Landslides are significant natural geological hazards.Landslide susceptibility evaluation involves the quantitative assessment and prediction of potential landslide locations and their probabilities.Research has explo...Landslides are significant natural geological hazards.Landslide susceptibility evaluation involves the quantitative assessment and prediction of potential landslide locations and their probabilities.Research has explored susceptibility assessment methods based on spatial-scale analysis.This evaluation integrates two models—global and local scale—using a CNN model and a PSO-CNN coupled model.Key aspects include selecting evaluation factors and optimizing model parameters for landslide susceptibility at different scales.A major focus of current landslide research is utilizing prediction results to enhance prevention and control measures.展开更多
AIM： To investigate the interrelationship of Epstein-Barr virus （EBV） and EBV- encoded proteins with Helicobacter pylori （H pylor/~ infection and the expression of c-met and c-myc oncogene proteins in gastric carc...AIM： To investigate the interrelationship of Epstein-Barr virus （EBV） and EBV- encoded proteins with Helicobacter pylori （H pylor/~ infection and the expression of c-met and c-myc oncogene proteins in gastric carcinoma, and to explore their role in gastric carcinogenesis. METHODS： One hundred and eighty-five gastric carcinoma tissues were detected by polymerase chain reaction （PCR）-Southern blot for EBV genome and in situ hybridization （ISH） for EBV-encoded small RNA 1 （EBER1）. Gastric carcinoma with positive EBER1 signals was confirmed EBV-associated gastric carcinoma （EBVaGC）. The status of Hpylori infection in 185 gastric carcinomas was assessed by rapid urease test and PCR. The samples with positive PCR and urease test were defined as H pylorl infection. The expression of c-met and c-myc oncogene proteins in tissues of EBVaGC and matched EBV-negative gastric carcinoma （EBVnGC） were examined by immunohistochemistry. RT-PCR and Southern hybridization were used to detect the expression of nuclear antigens （EBNAs） 1 and 2, latent membrane protein （LMP） 1, early genes BARF1 and BHRF1 in EBVaGC cases. RESULTS： The positive rate of H pylori and EBV in 185 gastric carcinomas was 59.45% （110/185） and 7.03% （13/185） respectively. No difference was found in sex, age, pathological differentiation, clinical stages and lymph node metastasis between H pylori-positive and H pylori-negative gastric carcinomas. However, the positive rate of H pylori infection in the antrum gastric carcinomas was higher than that of cardia and body gastric carcinomas. In our series, age, pathological differentiation, clinical stages, lymph node metastasis and location of cancer were not different between EBVnGC and EBVaGC, while the positive rate of EBV in male patients was significantly higher than that of female patients. The positivity of Hpylori in EBV-associated and EBV-negative gastric carcinomas was 46.15% （6/13） and 81.40%（104/172） respectively. There was no significant correlation between EBV and H pylori infection. The c-met overexpression was significantly higher in the EBVaGC group than in the EBVnGC group. However, c-met and c-myc expression did not show significant difference between the two groups. Transcripts of EBNA1 were detected in all 13 EBVaGCs, while both EBNA2 and LMP1 mRNA were not detected. Six of the 13 cases exhibited BARF1 transcripts and 2 exhibited BHRF1 transcripts. CONCLUSION： The positivity of H pylori in EBVnGCs is higher than that of EBVaGCs, but no significant correlation is found between EBV infection and H pylori infection. H pylori-positive gastric carcinoma is predominant in antrum location, while EBVaGC has a tendency of predominance in cardia/body location. EBV infection is associated with c-met abnormal expression but not with c-myc protein in EBVaGC. c-met overexpression is not induced by LMP1. BARF1 and BHRF1 may play important roles in the tumorigenesis of EBVaGC through different pathways.展开更多
Background and Objective: EBV BamHI fragment H rightward open reading frame 1 (BHRF1), the Epstein-Barr virus (EBV) early gene, is structurally and functionally homologous to the oncogene bcl-2 and may play an importa...Background and Objective: EBV BamHI fragment H rightward open reading frame 1 (BHRF1), the Epstein-Barr virus (EBV) early gene, is structurally and functionally homologous to the oncogene bcl-2 and may play an important role in the development of EBV-associated tumors. To characterize the polymorphisms of BHRF1 in EBV-associated tumors, we analyzed the sequences of BHRF1 in isolates from nasopharyngeal carcinoma (NPC) and EBV-associated gastric carcinoma (EBVaGC) biopsies as well as throat washing (TW) samples from healthy donors. Methods: BHRF1 DNA sequences were analyzed by polymerase chain reaction (PCR) and sequencing for 39 NPC samples, 40 EBVaGC samples, and 53 EBV-positive TW samples from healthy donors. The variants of BHRF1 gene were classified according to the signature changes. The EBV types 1 and 2 at nuclear antigen (EBNA) 3C locus were determined by PCR. Results: Compared with EBV standard cell line B95-8, all isolates carried a silent mutation at amino acid (AA) 80 (nucleotide 54616 T→C), the AA88 L→V mutation was found in most isolates, and the AA79 V→L mutation in a few isolates. Other mutations were sporadically distributed. Based on the mutations at AA88 and AA79, 3 distinct variants of BHRF1 genes, designated as 79V88V, 79L88L, and 79V88L, were identified. The 79V88V was the most common variant. The distribution of the BHRF1 variants among the NPC, EBVaGC, and TW samples was not significant. The corresponding regions of bcl-2 homologues were conserved in all isolates except for 3 samples. The distribution of BHRF1 variants in type 1 and type 2 strains was significant different (P < 0.001, contingency coefficient was 0.554). Conclusions: The 79V88V is the dominant variant in NPC, EBVaGC, and TW samples from healthy donors and preferential linkages between BHRF1 and EBNA3C variants exist. Conserved BHRF1 in Bcl-2 homologous domains is helpful to remain the important role of BHRF1.展开更多
Superoxide dismutase(SOD, EC 1.15.1.1) plays a key role in response to drought stress, and differences in SOD activity changes among cultivars are important under drought conditions. We obtained the full-length DNA of...Superoxide dismutase(SOD, EC 1.15.1.1) plays a key role in response to drought stress, and differences in SOD activity changes among cultivars are important under drought conditions. We obtained the full-length DNA of the chloroplast Cu/Zn-SOD gene(Ah CSD2)from 11 allotetraploid cultivars and 5 diploid wild species in peanut. BLAST search against the peanut genome showed that the Ah CSD2 genes g CSD2-1 and g CSD2-2 are located at the tops of chromosome A03(A genome) and B03(B genome), respectively, and both contain 8exons and 7 introns. Nucleotide sequence analyses indicated that g CSD2-2 sequences were identical among all the tested cultivars, while g CSD2-1 sequences showed allelic variations.The amino acid sequences deduced from g CSD2-1 and g CSD2-2 both contain a chloroplast transit peptide and are distinguished by 6 amino acid(aa) residue differences. The other 2aa residue variations in the mature peptide regions give rise to three-dimensional structure changes of the protein deduced from the genes g CSD2-1 and g CSD2-2. Sequences analyses of cultivars and wild species showed that g CSD2-2 of Arachis hypogaea and g Aip CSD2(Arachis ipaensis) are identical, and despite the abundant polymorphic loci between g CSD2-1 of A.hypogaea and sequences from A genome wild species, the deduced amino acid sequence of Ah CSD2-1(A. hypogaea) is identical to that of Adu CSD2(Arachis duranensis), whereas Aco CSD2(Arachis correntina) and Aca CSD2(Arachis cardenasii) both have 2 aa differences in the transit peptide region compared with Ah CSD2-1(A. hypogaea). Based on the Peanut Genome Project, promoter prediction revealed many stress-related cis-acting elements within the potential promoter regions(pp-A and pp-B). pp-A contains more binding sites for drought-associated transcriptional factors than pp-B. We hypothesize that the marked changes in SOD activity in different cultivars under drought stress are tightly regulated by transcription factors through transcription and expression of Ah CSD2 genes.展开更多
AIM： To study the apoptosis induced by preoperative oral 5＇-DFUR administration in gastric adenocarcinorna and its mechanism of action. METHODS： Sixty gastric cancer patients were divided randomly into three groups...AIM： To study the apoptosis induced by preoperative oral 5＇-DFUR administration in gastric adenocarcinorna and its mechanism of action. METHODS： Sixty gastric cancer patients were divided randomly into three groups （20 each group） before operation： group one： 5＇-DFUR oral administration at the dose of 800-1200mg/d for 3 - 5 d, group two： 500mg 5-FU ± 200 mg/d CF by venous drip for 3 - 5 d, group three （control group）. One or two days after chemotherapy, the patients were operated. Fas/FasL, PD-ECGF and PCNA were examined by immunohistochemistry and apoptotic tumor cells were detected by in situ TUNEL method. Fifty-four patients received gastrectomy, including 12 palliative resections and 42 radical resections. Six patients were excluded. Finally 18 cases in 5＇-DFUR group, 16 cases in CF ± 5-FU group, and 20 cases in control group were analyzed. RESULTS： There was no significant difference in patient mean age, gender, white blood cell count, haernatoglobin （HB）, thromboplastin, perioperative complication incidence, radical or palliation resection, invasion depth （T）, Iymphonode involvement （N）, metastasis （M） and TNM staging among the three groups. However, the PCNA index （PI） in 5＇-DFUR group （40.51 ± 12.62） and 5-FU ±CF group （41.12± 15.26） was significantly lower than that in control group （58.33± 15.69） （F=9.083, P= 0.000）. The apoptotic index （AI） in 5＇-DFUR group （14.39 ±9.49） and 5-FU±CF group （14.11±9.68） was significantly higher than that in control group （6.88 ± 7.37） （F= 4.409, P= 0.017）. The expression rates of Fas and FasL in group one and group three were 66.7% （12/18） and 50% （9/18）, 43.8% （7/16） and 81.3% （13/16）, 45.0% （9/20） and 85% （17/20）, respectively. The expression rate of FasL in 5＇-DFUR group was significantly lower than that in the other two groups （X^2=6.708, P= 0.035）. Meanwhile, the expression rate of PD-ECGF was significantly lower in 5＇-DFUR group （4/18, 28.6%） than in CF±5-FU group （9/16, 56.3%） and control group （13/20, 65.0%） （7,2= 7.542, P= 0.023）. The frequency of Fas expression was significantly correlated with palliative or radical resection （X^2= 7.651, P= 0.006）, invasion depth （X^2= 8.927, P= 0.003）, lymphatic spread （7,2= 4.488, P=0.034） and UICC stages （X^2=8.063, P=0.045） respectively. By the end of March 2005, 45 patients were followed up. The 0.5-, 1-, 2-, 3-year survival rates were 96%, 73%, 60%, 48%, respectively, which were related with T, N, M and Fas expression, but not with PDECGF and FasL expression. CONCLUSION： Preoperative oral 5＇-DFUR administration may induce apoptosis of gastric carcinoma cells and decrease tumor cell proliferation index, but cannot improve the prognosis of patients with gastric cancer. Downregulation of FasL and PD-ECGF expression mediated by 5＇-DFUR may be one of its anti-cancer mechanisms. Fas expression correlates with the progression of gastric carcinoma and may be an effective prognostic factor.展开更多
The relationship between the Filaggrin gene(FLG) rs2065955 polymorphism and susceptibility to Epstein-Barr virus(EBV)-associated gastric carcinoma(EBVa GC) and EBV-negative gastric carcinoma(EBVn GC) was investigated ...The relationship between the Filaggrin gene(FLG) rs2065955 polymorphism and susceptibility to Epstein-Barr virus(EBV)-associated gastric carcinoma(EBVa GC) and EBV-negative gastric carcinoma(EBVn GC) was investigated in Shandong Province,China.We detected the FLG rs2065955 genotype and allele distribution by using PCR and restriction fragment length polymorphism(RFLP) in 64 EBVa GC,82 EBVn GC,and 111 normal control samples.Immunohistochemistry was used to detect the level of FLG protein in 35 EBVa GC and 51 EBVn GC tumor tissues.Compared with normal controls,the genotype CC and allele C of FLG rs2065955 showed higher frequency in EBVa GC and EBVn GC.There was no significant difference between EBVa GC and EBVn GC in allele distribution of FLG rs2065955,but the genotype CC was found more frequently in EBVa GC than in EBVn GC.The risk of developing either EBVa GC or EBVn GC in genotype CC was higher than in other genotypes.Furthermore,genotype CC of FLG rs2065955 may contribute more to the risk of developing EBVa GC than EBVn GC.There was no significant difference in the expression level of FLG protein between EBVa GC and EBVn GC.In conclusion,the FLG rs2065955 polymorphism was significantly related to gastric carcinoma.Allele C of FLG rs2065955 could be a risk factor for EBVa GC or EBVn GC,while genotype CC of FLG rs2065955 was especially associated with EBVa GC.展开更多
The design of the poloidal field （PF） system includes the ohmic heating field system and the equilibrium （EQ） field system, and is the basis for the design of a magnetic confinement fusion device. A coupling betwe...The design of the poloidal field （PF） system includes the ohmic heating field system and the equilibrium （EQ） field system, and is the basis for the design of a magnetic confinement fusion device. A coupling between the poloidal and plasma currents, especially the eddy current in the stabilizing shell, yields design difficulties. The effects of the eddy current in the stabilizing shell on the poloidal magnetic field also cannot be ignored. A new PF system design is thus proposed. By using a low-μ material （μ = 0.001, ε = 1） instead of a conductive shell, an electromagnetic model is established that can provide a continuous eddy current distribution on the conductive shell. In this model, a 3D time-domain problem with shells translates into a 2D magnetostatic problem, and the accuracy of the calculation is improved. Based on these current distributions, we design the PF system and analyze how the EQ coils and conductive shell affect the plasma EQ when the plasma ramps up. To meet the mainframe design requirements and achieve an efficient power-supply design, the position and connection of the poloidal coils are optimized further.展开更多
Using Chandra ACIS S3 data we studied the X-ray properties of low-and highmass X-ray binary populations in the nearby spiral galaxy NGC 5055. A total of 43 X-ray point sources were detected within two effective radii,...Using Chandra ACIS S3 data we studied the X-ray properties of low-and highmass X-ray binary populations in the nearby spiral galaxy NGC 5055. A total of 43 X-ray point sources were detected within two effective radii, with 31 sources located on the disk and the rest 12 sources in the bulge. The resolved point sources dominate the X-ray emission of the galaxy, accounting for about 80% of the total counts in 0.3-10keV. From spectral fittings we calculated the 0.3-10.0keV luminosities of all the detected X-ray point sources and found that they span a wide range from a few times 10^37 erg s^-1 to over 10^39 erg s^-1. After compensating for incompleteness at the low luminosity end, we found that the corrected XLF of the bulge population is well fitted with a broken power-law with a break at 1.57-0.20^＋0.21 1038 erg s^-1, while the profile of the disk population＇s XLF agrees with a single powerlaw distribution of slope 0 9-0.06^＋0.07 The disk population is significantly richer at ≥ 2 × 10^38 erg s^- 1 than the bulge population, indicating that the disk may have undergone relatively recent, strong starbursts that significantly increased the HMXB population, although ongoing starbursts are also observed in the nuclear region. Similar XLF profiles of the bulge and disk populations were found in M81. However, in most other spiral galaxies different patterns of spatial variation of the XLF profiles from the bulge to the disk have been observed, indicating that the star formation and evolution history may be more complex than we have expected.展开更多
The discovery of ferroelectricity in HfO_(2)-based materials with high dielectric constant has inspired tremendous research interest for next-generation electronic devices.Importantly,films structure and strain are ke...The discovery of ferroelectricity in HfO_(2)-based materials with high dielectric constant has inspired tremendous research interest for next-generation electronic devices.Importantly,films structure and strain are key factors in exploration of ferroelectricity in fluorite-type oxide HfO_(2) films.Here we investigate the structures and straininduced ferroelectric transition in different phases of few-layer HfO_(2) films(layer number𝑁=1–5).It is found that HfO_(2) films for all phases are more stable with increasing films thickness.Among them,the Pmn2_(1)(110)-oriented film is most stable,and the films of𝑁=4,5 occur with a𝑃21 ferroelectric transition under tensile strain,resulting in polarization about 11.8μC/cm^(2) along in-plane𝑎-axis.The ferroelectric transition is caused by the strain,which induces the displacement of Hf and O atoms on the surface to non-centrosymmetric positions away from the original paraelectric positions,accompanied by the change of surface Hf–O bond lengths.More importantly,three new stable HfO_(2)2D structures are discovered,together with analyses of computed electronic structures,mechanical,and dielectric properties.This work provides guidance for theoretical and experimental study of the new structures and strain-tuned ferroelectricity in freestanding HfO_(2) films.展开更多
Defect engineering represents a potent strategy for the modification of electronic properties by introducing atomic vacancies in photocatalysts.However,the synergistic enhancement attributable to different types of at...Defect engineering represents a potent strategy for the modification of electronic properties by introducing atomic vacancies in photocatalysts.However,the synergistic enhancement attributable to different types of atomic vacancies within a heterojunction,as well as their underlying mechanisms,remains sparsely studied.Here,the flexible g-C_(3)N_(4)materials with varying nitrogen vacancies were prepared via a facile calcination method under different atmospheric conditions and then composited with CeO_(2)nanocubes to construct Z-scheme heterojunction.It was observed that CeO_(2)has abundant O vacancies,and the g-C_(3)N_(4)form tertiary nitrogen defects at the center of the heptazine units under an NH3 atmosphere treatment.The resulting enhancement in the interfacial built-in electric field,coupled with the synergistic effect of O and N vacancies within the Z-scheme heterojunction,has been demonstrated to significantly enhance charge transfer efficiency.This results in an optimized photoactivity with a H_(2)O_(2)generation rate of 2.01 mmol g^(-1)h^(-1).This work opens an avenue for constructing and optimizing the heterogeneous photocatalysts by defect engineering technology,and provides deep insight to understand the nature of vacancy engineering in designing effective catalysts for solar energy conversion.展开更多
Lunar surface additive manufacturing with lunar regolith is a key step in in-situ resource utilization.The powder spreading process is the key process,which has a major impact on the quality of the powder bed and the ...Lunar surface additive manufacturing with lunar regolith is a key step in in-situ resource utilization.The powder spreading process is the key process,which has a major impact on the quality of the powder bed and the precision of molded parts.In this study,the discrete element method(DEM)was adopted to simulate the powder spreading process with a roller.The three powder bed quality indicators,including the molding layer offset,voidage fraction,and surface roughness,were established.Besides,the influence of the three process parameters,which are roller’s translational speed,rotational speed,and powder spreading layer thickness on the powder bed quality indicators was also analyzed.The results show that with the reduction of the powder spreading layer thickness and the increase of the rotational speed,the offset increased significantly;when the translational speed increased,the offset first increased and then decreased,which resulted in an extreme value;with the increase of the layer thickness and the decrease of the translational speed,the values for voidage fraction and surface roughness significantly reduced.The powder bed quality indicators were adopted as the optimization objective,and the multi-objective parameter optimization was carried out.The predicted optimal powder spreading parameters and powder bed quality indicators were then obtained.Moreover,the optimal values were then verified.This study can provide informative guidance for in-situ manufacturing at the moon in future deep space exploration missions.展开更多
Accurately identifying the location and type of internal defects in gas-insulated switchgear(GIS)is a challenge.To address this challenge,this study proposes a novel method for the nondestructive detection of GIS inte...Accurately identifying the location and type of internal defects in gas-insulated switchgear(GIS)is a challenge.To address this challenge,this study proposes a novel method for the nondestructive detection of GIS internal defects.This method is based on x-ray digital radiography(X-DR)technology and an improved real-time models for object detection(RTMdet)algorithm,namely GIS-specific localised internal defect-RTMdet.Firstly,the X-DR images of GIS are preprocessed by dynamic limit adaptive histogram equalisation algorithm to improve the images contrast.Then,a convolution shuffle upsample module for upsampling is proposed,which enlarges the defect feature map by multi-convolution and pixel shuffling,reduces the information loss,and enhances the interaction between the feature information.Finally,both the multi-channel attention net and the global attention mechanism are integrated into the neck network for enhancing local feature extraction and global information association.Experiments demonstrate that the pro-posed method achieves a mean average precision@0.5:0.95 of 94.9%,showcasing excellent overall performance and generalisation ability,and is more suitable for accurate nondestructive detection of internal defects of GIS in complex scenarios.展开更多
Large igneous provinces are generally thought to promote the formation of hydrothermal dolomites and associated reservoirs via tectonic-hydrothermal activity and thermal convection.However,this view has been recently ...Large igneous provinces are generally thought to promote the formation of hydrothermal dolomites and associated reservoirs via tectonic-hydrothermal activity and thermal convection.However,this view has been recently challenged,as abundant non-hydrothermal dolomites have been discovered around the center of the Permian Emeishan Large Igneous Province in the Sichuan Basin,China.To better understand the effects of large igneous provinces on dolomite,we review the current research status in this field and also present a case study of a petrological and geochemical investigation of the Maokou Formation in the Xinjigu section in the intermediate zone of the Emeishan Large Igneous Province.The reviews show that largescale dolomitization associated with large igneous provinces is universally attributable to tectonic-hydrothermal processes and thermal convection,both of which are related to thermal effects,and the properties of the dolomitizing fluids control the differences in the dolomite reservoirs.Our study found that the finely crystalline dolomites in the Xinjigu section are the products of coeval seawater dolomitization,while the hydrothermal dolomites(i.e.,medium-grained dolomites)are developed on a limited scale due to the minor regional tectonism and absence of pathways for hydrothermal fluids.The differential upliftsubsidence caused by the ascending Emeishan mantle plume controls the penecontemporaneous dolomitization and karstification,which leads to large-scale facies-controlled dolomites and reservoirs.These dolomites are mainly distributed in the sedimentary highland areas controlled by the inner and intermediate zones of the Emeishan Large Igneous Province and the extensional margin.These dolomites are larger in scale than hydrothermal dolomites,and thus of great significance for oil and gas exploration.展开更多
The development of highly sensitive and reliable gas sensors is crucial for environmental monitoring,industrial safety,and healthcare applications.We report a facile block copolymer self-assembly approach for fabricat...The development of highly sensitive and reliable gas sensors is crucial for environmental monitoring,industrial safety,and healthcare applications.We report a facile block copolymer self-assembly approach for fabricating plasmonic Au nanoparticle-decorated WO_(3)three-dimensional cross-stacked nanowire arrays on microchips for enhanced gas sensing.The porous nanostructure of 3D WO_(3)NW framework,coupled with the catalytic and surface plasmon resonance properties of Au NPs,synergistically boosts the NO_(2)sensing performance.The Au/WO_(3)sensor exhibits an exceptional response of 340.7 to 50 ppm NO_(2)at 150℃ in dark conditions,which further increases to 980 under white light illumination,along with rapid response/recovery times,a low detection limit,and excellent stability.To elucidate the gas sensing mechanisms,we employ environmental operando micro-spectroscopy techniques,including conductive atomic force microscopy,Kelvin probe force microscopy,and diffuse reflectance infrared Fourier transform spectroscopy.These advanced characterizations,combined with theoretical calculations,provide direct evidence for the efficient generation and transfer of hot electrons from Au NPs to the WO_(3)NW matrix under light irradiation,revealing their pivotal role in enhancing NO_(2)adsorption and expanding the electron depletion layer.In-situ measurements also unveil the dynamic modulation of the Schottky barrier height at the Au/WO_(3)junction,offering deeper insights into the interplay between environmental factors,hot electrons,and resistance alteration in the metal-semiconductor system.This work provides a promising strategy for designing high-performance gas sensors and paves the way for probing complex gas sensing mechanisms.展开更多
In order to solve the problem that target tracking frames are lost during the visual tracking of pigs,this research proposed an algorithm for multi target pigs tracking loss correction based on Faster R-CNN.The video ...In order to solve the problem that target tracking frames are lost during the visual tracking of pigs,this research proposed an algorithm for multi target pigs tracking loss correction based on Faster R-CNN.The video of live pigs was processed by Faster R-CNN to get the object bounding box.Then,the SURF and background difference method were combined to predict whether the target pig will be occluded in the next frame.According to the occlusion condition,the maximum value of the horizontal and vertical coordinate offset of the bounding box in the adjacent two frames of the frame image in continuous N(N is the value of the video frame rate)were calculated.When bounding boxes in a video frame are merged into one bounding box,this maximum value was used to correct the current tracking frame offset in order to achieve the purpose of solving the tracking target loss problem.The experiment results showed that the success rate range of RP Faster-RCNN in the data set was 80%-97% while in term of Faster-RCNN was 40%-85%.And the average center point error of RP Faster-RCNN was 1.46 lower than Faster-RCNN which was about 2.60.The new algorithm was characterized by good robustness and adaptability,which could solve the problem of missing tracking target and accurately track multiple targets when the targets occlude each other.展开更多
Plasmonic nanomaterial catalysis is currently at the frontier of photocatalysis,overcoming the limitations of wide bandgap semiconductors for light absorption.Its localized surface plasmon resonance(LSPR)properties al...Plasmonic nanomaterial catalysis is currently at the frontier of photocatalysis,overcoming the limitations of wide bandgap semiconductors for light absorption.Its localized surface plasmon resonance(LSPR)properties allow broad ultraviolet-visible-near infrared ray(UV-vis-NIR)absorption,making it an ideal material for solar energy conversion.Most plasmonic nanostructures rely on precious metals.Although noble metal plasmonic nanomaterials have proven to be one of the strategies for enhancing photocatalytic activity,their expensive cost and limitations in light absorption range have hindered their practical application.As a result,noble-metal free plasmonic nanomaterials have risen to the top of the research priority list.Therefore,this paper reviews the fundamental principles and classification of the LSPR effect of noble-metal free plasmonic nanomaterials in photocatalytic and their recent applications in hydrogen generation,carbon dioxide reduction,and pollutant degradation.Specific cases elucidate the possible working mechanism of enhanced photocatalysis by noble-metal free plasmonic nanomaterials.Finally,the challenges and future opportunities for noble-metal free plasmonic nanomaterials in energy conversion and storage are discussed and envisioned.展开更多
As the core equipment of transmission and distribution hubs,the operational status of gas-insulated switchgear(GIS)is closely linked to the safety of the power system.Recently,X-ray digital imaging technology has been...As the core equipment of transmission and distribution hubs,the operational status of gas-insulated switchgear(GIS)is closely linked to the safety of the power system.Recently,X-ray digital imaging technology has been extensively used in GIS equipment fault detection.However,the X-ray image of GIS is blurred,which is not conducive to the detection of tiny defects.Thus,a super-resolution method for GIS X-ray images based on multi-scale context transformers is proposed in this study,namely MCTSR.Firstly,a second-order image degradation model is introduced to generate GIS X-ray lowresolution images that more closely resemble the real world.Secondly,a contextual transformer gate module is constructed to improve attention to tiny defects in GIS X-ray images.Thirdly,a U-Net discriminator network based on multi-scale contextual transformers is intended to enrich the information of the generated images.Finally,the proposed discriminator is combined with the existing generator to compose a superresolution method applicable to GIS X-ray images.The experimental results demonstrate that the method outperforms other methods in peak signal-to-noise ratio and structural similarity on the constructed GIS X-ray image dataset.In addition,the output image of the proposed method facilitates the subsequent defect detection.展开更多
基金Jiangxi Provincial Innovative Training Project“Post-earthquake Landslide Risk Evaluation Study under Spatial Scale Modelling”(Project No.:S202311318050)。
文摘Landslides are significant natural geological hazards.Landslide susceptibility evaluation involves the quantitative assessment and prediction of potential landslide locations and their probabilities.Research has explored susceptibility assessment methods based on spatial-scale analysis.This evaluation integrates two models—global and local scale—using a CNN model and a PSO-CNN coupled model.Key aspects include selecting evaluation factors and optimizing model parameters for landslide susceptibility at different scales.A major focus of current landslide research is utilizing prediction results to enhance prevention and control measures.
文摘AIM： To investigate the interrelationship of Epstein-Barr virus （EBV） and EBV- encoded proteins with Helicobacter pylori （H pylor/~ infection and the expression of c-met and c-myc oncogene proteins in gastric carcinoma, and to explore their role in gastric carcinogenesis. METHODS： One hundred and eighty-five gastric carcinoma tissues were detected by polymerase chain reaction （PCR）-Southern blot for EBV genome and in situ hybridization （ISH） for EBV-encoded small RNA 1 （EBER1）. Gastric carcinoma with positive EBER1 signals was confirmed EBV-associated gastric carcinoma （EBVaGC）. The status of Hpylori infection in 185 gastric carcinomas was assessed by rapid urease test and PCR. The samples with positive PCR and urease test were defined as H pylorl infection. The expression of c-met and c-myc oncogene proteins in tissues of EBVaGC and matched EBV-negative gastric carcinoma （EBVnGC） were examined by immunohistochemistry. RT-PCR and Southern hybridization were used to detect the expression of nuclear antigens （EBNAs） 1 and 2, latent membrane protein （LMP） 1, early genes BARF1 and BHRF1 in EBVaGC cases. RESULTS： The positive rate of H pylori and EBV in 185 gastric carcinomas was 59.45% （110/185） and 7.03% （13/185） respectively. No difference was found in sex, age, pathological differentiation, clinical stages and lymph node metastasis between H pylori-positive and H pylori-negative gastric carcinomas. However, the positive rate of H pylori infection in the antrum gastric carcinomas was higher than that of cardia and body gastric carcinomas. In our series, age, pathological differentiation, clinical stages, lymph node metastasis and location of cancer were not different between EBVnGC and EBVaGC, while the positive rate of EBV in male patients was significantly higher than that of female patients. The positivity of Hpylori in EBV-associated and EBV-negative gastric carcinomas was 46.15% （6/13） and 81.40%（104/172） respectively. There was no significant correlation between EBV and H pylori infection. The c-met overexpression was significantly higher in the EBVaGC group than in the EBVnGC group. However, c-met and c-myc expression did not show significant difference between the two groups. Transcripts of EBNA1 were detected in all 13 EBVaGCs, while both EBNA2 and LMP1 mRNA were not detected. Six of the 13 cases exhibited BARF1 transcripts and 2 exhibited BHRF1 transcripts. CONCLUSION： The positivity of H pylori in EBVnGCs is higher than that of EBVaGCs, but no significant correlation is found between EBV infection and H pylori infection. H pylori-positive gastric carcinoma is predominant in antrum location, while EBVaGC has a tendency of predominance in cardia/body location. EBV infection is associated with c-met abnormal expression but not with c-myc protein in EBVaGC. c-met overexpression is not induced by LMP1. BARF1 and BHRF1 may play important roles in the tumorigenesis of EBVaGC through different pathways.
基金National Natural Science Foundation of China (No30740068)Natural Science Foundation of Shandong Province, China(No Y2008C90)
文摘Background and Objective: EBV BamHI fragment H rightward open reading frame 1 (BHRF1), the Epstein-Barr virus (EBV) early gene, is structurally and functionally homologous to the oncogene bcl-2 and may play an important role in the development of EBV-associated tumors. To characterize the polymorphisms of BHRF1 in EBV-associated tumors, we analyzed the sequences of BHRF1 in isolates from nasopharyngeal carcinoma (NPC) and EBV-associated gastric carcinoma (EBVaGC) biopsies as well as throat washing (TW) samples from healthy donors. Methods: BHRF1 DNA sequences were analyzed by polymerase chain reaction (PCR) and sequencing for 39 NPC samples, 40 EBVaGC samples, and 53 EBV-positive TW samples from healthy donors. The variants of BHRF1 gene were classified according to the signature changes. The EBV types 1 and 2 at nuclear antigen (EBNA) 3C locus were determined by PCR. Results: Compared with EBV standard cell line B95-8, all isolates carried a silent mutation at amino acid (AA) 80 (nucleotide 54616 T→C), the AA88 L→V mutation was found in most isolates, and the AA79 V→L mutation in a few isolates. Other mutations were sporadically distributed. Based on the mutations at AA88 and AA79, 3 distinct variants of BHRF1 genes, designated as 79V88V, 79L88L, and 79V88L, were identified. The 79V88V was the most common variant. The distribution of the BHRF1 variants among the NPC, EBVaGC, and TW samples was not significant. The corresponding regions of bcl-2 homologues were conserved in all isolates except for 3 samples. The distribution of BHRF1 variants in type 1 and type 2 strains was significant different (P < 0.001, contingency coefficient was 0.554). Conclusions: The 79V88V is the dominant variant in NPC, EBVaGC, and TW samples from healthy donors and preferential linkages between BHRF1 and EBNA3C variants exist. Conserved BHRF1 in Bcl-2 homologous domains is helpful to remain the important role of BHRF1.
基金financial support by the Natural Science Foundation of China (NSFC) (31201167)the earmarked fund for China Agriculture Research System (CARS-14)+1 种基金the Peanut Seed Industry Project in Shandong province of Chinathe earmarked fund for Agriculture Research System in Shandong province of China
文摘Superoxide dismutase(SOD, EC 1.15.1.1) plays a key role in response to drought stress, and differences in SOD activity changes among cultivars are important under drought conditions. We obtained the full-length DNA of the chloroplast Cu/Zn-SOD gene(Ah CSD2)from 11 allotetraploid cultivars and 5 diploid wild species in peanut. BLAST search against the peanut genome showed that the Ah CSD2 genes g CSD2-1 and g CSD2-2 are located at the tops of chromosome A03(A genome) and B03(B genome), respectively, and both contain 8exons and 7 introns. Nucleotide sequence analyses indicated that g CSD2-2 sequences were identical among all the tested cultivars, while g CSD2-1 sequences showed allelic variations.The amino acid sequences deduced from g CSD2-1 and g CSD2-2 both contain a chloroplast transit peptide and are distinguished by 6 amino acid(aa) residue differences. The other 2aa residue variations in the mature peptide regions give rise to three-dimensional structure changes of the protein deduced from the genes g CSD2-1 and g CSD2-2. Sequences analyses of cultivars and wild species showed that g CSD2-2 of Arachis hypogaea and g Aip CSD2(Arachis ipaensis) are identical, and despite the abundant polymorphic loci between g CSD2-1 of A.hypogaea and sequences from A genome wild species, the deduced amino acid sequence of Ah CSD2-1(A. hypogaea) is identical to that of Adu CSD2(Arachis duranensis), whereas Aco CSD2(Arachis correntina) and Aca CSD2(Arachis cardenasii) both have 2 aa differences in the transit peptide region compared with Ah CSD2-1(A. hypogaea). Based on the Peanut Genome Project, promoter prediction revealed many stress-related cis-acting elements within the potential promoter regions(pp-A and pp-B). pp-A contains more binding sites for drought-associated transcriptional factors than pp-B. We hypothesize that the marked changes in SOD activity in different cultivars under drought stress are tightly regulated by transcription factors through transcription and expression of Ah CSD2 genes.
基金Supported by Natural Science Foundation of Zhejiang Province, No. 20010536
文摘AIM： To study the apoptosis induced by preoperative oral 5＇-DFUR administration in gastric adenocarcinorna and its mechanism of action. METHODS： Sixty gastric cancer patients were divided randomly into three groups （20 each group） before operation： group one： 5＇-DFUR oral administration at the dose of 800-1200mg/d for 3 - 5 d, group two： 500mg 5-FU ± 200 mg/d CF by venous drip for 3 - 5 d, group three （control group）. One or two days after chemotherapy, the patients were operated. Fas/FasL, PD-ECGF and PCNA were examined by immunohistochemistry and apoptotic tumor cells were detected by in situ TUNEL method. Fifty-four patients received gastrectomy, including 12 palliative resections and 42 radical resections. Six patients were excluded. Finally 18 cases in 5＇-DFUR group, 16 cases in CF ± 5-FU group, and 20 cases in control group were analyzed. RESULTS： There was no significant difference in patient mean age, gender, white blood cell count, haernatoglobin （HB）, thromboplastin, perioperative complication incidence, radical or palliation resection, invasion depth （T）, Iymphonode involvement （N）, metastasis （M） and TNM staging among the three groups. However, the PCNA index （PI） in 5＇-DFUR group （40.51 ± 12.62） and 5-FU ±CF group （41.12± 15.26） was significantly lower than that in control group （58.33± 15.69） （F=9.083, P= 0.000）. The apoptotic index （AI） in 5＇-DFUR group （14.39 ±9.49） and 5-FU±CF group （14.11±9.68） was significantly higher than that in control group （6.88 ± 7.37） （F= 4.409, P= 0.017）. The expression rates of Fas and FasL in group one and group three were 66.7% （12/18） and 50% （9/18）, 43.8% （7/16） and 81.3% （13/16）, 45.0% （9/20） and 85% （17/20）, respectively. The expression rate of FasL in 5＇-DFUR group was significantly lower than that in the other two groups （X^2=6.708, P= 0.035）. Meanwhile, the expression rate of PD-ECGF was significantly lower in 5＇-DFUR group （4/18, 28.6%） than in CF±5-FU group （9/16, 56.3%） and control group （13/20, 65.0%） （7,2= 7.542, P= 0.023）. The frequency of Fas expression was significantly correlated with palliative or radical resection （X^2= 7.651, P= 0.006）, invasion depth （X^2= 8.927, P= 0.003）, lymphatic spread （7,2= 4.488, P=0.034） and UICC stages （X^2=8.063, P=0.045） respectively. By the end of March 2005, 45 patients were followed up. The 0.5-, 1-, 2-, 3-year survival rates were 96%, 73%, 60%, 48%, respectively, which were related with T, N, M and Fas expression, but not with PDECGF and FasL expression. CONCLUSION： Preoperative oral 5＇-DFUR administration may induce apoptosis of gastric carcinoma cells and decrease tumor cell proliferation index, but cannot improve the prognosis of patients with gastric cancer. Downregulation of FasL and PD-ECGF expression mediated by 5＇-DFUR may be one of its anti-cancer mechanisms. Fas expression correlates with the progression of gastric carcinoma and may be an effective prognostic factor.
基金funded by the National Natural Science Foundation of China (NSFC 81571995)Specialized Research Fund for the Doctoral Program of Higher Education,(20133706110001)the Natural Science Foundation of Shandong Province (ZR2015HM069)
文摘The relationship between the Filaggrin gene(FLG) rs2065955 polymorphism and susceptibility to Epstein-Barr virus(EBV)-associated gastric carcinoma(EBVa GC) and EBV-negative gastric carcinoma(EBVn GC) was investigated in Shandong Province,China.We detected the FLG rs2065955 genotype and allele distribution by using PCR and restriction fragment length polymorphism(RFLP) in 64 EBVa GC,82 EBVn GC,and 111 normal control samples.Immunohistochemistry was used to detect the level of FLG protein in 35 EBVa GC and 51 EBVn GC tumor tissues.Compared with normal controls,the genotype CC and allele C of FLG rs2065955 showed higher frequency in EBVa GC and EBVn GC.There was no significant difference between EBVa GC and EBVn GC in allele distribution of FLG rs2065955,but the genotype CC was found more frequently in EBVa GC than in EBVn GC.The risk of developing either EBVa GC or EBVn GC in genotype CC was higher than in other genotypes.Furthermore,genotype CC of FLG rs2065955 may contribute more to the risk of developing EBVa GC than EBVn GC.There was no significant difference in the expression level of FLG protein between EBVa GC and EBVn GC.In conclusion,the FLG rs2065955 polymorphism was significantly related to gastric carcinoma.Allele C of FLG rs2065955 could be a risk factor for EBVa GC or EBVn GC,while genotype CC of FLG rs2065955 was especially associated with EBVa GC.
基金supported by the National Magnetic Confinement Fusion Research Program of China (2011GB106000)
文摘The design of the poloidal field （PF） system includes the ohmic heating field system and the equilibrium （EQ） field system, and is the basis for the design of a magnetic confinement fusion device. A coupling between the poloidal and plasma currents, especially the eddy current in the stabilizing shell, yields design difficulties. The effects of the eddy current in the stabilizing shell on the poloidal magnetic field also cannot be ignored. A new PF system design is thus proposed. By using a low-μ material （μ = 0.001, ε = 1） instead of a conductive shell, an electromagnetic model is established that can provide a continuous eddy current distribution on the conductive shell. In this model, a 3D time-domain problem with shells translates into a 2D magnetostatic problem, and the accuracy of the calculation is improved. Based on these current distributions, we design the PF system and analyze how the EQ coils and conductive shell affect the plasma EQ when the plasma ramps up. To meet the mainframe design requirements and achieve an efficient power-supply design, the position and connection of the poloidal coils are optimized further.
基金the National Natural Science Foundation of China.
文摘Using Chandra ACIS S3 data we studied the X-ray properties of low-and highmass X-ray binary populations in the nearby spiral galaxy NGC 5055. A total of 43 X-ray point sources were detected within two effective radii, with 31 sources located on the disk and the rest 12 sources in the bulge. The resolved point sources dominate the X-ray emission of the galaxy, accounting for about 80% of the total counts in 0.3-10keV. From spectral fittings we calculated the 0.3-10.0keV luminosities of all the detected X-ray point sources and found that they span a wide range from a few times 10^37 erg s^-1 to over 10^39 erg s^-1. After compensating for incompleteness at the low luminosity end, we found that the corrected XLF of the bulge population is well fitted with a broken power-law with a break at 1.57-0.20^＋0.21 1038 erg s^-1, while the profile of the disk population＇s XLF agrees with a single powerlaw distribution of slope 0 9-0.06^＋0.07 The disk population is significantly richer at ≥ 2 × 10^38 erg s^- 1 than the bulge population, indicating that the disk may have undergone relatively recent, strong starbursts that significantly increased the HMXB population, although ongoing starbursts are also observed in the nuclear region. Similar XLF profiles of the bulge and disk populations were found in M81. However, in most other spiral galaxies different patterns of spatial variation of the XLF profiles from the bulge to the disk have been observed, indicating that the star formation and evolution history may be more complex than we have expected.
基金supported by the National Key R&D Program of China(Grant No.2023YFB4402600)the National Natural Science Foundation of China(Grant Nos.12074241,11929401,52130204,12311530675,and 52271007)+5 种基金Key Research Project of Zhejiang Lab(Grant No.2021PE0AC02)Science and Technology Commission of Shanghai Municipality(Grant Nos.22XD1400900,20501130600,21JC1402700,and 21JC1402600)supports from the open projects of Key Laboratory of Green Fabrication and Surface Technology of Advanced Metal Materials(Anhui University of Technology),Ministry of Education(Grant No.GFST2022KF08)State Key Laboratory of Surface Physics(Fudan University)(Grant No.KF202210)State Key Laboratory of Infrared Physics,Shanghai Institute of Technical Physics,Chinese Academy of Sciences(Grant No.SITP-NLIST-YB-2022-08)the support of China Scholarship Council,and thanks Mr.Xiaowen Shi(from HZWTECH)for helpful discussions.
文摘The discovery of ferroelectricity in HfO_(2)-based materials with high dielectric constant has inspired tremendous research interest for next-generation electronic devices.Importantly,films structure and strain are key factors in exploration of ferroelectricity in fluorite-type oxide HfO_(2) films.Here we investigate the structures and straininduced ferroelectric transition in different phases of few-layer HfO_(2) films(layer number𝑁=1–5).It is found that HfO_(2) films for all phases are more stable with increasing films thickness.Among them,the Pmn2_(1)(110)-oriented film is most stable,and the films of𝑁=4,5 occur with a𝑃21 ferroelectric transition under tensile strain,resulting in polarization about 11.8μC/cm^(2) along in-plane𝑎-axis.The ferroelectric transition is caused by the strain,which induces the displacement of Hf and O atoms on the surface to non-centrosymmetric positions away from the original paraelectric positions,accompanied by the change of surface Hf–O bond lengths.More importantly,three new stable HfO_(2)2D structures are discovered,together with analyses of computed electronic structures,mechanical,and dielectric properties.This work provides guidance for theoretical and experimental study of the new structures and strain-tuned ferroelectricity in freestanding HfO_(2) films.
基金financially supported by the Shaanxi Provin-cial Natural Science Basic Research Program(No.2023-JC-YB-457)the National Natural Science Foundation of China(Nos.52025061 and 52106270)+3 种基金the China Postdoctoral Science Foun-dation(No.2020M683472)the China Fundamental Research Funds for the Central Universitiessupported by the Zhuhai Innovation and Entrepreneurship Team Project(No.2120004000225)the Project of Shaanxi Provincial Science and Technology Innovation Team(No.2023-CX-TD-25).
文摘Defect engineering represents a potent strategy for the modification of electronic properties by introducing atomic vacancies in photocatalysts.However,the synergistic enhancement attributable to different types of atomic vacancies within a heterojunction,as well as their underlying mechanisms,remains sparsely studied.Here,the flexible g-C_(3)N_(4)materials with varying nitrogen vacancies were prepared via a facile calcination method under different atmospheric conditions and then composited with CeO_(2)nanocubes to construct Z-scheme heterojunction.It was observed that CeO_(2)has abundant O vacancies,and the g-C_(3)N_(4)form tertiary nitrogen defects at the center of the heptazine units under an NH3 atmosphere treatment.The resulting enhancement in the interfacial built-in electric field,coupled with the synergistic effect of O and N vacancies within the Z-scheme heterojunction,has been demonstrated to significantly enhance charge transfer efficiency.This results in an optimized photoactivity with a H_(2)O_(2)generation rate of 2.01 mmol g^(-1)h^(-1).This work opens an avenue for constructing and optimizing the heterogeneous photocatalysts by defect engineering technology,and provides deep insight to understand the nature of vacancy engineering in designing effective catalysts for solar energy conversion.
文摘Lunar surface additive manufacturing with lunar regolith is a key step in in-situ resource utilization.The powder spreading process is the key process,which has a major impact on the quality of the powder bed and the precision of molded parts.In this study,the discrete element method(DEM)was adopted to simulate the powder spreading process with a roller.The three powder bed quality indicators,including the molding layer offset,voidage fraction,and surface roughness,were established.Besides,the influence of the three process parameters,which are roller’s translational speed,rotational speed,and powder spreading layer thickness on the powder bed quality indicators was also analyzed.The results show that with the reduction of the powder spreading layer thickness and the increase of the rotational speed,the offset increased significantly;when the translational speed increased,the offset first increased and then decreased,which resulted in an extreme value;with the increase of the layer thickness and the decrease of the translational speed,the values for voidage fraction and surface roughness significantly reduced.The powder bed quality indicators were adopted as the optimization objective,and the multi-objective parameter optimization was carried out.The predicted optimal powder spreading parameters and powder bed quality indicators were then obtained.Moreover,the optimal values were then verified.This study can provide informative guidance for in-situ manufacturing at the moon in future deep space exploration missions.
基金National Engineering Research Center of UHV Technology and New Electrical Equipment Basis of China Southern Power Grid Research Institute Co.,Ltd,Grant/Award Number:NERCUTNEEB-2022-KF-08。
文摘Accurately identifying the location and type of internal defects in gas-insulated switchgear(GIS)is a challenge.To address this challenge,this study proposes a novel method for the nondestructive detection of GIS internal defects.This method is based on x-ray digital radiography(X-DR)technology and an improved real-time models for object detection(RTMdet)algorithm,namely GIS-specific localised internal defect-RTMdet.Firstly,the X-DR images of GIS are preprocessed by dynamic limit adaptive histogram equalisation algorithm to improve the images contrast.Then,a convolution shuffle upsample module for upsampling is proposed,which enlarges the defect feature map by multi-convolution and pixel shuffling,reduces the information loss,and enhances the interaction between the feature information.Finally,both the multi-channel attention net and the global attention mechanism are integrated into the neck network for enhancing local feature extraction and global information association.Experiments demonstrate that the pro-posed method achieves a mean average precision@0.5:0.95 of 94.9%,showcasing excellent overall performance and generalisation ability,and is more suitable for accurate nondestructive detection of internal defects of GIS in complex scenarios.
基金supported by the National Natural Science Foundation of China(Grant Nos.42172166 and 42472167)Science and Technology Cooperation Project of the CNPC-SWPU Innovation Alliance(Grant No.2020CX010300)。
文摘Large igneous provinces are generally thought to promote the formation of hydrothermal dolomites and associated reservoirs via tectonic-hydrothermal activity and thermal convection.However,this view has been recently challenged,as abundant non-hydrothermal dolomites have been discovered around the center of the Permian Emeishan Large Igneous Province in the Sichuan Basin,China.To better understand the effects of large igneous provinces on dolomite,we review the current research status in this field and also present a case study of a petrological and geochemical investigation of the Maokou Formation in the Xinjigu section in the intermediate zone of the Emeishan Large Igneous Province.The reviews show that largescale dolomitization associated with large igneous provinces is universally attributable to tectonic-hydrothermal processes and thermal convection,both of which are related to thermal effects,and the properties of the dolomitizing fluids control the differences in the dolomite reservoirs.Our study found that the finely crystalline dolomites in the Xinjigu section are the products of coeval seawater dolomitization,while the hydrothermal dolomites(i.e.,medium-grained dolomites)are developed on a limited scale due to the minor regional tectonism and absence of pathways for hydrothermal fluids.The differential upliftsubsidence caused by the ascending Emeishan mantle plume controls the penecontemporaneous dolomitization and karstification,which leads to large-scale facies-controlled dolomites and reservoirs.These dolomites are mainly distributed in the sedimentary highland areas controlled by the inner and intermediate zones of the Emeishan Large Igneous Province and the extensional margin.These dolomites are larger in scale than hydrothermal dolomites,and thus of great significance for oil and gas exploration.
基金supported by the Key Research and Development Plan of Shaanxi Province(2024GX-ZDCYL-01-06)the National Natural Science Foundation of China(62074123 and 52106270)。
文摘The development of highly sensitive and reliable gas sensors is crucial for environmental monitoring,industrial safety,and healthcare applications.We report a facile block copolymer self-assembly approach for fabricating plasmonic Au nanoparticle-decorated WO_(3)three-dimensional cross-stacked nanowire arrays on microchips for enhanced gas sensing.The porous nanostructure of 3D WO_(3)NW framework,coupled with the catalytic and surface plasmon resonance properties of Au NPs,synergistically boosts the NO_(2)sensing performance.The Au/WO_(3)sensor exhibits an exceptional response of 340.7 to 50 ppm NO_(2)at 150℃ in dark conditions,which further increases to 980 under white light illumination,along with rapid response/recovery times,a low detection limit,and excellent stability.To elucidate the gas sensing mechanisms,we employ environmental operando micro-spectroscopy techniques,including conductive atomic force microscopy,Kelvin probe force microscopy,and diffuse reflectance infrared Fourier transform spectroscopy.These advanced characterizations,combined with theoretical calculations,provide direct evidence for the efficient generation and transfer of hot electrons from Au NPs to the WO_(3)NW matrix under light irradiation,revealing their pivotal role in enhancing NO_(2)adsorption and expanding the electron depletion layer.In-situ measurements also unveil the dynamic modulation of the Schottky barrier height at the Au/WO_(3)junction,offering deeper insights into the interplay between environmental factors,hot electrons,and resistance alteration in the metal-semiconductor system.This work provides a promising strategy for designing high-performance gas sensors and paves the way for probing complex gas sensing mechanisms.
基金The authors acknowledge that this research was financially supported by the National High Technology Research and Development Program of China(2013AA102306).
文摘In order to solve the problem that target tracking frames are lost during the visual tracking of pigs,this research proposed an algorithm for multi target pigs tracking loss correction based on Faster R-CNN.The video of live pigs was processed by Faster R-CNN to get the object bounding box.Then,the SURF and background difference method were combined to predict whether the target pig will be occluded in the next frame.According to the occlusion condition,the maximum value of the horizontal and vertical coordinate offset of the bounding box in the adjacent two frames of the frame image in continuous N(N is the value of the video frame rate)were calculated.When bounding boxes in a video frame are merged into one bounding box,this maximum value was used to correct the current tracking frame offset in order to achieve the purpose of solving the tracking target loss problem.The experiment results showed that the success rate range of RP Faster-RCNN in the data set was 80%-97% while in term of Faster-RCNN was 40%-85%.And the average center point error of RP Faster-RCNN was 1.46 lower than Faster-RCNN which was about 2.60.The new algorithm was characterized by good robustness and adaptability,which could solve the problem of missing tracking target and accurately track multiple targets when the targets occlude each other.
基金the financial support from the National Natural Science Foundation of China(No.52025061)Royal Society-Newton Advanced Fellowship grant(No.NAF/R1/191163)supported by the China Fundamental Research Funds for the Central Universities.
文摘Plasmonic nanomaterial catalysis is currently at the frontier of photocatalysis,overcoming the limitations of wide bandgap semiconductors for light absorption.Its localized surface plasmon resonance(LSPR)properties allow broad ultraviolet-visible-near infrared ray(UV-vis-NIR)absorption,making it an ideal material for solar energy conversion.Most plasmonic nanostructures rely on precious metals.Although noble metal plasmonic nanomaterials have proven to be one of the strategies for enhancing photocatalytic activity,their expensive cost and limitations in light absorption range have hindered their practical application.As a result,noble-metal free plasmonic nanomaterials have risen to the top of the research priority list.Therefore,this paper reviews the fundamental principles and classification of the LSPR effect of noble-metal free plasmonic nanomaterials in photocatalytic and their recent applications in hydrogen generation,carbon dioxide reduction,and pollutant degradation.Specific cases elucidate the possible working mechanism of enhanced photocatalysis by noble-metal free plasmonic nanomaterials.Finally,the challenges and future opportunities for noble-metal free plasmonic nanomaterials in energy conversion and storage are discussed and envisioned.
基金Guangdong Science and Technology Innovation Strategy Special Funds Project,Grant/Award Number:pdjh2022b0545。
文摘As the core equipment of transmission and distribution hubs,the operational status of gas-insulated switchgear(GIS)is closely linked to the safety of the power system.Recently,X-ray digital imaging technology has been extensively used in GIS equipment fault detection.However,the X-ray image of GIS is blurred,which is not conducive to the detection of tiny defects.Thus,a super-resolution method for GIS X-ray images based on multi-scale context transformers is proposed in this study,namely MCTSR.Firstly,a second-order image degradation model is introduced to generate GIS X-ray lowresolution images that more closely resemble the real world.Secondly,a contextual transformer gate module is constructed to improve attention to tiny defects in GIS X-ray images.Thirdly,a U-Net discriminator network based on multi-scale contextual transformers is intended to enrich the information of the generated images.Finally,the proposed discriminator is combined with the existing generator to compose a superresolution method applicable to GIS X-ray images.The experimental results demonstrate that the method outperforms other methods in peak signal-to-noise ratio and structural similarity on the constructed GIS X-ray image dataset.In addition,the output image of the proposed method facilitates the subsequent defect detection.
