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1.
Nano Lett ; 24(33): 10348-10354, 2024 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-39109804

RESUMEN

Carrier transport capacity with high mobility and long-range diffusion length holds particular significance for the advancement of modern optoelectronic devices. Herein, we have unveiled the carrier dynamics and transport properties of a pristine violet phosphorus (VP) nanosheet by a transient absorption microscopy. Under the excitation (2.41 eV) above the exciton band, two photoinduced absorption peaks with the energy difference of approximately 520 meV emerge within a broadband transient absorption background which originates from the prompt generation of free carriers and the concomitant formation of excitons (lifetime of 467.21 ps). This observation is consistent with the established band-edge model of VP. Intriguingly, we have determined the ambipolar diffusion coefficient and mobility of VP to be approximately 47.32 cm2·s-1 and 1798 cm2·V-1·s-1, respectively, which further indicate a long-range carrier transport of approximately 2.10 µm. This work unveils the significant carrier transport capacity of VP, highlighting its potential for future optoelectronic and excitonic applications.

2.
Small ; 20(3): e2304839, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37702144

RESUMEN

The construction of nanostructured Z-scheme heterostructure is a powerful strategy for realizing high-performance photoelectrochemical (PEC) devices such as self-powered photodetectors and water splitting. Considering the band structure and internal electric field direction, BiVO4 is a promising candidate to construct SnS2 -based heterostructure. Herein, the direct Z-scheme heterostructure of vertically oriented SnS2 nanosheet on BiVO4 nanoflower is rationally fabricated for efficient self-powered PEC photodetectors. The Z-scheme heterostructure is identified by ultraviolet photoelectron spectroscopy, photoluminescence spectroscopy, PEC measurement, and water splitting. The SnS2 /BiVO4 heterostructure shows a superior photodetection performance such as excellent photoresponsivity (10.43 mA W-1 ), fast response time (6 ms), and long-term stability. Additionally, by virtue of efficient Z-scheme charge transfer and unique light-trapping nanostructure, the SnS2 /BiVO4 heterostructure also displays a remarkable photocatalytic hydrogen production rate of 54.3 µmol cm-2 h-1 in Na2 SO3 electrolyte. Furthermore, the synergistic effect between photo-activation and bias voltage further improves the PEC hydrogen production rate of 360 µmol cm-2 h-1 at 0.8 V, which is an order of magnitude above the BiVO4 . The results provide useful inspiration for designing direct Z-scheme heterostructures with special nanostructured morphology to signally promote the performance of PEC devices.

3.
Small ; 20(27): e2308590, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38295096

RESUMEN

Flexible broadband photodetectors are desired but challenging to be fabricated for next-generation wearable intelligent optoelectronic devices. Considering the narrow bandgap and strong light absorption, molybdenum telluride (MoTe2) based photoelectrochemical photodetectors are successfully assembled by liquid phase exfoliation accompanied with the electrophoretic deposited method. This MoTe2-based photodetector shows a broadband detection in ultraviolet-near-infrared band, long-term stability within 18000 s, and fast response in millisecond-level (response time≈19 ms, recovery time≈26 ms). More importantly, even though the MoTe2 photodetector is bent and twisted at a high degree for several hundred times, it still shows excellent flexibility with stable on-off switching characteristics. Additionally, this photodetector displays a good response for rotation angles in the range from 0° to 360°, and the extracted Iph maintain almost the same value approximately 0.97 µA cm-2, suggesting an omnidirectional detection capability. This work demonstrates the proposed flexible photoanode shows a great potential in future broadband omnidirectional detection systems.

4.
Small ; : e2404622, 2024 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-39058229

RESUMEN

Inspired by natural photosynthesis, the visible-light-driven Z-scheme system is very effective and promising for boosting photocatalytic hydrogen production and pollutant degradation. Here, a synergistic Z-scheme photocatalyst is constructed by coupling ReS2 nanosheet and ZnIn2S4 nanoflower and the experimental evidence for this direct Z-scheme heterostructure is provided by X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and electron paramagnetic resonance. Consequently, such a unique nanostructure makes this Z-scheme heterostructure exhibit 23.7 times higher photocatalytic hydrogen production than that of ZnIn2S4 nanoflower. Moreover, the ZnIn2S4/ReS2 photocatalyst is also very stable for photocatalytic hydrogen evolution, almost without activity decay even storing for two weeks. Besides, this Z-scheme heterostructure also exhibits superior photocatalytic degradation rates of methylene blue (1.7 × 10-2 min-1) and mitoxantrone (4.2 × 10-3 min-1) than that of ZnIn2S4 photocatalyst. The ultraviolet-visible absorption spectra, transient photocurrent spectra, open-circuit potential measurement, and electrochemical impedance spectroscopy reveal that the superior photocatalytic performance of ZnIn2S4/ReS2 heterostructure is mostly attributed to its broad and strong visible-light absorption, effective separation of charge carrier, and improved redox ability. This work provides a promising nanostructure design of a visible-light-driven Z-scheme heterostructure to simultaneously promote photocatalytic reduction and oxidation activity.

5.
Ecotoxicol Environ Saf ; 281: 116615, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38905933

RESUMEN

BACKGROUND: Paraquat (PQ) is a widely used herbicide that poisons human by accident or intentional ingestion. PQ poisoning causes systemic inflammatory response syndrome (SIRS) resulting in acute lung injury (ALI) with an extremely high mortality rate. Blood trematode Schistosoma japonicum-produced cystatin (Sj-Cys) is a strong immunomodulatory protein that has been experimentally used to treat inflammation related diseases. In this study, Sj-Cys recombinant protein (rSj-Cys) was used to treat PQ-induced lung injury and the immunological mechanism underlying the therapeutic effect was investigated. METHODS: PQ-induced acute lung injury mouse model was established by intraperitoneally injection of 20 mg/kg of paraquat. The poisoned mice were treated with rSj-Cys and the survival rate was observed up to 7 days compared with the group without treatment. The pathological changes of PQ-induced lung injury were observed by examining the histochemical sections of affected lung tissue and the wet to dry ratio of lung as a parameter for inflammation and edema. The levels of the inflammation related cytokines IL-6 and TNF-α and regulatory cytokines IL-10 and TGF-ß were measured in sera and in affected lung tissue using ELISA and their mRNA levels in lung tissue using RT-PCR. The macrophages expressing iNOS were determined as M1 and those expressing Arg-1 as M2 macrophages. The effect of rSj-Cys on the transformation of inflammatory M1 to regulatory M2 macrophages was measured in affected lung tissue in vivo (EKISA and RT-PCR) and in MH-S cell line in vitro (flow cytometry). The expression levels of TLR2 and MyD88 in affected lung tissue were also measured to determine their role in the therapy of rSj-Cys on PQ-induced lung injury. RESULT: We identified that treatment with rSj-Cys significantly improved the survival rate of mice with PQ-induced lung injury from 30 % (untreated) to 80 %, reduced the pathological damage of poisoning lung tissue, associated with significantly reduced levels of proinflammatory cytokines (IL-6 from 1490 to 590 pg/ml, TNF-α from 260 to 150 pg/ml) and increased regulatory cytokines (IL-10 from360 to 550 pg/ml, and TGF-ß from 220 to 410 pg/ml) in both sera (proteins) and affected lung tissue (proteins and mRNAs). The polarization of macrophages from M1to M2 type was found to be involved in the therapeutic effect of rSj-Cys on the PQ-induced acute lung injury, possibly through inhibiting TLR2/MyD88 signaling pathway. CONCLUSIONS: Our study demonstrated the therapeutic effect of rSj-Cys on PQ poisoning caused acute lung injury by inducing M2 macrophage polarization through inhibiting TLR2/MyD88 signaling pathway. The finding in this study provides an alternative approach for the treatment of PQ poisoning and other inflammatory diseases.


Asunto(s)
Lesión Pulmonar Aguda , Cistatinas , Paraquat , Schistosoma japonicum , Animales , Paraquat/toxicidad , Lesión Pulmonar Aguda/inducido químicamente , Lesión Pulmonar Aguda/patología , Lesión Pulmonar Aguda/tratamiento farmacológico , Ratones , Herbicidas/toxicidad , Macrófagos/efectos de los fármacos , Pulmón/patología , Pulmón/efectos de los fármacos , Masculino , Citocinas/metabolismo , Modelos Animales de Enfermedad
6.
Anim Biotechnol ; 34(9): 4803-4808, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37079337

RESUMEN

Inclement weather conditions, especially cold stress, have threatened the cattle industry. Cattle exposed to cold environments for a longer time suffer developmental delay, immunity decline, and eventually death. WNK1 is a member of With-no-lysine kinases (WNKs), widely expressed in animal organs and tissues. WNK1 and WNK4 are expressed in adipose tissue, and WNK4 promotes adipogenesis. WNK1 does not directly affect adipogenesis but has been shown to promote WNK4 expression in several tissues or organs. One missense mutation NC_037346.1:g.107692244, A > G, rs208265410 in the WNK1 gene was detected from the database of bovine genomic variation (BGVD). Here, we collected 328 individuals of 17 breeds representing four groups of Chinese cattle, northern group cattle, southern group cattle, central group cattle, and special group cattle (Tibetan cattle). We also collected the temperature and humidity data records from their relative locations. The frequencies of the G allele in Chinese breeds increased from northern China to southern China, and the frequencies of the A allele showed an opposite trend. Our results indicate that the WNK1 gene might be a candidate gene marker associated with cold tolerance.


Asunto(s)
Mutación Missense , Proteínas Serina-Treonina Quinasas , Humanos , Bovinos/genética , Animales , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Proteína Quinasa Deficiente en Lisina WNK 1/genética , Antígenos de Histocompatibilidad Menor/genética , China
7.
Opt Lett ; 47(5): 1206-1209, 2022 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-35230328

RESUMEN

Quantum interference (QuI) effect is a powerful method to generate and control the ultrafast photocurrent in semiconductors. We utilize two-color pulsed light excitation in bismuth sulfide (Bi2S3) film to induce the photocurrent through the QuI effect. Experimentally, the photocurrent is indirectly monitored using a standard terahertz (THz) time-domain spectroscopic system. Due to the QuI, an asymmetric photon injection occurs in Bi2S3 film, resulting in coherent injection current and subsequently THz wave generation. Our results on the pump pulse energy dependence of the THz electric field suggests that the THz wave generation process follows the third-order nonlinear optical process.

8.
Nanotechnology ; 33(8)2021 Dec 03.
Artículo en Inglés | MEDLINE | ID: mdl-34768252

RESUMEN

The development of powerful terahertz (THz) emitters is the cornerstone for future THz applications, such as communication, medical biology, non-destructive inspection, and scientific research. Here, we report the THz emission properties and mechanisms of mushroom-shaped InAs nanowire (NW) network using linearly polarized laser excitation. By investigating the dependence of THz signal to the incidence pump light properties (e.g. incident angle, direction, fluence, and polarization angle), we conclude that the THz wave emission from the InAs NW network is induced by the combination of linear and nonlinear optical effects. The former is a transient photocurrent accelerated by the photo-Dember field, while the latter is related to the resonant optical rectification effect. Moreover, thep-polarized THz wave emission component is governed by the linear optical effect with a proportion of ∼85% and the nonlinear optical effect of ∼15%. In comparison, thes-polarized THz wave emission component is mainly decided by the nonlinear optical effect. The THz emission is speculated to be enhanced by the localized surface plasmon resonance absorption of the In droplets on top of the NWs. This work verifies the nonlinear optical mechanism in the THz generation of semiconductor NWs and provides an enlightening reference for the structural design of powerful and flexible THz surface and interface emitters in transmission geometry.

9.
Virus Genes ; 57(4): 390-394, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34021872

RESUMEN

Multiple novel circular replication-associated protein (Rep)-encoding single stranded (CRESS) DNA viruses have been extensively identified in the feces of humans and animals. Here, we first detected CRESS DNA virus (named Horse-CRESS DNA-like virus, HCLV) in two fecal samples from 10 imported thoroughbred (TB) horses in the customs quarantine station in North Xinjiang province, China. Additionally, we found that this virus was not detected in local breeds (LBs) (0/41) and was found only in imported TB horses (2/73). We obtained the whole-genome sequences of four viruses (HCLV ALSK-3-4, ALSK-13-10, CJ-1-2, and CJ-13-1). Unlike Circovirus and Cyclovirus, whose genome sequences have 1700 to 2100 nucleotides (nt), these HCLVs have circular genome with 3503, 3504, 3485, 3491 nt, respectively and five major ORFs. The ORF1 gene encodes the Rep protein in HCLVs. Furthermore, the Rep protein of the four HCLVs share 23.3-84.8%, 21.6-27.4%, 23.7-27.2% amino acid identity with the corresponding reference viruses of Kirkoviruses, genus Circovirus, and genus Cyclovirus, respectively. Moreover, RCR domain, P-loop NTPase domains, and nonanucleotide motif (TAGTATTAC) of the HCLVs are similar to Circovirus and Cyclovirus. Phylogenetic analysis showed that the virus was grouped together with members in Kirkoviruses. These results suggest the HCLV probably entered Xinjiang province via the international trade of horses.


Asunto(s)
Infecciones por Virus ADN/genética , Virus ADN/genética , Genoma Viral/genética , Genómica , Animales , China/epidemiología , Infecciones por Virus ADN/veterinaria , Infecciones por Virus ADN/virología , Enfermedades de los Caballos/genética , Enfermedades de los Caballos/virología , Caballos/genética , Caballos/virología , Secuenciación Completa del Genoma
10.
Opt Express ; 28(21): 30675-30685, 2020 Oct 12.
Artículo en Inglés | MEDLINE | ID: mdl-33115063

RESUMEN

We propose a switchable broadband and wide-angular terahertz asymmetric transmission based on a spiral metasurface composed of metal and VO2 hybrid structures. Results show that asymmetric transmission reaching up to 15% can be switched on or off for circularly polarized terahertz waves when the phase of VO2 transits from the insulting state to the conducting state or reversely. Strikingly, we find that relatively high asymmetric transmission above 10% can be maintained over a broad bandwidth of 2.6-4.0 THz and also over a large incident angular range of 0°-45°. We further discover that as the incident angle increases, the dominant chirality of the proposed metasurface with VO2 in the conducting state can shift from intrinsic to extrinsic chirality. We expect this work will advance the engineering of switchable chiral metasurfaces and promote terahertz applications.

11.
Phys Chem Chem Phys ; 22(37): 21428-21435, 2020 Oct 07.
Artículo en Inglés | MEDLINE | ID: mdl-32944724

RESUMEN

Tunable optical properties play an important role in the high performance of optoelectronic applications based on two-dimensional (2D) transition metal carbide and nitride (MXene) materials. Herein, the optical properties of functionalized MXene monolayers Sc2CT2 (T = O and OH) are investigated by strain engineering. The strain-dependent linear optical properties of Sc2CT2 possess broadband optical response due to the geometry and orbital overlap effect. The peaks from the second-order nonlinear coefficient elements d (d15, d16, and d31) at around half the band-gap exhibit a redshift for Sc2CO2 (blueshift for Sc2C(OH)2) with the increase of strain. The strain-dependent d reveals that Sc2CO2 with -1268 pm V-1 %-1 has a larger photoelastic coefficient than that of Sc2C(OH)2 with -574 pm V-1 %-1 at 1% strain. Meanwhile, the photoelastic tensors can not only be increased but also reduced with the increase of strain due to the dispersion relation. Moreover, the azimuthal angle-dependent second harmonic generation (SHG) from strained Sc2CT2 monolayers depends highly on the strained states and the pumping photon energy. The results pave the way for the tunable, broadband, and anisotropic applications of nonlinear optoelectronic devices based on MXenes based on strain engineering.

12.
Appl Opt ; 59(12): 3686-3691, 2020 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-32400491

RESUMEN

Chirality has received wide attention due to its promising applications in biopharmaceuticals, chemical detection, and polarized optoelectronic devices. Herein, metamaterials with layered Tai Chi patterns are proposed to get strong and tunable chirality. Based on the surface current distribution analysis, a coupling model considering both the magnetic and electric dipoles in the upper and bottom metallic structures is proposed to understand the circular dichroism. Accordingly, both an external chiral modulation by changing the incident angle and an internal chiral modulation by changing the twist angle are achieved. Incident-angle-dependent circular dichroism modulation exhibits a range of 0.44-0.62 and the twist-angle-dependent modulation range is ${-}{0.6 - 0.42}$-0.6-0.42, where the negative value means the polarity of the circular dichroism can also be tuned. This work deepens the understanding of angular-dependent chirality in metamaterials and expands the potential for terahertz polarization optoelectronic applications.

13.
Nanotechnology ; 30(19): 195705, 2019 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-30699402

RESUMEN

Broadband terahertz (THz) impedance matching is important for both spectral resolution improvement and THz anti-radar technology. Herein, graphene-silicon hybrid structure has been proposed for active broadband THz wave impedance matching with optical tunability. The main transmission pulse measured in the time domain indicates a modulation depth as high as 92.7% totally from the graphene-silicon interface. The interface reflection from the graphene-silicon junction implies that an impedance matching condition can be actively achieved by optical doping. To reveal the mechanism, we propose a graphene-silicon heterojunction model, which gives a full consideration of both the THz conductivity of graphene and the loss in doped junction layer. The theory fits well with the experimental results. This work proves active THz wave manipulation by junction effect and paves the way for active anti-reflection coating for THz components.

14.
Nanotechnology ; 28(33): 335602, 2017 Aug 18.
Artículo en Inglés | MEDLINE | ID: mdl-28617245

RESUMEN

A scalable liquid exfoliation of layered Bi2S3 employing a mixed-solvent strategy was used for the fabrication of Bi2S3 nanosheets. We found that 10% deionized water in 90% isopropyl alcohol is the best mixed solvent for the efficient and effective exfoliation of layered Bi2S3. These results are consistent with the absorbance spectra and enthalpy of mixing theory. The obtained Bi2S3 nanosheets had few-quintuple layers and were investigated by transmission electron microscopy, atomic force microscopy, and Raman spectroscopy. These Bi2S3 nanosheets can be used to fabricate large-scale thin films by filtration method; the films demonstrated sensitive photoelectric response with the rise and decay response of photocurrent on the sub-second scale under visible light excitation. The electronic structures of bulk and one-quintuple layer Bi2S3 are calculated by first-principle calculation for better understanding of the photoelectric response. A green mixed-solvent processing of Bi2S3 opens up the potential application of Bi2S3 optoelectric films to photoelectric detection and solar energy conversion devices.

15.
Cell Physiol Biochem ; 38(5): 1952-62, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27161043

RESUMEN

BACKGROUND/AIMS: Glycine is a strychnine-sensitive inhibitory neurotransmitter in the central nervous system (CNS), especially in the spinal cord, brainstem, and retina. The objective of the present study was to investigate the potential neuroprotective effects of GlyT1 inhibitor N [3-(4'-fluorophenyl)-3-(4'-phenylphenoxy) propyl] sarcosine (NFPS) in the rat model of experimental stroke. METHODS: In vivo ischaemia was induced by transient middle cerebral artery occlusion (tMCAO). The methods of Western Blotting, Nissl Staining and Morris water maze methods were applied to analyze the anti-ischaemia mechanism. RESULTS: The results showed that high dose of NFPS (H-NFPS) significantly reduced infarct volume, neuronal injury and the expression of cleaved caspase-3, enhanced Bcl-2/Bax, and improved spatial learning deficits which were administered three hours after transient middle cerebral artery occlusion (tMCAO) induction in rats, while, low dose of NFPS (L-NFPS) exacerbated the injury of ischaemia. These findings suggested that low and high dose of NFPS produced opposite effects. Importantly, it was demonstrated that H-NFPS-dependent neuronal protection was inverted by salicylate (Sal), a specific GlyR x0251;1 antagonist. Such effects could probably be attributed to the enhanced glycine level in both synaptic and extrasynaptic clefts and the subsequently altered extrasynaptic GlyRs and their subtypes. CONCLUSIONS: These data imply that GlyT1 inhibitor NFPS may be a novel target for clinical treatment of transient focal cerebral ischaemia and reperfusion which are associated with altered GlyR alpha 1 subunits.


Asunto(s)
Proteínas de Transporte de Glicina en la Membrana Plasmática/antagonistas & inhibidores , Ataque Isquémico Transitorio/patología , Fármacos Neuroprotectores/farmacología , Receptores de Glicina/metabolismo , Sarcosina/análogos & derivados , Animales , Western Blotting , Encéfalo/patología , Caspasa 3/metabolismo , Modelos Animales de Enfermedad , Glicina/metabolismo , Proteínas de Transporte de Glicina en la Membrana Plasmática/metabolismo , Inmunohistoquímica , Infarto de la Arteria Cerebral Media/complicaciones , Ataque Isquémico Transitorio/etiología , Ataque Isquémico Transitorio/metabolismo , Masculino , Aprendizaje por Laberinto , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Ratas , Ratas Sprague-Dawley , Receptores de Glicina/antagonistas & inhibidores , Salicilatos/farmacología , Sarcosina/farmacología , Proteína X Asociada a bcl-2/metabolismo
16.
Appl Opt ; 54(22): 6732-6, 2015 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-26368087

RESUMEN

Two-dimensional materials such as MoS2 have attracted much attention in recent years due to their fascinating optoelectronic properties. The dielectric response of MoS2 crystal in both the terahertz (THz) and visible regions is studied in this work. Time-domain THz spectroscopy is employed for the THz property investigation. The real and imaginary parts of the complex dielectric constant of MoS2 crystal are found to follow a Drude model, which is due to the intrinsic carrier absorption. In the visible region, ellipsometry is used to investigate the dielectric response. The general trend of the complex dielectric constant is found to be described with a Lorentz model, while two remarkable dielectric response peaks are observed to be located at 1.85 and 2.03 eV, which has been attributed to the splitting arising from the combined effect of interlayer coupling and spin-orbit coupling. This work can be the research foundation for future optoelectronic applications with MoS2.

17.
ACS Nano ; 2024 Oct 22.
Artículo en Inglés | MEDLINE | ID: mdl-39437429

RESUMEN

Ultrafast charge transfer in van der Waals heterostructures can effectively engineer the optical and electrical properties of two-dimensional semiconductors for designing photonic and optoelectronic devices. However, the nonlinear absorption conversion dynamics with the pump intensity and the underlying physical mechanisms in a type-II heterostructure remain largely unexplored, yet hold considerable potential for all-optical logic gates. Herein, two-dimensional ReSe2/ReS2 heterostructure is designed to realize an unusual transition from reverse saturable absorption to saturable absorption (SA) with a conversion pump intensity threshold of approximately 170 GW/cm2. Such an intriguing phenomenon is attributed to the decrease of two-photon absorption (TPA) of ReS2 and the increase of SA of ReSe2 with the pump intensity. Based on the characterization results of X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, femtosecond transient absorption spectrum, Kelvin probe force microscopy, and density functional theory calculation, a type-II charge-transfer-energy level model is proposed combined with the TPA of ReS2 and SA of ReSe2 processes. The results reveal the critical role of ultrafast interfacial charge transfer in tuning the unusual nonlinear absorption and improving the SA of ReSe2/ReS2 under different excitation wavelengths. Our finding deepens the understanding of nonlinear absorption physical mechanisms in two-dimensional heterostructure materials, which may further diversify the nonlinear optical materials and photonic devices.

18.
PLoS One ; 19(6): e0303698, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38875305

RESUMEN

Debris flow risk assessment can provide some reference for debris flow prevention and control projects. In risk assessment, researchers often only focus on the impact of objective or subjective indicators. For this purpose, this paper proposed a weight calculation method based on t-distribution and linear programming optimization algorithm (LPOA). Taking 72 mudslides in Beichuan County as an example, this paper used analytic hierarchy process (AHP), entropy weight method (EWM) and variation coefficient method (VCM) to obtain the initial weights. Based on the initial weights, weight intervals with different confidence levels were obtained by t-distribution. Subsequently, the final weights were obtained by LOPA in the 90% confidence interval. Finally, the final weights were used to calculate the risk score for each debris flow, thus delineating the level of risk for each debris flow. The results showed that this paper's method can avoid overemphasizing the importance of a particular indicator compared to EWM and VCM. In contrast, EWM and VCM ignored the effect of debris flow frequency on debris flow risk. The assessment results showed that the 72 debris flows in Beichuan County were mainly dominated by moderate and light risks. Of these, there were 8 high risk debris flows, 24 medium risk debris flows, and 40 light risk debris flows. The excellent triggering conditions provide favorable conditions for the formation of high-risk debris flows. Slightly and moderate risk debris flows are mainly located on both sides of highways and rivers, still posing a minor threat to Beichuan County. The proposed fusion weighting method effectively avoids the limitations of single weight calculating method. Through comparison and data analysis, the rationality of the proposed method is verified, which can provide some reference for combination weighting method and debris flow risk assessment.


Asunto(s)
Algoritmos , Medición de Riesgo/métodos , Programación Lineal , China , Monitoreo del Ambiente/métodos
19.
Heliyon ; 10(16): e35871, 2024 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-39220969

RESUMEN

Slope instability through can cause catastrophic consequences, so slope stability analysis has been a key topic in the field of geotechnical engineering. Traditional analysis methods have shortcomings such as high operational difficulty and time-consuming, for this reason many researchers have carried out slope stability analysis based on AI. However, the current relevant studies only judged the importance of each factor and did not specifically quantify the correlation between factors and slope stability. For this purpose, this paper carried out a sensitivity analysis based on the XGBoost and SHAP. The sensitivity analysis results of SHAP were also validated using GeoStudio software. The selected influence factors included slope height ( H ), slope angle ( ß ), unit weight ( γ ), cohesion ( c ), angle of internal friction ( φ ) and pore water pressure coefficient ( r u ). The results showed that c and γ were the most and least important influential parameters, respectively. GeoStudio simulation results showed a negative correlation between γ , ß , H , r u and slope stability, while a positive correlation between c , φ and slope stability. However, for real data, SHAP misjudged the correlation between γ and slope stability. Because current AI lacked common sense knowledge and, leading SHAP unable to effectively explain the real mechanism of slope instability. For this reason, this paper overcame this challenge based on the priori data-driven approach. The method provided more reliable and accurate interpretation of the results than a real sample, especially with limited or low-quality data. In addition, the results of this method showed that the critical values of c , φ , ß , H , and r u in slope destabilization are 18 Kpa, 28°, 32°, 30 m, and 0.28, respectively. These results were closer to GeoStudio simulations than real samples.

20.
Sci Rep ; 14(1): 8377, 2024 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-38600355

RESUMEN

Accumulation landslides are prone to occur during the continuous infiltration of heavy rainfall, which seriously threatens the lives and property safety of local residents. In this paper, based on the Green-Ampt (GA) infiltration model, a new slope rainfall infiltration function is derived by combining the effect of air resistance and lateral seepage of saturated zone. Considering that when the soil layer continues to infiltrate after the saturation zone is formed, the air involvement cannot be discharged in time, which delays the infiltration process. Therefore, the influence of air resistance factor in soil pores is added. According to the infiltration characteristics of finite long slope, the lateral seepage of saturated zone is introduced, which makes up for the deficiency that GA model is only applicable to infinite long slope. Finally, based on the seepage characteristics of the previous analysis, the overall shear strength criterion is used to evaluate the stability of the slope. The results show that the safety factor decreases slowly with the increase of size and is inversely correlated with the slope angle and initial moisture content. The time of infiltration at the same depth increases with the increase of size and slope angle, and is inversely correlated with the initial moisture content, but is less affected by rainfall intensity. By comparing with the results of experimental data and other methods, the results of the proposed method are more consistent with the experimental results than other methods.

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