nanoribbons oriented exclusively along the [100] crystal direction. With comprehensive structural calculations, we discover that self-passivation at the zigzag edges holds the key to the preferential one-dimensional growth. Field-effect transistors based on individual nanoribbons exhibit on/off ratios up to ~104, confirming the good semiconducting behaviour of the nanoribbons. These results demonstrate the potential of black phosphorus nanoribbons for nanoelectronic devices and also provide a platform for investigating the exotic physics in black phosphorus.

Mammals have evolved to adapt to differences in oxygen availability. Although systemic oxygen homeostasis relies on respiratory and circulatory responses, cellular adaptation to hypoxia involves the transcription factor hypoxia-inducible factor (HIF). Given that many cardiovascular diseases involve some degree of systemic or local tissue hypoxia, oxygen therapy has been used liberally over many decades for the treatment of cardiovascular disorders. However, preclinical research has revealed the detrimental effects of excessive use of oxygen therapy, including the generation of toxic oxygen radicals or attenuation of endogenous protection by HIFs. In addition, investigators in clinical trials conducted in the past decade have questioned the excessive use of oxygen therapy and have identified specific cardiovascular diseases in which a more conservative approach to oxygen therapy could be beneficial compared with a more liberal approach. In this Review, we provide numerous perspectives on systemic and molecular oxygen homeostasis and the pathophysiological consequences of excessive oxygen use. In addition, we provide an overview of findings from clinical studies on oxygen therapy for myocardial ischaemia, cardiac arrest, heart failure and cardiac surgery. These clinical studies have prompted a shift from liberal oxygen supplementation to a more conservative and vigilant approach to oxygen therapy. Furthermore, we discuss the alternative therapeutic strategies that target oxygen-sensing pathways, including various preconditioning approaches and pharmacological HIF activators, that can be used regardless of the level of oxygen therapy that a patient is already receiving.

The graphene oxide (GO) was used to improve the mechanical performances of epoxy asphalt (EA) by preparing GO/EA composite. The influence of the GO dosage on the micro-structure, curing rheology, mechanical and thermal properties of GO/EA was investigated. According to the XRD and Fourier transform infrared spectra, the GO was exfoliated in the EA matrix and modified EA by non-covalent strategy. GO decreased the rotational viscosity of EA and increased the pot life. The GO/EA with 0.1 wt.% GO showed excellent toughness that the elongation at break was increased by 164%, and the tensile and pull-off adhesion strength were nearly equal to that of EA. The addition of GO improved the original thermal decomposition temperature (T5%), glass transition temperature (Tg), compatibility and stiffness of the EA. The improved mechanical and thermal properties of GO/EA may be attributed to (1) excellent performances of GO and (2) inhibiting effect of GO on the EA curing process.

One-dimensional electron systems exhibit fundamentally different properties than higher-dimensional systems. For example, electron–electron interactions in one-dimensional electron systems have been predicted to induce Tomonaga–Luttinger liquid behaviour. Naturally occurring grain boundaries in single-layer transition metal dichalcogenides exhibit one-dimensional conducting channels that have been proposed to host Tomonaga–Luttinger liquids, but charge density wave physics has also been suggested to explain their behaviour. Clear identification of the electronic ground state of this system has been hampered by an inability to electrostatically gate such boundaries and tune their charge carrier concentration. Here we present a scanning tunnelling microscopy and spectroscopy study of gate-tunable mirror twin boundaries in single-layer 1H-MoSe2devices. Gating enables scanning tunnelling microscopy and spectroscopy for different mirror twin boundary electron densities, thus allowing precise characterization of electron–electron interaction effects. Visualization of the resulting mirror twin boundary electronic structure allows unambiguous identification of collective density wave excitations having two velocities, in quantitative agreement with the spin–charge separation predicted by finite-length Tomonaga–Luttinger liquid theory.

Quantum spin liquids are highly entangled, disordered magnetic states that are expected to arise in frustrated Mott insulators and to exhibit exotic fractional excitations such as spinons and chargons. Despite being electrical insulators, some quantum spin liquids are predicted to exhibit gapless itinerant spinons that yield metallic behaviour in the charge-neutral spin channel. We deposited isolated magnetic atoms onto single-layer 1T-TaSe2, a candidate gapless spin liquid, to probe how itinerant spinons couple to impurity spin centres. Using scanning tunnelling spectroscopy, we observe the emergence of new, impurity-induced resonance peaks at the 1T-TaSe2Hubbard band edges when cobalt adatoms are positioned to have maximal spatial overlap with the local charge distribution. These resonance peaks disappear when the spatial overlap is reduced or when the magnetic impurities are replaced with nonmagnetic impurities. Theoretical simulations of a modified Anderson impurity model show that the observed peaks are consistent with a Kondo resonance induced by spinons combined with spin-charge binding effects that arise due to fluctuations of an emergent gauge field.

Two-dimensional triangular-lattice antiferromagnets are predicted under some conditions to exhibit a quantum spin liquid ground state with no energy barrier to create emergent, fractionalized spinon excitations that carry spin but no charge. Materials that realize this kind of spin liquid are expected to have a low-energy behaviour described by a spinon Fermi surface. Directly imaging the resulting spinons, however, is difficult due to their chargeless nature. Here we use scanning tunnelling spectroscopy to image density waves consistent with the predictions of spinon density modulation arising from a spinon Fermi surface instability in single-layer 1T-TaSe2. We confirm the existence of a triangular lattice of localized spins in this material by contacting it with a metallic 1H-TaSe2substrate and measuring the Kondo effect. Spectroscopic imaging of isolated single-layer 1T-TaSe2reveals long-wavelength super-modulations at Hubbard band energies, consistent with the predicted behaviour of itinerant spinons. These super-modulations allow the direct experimental measurement of the spinon Fermi wavevector, in good agreement with theoretical predictions for a two-dimensional quantum spin liquid.

Two-dimensional materials represent a major frontier for research into exotic many-body quantum phenomena. In the extreme two-dimensional limit, electron-electron interaction often dominates over other electronic energy scales, leading to strongly correlated effects such as quantum spin liquid and unconventional superconductivity. The dominance is conventionally attributed to the lack of electron screening in the third dimension. Here, we discover an intriguing metal to Mott insulator transition in 1T-TaSe2that defies conventional wisdom. Specifically, we find that dimensionality crossover, instead of reduced screening, drives the transition in atomically thin 1T-TaSe2. A dispersive band crossing the Fermi level is found to be responsible for the bulk metallicity in the material. Reducing the dimensionality, however, effectively quenches the kinetic energy of these initially itinerant electrons, and drives the material into a Mott insulating state. The dimensionality-driven metal to Mott insulator transition resolves the long-standing dichotomy between metallic bulk and insulating surface of 1T-TaSe2. Our work further reveals a new pathway for modulating two-dimensional materials that enables exploring strongly correlated systems across uncharted parameter space.Researchers have revealed an unprecedent metallic state and dimensionality-driven metal to Mott-insulator transition in 1T-TaSe2, shedding light on a new pathway for modulating two-dimensional strongly-correlated materials.

The circadian clock evolved in diverse organisms to integrate external environmental changes and internal physiology. The clock endows the host with temporal precision and robust adaptation to the surrounding environment. When circadian rhythms are perturbed or misaligned, as a result of jet lag, shiftwork or other lifestyle factors, adverse health consequences arise, and the risks of diseases such as cancer, cardiovascular diseases or metabolic disorders increase. Although the negative impact of circadian rhythm disruption is now well established, it remains underappreciated how to take advantage of biological timing, or correct it, for health benefits. In this Review, we provide an updated account of the circadian system and highlight several key disease areas with altered circadian signalling. We discuss environmental and lifestyle modifications of circadian rhythm and clock-based therapeutic strategies, including chronotherapy, in which dosing time is deliberately optimized for maximum therapeutic index, and pharmacological agents that target core clock components and proximal regulators. Promising progress in research, disease models and clinical applications should encourage a concerted effort towards a new era of circadian medicine.

Strong electron correlation can induce Mott insulating behaviour and produce intriguing states of matter such as unconventional superconductivity and quantum spin liquids. Recent advances in van der Waals material synthesis enable the exploration of Mott systems in the two-dimensional limit. Here we report characterization of the local electronic properties of single- and few-layer 1T-TaSe2via spatial- and momentum-resolved spectroscopy involving scanning tunnelling microscopy and angle-resolved photoemission. Our results indicate that electron correlation induces a robust Mott insulator state in single-layer 1T-TaSe2that is accompanied by unusual orbital texture. Interlayer coupling weakens the insulating phase, as shown by reduction of the energy gap and quenching of the correlation-driven orbital texture in bilayer and trilayer 1T-TaSe2. This establishes single-layer 1T-TaSe2as a useful platform for investigating strong correlation physics in two dimensions.

In this study, Si@C/Graphite composite anodes were synthesized through spray drying and pyrolysis using silica, artificial graphite, and two kinds of organics (phenolic resin or pitch). The Si@PR-C/Graphite exhibits enhanced electrochemical performance for lithium-ion batteries. The first charge-discharge specific capacity is 512.8mAh/g and 621.8mAh/g, respectively, the initial coulombic efficiency is 82.5% at 100mA/g, and its capacity retention rate reached as high as 85.4% with the capacity fade rate of less than 0.18% per cycle after 85 cycles. The Si@PI-C/Graphite also presents excellent discharge specific capacity of 702.8mAh/g with the capacity retention rate of 76.9% after 30 cycles. Mechanisms for high electrochemical performances of the Si@C/Graphite composite anode are discussed. It found that the enhanced electrochemical performance due to the formation of core/shell microstructure. These encouraging experimental results suggest that proper organic carbon source has great potential for improvement of electrochemical properties of pure silicon as anode. Key words:lithium-ion batteries; anode; Si@C/Graphite composite; electrochemical performance

Layer-by-layer (LbL) assembly is widely applied as a coating technique for the nanoscale control of architecture and related properties. However, its translational applications are limited by the time-consuming and laborious nature of the process. Inspired by the blood-clotting process, herein, we develop a shear-flow-driven LbL (SF-LbL) self-assembly approach that accelerates the adsorption rate of macromolecules by mechanically configuring the polymer chain viaa coil–stretch transition, which effectively simplifies and speeds the diffusion-controlled assembly process. The structural characteristics and surface homogeneity of the SF-LbL films are improved, and diverse three-dimensional structures can be achieved. Functional SF-LbL-assembled surfaces for corneal modification are successfully fabricated, and the surface of wounded rat corneas and skin can be directly decorated in situwith SF-LbL nanofilms due to the advantages of this approach. Furthermore, in situSF-LbL self-assembly has promise as a simple approach for the wound dressing for interventional therapeutics in the clinic, as illustrated by the successful in situfabrication of drug-free layers consisting of chitosan and heparin on the dorsal skin of diabetic mice to rescue defective wound healing. This bioinspired self-assembly approach is expected to provide a robust and versatile platform with which to explore the surface engineering of nanofilms in science, engineering, and medicine.

In cuprate superconductors, the existence of various intertwined orders associated with spin, charge and Cooper pairs1,2is an obstacle in understanding the mechanism of Cooper pairing. The ubiquitous charge order is particularly important2–7. Various theories have been proposed to explain the origin of the charge order and its implications for the superconducting phase, including charge stripes8, electronic nematicity8,9and Fermi surface instability5,10. A highly appealing physical picture is the ‘pair density wave’, a spatially periodic modulation of Cooper pairing, which may also induce a charge order2,11–21. To elucidate the existence and nature of the pair density wave, we use scanning tunnelling microscopy to investigate a severely underdoped cuprate, in which superconductivity just emerges on top of a pronounced chequerboard charge order. We observe a periodic modulation of both the superconducting coherence peak and gap depth, indicating the existence of a density wave order of Cooper pairing based on the empirical relationship between superconducting coherence and superfluid density22–27. The pair density wave has the same spatial periodicity as the charge order, and the amplitudes of the two orders exhibit clear positive correlation. These results shed new light on the origin of and interplay between the charge order and Cooper pairing modulation in the cuprates.

Since the discovery of graphene, the development of two-dimensional material research has enabled the exploration of a rich variety of exotic quantum phenomena that are not accessible in bulk materials. These two-dimensional materials offer a unique platform to build novel quantum devices. Layered transition metal dichalcogenides, when thinned down to atomic thicknesses, exhibit intriguing physical properties such as strong electron correlations. The study of strongly-correlated phenomena in two-dimensional transition metal dichalcogenides has been a major research frontier in condensed matter physics. In this article, we review recent progress on strongly-correlated phenomena in two-dimensional transition metal dichalcogenides, including Mott insulators, quantum spin liquids, and Wigner crystals. These topics represent a rapidly developing research area, where tremendous opportunities exist in discovering exotic quantum phenomena, and in exploring their applications for future electronic devices.

The PHD–pVHL pathway is essential for oxygen-dependent prolyl hydroxylation of HIFA. A recent study identifies RIPK1 as a hydroxylation target in this pathway during hypoxia-induced cell death and presents a 2.8 Å resolution crystal structure of the pVHL–elongin B/C complex bound to hydroxylated RIPK1.

Ziziphus jujubapulp could be utilized for Ziziphus jujubavinegar (ZJV) production to reduce waste. However, how to specifically regulate microorganisms during ZJV fermentation to improve its flavor remains an industrial problem. This study evaluated the contribution of ZJV's two-stage fermentation (alcohol fermentation (AF) and acetic acid fermentation (AAF)) to flavor metabolites and microbial community assembly. The ZJV production can represent a sustainable strategy in the management of Ziziphus jujubapulp wastes. Temperature, alcohol and acid were driving forces of microbiota succession. AF is an important stage for the formation of alcohols, esters, non-volatile acids, and various amino acids. Bacteria and fungi mainly generated esters and alcohols in AF, respectively. Microorganisms capable of protease production and strong stress resistance were conducive to amino acid production (e.g., Virgibacillusand Saccharomycesin AF, Bacillusand Xeromycesin AAF). Solid-state AAF was the key step of acetic acid production and flavor metabolite accumulation. Komagataeibacterwith higher acid-tolerant than Acetobacterdominated late AAF and showed a positive correlation with acetic acid. Dominant bacteria promoted the accumulation of various volatile flavor substances (esters, acids, aldehydes, and ketones), while low-abundance fungi facilitated the accumulation of functional metabolites (GABA, acetoin, tetramethylpyrazine). These results guided the targeted control of ZJV fermentation to improve its flavor quality and provided valuable insights for ZJV manufacturers.

High-temperature superconductivity in the cuprates is widely believed to originate from an antiferromagnetic parent Mott insulator when doped with charge carriers. In terms of the electronic structure, the key question is how the large charge transfer gap evolves into the pseudogap and then the d-wave superconducting gap. However, whether superconductivity or some other symmetry-breaking state (such as charge or spin orders) emerges first on doping a Mott insulator is debatable. To address these issues, here we use scanning tunnelling microscopy to investigate the local electronic structure of lightly doped cuprates in the antiferromagnetic insulating regime. We show that the doped charge induces a spectral weight transfer from the high-energy Hubbard bands to low-energy states within the charge transfer gap. With increasing doping, a V-shaped density-of-state suppression reminiscent of the pseudogap occurs at the Fermi level, which is accompanied by the emergence of chequerboard charge order. Our data suggest that the cuprates first become a charge-ordered insulator on doping, and the Fermi surface and high-temperature superconductivity becomes manifest on further doping.

Layered transition metal dichalcogenides are ideal systems for exploring the effects of dimensionality on correlated electronic phases such as charge density wave (CDW) order and superconductivity. In bulk NbSe2a CDW sets in at TCDW= 33 K and superconductivity sets in at Tc= 7.2 K. Below Tcthese electronic states coexist but their microscopic formation mechanisms remain controversial. Here we present an electronic characterization study of a single two-dimensional (2D) layer of NbSe2by means of low-temperature scanning tunnelling microscopy/spectroscopy (STM/STS), angle-resolved photoemission spectroscopy (ARPES), and electrical transport measurements. We demonstrate that 3 × 3 CDW order in NbSe2remains intact in two dimensions. Superconductivity also still remains in the 2D limit, but its onset temperature is depressed to 1.9 K. Our STS measurements at 5 K reveal a CDW gap of Δ = 4 meV at the Fermi energy, which is accessible by means of STS owing to the removal of bands crossing the Fermi level for a single layer. Our observations are consistent with the simplified (compared to bulk) electronic structure of single-layer NbSe2, thus providing insight into CDW formation and superconductivity in this model strongly correlated system.

Mechanical analysis of flexible pipe during installation is presented in this paper. The configuration, tension and bending moment of the flexible are important issues during the installation. A reasonable theoretical model is proposed to handle the pipe configuration and the loads during installation. Numerical iteration program for the model is developed to get the tension, bending moment distribution and the pipe configuration. Two segments which are suspended segment and seabed segment are analyzed with different calculation model for their different load conditions and boundary conditions. Finite element model is established by Abaqus to verify the results from the theoretical model. The results from theoretical are very close to the ones got from FEM. Typical installation method J-lay method is applied to perform the FEM and numerical analysis.

Lead-based piezoelectric ceramics have excellent piezoelectric properties with the compositions near the rhombohedral-tetragonal morphotropic phase boundary (MPB)[1,2]. In these materials, the dielectric and piezoelectric properties show the maximal values at MPB. For lead-free piezoelectric ceramics, finding the MPB area is a promising way to improve their properties. In this paper, the (1-x-y)BaZrO3-x(K0.45Na0.5Li0.05)NbO3-yBi (Mg0.5Ti0.5)O3 lead-free piezoelectric ceramics were prepared by solid-state reaction method, and their piezoelectric properties and dielectric properties were investigated. With the increase of KNLN content, the crystal structure changed from rombohedral phase to tetragonal phase, thus existed a MPB[3,4] between rombohedral and tetragonal phase. At room temperature, the specimen with the composition at MPB (x=0.93, y=0.01) shows the optimal piezoelectric properties (d33=225pC/N and kp=45%), which indicates that this material is a potential lead-free piezoceramic.

This paper presents the realization of a kind of hardware encryptor and decryptor, which is based on Logarithmic Function principle. It shows how to design the encryption circuit and the decryption circuit by the sequential circuit. It had been designed in VHDL and simulated by Modelsim software, and then synthesized as well as realized on the FPGA chip EP2C5T144 by QuartusII software, last finished the test.

As the key components of the receiver in the GPS(Global Positioning System) system, the performance of the antenna has an important impact on the accuracy of navigation and positioning for a GPS receiver. The paper shows a novel microstrip antenna on the basis of the slot loaded method. The simulated results and the experimental test results indicate that the characteristics of impedance and circular polarization, as well as the radiation pattern of the proposed antenna can meet the requirements of the applications of GPS, which provides the theoretical and experimental basis for the practical applications of the proposed antenna.

Trade-off between vegetative growth and reproduction is an important plant adaptive strategy to environmental variability. The study investigated the Stipa grandis resource allocation and the relationship between its sexual reproduction and climate factors among three sites located along a typical environmental gradient in the Inner Mongolian Plateau. The results show that different climatic characteristics among three habitats cause the growth differentiation of S. grandis. S. grandis exhibits a prominent change on the resource allocation patterns. The number of reproductive tillers and panicles biomass allocation are significantly increased along the gradient of water availability and temperature whereas the number of vegetative tillers and root biomass allocation are reduced. The rate of the percentage increase is prominently reduced although the foliage allocation increased. It suggests that under the environments with drought and high temperature, S. grandis allocates more resources to sexual reproduction but reduces the investment in vegetative growth and asexual reproduction. Moreover, the amount of precipitation in April and May are significantly correlated with the sexual reproductive allocation of S. grandis.

In order to analyze the transmission characteristics of the knuckle-triangle working mechanism for servo mechanical presses, an experimental prototype was set up, and a wireless measurement system was developed, to measure the kinematic and dynamic characteristics of the working mechanism. The working principle of the dynamic measurement was expressed. The forming force applied to the slide was measured by a donut-shaped load cell. The driving torque applied to the crank was measured by a resistance strain gage. To collect the testing signals of the forming force and driving torque conveniently and synchronously, a wireless measure system based on WiFi is proposed. Moreover, when the input crank rotates at different angular speeds, the slide stroke curves were measured by a grating scale. The experimental results showed that the developed system can perform wireless measurement, and provide experimental basis for the analysis of kinematic and dynamic characteristics of the working mechanism with servo input.

Based on analysis of press working characteristics, some of the main kinematics requirements for working mechanisms of servo mechanical presses were put forward: fast in empty stroke, slow and uniform in working stroke and big force gain. Crank link and knuckle-straight link are the most common working mechanisms in mechanical presses. To meet the requirement of servo mechanical presses, another mechanism, knuckle-triangle link, was designed. The kinematics simulations of the three mechanisms for a 1600kN press were conducted by dynamic software ADAMS. Knuckle-triangle link had the most uniform and lowest slide’s average velocity and biggest force gain within the working stroke. For the same nominal pressure of 1600kN, the required input torque of knuckle-triangle link was 9108Nm. In comparison with crank link and knuckle-straight link, the crank’s input torque was reduced by 84% and 76% respectively without considering the influence of friction and inertia. In conclusion, knuckle-triangle link mechanism is more suitable for large-tonnage servo presses.

Electrostrictive materials exhibit high induced strain under dc electric fields and this effect is important in generator application. This paper studied the energy‐harvesting performances of La‐doped PMN‐PT electrostrictive ceramics that have rarely been reported. A multilayer structured electrostrictive energy harvester with high dielectric constant and electrostrictive coefficient is proposed. With a strain Sm= 7 × 10−5(m/m), a peak current value of 630 µA is obtained across a small matched resistance of 450 Ω under a dc electrical field of 1.5 V/µm. The working principle of the device is reviewed and improved to predict the current and power generated by the harvester. Experimental results are compared to the theoretic behaviors of the improved model. A good agreement is observed by the two sets of data. The study on the efficiency of the energy conversion showed that a positive balance between the consumed power and the harvested power was presented by the device. The result demonstrates the potential perspective of the electrostrictive device in energy harvesting applied to low‐power electronics.

Abstract: Lanthanum-free high-transparency ferroelectric ceramics PbMg1/3Nb2/3O3−xPbZr0.53Ti0.47O3 (PMN-xPZT) have been prepared for the first time by a two-stage sintering method. The dielectric and electro-optical properties of the PMN-xPZT ceramics of different compositions, with the values of x both far from the morphotropic phase boundary (x = 10, 16, 23%) and close to it (x = 33%), have been studied. It has been shown that, in compositions lying closer to the morphotropic phase boundary (x = 23 and 33%), one observes, with no electric field applied, a first-order phase transition to a macrodomain ferroelectric phase, whereas the compositions far from the boundary (x = 10, 16%) persist in the relaxor cubic phase down to the low-temperature domain. It has been found that, in the ceramic with x = 33%, the quadratic electro-optical coefficients have at high temperatures (T > 340 K) the largest value among the relaxor systems, which expands the temperature interval of applicability of these solid solutions in industry.

To explore the influence of slide stroke curves on deep drawing and solve the problems of cracking and wrinkling during drawing, the deep drawing processes of box shaped part with the conventional mechanical press and servo press were simulated, respectively. The variation rules of cracking and wrinkling for box shaped part by different slide stroke curves were obtained. It shows that the qualified parts can be obtained more easily when drawing with servo presses by decreasing the rotational speed of servo motor at the forming stage due to its variability; drawing cycle can be shorten effectively by adjusting the variable displacement-velocity curves of servo press.

Laser welding includes the heat conduction welding and the deep penetration welding. Deep penetration welding can not only penetrate the material completely, but also can vaporize the material. An important phenomenon during deep penetration welding is that molten pool in the weldment will appear a keyhole. The formation of the keyhole leads to a deep penetration weld with a high aspect ratio and this is the most advantageous feature of welding by high-energy-density beams. Small focus wandering off weld seam may result in lack of penetration or unacceptable welds, and largely reduce heating efficiency. In a fiber laser butt-joint welding of Type 304 austenitic stainless steel plate with a high power 6kW continuous wave fiber laser, an infrared sensitive high-speed video camera was used to capture the dynamic images of the molten pools. The configurations of molten pools were analyzed through image processing techniques such as median filtering, partial Otsu threshold segmentation and Canny edge to obtain the edge of keyholes and molten pools. The circular degree and the area of keyholes and the width and average gray of molten pools were defined as characteristic parameters to reflect the seam offset between the laser beam and the weld center. By analyzing the change of characteristic parameters during welding process, it was found that these parameters were related to the seam offset. Welding experimental results and analysis of characteristic parameters confirmed that the seam offset could be monitored and distinguished by molten pools configuration during high-power fiber laser welding.

In order to explore the influence of slide stroke curves on drawing process and solve the problems of springback and serious thickness thinning during forming, the deep drawing processes of box shaped part based on the conventional mechanical press and servo press were simulated. The springback and thickness variation of box shaped part by different slide stroke curves were obtained. It shows that comparing with the deep drawing with conventional mechanical press, the springback of drawn workpiece decreases by pressure-keeping drawing; the maximum thickness thinning ratio of drawn workpiece is smaller by staged drawing, and the distribution of workpiece thickness is more uniform.

Punching mechanisms with servo input are typical variable-input controllable mechanisms. By means of extending the output link infinitely, the Stephenson Ⅲ six-bar linkage is evolved into a six-bar punching mechanism with a slide. A virtual prototype model of this novel punching mechanism was established by using the software ADAMS. The model includes geometry, load and drive, total three sub-models. Based on the model, the kinematic and dynamic characteristics of the slide with variable-input crank motion and instantaneous large load were simulated. The numerical results showed that the Stephenson’s six-bar punching mechanism had good transmission characteristics, improving the working performances and production efficiency, reducing the manufacturing costs of servo mechanical presses.

Energy saving in manufacturing is the key to reduce energy consumption of unit GDP. Forming equipments are one of the biggest energy consumers. The basic reason of high energy consumption and low efficiency for current forming equipments is the mismatch between uncontrollable driving characteristics and the variable loads in forming processes. Complex transmission and control mechanisms are needed, wasting a lot of energy. The basic principles of driving were put forward to realize energy saving for forming equipments: faster in virtual strokes, slower in working strokes, stop when idling and recycling excessive energy. The servo driving based on large AC servo motors can make the driving and forming loads match each other well, realizing not only high automation and intelligence, but energy saving greatly as well. Theoretical analysis and experiments showed that by adopting AC servo driving the crank presses, hydraulic presses and screw presses could get the energy saving results of 25-70%.

Monolayer of polymer latex spheres was prepared at the air/water interface and deposited onto glass slides through Langmuir—Blodgett (LB) technique. Large-scale, high quality hexagonally close-packed domains were found in scanning electron microscopic pictures. Details of the monolayer-forming ability were discussed. Suitable surface characteristics of the colloidal particles, especially the hydrophilic and hydrophobic properties, are the keys for the formation of ordered monolayer films. The film can be transferred onto various kinds of substrates, even high curvature surface articles, such as fibers, decorations etc, can also be used as substrates. The advantages of this fabrication method of polymer latex spheres monolayer are fast, flexible, simple and very neat.

Abstract:: We give a rigorous proof of existence of infinitely many black hole solutions to the Einstein–Yang–Mills equations with gauge group SU(3). In the case that the radius of event horizon is not too small, we show that there is a black hole solution for any possible numbers of zeros of the two field variables.

Previous studies implicated the neuronal guidance molecule netrin-1 in attenuating myocardial ischemia-reperfusion injury. However, the tissue-specific sources and receptor signaling events remain elusive. Neutrophils are among the first cells responding to an ischemic insult and can be associated with tissue injury or rescue. We found netrin-1 levels were elevated in the blood of patients with myocardial infarction, as well as in mice exposed to myocardial ischemia-reperfusion. Selectively increased infarct sizes and troponin levels were found in Ntn1loxP/loxP Lyz2 Cre+ mice, but not in mice with conditional netrin-1 deletion in other tissue compartments. In vivo studies using neutrophil depletion identified neutrophils as the main source for elevated blood netrin-1 during myocardial injury. Finally, pharmacologic studies using treatment with recombinant netrin-1 revealed a functional role for purinergic signaling events through the myeloid adenosine A2b receptor in mediating netrin-1–elicited cardioprotection. These findings suggest an autocrine signaling loop with a functional role for neutrophil-derived netrin-1 in attenuating myocardial ischemia-reperfusion injury through myeloid adenosine A2b signaling.

Perioperative complications of transcatheter aortic valve replacement (TAVR) are decreasing but can be catastrophic when they occur. Systematic reports of the nature of these events are lacking in the contemporary era. Our study aimed to report the incidence, outcomes, and perioperative management of catastrophic cardiac events in patients undergoing TAVR and to propose a working strategy to address these complications.

All-inorganic CsPbI2Br perovskite with suitable bandgap and excellent thermal stability has been reported as the most promising candidate for efficient perovskite solar cells (PSCs). However, the high annealing temperature (> 250 °C) and poor stability of α-CsPbI2Br greatly limit the future application in photovoltaic field. Herein, a facile method is reported to prepare α-CsPbI2Br perovskite film with high stability at low temperature (70 °C) by incorporating a small amount of γ-aminobutyric acid (GABA) in the precursor solutions. The devices exhibit reproducible photovoltaic performance with a champion efficiency up to 15.16%, along with the excellent stability, maintaining more than 80% of its initial efficiency after stored in ambient condition for 600 h without any encapsulation. Most importantly, the method enables fabrication of semitransparent CsPbI2Br PSCs with a PCE of 6.76%, as well as an average visible transparency (AVT) of 25.38%. To the best of our knowledge, this is the first attempt to apply CsPbI2Br to the semitransparent solar cells.

Bradysia odoriphaga Yang & Zhang (Diptera: Sciaridae) is the most serious pest of Chinese chive, Allium tuberosum. Chemical pesticide application has become a necessary step to control B. odoriphaga after each of the four to six harvests during the growing season. We compared the effects of application type (nematode-infected cadaver, aqueous nematode suspension, and mixture of cadaver and aqueous suspension) and nematode species (Heterorhabditis bacteriophora vs. Steinernema carpocapsae) on B. odoriphaga control. Nematode species combinations and the use of the cadaver method has only been tested in a relatively few studies, and has not been tested for this target pest, B. odoriphaga. Furthermore, this is the first report of combining application methods (aqueous and cadaver). Results indicated that the cadaver treatment produced higher mortality of B. odoriphaga than the aqueous treatment, and H. bacteriophora caused higher mortality of B. odoriphaga than S. carpocapsae. The mortality of B. odoriphaga was 96.7% in H. bacteriophora cadaver treatment and only 27.5% in control treatment without nematode addition. Cadaver treatments caused higher biomass of A. tuberosum than that of aqueous treatment. The plant biomass in H. bacteriophora cadaver treatment was 10 folds as much as that in the control treatment. The mixed aqueous suspension of H. bacteriophora and S. carpocapsae did not increase the mortality in pot trial. Our findings indicate that entomopathogenic nematodes applied as cadavers might be a potential alternative biological agent in the integrated management of B. odoriphaga for Chinese chive production.

Dielectric, hysteresis (P–E) loops and TSDC properties of transparent 85PZN–15BT ceramic over -150–150°C were investigated. The sample was found to exhibit a strong relaxor behavior and a relatively small remanent polarization. TSDC studies showed that there existed an electric field-dependent peak in the p versus T. Such interesting features were attributed to the electric field-induced transition and coexistence of polar nanoregion, long-range ordered polar region and nonpolarizable BZN-rich region.