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The highly-sensitive, an rapid-response and self-powered photodetectors based on a single-layer carbon QD layers (CQDL) exhibit the remarkable photoresponsivity above 9.4 mA W−1, and detectivity above 5.9 × 1012 under broadband-light illuminations.

Photonic and phononic topological insulators (TIs) offer numerous opportunities for manipulating light and sound with high efficiency and resiliency. On the other hand, inverse design methodologies, such as gradient-based approaches, evolutionary approaches, and deep-learning methods, provide a cost-effective strategy for developing photonic and phononic structures with unique features in steering light and sound. Here, we discuss recent advances and achievements in the development of photonic and phononic TIs employing inverse design methodologies, including one-dimensional TIs, TIs based on the quantum spin Hall effect (QSHE) and quantum valley Hall effect (QVHE), and high-order TIs in lattices with diverse symmetries. Several inversely designed photonic and phononic TIs with superior performance are exhibited. In addition, we offer our perspectives on the future of this emerging study field.

Objective: Acute pancreatitis (AP) is a common acute abdominal disease characterized by pancreatic acinar cell death and inflammation. Excessive autophagy of acinar cells will aggravate AP, further develop into SAP, and even endanger life. Dachengqi Decoction (DCQD) is a commonly used drug in clinic for acute pancreatitis. Beclin1 is a vital autophagy-related molecule in disease. We investigated DCQD treat acute pancreatitis by intervening Beclin1 to regulate the autophagy of acinar cells.Methods: Wistar rats were injected intraperitoneally with 20% L-arginine to reproduce AP rat model. AP rat were treated with DCQD and 3-Methyladenine (3-MA) and compared to AP rats pre-treated with 20% L-arginine. we examined the levels of serum TNF-α, Beclin1 and Reactive Oxygen Species (ROS) by ELISA; stained the pancreas tissues of rats with Hematoxylin-eosin staining (HE); observed the autophagy formation in pancreas tissues by transmission electron microscopy; and detected the expression of Beclin1 and light chain 3-Ⅱ(LC3-II) protein level in pancreas tissues by Western blot and immunohistochemistry.Result: The levels of serum Amylase, Beclin1, ROS, TNF-α and pathological scores of pancreas were significantly elevated by injected intraperitoneally with 20% L-arginine. The results of electron microscopy showed that the autophagy of pancreatic tissue increased significantly in AP rats, but decreased in rats treated with DCQD or 3-MA. DCQD and 3-MA could significantly reduce the levels of serum Amylase, Beclin1, ROS and TNF-α in rats. Western blot and immunohistochemical results showed that DCQD and 3-MA significantly reduced Beclin1 and LC3-II proteins.Conclusion: Our studies showed that Beclin1 is closely related to acute pancreatitis, and DCQD could inhabited Beclin1 and excessive autophagy.

Second-order photonic topological insulators (SPTIs) with topologically protected corner states provide a unique platform for realizing the robust manipulation of light in lower dimensions. Previous SPTIs proposed in C 4v -symmetric lattices are mainly based on the two-dimensional (2D) Su-Schrieffer–Heeger (SSH) model consisting of an even number of sites in the unit cell. Moreover, second-order topological phases within high-order band gaps are rarely explored. Here, we propose a new principle of SPTIs beyond the 2D SSH model, which is realized in C 4v-symmetric lattices consisting of an odd number of sites in the unit cell. The midgap-gap-ratios of these odd-order band gaps, from the first-order to the nineteenth-order with step of two-order, are maximized by the method of topology optimization. Second-order topological phases are successfully created within these sizeable band gaps and highly localized corner states are observed. Our work offers a new route for exploring high-order topological states in photonics and other classical systems.

Second-order photonic topological insulators (SPTIs) featured with topological edge and corner states provide an intriguing way for steering light in integrated optics. However, existing SPTIs have narrow bulk gaps for tightly confining topological edge and corner states. In this paper, we propose a bi-directional evolutionary structural optimization (BESO) method to inversely engineer SPTIs in C3-symmetric lattices. At first, we maximize the first band gap of a photonic crystal (PC) enforced with C3 symmetry. Then, the topological phase transition is achieved by inverting the optimized PC. Highly localized topological edge and corner states are formed at the boundary and corner between the optimized PC and its inversion-symmetry partner. The bandwidth of the topological edge state for TE modes achieves 44.9%, exceeding two times of the current record. The robust of the topological corner states is further demonstrated. Our work provides a new route for designing SPTIs, paving the way towards their practical application.

The experimental investigation of the critical heat flux (CHF) of saturated nucleate pool boiling of pure water and water-based Al2O3 nanofluids on the platinum wire with a diameter of 50 µm was conducted under earth gravity and hypergravity. The gravity level ranges from 1 to 3 g, the saturation pressures range from 0.1 to 0.6 MPa, and the Al2O3 concentrations in the nanofluids ranges from 0.001wt% to 0.015wt%. The experimental results show that both pressure and gravity are vital factors enhancing the CHF, with the effect of pressure more pronounced. The mechanisms of CHF enhancement due to pressure increasing is that increasing pressure changes the fluid properties, yielding the synthetical results of activating more nucleate sites and increasing the bubble departure frequency. The reasons for the CHF enhancement by hypergravity may mainly be that the buoyancy force increases with increasing gravity levels, which makes the bubbles more likely to be removed from the surface, and that the formation of large vapor patches covering the heating wire gets harder. Besides, a nanofluid has a stronger enhancement to the pool boiling CHF than the combination of the heating surface coated with the same kind of nanoparticles and the base fluid. The reason may be that the latter mainly relies on the heater surface modification, while the former relies on the nanoparticle suspension in the nanofluid and the interaction between the nanoparticle deposition and the nanoparticle suspension, plus the heater surface modification.

A WC/WO2–WO3 nanosheet heterostructure has been fabricated by an in situ electrochemical reconstruction approach, which significantly elevates the HOR performance by 7 times owing to the synergistic catalytic effect between WC and WOx species.

Developing highly efficient, cost effective and durable bifunctional electrocatalyst remains a key challenge for overall water splitting. Herein, a bifunctional catalyst CoP2-Mo4P3/NF with rich heterointerfaces was successfully prepared by a two-step hydrothermal-phosphorylation method. The synergistic interaction between CoP2 and Mo4P3 heterogeneous interfaces can optimize the electronic structure of active sites, leading to the weak adsorption of H on the Mo sites and the increased redox activity of the Co site, resultantly improving the HER/OER bifunctional catalytic activity. The synthesized CoP2-Mo4P3/NF catalyst exhibits excellent electrocatalytic activity in 1.0 M KOH with low overpotentials of 77.6 and 300.3 at 100 mA cm−2 for HER and OER, respectively. Additionally, the assembled CoP2-Mo4P3/NF||CoP2-Mo4P3/NF electrolyzer delivers a current density of 100 mA cm−2 at a cell voltage of 1.59 V and remains stable for at least 370 h at 110 mA cm−2, indicating the potential application prospective in water splitting.

Developing highly efficient, cost effective and durable bifunctional electrocatalyst remains a key challenge for overall water splitting. Herein, a bifunctional catalyst CoP

Training robust speaker verification systems without speaker labels has long been a challenging task. Previous studies observed a large performance gap between self-supervised and fully supervised methods. In this paper, we apply a non-contrastive self-supervised learning framework called DIstillation with NO labels (DINO) and propose two regularization terms applied to embeddings in DINO. One regularization term guarantees the diversity of the embeddings, while the other regularization term decorrelates the variables of each embedding. The effectiveness of various data augmentation techniques are explored, on both time and frequency domain. A range of experiments conducted on the VoxCeleb datasets demonstrate the superiority of the regularized DINO framework in speaker verification. Our method achieves the state-of-the-art speaker verification performance under a single-stage self-supervised setting on VoxCeleb.

Single-pixel imaging (SPI) is a new technology with many applications and prospects. Polarization detection technology can improve the detection and identification ability of the imaging system. A near-infrared polarization SPI lidar system is designed to realize detection and polarization imaging of outdoor long-range targets. The depth, intensity, linear polarization, and polarization degree images of typical remote targets are obtained. The results show that the polarization image contains many details and contour information of the target, and the intensity image contains brightness and reflectivity information. Intensity and polarization information complement each other. The characteristics of intensity and polarization images at different spatial frequencies are analyzed for the first time, to our knowledge, by taking advantage of the Fourier modulation mode. We found that the proportion of high-frequency information in the polarization image is much higher than that of the intensity image. The sampling strategy of collecting only low-frequency components is applicable in intensity imaging but needs further improvement in polarization imaging. The polarization SPI lidar system can enrich the target information acquired, improve imaging contrast, and have significant application value for target detection and identification in complex backgrounds.

Earth-abundant tungsten carbide exhibits potential hydrogen evolution reaction (HER) catalytic activity owing to its Pt-like d-band electronic structure, which, unfortunately, suffers from the relatively strong tungsten-hydrogen binding, deteriorating its HER performance. Herein, a catalyst design concept of incorporating late transition metal into early transition metal carbide is proposed for regulating the metal-H bonding strength and largely enhancing the HER performance, which is employed to synthesize CoW bi-metallic carbide Co

Using hydrazine oxidation reaction (HzOR) substituting for oxygen evolution reaction can realize hydrogen production at largely reduced energy consumption. While the HzOR mechanism and the electrochemical utilization rate of hydrazine are still ambiguous. Herein, a bimetallic phosphide heterostructure nanoarrays (Ni-Co-P/NF) fabricated by an interface engineering strategy was used to catalyze both HzOR and hydrogen evolution reaction (HER), and more intensively, probe the HzOR mechanism. The extra-high HzOR performance is attributed to the instantaneous recovery of metal phosphide active site by hydrazine and the extremely low energy barrier with even a new HzOR pathway of N-N bond breakage, which enables the electrolyzer catalyzed by Ni-Co-P/NF to reach 500 mA cm-2 for H2 production at as low as 0.498 V, and offers a high hydrazine electrochemical utilization rate of 93%. The constructed electrolyzer can be powered by the direct hydrazine fuel cell with Ni-Co-P/NF as anodic catalyst, achieving self-powered hydrogen production at the rate up to 19.6 mol h-1 m-2.

Experiments on R1234yf flow boiling in a horizontal 2.01 mm copper tube under hypergravity are conducted to investigate the effect of gravity on two-phase flow boiling heat transfer coefficient (HTC). The experimental range of parameters is gravity levels of 1–3.16 g, mass fluxes of 365 and 570 kg m−2 s−1, saturation pressures of 0.62 and 0.70 MPa, heat fluxes of 47.6 and 97.5 kW m−2, and vapor qualities up to 0.985. Based on the experimental data, the effects of gravity, quality, heat flux, mass flux, and saturation pressure on the HTCs were analyzed. The results show that the HTCs increase with increasing gravity levels for the qualities up to around 0.7, and the gravity effects become indistinct and inconsistent when the quality is high (x > 0.8). The trends of the HTC variation with quality and the effects of the heat flux, mass flux and saturation pressure on the HTCs are similar under different gravity levels. When x 0.7 or higher, and they occur earlier when the gravity level is higher. The comparison of the experimental data with existing saturated flow boiling HTCs for normal gravity shows that the Fang (2013b) correlation for R134a performs best with a mean absolute deviation (MAD), and that all of the top four correlations in prediction accuracy under-predict the experimental HTCs, which is consistent with the experimental results that hypergravity enhances flow boiling heat transfer.

Among various earth-abundant and noble metal-free catalysts for oxygen reduction reaction (ORR), Mn and N co-doped carbon (Mn-N-C) is highly desirable and promising, which, however, suffer from the limited amount of active sites largely abating its ORR catalytic performance. Herein we demonstrate an effective strategy to elevate the ORR active site density by designing a helical graphitized carbon tubes to highly disperse the single Mn atomic sites coordinated with nitrogen. The obtained polydopamine-modified helical MnNC-PDA-700 catalyst shows excellent ORR electrocatalytic performance with a half-wave potential of 0.87 V and extra-high Zn-air battery power density of 122.7 mW cm−2, which are comparable to and even higher than those of Pt/C. Such an excellent electrocatalytic performance is attributed to the much enhanced amount of MnN4 active sites created on the helical graphitized carbon tubes owing to high surface area helical structure of the carbon tubes and the strong bonding of polydopamine molecules onto the tubes. The density functional theory (DFT) calculations further confirm that the MnN4 sites are the origin of the superior ORR activity via a 4e− pathway in alkaline media.

The development of bifunctional electrocatalysts with efficient oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is still a key challenge at the current stage. Herein, FeNi LDH/V2CTx/nickel foam (NF) self-supported bifunctional electrode was prepared via deposition of FeNi LDH on V2CTx/NF substrate by hydrothermal method. Strong interfacial interaction between V2CTx/NF and FeNi LDH effectively prevented the aggregation of FeNi LDH, thus exposing more catalytic active sites, which improved electrical conductivity of the nanohybrids and structural stability. The results indicated that the prepared FeNi LDH/V2CTx/NF required 222 mV and 151 mV overpotential for OER and HER in 1 M KOH to provide 10 mA cm−2, respectively. Besides, the FeNi LDH/V2CTx/NF electrocatalysts were applied to overall water splitting, which achieved a current density of 10 mA cm−2 at 1.74 V. This work provides ideas for improving the electrocatalytic performance of electrocatalysts through simple synthesis strategies, structural adjustment, use of conductive substrates and formation of hierarchical structures.

The development of bifunctional electrocatalysts with efficient oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is still a key challenge at the current stage. Herein, FeNi LDH/V

A novel Zn-Fe flow battery featuring an Fe

Eliminating indoor formaldehyde (HCHO) pollution at room temperature is highly needed to improve the environment while saving energy. Herein, Pd/CeO2 catalysts with different morphologies of the CeO2 support were employed to investigate their performance for HCHO oxidation. The Pd/CeO2 nanocube (Pd/CeO2-C) catalyst exhibited excellent catalytic activity compared to commercial CeO2 and CeO2 nanorods. HCHO can be completely converted into CO2 and H2O over the Pd/CeO2-C (0.64 wt% Pd) catalyst at a weight hourly space velocity of 36 000 mL g−1 h−1 at room temperature. Multiple characterization results confirmed that the strong interfacial interaction between Pd and the CeO2-C support guarantees a high percentage of metallic Pd on the CeO2-C surface and its high dispersion, which is crucial for the oxidation of formaldehyde at low temperature. The in situ diffuse reflectance infrared Fourier transform results indicated that CO, formate and dioxymethylene species are the main intermediates over the Pd/CeO2-C catalyst, and the active O species is responsible for their decomposition and oxidation. This work may promote the practical application of high performance Pd-based catalysts for indoor HCHO purification and related catalytic processes.

Hepatic stellate cells (HSCs) play a crucial role in the progression of liver fibrosis, which can be considered as the specific therapeutic target of anti-fibrotic treatment. Targeted induction of HSCs to hepatocytes via delivery of clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (dCas9) system holds promise for hepatic fibrosis treatment. Our study here revealed that CRISPR/dCas9-VP64 system encapsulated in AML12 cell-derived exosomes could efficiently and successfully be delivered into the HSCs. In turn, the CRISPR/dCas9-VP64 system loaded in the exosomes can be efficiently released into the HSCs. As a proof-of-concept study, gRNA against hepatocyte nuclear factor 4α (HNF4α) together with the delivery of CRISPR/dCas9-VP64 system induced the HSCs to hepatocyte-like phenotype. In conclusion, our study here revealed that CRISPR/dCas9-VP64 system encapsulated in AML12 cell-derived exosomes could be functional in HSCs, emerging as a gene therapy strategy for hepatic fibrosis.

Platinum (Pt) is an efficient catalyst for hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR), but the debate of the relevance between the Pt particle size and its electrocatalytic activity still exist. The strong metal-support interaction (SMSI) between the metal and carrier causes the charge transfer and mass transport from the support to the metal. Herein, Pt species (0.5 wt.%) with various particle sizes supported on carbon nanotubes (CNTs) have been synthesized by a photo-reduction method. The ~1.5 nm-sized Pt catalyst shows much higher HER performance than the counterparts in all pH solutions, and the mass activity of it is even 23–36 times that of Pt/C. While for ORR, the ~3 nm-sized Pt catalyst exhibits the optimal performance, and the mass activity is 3 times and even 16 times that of Pt/C in acidic and alkaline media, respectively. The high HER and ORR performances of the ~1.5 nm- and ~3 nm-sized Pt catalysts benefit from the SMSI between Pt and the CNTs matrix and the higher ratio of face sites to edge sites, which is meaningful for the design of efficient electrocatalysts for renewable energy application.

Target tracking has found important applications in particle tracking, vehicle navigation, aircraft monitoring, etc. However, employing single-pixel imaging techniques to track a fast-moving object with a high frame rate is still a challenge, due to the limitation of the modulation frequency of the spatial light modulator and the number of required patterns. Here we report a complementary single-pixel object tracking approach which requires only two geometric moment patterns to modulate the reflected light from a moving object in one frame. Using the complementary nature of a digital micromirror device (DMD), two identical single-pixel detectors are used to measure four intensities which can be used to acquire the values of zero-order and first-order geometric moments to track the centroid of a fast-moving object. We experimentally demonstrate that the proposed method successfully tracks a fast-moving object with a frame rate of up to 11.1 kHz in the first two experiments. In the third experiment, we compare previous works and find that the method can also accurately track a fast-moving object with a changing size and moving speed of 41.8 kilopixel/s on the image plane. The root mean squared errors in the transverse and axial directions are 0.3636 and 0.3640 pixels, respectively. The proposed method could be suitable for ultrafast target tracking.

When imaging moving objects, single-pixel imaging produces motion blur. This paper proposes a new single-pixel imaging method, which can achieve anti-motion blur imaging of a fast-moving object. The geometric moment patterns and Hadamard patterns are used to alternately encode the position information and the image information of the object with time-division multiplexing. In the reconstruction process, the object position information is extracted independently and combining motion-compensation reconstruction algorithm to decouple the object motion from image information. As a result, the anti-motion blur image and the high frame rate object positions are obtained. Experimental results show that for a moving object with an angular velocity of up to 0.5rad/s relative to the imaging system, the proposed method achieves a localization frequency of 5.55kHz, and gradually reconstructs a clear image of the fast-moving object with a pseudo resolution of 512x512. The method has application prospects in single-pixel imaging of the fast-moving object., Comment: 13 pages,7figures

Unsupervised clustering on speakers is becoming increasingly important for its potential uses in semi-supervised learning. In reality, we are often presented with enormous amounts of unlabeled data from multi-party meetings and discussions. An effective unsupervised clustering approach would allow us to significantly increase the amount of training data without additional costs for annotations. Recently, methods based on graph convolutional networks (GCN) have received growing attention for unsupervised clustering, as these methods exploit the connectivity patterns between nodes to improve learning performance. In this work, we present a GCN-based approach for semi-supervised learning. Given a pre-trained embedding extractor, a graph convolutional network is trained on the labeled data and clusters unlabeled data with "pseudo-labels". We present a self-correcting training mechanism that iteratively runs the cluster-train-correct process on pseudo-labels. We show that this proposed approach effectively uses unlabeled data and improves speaker recognition accuracy., Comment: Accepted by ICASSP 2022

Fe-N-C electrocatalysts have been demonstrated to be the most promising substitutes for benchmark Pt/C catalysts for the oxygen reduction reaction (ORR). Herein, we report that N-doped carbon materials with trace amounts of iron (0-0.08 wt. %) show excellent ORR activity and durability comparable and even superior to those of Pt/C in both alkaline and acidic media without significant contribution by the metal sites. Such an N-doped carbon (denoted as N-HPCs) features a hollow and hierarchically porous architecture, and more importantly, a noncovalently bonded N-deficient/N-rich heterostructure providing the active sites for oxygen adsorption and activation owing to the efficient electron transfer between the layers. The primary Zn-air battery using N-HPCs as the cathode delivers a much higher power density of 158 mW cm

Background:At present, the mechanism of reciprocal ST-segment depression(RSTD) is still not clear. Purpose : We proposed the mechanism of RSTD: the action potential of negative electrode of the lead was weakened or disappeared, and the AP of positive electrode could not be completely offset. The electrocardiograms of patients with acute STEMI were analyzed to explore the mechanism of RSTD. Methods: The electrocardiogram and angiography of 85 STEMI patients were retrospectively analyzed to summarize the characteristics of ST segment changes. Results: A total of 85 patients were included, of which 75 were patients with RSTD (10 patients with anterior myocardial infarction had no RSTD), all 45 patients with inferior myocardial infarction had limb leads RSTD, and 37 of them had anterior lead ST segment depression.Thirty patients with anterior myocardial infarction were accompanied by mild ST segment changes in the limb leads. According to the characteristics of RSTD, it is speculated that the mechanism of RSTD is that the action potential of infarct area decreased , which could not offset the action potential in non-infarct area. By using this mechanism, all ST segment changes in STEMI can be explained by the proposed mechanism, and the value of the ST segment changes can be calculated in limb leads. Conclusion: the mechanism of RSTD in acute myocardial infarction is that the negative electrode action potential of the lead was weakened or disappeared, and the positive electrode action potential could not be completely offset, resulting in ST segment depression.