Human umbilical cord mesenchymal stem cell-derived exosomes loaded into a composite conduit promote functional recovery after peripheral nerve injury in rats

Complete transverse injury of peripheral nerves is challenging to treat.Exosomes secreted by human umbilical cord mesenchymal stem cells are considered to play an important role in intercellular communication and regulate tissue regeneration.In previous studies,a collagen/hyaluronic acid sponge was shown to provide a suitable regeneration environment for Schwann cell proliferation and to promote axonal regeneration.This three-dimensional(3D)composite conduit contains a collagen/hyaluronic acid inner sponge enclosed in an electrospun hollow poly(lactic-co-glycolic acid)tube.However,whether there is a synergy between the 3D composite conduit and exosomes in the repair of peripheral nerve injury remains unknown.In this study,we tested a comprehensive strategy for repairing long-gap(10 mm)peripheral nerve injury that combined the 3D composite conduit with human umbilical cord mesenchymal stem cell-derived exosomes.Repair effectiveness was evaluated by sciatic functional index,sciatic nerve compound muscle action potential recording,recovery of muscle mass,measuring the cross-sectional area of the muscle fiber,Masson trichrome staining,and transmission electron microscopy of the regenerated nerve in rats.The results showed that transplantation of the 3D composite conduit loaded with human umbilical cord mesenchymal stem cell-derived exosomes promoted peripheral nerve regeneration and restoration of motor function,similar to autograft transplantation.More CD31-positive endothelial cells were observed in the regenerated nerve after transplantation of the loaded conduit than after transplantation of the conduit without exosomes,which may have contributed to the observed increase in axon regeneration and distal nerve reconnection.Therefore,the use of a 3D composite conduit loaded with human umbilical cord mesenchymal stem cell-derived exosomes represents a promising cell-free therapeutic option for the treatment of peripheral nerve injury.

Benchmark experiment on slab^(238)U with D-T neutrons for validation of evaluated nuclear data

A benchmark experiment on^(238)U slab samples was conducted using a deuterium-tritium neutron source at the China Institute of Atomic Energy.The leakage neutron spectra within energy levels of 0.8-16 MeV at 60°and 120°were measured using the time-of-flight method.The samples were prepared as rectangular slabs with a 30 cm square base and thicknesses of 3,6,and 9 cm.The leakage neutron spectra were also calculated using the MCNP-4C program based on the latest evaluated files of^(238)U evaluated neutron data from CENDL-3.2,ENDF/B-Ⅷ.0,JENDL-5.0,and JEFF-3.3.Based on the comparison,the deficiencies and improvements in^(238)U evaluated nuclear data were analyzed.The results showed the following.(1)The calculated results for CENDL-3.2 significantly overestimated the measurements in the energy interval of elastic scattering at 60°and 120°.(2)The calculated results of CENDL-3.2 overestimated the measurements in the energy interval of inelastic scattering at 120°.(3)The calculated results for CENDL-3.2 significantly overestimated the measurements in the 3-8.5 MeV energy interval at 60°and 120°.(4)The calculated results with JENDL-5.0 were generally consistent with the measurement results.

同轴静电共喷纺及其在锂离子电池复合隔膜改性中的应用

文中介绍了一种制备纳米复合膜的方法——同轴静电共喷纺。首先组装了由外喷嘴和内喷嘴构成的同轴共喷纺装置,将静电纺丝与静电喷涂结合起来,利用该技术制备纳米纤维/颗粒复合膜。将聚偏氟乙烯(PVDF)/SiO_(2)溶于N,N-二甲基甲酰胺(DMF)中,从外喷口制备颗粒;PVDF溶于DMF和丙酮混合物中,从内喷口制备纤维,成功制备了同时含颗粒和纤维的PVDF&PVDF/SiO_(2)复合膜,复合膜中颗粒的平均粒径为2.01μm,纤维平均直径为0.43μm。然后将PVDF&PVDF/SiO_(2)复合膜原位涂覆在商用超高分子量聚乙烯(UHMWPE)隔膜上,从而制备了一种新型锂离子电池复合隔膜。测试结果表明,该复合隔膜的孔隙率为85.96%,比UHMWPE基材膜的37.85%有明显的提高,纵向收缩率由7.28%降低到5.26%,复合隔膜接触角由48.55°降低到14.93°。与未改性的商用隔膜相比,同轴静电共喷纺制备的复合隔膜首次充放电比容量由107.8 mAh/g提高到122.4 mAh/g,经50次循环后,仍具有良好的循环稳定性。

Acaricidal effect of the antimicrobial metabolite xenocoumacin 1 on spider mite control

The two-spotted spider mite,Tetranychus urticae Koch,is one of the most harmful pests in many agroecosystems worldwide.To effectively manage this pest,there is an urgent need to develop novel bio-active acaricides that support integrated pest management strategies targeting T.urticae.In this study,we explored the acaricidal effects of xenocoumacin 1 (Xcn1) on T.urticae and its predator Neoseiulus californicus using the highly puri?ed compound.Xcn1 was extracted and purified from the cell-free supernatant of the Xenorhabdus nematophila CB6 mutant constructed by the easy promoter activated compound identi?cation (easyPACId) method.When the concentration of Xcn1 exceeded 100μg mL~(–1),the survival rate of spider mite adults declined to below 40%and the fecundity was decreased by 80%at six days post-application.At concentrations of 25 and 50μg mL~(–1),Xcn1 signi?cantly impeded spider mite development by inhibiting the molt.However,neither concentration had any adverse effects on the survival or reproduction of the predatory mite N.californicus.The results from laboratory and semi-?eld experiments consistently demonstrated the effectiveness of the antimicrobial metabolite Xcn1 in controlling pest mites at both the molecular and physiological levels.Our study offers a promising possibility that combines the compatible biocontrol agents of Xcn1 and predatory mites for integrated pest mite control.

Apically guiding electron/mass transfer reaction induced by Ag/FeN_(x)Mott-Schottky effect within a hollow star reactor toward high performance zinc-air batteries

The disparity in the transfer of carriers(electrons/mass)during the reaction in zinc-air batteries(ZABs)results in sluggish kinetics of the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER),along with elevated overpotentials,thereby imposing additional constraints on its utilization.Therefore,the pre-design and target-development of inexpensive,high-performance,and long-term stable bifunctional catalysts are urgently needed.In this work,an apically guiding dual-functional electrocatalyst(Ag-FeN_(x)-N-C)was prepared,in which a hierarchical porous nitrogen-doped carbon with three-dimensional(3D)hollow star-shaped structure is used as a substrate and high-conductivity Ag nanoparticles are coupled with iron nitride(FeN_(x))nanoparticles.Theoretical calculations indicate that the Mott-Schottky heterojunction as an inherent electric field comes from the two-phase bound of Ag and FeN_(x),of which electron accumulation in the FeN_(x)phase region and electron depletion in the Ag phase region promote orientated-guiding charge migration.The effective modulation of local electronic structures felicitously reforms the d-band electron-group distribution,and intellectually tunes the masstransfer reaction energy barriers for both ORR/OER.Additionally,the hollow star-s haped hierarchical porous structure provides an apical region for fast mass transfer.Experimental results show that the halfwave potential for ORR is 0.914 V,and the overpotential for OER is only 327 mV at 10 mA cm^(-2).A rechargeable ZAB with Ag-FeN_(x)-N-C as the air cathode demonstrates long-term cycling performance exceeding 1500 cycles(500 h),with a power density of 180 mW cm^(-2).Moreover,when employing AgFeN_(x)-N-C as the air cathode,flexible ZABs demonstrate a notable open-circuit voltage of 1.42 V and achieve a maximum power density of 65.6 mW cm^(-2).Ag-FeN_(x)-N-C shows guiding electron/mass transfer route and apical reaction microenvironment for the electrocatalyst architecture in the exploration prospects of ZABs.

Nondestructive technique for identifying nuclides using neutron resonance transmission analysis at CSNS Back-n

Nondestructive and noninvasive neutron assays are essential applications of neutron techniques.Neutron resonance transmission analysis(NRTA)is a powerful nondestructive method for investigating the elemental composition of an object.The back-streaming neutron line(Back-n)is a newly built time-of-flight facility at the China Spallation Neutron Source(CSNS)that provides neutrons in the eV to 300 MeV range.A feasibility study of the NRTA method for nuclide identification was conducted at the CSNS Back-n via two test experiments.The results demonstrate that it is feasible to identify different elements and isotopes in samples using the NRTA method at Back-n.This study reveals its potential future applications.

Simplified quantitative analysis method and its application in the insitu synthesized copper-based azide chips

Copper-based azide(Cu(N_(3))2 or CuN_(3),CA)chips synthesized by in-situ azide reaction and utilized in miniaturized explosive systems has become a hot research topic in recent years.However,the advantages of in-situ synthesis method,including small size and low dosage,bring about difficulties in quantitative analysis and differences in ignition capabilities of CA chips.The aim of present work is to develop a simplified quantitative analysis method for accurate and safe analysis of components in CA chips to evaluate and investigate the corresponding ignition ability.In this work,Cu(N_(3))2 and CuN_(3)components in CA chips were separated through dissolution and distillation by utilizing the difference in solubility and corresponding content was obtained by measuring N_(3)-concentration through spectrophotometry.The spectrophotometry method was optimized by studying influencing factors and the recovery rate of different separation methods was studied,ensuring the accuracy and reproducibility of test results.The optimized method is linear in range from 1.0-25.0 mg/L,with a correlation coefficient R^(2)=0.9998,which meets the requirements of CA chips with a milligram-level content test.Compared with the existing ICP method,component analysis results of CA chips obtained by spectrophotometry are closer to real component content in samples and have satisfactory accuracy.Moreover,as its application in miniaturized explosive systems,the ignition ability of CA chips with different component contents for direct ink writing CL-20 and the corresponding mechanism was studied.This study provided a basis and idea for the design and performance evaluation of CA chips in miniaturized explosive systems.

Study of the response of 10B-doped MCP to wide-energy range neutrons from eV to MeV

Neutron-sensitive microchannel plates(nMCPs)have applications in neutron detection,including energy spectrum measurements,neutron-induced cross sections,and neutron imaging.10B-doped MCPs(B-MCPs)have attracted significant attention owing to their potential for exhibiting a high neutron detection efficiency over a large neutron energy range.Good spatial and temporal resolutions are useful for neutron energy-resolved imaging.However,their practical applications still face many technical challenges.In this study,a B-MCP with 10 mol%10B was tested for its response to wide-energy neutrons from eV to MeV at the Back-n white neutron source at the China Spallation Neutron Source.The neutron detection efficiency was calibrated at 1 eV,which is approximately 300 times that of an ordinary MCP and indicates the success of 10 B doping.The factors that caused the reduction in the detection efficiency were simulated and discussed.The neutron energy spectrum obtained using B-MCP was compared with that obtained by other measurement methods,and showed very good consistency for neutron energies below tens of keV.The response is more complicated at higher neutron energy,at which point the elastic and nonelastic reactions of all nuclides of B-MCP gradually become dominant.This is beneficial for the detection of neutrons,as it compensates for the detection efficiency of B-MCP for high-energy neutrons.

Mito-specific cascade amplifier sniping metabolism homeostasis for multimodal imaging-guided antitumor bioenergetic therapy

Nicotinamide adenine dinucleotide (NAD+/NADH) pools homeostasis is recognized as an Achilles’ Heel in tumor metabolism reprogramming. However, mitochondria can enable cancer cells to overcome NADH exhaustion by providing NAD+ precursors and/or intermediates, thus promoting their survival rate and potentially driving uncontrollable proliferation. Here, a synergistic intervention NAD+/NADH homeostasis and mitochondrial metabolism strategy with magnetic resonance imaging (MRI)/photoacoustic imaging (PAI) are developed to address grand challenge of metabolic reprogramming for antitumor bioenergetic therapy. A mitochondrial-targeted cascade amplification nanoplatform ([β-MQ]TRL), triggered by NAD(P)H: quinone oxidoreductase-1 (NQO1), can enable a continuous depletion of cytosol NADH until cell death. The end-product, hydrogen peroxide (H_(2)O_(2)), can be further catalytically converted to higher toxic ·OH in proximity to mitochondria based on [β-MQ]TRL mediated Fenton-like reaction, hijacking tumorigenic energy sources and leading to mitochondrial dysfunction. Additionally, the mild thermal ablation enabled by [β-MQ]TRL further amplifies this cascade reaction to effectively prevent tumor metastasis and recurrence. This synchronous intervention strategy with MRI/PAI establishes unprecedented efficiency in antitumor bioenergetic therapy in vivo, which shows excellent promise for clinical application.

10B-doped MCP detector developed for neutron resonance imaging at Back-n white neutron source

Neutron resonance imaging(NRI)has recently emerged as an appealing technique for neutron radiography.Its complexity surpasses that of conventional transmission imaging,as it requires a high demand for both a neutron source and detector.Consequently,the progression of NRI technology has been sluggish since its inception in the 1980s,particularly considering the limited studies analyzing the neutron energy range above keV.The white neutron source(Back-n)at the China Spallation Neutron Source(CSNS)provides favorable beam conditions for the development of the NRI technique over a wide neutron energy range from eV to MeV.Neutron-sensitive microchannel plates(MCP)have emerged as a cutting-edge tool in the field of neutron detection owing to their high temporal and spatial resolutions,high detection efficiency,and low noise.In this study,we report the development of a 10B-doped MCP detector,along with its associated electronics,data processing system,and NRI experiments at the Back-n.Individual heavy elements such as gold,silver,tungsten,and indium can be easily identified in the transmission images by their characteristic resonance peaks in the 1–100 eV energy range;the more difficult medium-weight elements such as iron,copper,and aluminum with resonance peaks in the 1–100 keV energy range can also be identified.In particular,results in the neutron energy range of dozens of keV(Aluminum)are reported here for the first time.

In-beam gamma rays of CSNS Back-n characterized by black resonance filter

The back-streaming white-neutron beamline(Back-n)of the China Spallation Neutron Source is an essential neutronresearch platform built for the study of nuclear data,neutron physics,and neutron applications.Many types of cross-sectional neutron-reaction measurements have been performed at Back-n since early 2018.These measurements have shown that a significant number of gamma rays can be transmitted to the experimental stations of Back-n along with the neutron beam.These gamma rays,commonly referred to as in-beam gamma rays,can induce a non-negligible experimental background in neutron-reaction measurements.Studying the characteristics of in-beam gamma rays is important for understanding the experimental background.However,measuring in-beam gamma rays is challenging because most gamma-ray detectors are sensitive to neutrons;thus,discriminating between neutron-induced signals and those from in-beam gamma rays is difficult.In this study,we propose the use of the black resonance filter method and a CeBr_(3) scintillation detector to measure the characteristics of the in-beam gamma rays of Back-n.Four types of black resonance filters,^(181)Ta,^(59)Co,^(nat)Ag,and^(nat)Cd,were used in this measurement.The time-of-flight(TOF)technique was used to select the detector signals remaining in the absorption region of the TOF spectra,which were mainly induced by in-beam gamma rays.The energy distribution and flux of the in-beam gamma rays of Back-n were determined by analyzing the deposited energy spectra of the CeBr_(3) scintillation detector and using Monte Carlo simulations.Based on the results of this study,the background contributions from in-beam gamma rays in neutron-reaction measurements at Back-n can be reasonably evaluated,which is beneficial for enhancing both the experimental methodology and data analysis.

Aspirin suppresses hepatocellular carcinoma progression by inhibiting platelet activity

BACKGROUND Hepatocellular carcinoma(HCC)is the most common malignant liver disease in the world.Platelets(PLTs)are known to play a key role in the maintenance of liver homeostasis and the pathophysiological processes of a variety of liver diseases.Aspirin is the most classic antiplatelet agent.However,the molecular mechanism of platelet action and whether aspirin can affect HCC progression by inhibiting platelet activity need further study.AIM To explore the impact of the antiplatelet effect of aspirin on the development of HCC.METHODS Platelet-rich plasma,platelet plasma,pure platelet,and platelet lysate were prepared,and a coculture model of PLTs and HCC cells was established.CCK-8 analysis,apoptosis analysis,Transwell analysis,and real-time polymerase chain reaction(RT-PCR)were used to analyze the effects of PLTs on the growth,metastasis,and inflammatory microenvironment of HCC.RT-PCR and Western blot were used to detect the effects of platelet activation on tumor-related signaling pathways.Aspirin was used to block the activation and aggregation of PLTs both in vitro and in vivo,and the effect of PLTs on the progression of HCC RESULTS PLTs significantly promoted the growth,invasion,epithelial-mesenchymal transition,and formation of an inflammatory microenvironment in HCC cells.Activated PLTs promoted HCC progression by activating the mitogenactivated protein kinase/protein kinase B/signal transducer and activator of transcription three(MAPK/AKT/STAT3)signaling axis.Additionally,aspirin inhibited HCC progression in vitro and in vivo by inhibiting platelet activation.CONCLUSION PLTs play an important role in the pathogenesis of HCC,and aspirin can affect HCC progression by inhibiting platelet activity.These results suggest that antiplatelet therapy has promising application prospects in the treatment and combined treatment of HCC.

Influencing factors of self-management ability among dry eye patients in west China

AIM:To investigate the current situation and influencing factors of self-management ability in dry eye patients in west China.METHODS:A total of 265 patients clinically diagnosed with dry eye received a convenience survey questionnaire at West China Hospital of Sichuan University.All participants completed the rating scale of health self-management skill for adults(AHSMSRS),Huaxi Emotional-Distress Index(HEI),e-health literacy scale(e-HEALS)and Brief Illness Perception Questionnaire(Brief-IPQ).A generalized linear model was employed to establish a multivariate linear model with demographic data,psychological state,e-HEALS,and illness perception as independent variables and health selfmanagement skill score as the dependent variable.RESULTS:The mean score for health self-management skill was 165.58±15.79.Multivariate analysis revealed that advanced age,better illness perception and improved psychological state were associated with better health selfmanagement ability among dry eye patients.Furthermore,the health self-management ability of patients with a disease duration less than 1y was found to be higher compared to those with a disease duration exceeding 1y.CONCLUSION:The health self-management ability of dry eye patients in west China is relatively high.Age,duration of disease,illness perception and psychological state are the influencing factors on the health selfmanagement ability of dry eye patients.

Application of contrast-enhanced ultrasound after livertransplantation:Current status and perspectives

Liver transplantation is an effective treatment for patients with end-stage liver disease. Accurate imaging evaluation of the transplanted patient is critical for ensuring that the limited donor liver is functioning appropriately. Ultrasound contrast agents(UCAs), in combination with contrastspecific imaging techniques, are increasingly accepted in clinical use for the assessment of the hepatic vasculature, bile ducts and liver parenchyma in pre-, intra- and posttransplant patients. We describe UCAs, their technical requirements, the recommended clinical indications, image interpretation and the limitations for contrastenhanced ultrasound applications in liver transplantation.

Characterization of Wnt1-inducible Signaling Pathway Protein-1 in Obese Children and Adolescents

Wnt1-inducible signaling pathway protein-1(WISP1),a member of the CCN family,is increasingly being recognized as a potential target for obesity and type 2 diabetes mellitus.Recent studies have shown that WISP1 can regulate low-grade inflammation in obese mice,and circulating WISP1 levels are associated with obesity and type 2 diabetes mellitus in adults.Herein,we measured serum WISP1 levels in obese youth and explored its relationships with pro-inflammatory cytokine interleukin 18(IL-18)and other metabolic indexes.Totally,44 normal-weight and 44 obese children and adolescents were enrolled.Physical and laboratory data were recorded,and then serum levels of WISP1 and IL-18 were determined by enzyme-linked immunosorbent assays.Results showed that serum levels of WISP1 were significantly higher in obese children and adolescents than in normal-weight healthy controls (1735.444-15.29 vs. 1364.084-18.69 pg/mL).WISP1 levels were significantly positively correlated with body mass index (BMI)and BMI z-score (r=0.392,P=0.008;r=0.474,P=0.001,respectively) in obese group;circulating IL-18 was increased in obese individuals (1229.064-29.42 vs. 295.874-13.30 pg/mL).Circulating WISP1 levels were significantly correlated with IL-18 (r=0.542,P<0.001),adiponectin (r=0.585,P<0.001)and leptin (r=0.592,P<0.001).The multivariate stepwise regression analysis showed that higher IL-18 levels represented the main determinant of increased WISP1 levels after adjusting for BMI,waist circumference, fasting insulin,homeostatic model assessment of insulin resistance (HOMA-IR)and HbAlc in obese individuals (β=0.542,P=0.000).WISP1 can be involved in glucose/lipid metabolism in obese youth,which may be modulated by IL-18.Increased WISP1 levels may be a risk factor of obesity and insulin resistance,and WISP1 has a potential therapeutic effect on insulin resistance in obese children and adolescents.

Poleward-moving recurrent auroral arcs associated with impulse-excited standing hydromagnetic waves

In Earth's high-latitude ionosphere, the poleward motion of east–west elongated auroral arcs has been attributed to standing hydromagnetic waves, especially when the auroral arcs appear quasi-periodically with a recurrence time of a few minutes. The validation of this scenario requires spacecraft observations of ultra-low-frequency hydromagnetic waves in the magnetosphere and simultaneous observations of poleward-moving auroral arcs near the spacecraft footprints. Here we present the first observational evidence from the multi-spacecraft THEMIS (Time History of Events and Macroscale Interactions during Substorms) mission and the conjugated all-sky imager to support the scenario that standing hydromagnetic waves can generate the quasi-periodic appearance of poleward-moving auroral arcs. In this specific event, the observed waves were toroidal branches of the standing hydromagnetic waves, which were excited by a pulse in the solar wind dynamic pressure. Multi-spacecraft measurements from THEMIS also suggest higher wave frequencies at lower L shells (consistent with the distribution of magnetic field line eigenfrequencies), which indicates that the phase difference across latitudes would increase with time. As time proceeds, the enlarged phase difference corresponds to a lower propagation speed of the auroral arcs, which agrees very well with the ground-based optical data.

Managing Quantum Heat Transfer in a Nonequilibrium Qubit-Phonon Hybrid System with Coherent Phonon States

We investigate quantum heat transfer in a nonequilibrium qubit-phonon hybrid open system,dissipated by external bosonic thermal reservoirs.By applying coherent phonon states embedded in the dressed quantum master equation,we are capable of dealing with arbitrary qubit-phonon coupling strength.It is counterintuitively found that the effect of negative differential thermal conductance is absent at strong qubit-phonon hybridization,but becomes profound at weak qubit-phonon coupling regime.The underlying mechanism of decreasing heat flux by increasing the temperature bias relies on the unidirectional transitions from the up-spin displaced coherent phonon states to the down-spin counterparts,which seriously freezes the qubit and prevents the system from completing a thermodynamic cycle.Finally,the effects of perfect thermal rectification and giant heat amplification are unraveled,thanks to the effect of negative differential thermal conductance.These results of the nonequilibrium qubit-phonon open system would have potential implications in smart energy control and functional design of phononic hybrid quantum devices.

Defects of laser-irradiated KDP crystals with different fluences studied by photoluminescence spectroscopy

Photoluminescence(PL)bands from potassium dihydrogen phosphate(KDP)crystals are studied by time-resolved PL spectroscopy.KDPcrystals irradiated at a laser fluence of 11.5 J/cm^(2) are found to have the highest probability of phosphorus–oxygen hole center defects and the lowest probability of phosphorus-oxygen electric center defects,in contrast to the probabilities of these defects forKDPcrystals irradiated at 9.0 J/cm^(2).The probabilities of these two defects occurring in retired components are found to be intermediate between those for crystals irradiated at the two different fluences.The two types of defects may result fromtwo differentmechanisms and may interconvert under certain conditions.Thus,there are differences between the defects in KDP crystals irradiated at a high laser fluence and those in retired components.

The Simulation of Surface Charge Accumulation on PMMA with Different Surface Roughness in Vacuum

The surface insulation properties of insulating material under DC voltage are closely related to the characteristics of surface charge accumulation, and the surface roughness of these materials has a direct impact on the surface charge distribution in vacuum. Therefore, it is significant to study their connection. In this paper, based on the secondary electron emission avalanche model, the surface charge accumulation on polymethyl methacrylate (PMMA) with different surface roughness was simulated by using particle in cell and Monte Carlo Collision method. The simulated environment was under the finger shaped electrode and in vacuum. The results showed that under the action of the electric field the electrons emitted from the cathode triple junction moved forward and collided with the insulating material, which may lead to the generation of secondary electrons or the accumulation of surface charge. The surface charge near the cathode was mostly negative since the effect of surface electron injection was greater than that of the collision ionization. Due to the change of electron energy and the influence of electric field distribution, the number of positive charge on the insulator gradually increased, reached the maximum, and then gradually reduced with the approaching of the anode. Moreover, when the surface roughness of the material increases or the secondary electron emission coefficient decreases, the amount of surface charge accumulated on the PMMA will reduce. This paper can provide some guidance for the practical application of insulating materials.

基于虚拟仿真技术的高校实验教学改革与实践

随着国家信息化教育战略和工程教育改革的不断推进,虚拟仿真技术在以学生为中心的智慧教学改革方面发挥了重要作用。通过对水利类各专业《水工建筑物》核心主干课程中“土石坝渗流分析”这一重难点内容进行实验教学方案设计,提出一套完整的信息化土石坝水利枢纽工程渗流演进,以及渗透破坏“蓄—稳—降—破坏—除险”的全过程实验教学系统。课程的虚拟仿真实验教学依托学科优势和专业特色,校企合作共同开发,解决了传统实体实验不能解决的诸多问题。教学实践过程突出以学生为主体、以教师为主导的核心思想,重自主能力培养轻讲解、重工程实践应用轻理论、重专业价值塑造轻传授,对培养学生的工程实践能力和创新应用能力具有重要意义。