Effective inhibition of anomalous grain coarsening in cast AZ91 alloys during fast cooling via nanoparticle addition

In this work, the effects of Ti CN and γ-Al_(2)O_(3) nanoparticle(NP) addition on the microstructural evolution of cast AZ91 alloys at the cooling rate ranging from 15 to 120 K/s have been systematically investigated. Experimental results reveal that grain coarsening occurs in cast AZ91 alloys when the cooling rate exceeds 90 K/s, while it can be effectively inhibited upon addition of NPs. The marked inhibition effect may originate from the formation of Ti CN or γ-Al_(2)O_(3) NP-induced undercooling zone ahead of solid/liquid(S/L) front of α-Mg, which not only can restrict grain growth effectively, but also can reactivate the native nucleants that are inactive in AZ91 melts to participate in nucleation events. And if possessing high nucleation potency, NPs can also promote further nucleation events and lead to significant grain refinement. An analytical model has been established to quantitatively account for the restriction effect of NPs on grain growth. The present work may shed a new light on the grain coarsening of cast alloys during fast cooling and provide an effective approach to circumvent it.

A Hybrid Model Based on ResNet and GCN for sEMG-Based Gesture Recognition

The surface electromyography(sEMG)is one of the basic processing techniques to the gesture recognition because of its inherent advantages of easy collection and non-invasion.However,limited by feature extraction and classifier selection,the adaptability and accuracy of the conventional machine learning still need to promote with the increase of the input dimension and the number of output classifications.Moreover,due to the different characteristics of sEMG data and image data,the conventional convolutional neural network(CNN)have yet to fit sEMG signals.In this paper,a novel hybrid model combining CNN with the graph convolutional network(GCN)was constructed to improve the performance of the gesture recognition.Based on the characteristics of sEMG signal,GCN was introduced into the model through a joint voting network to extract the muscle synergy feature of the sEMG signal.Such strategy optimizes the structure and convolution kernel parameters of the residual network(ResNet)with the classification accuracy on the NinaPro DBl up to 90.07%.The experimental results and comparisons confirm the superiority of the proposed hybrid model for gesture recognition from the sEMG signals.

A Study on the Interest Linkage Mechanism of the Taxus Industry Chain in Pengshui Miao and Tujia Autonomous County

At the Taxus base of Pengshui Miao and Tujia Autonomous County,Chongqing,the comprehensive development and utilization of Taxus was carried out with seedling cultivation,understory economy,product processing,ecotourism and other aspects as the main line.The benefit linkage mechanism of the operation of the Taxus industrial chain was explored and analyzed,so as to extend and supplement the Taxus industrial chain.The two models of"company+farmer"and"company+village collective+farmer"are relatively close benefit linkage models,which indirectly promote the increase of farmers income and smoothly guarantee the operation of the industrial chain,thereby playing a positive role during the development of the Taxus industry.This study provides reliable countermeasures and suggestions for the sustained and healthy development of the Taxus industry in Pengshui County.

Ototoxic effects and mechanisms of loop diuretics

Over the past two decades considerable progress has been made in understanding the ototoxic effects and mechanisms underlying loop diuretics. As typical representative of loop diuretics ethacrynic acid or furosemide only induces temporary hearing loss, but rarely permanent deafness unless applied in severe acute or chronic renal failure or with other ototoxic drugs. Loop diuretic induce unique pathological changes in the cochlea such as formation of edematous spaces in the epithelium of the stria vascularis, which leads to rapid decrease of the endolymphatic potential and eventual loss of the cochlear microphonic potential, summating potential, and compound action potential. Loop diuretics interfere with strial adenylate cyclase and Nat/Kt-ATPase and inhibit the Na-K-2Cl cotransporter in the stria vascularis, however recent reports indicate that one of the earliest effects in vivo is to abolish blood flow in the vessels supplying the lateral wall. Since ethacrynic acid does not damage the stria vascularis in vitro, the changes in Nat/Kt-ATPase and Na-K-2Cl seen in vivo may be secondary effects results from strial ischemia and anoxia. Recent observations showing that renin is present in pericytes surrounding stria arterioles suggest that diuretics may induce local vasoconstriction by renin secretion and angiotensin formation. The tight junctions in the blood-cochlea barrier prevent toxic molecules and pathogens from entering cochlea, but when diuretics induce a transient ischemia, the barrier is temporarily disrupted allowing the entry of toxic chemicals or pathogens.

Cisplatin-induced vestibular hair cell lesion-less damage at high doses

Cisplatin, a widely used anticancer drug, damages hair cells in cochlear organotypic cultures at low doses, but paradoxically causes little damage at high doses resulting in a U-shaped dose-response function. To determine if the cisplatin dose-response function for vestibular hair cells follows a similar pattern, we treated vestibular organotypic cultures with doses of cisplatin ranging from 10 to 1000 μM. Vestibular hair cell lesions progressively increased as the dose of cisplatin increased with maximum damage occurring around 50-100 μM, but the lesions progressively decreased at higher doses resulting in little hair cell loss at 1000 μM. The U-shaped doseresponse function for cisplatin-treated vestibular hair cells in culture appears to be regulated by copper transporters, Ctrl, ATP7A and ATP7B, that dose-dependently regulate the uptake, sequestration and extrusion of cisplatin.

Antioxidative stress-induced damage in cochlear explants

The imbalance of reactive oxygen species and antioxidants is considered to be an important factor in the cellular injury of the inner ear. At present, great attention has been placed on oxidative stress. However,little is known about fighting oxidative stress. In the current study, we evaluated antioxidant-induced cochlear damage by applying several different additional antioxidants. To determine whether excessive antioxidants can cause damage to cochlear cells, we treated cochlear explants with 50 m M M40403, a superoxide dismutase mimetic, 50 m M coenzyme Q-10, a vitamin-like antioxidant, or 50 m M d-methionine, an essential amino acid and the important antioxidant glutathione for 48 h. Control cochlear explants without the antioxidant treatment maintained their normal structures after incubation in the standard serum-free medium for 48 h, indicating the maintenance of the inherent oxidative and antioxidant balance in these cochlear explants. In contrast, M40403 and coenzyme Q-10-treated cochlear explants displayed significant hair cell damage together with slight damage to the auditory nerve fibers.Moreover, d-methiodine-treated explants exhibited severe damage to the surface structure of hair cells and the complete loss of the spiral ganglion neurons and their peripheral fibers. These results indicate that excessive antioxidants are detrimental to cochlear cells, suggesting that inappropriate dosages of antioxidant treatments can interrupt the balance of the inherent oxidative and antioxidant capacity in the cell.

Pattern of hair cell loss and delayed peripheral neuron degeneration in inner ear by a high-dose intratympanic gentamicin

To gain insights into the ototoxic effects of aminoglycoside antibiotics(AmAn) and delayed peripheral ganglion neuron death in the inner ear.experimental animal models were widely used with several different approaches including AmAn systemic injections,combination treatment of AmAn and diuretics,or local application of AmAn.In these approaches,systemic AmAn treatment alone usually causes incomplete damage to hair cells in the inner ear.Co-administration of diuretic and AmAn can completely destroy the cochlear hair cells,but it is impossible to damage the vestibular system.Only the approach of AmAn local application can selectively eliminate most sensory hair cells in the inner ear.Therefore,AmAn local application is more suitable for studies for complete hair cell destructions in cochlear and vestibular system and the following delayed peripheral ganglion neuron death.In current studies,guinea pigs were unilaterally treated with a high concentration of gentamicin(GM,40 nig/ml) through the tympanic membrane into the middle ear cavity.Auditory functions and vestibular functions were measured before and after GM treatment.The loss of hair cells and delayed degeneration of ganglion neurons in both cochlear and vestibular system were quantified 30 days or 60 days after treatment.The results showed that both auditory and vestibular functions were completely abolished after GM treatment.The sensory hair cells were totally missing in the cochlea,and severely destroyed in vestibular end-organs.The delayed spiral ganglion neuron death 60 days after the deafening procedure was over 50%.However,no obvious pathological changes were observed in vestibular ganglion neurons 60 days post-treatment.These results indicated that a high concentration of gentamycin delivered to the middle ear cavity can destroy most sensory hair cells in the inner ear that subsequently causes the delayed spiral ganglion neuron degeneration.This model might be useful for studies of hair cell regenerations,delayed degeneration of peripheral auditory neurons,and/or vestibular compensation.In addition,a potential problem of ABR recording for unilateral deafness and issues about vestibular compensation are also discussed.

Retrospective Studies on Clinical Features of Melanosis of the Colon and Its Correlation with the Polypus and Carcinoma of Large Intestine

OBJECTIVE To investigate the clinical characteristics ofmelanosis of the colon (MC) and its correlation with polypus andcarcinoma of the large intestine.METHODS Clinical feature and colonoscopic findings of 156MC patients were retrospectively analyzed. Final diagnosis of MCcase was made after colonoscopic and pathological examination,and data of the case history was recorded.RESULTS The overall detection rate of MC was 1.12%, with0.46% in males, 0.66% in females. An 82.69% of the patientssuffered various constipations and had a history of takingcathartics. The clinical manifestation of total-colon melanosisoccurred in 83.97% of the patients. There was no significantdifference between the rate of concomitant polypus (27.56%) inthe MC patients and the detection rate of polypus in the patientswho underwent a synchronous colonoscopy (x^2 = 1.205, P = 0.298).Also there was no significant difference between the detectionrate of carcinoma of the large intestine (8.97%) in MC patientsand the detection rate of the same disease in the patients whounderwent synchronous colonoscopy (x^2 = 0.268, P = 0.604). Alogistic regression analysis has shown that the older the age of MCpatients is, the more opportunities of MC and the concomitantpolypus would occur.CONCLUSION MC may be related to constipations and along-term administration of cathartics, among which total-colonmelanosis ranks first in the cases. There is an earlier age of onsetin the females, with a higher detection rate. The older the age ofthe patients is, the higher the detection rate of MC is, and the morepossibility the onset of the concomitant polypus.

Standardization of experimental animals temporal bone sections

Preparation of the temporal bone for light microscopy is an important step in histological studies of the inner ear. Due to the complexity of structures of the inner ear, it is difficult to measure or compare structures of interest without a commonly accepted standardized measure of temporal bone sections. Therefore, standardization of temporal bone sections is very important for histological assessment of sensory hair cells and peripheral ganglion neurons in the cochlear and vestibular systems. The standardized temporal bone sectioning is oriented to a plane parallel to the outer and internal auditory canals. Sections are collected from the epitympanum to the hypotympanum to reveal layers in the order of the crista ampullaris of the superior and lateral semicircular canals, macula utriculi and macula sacculi, superior vestibular ganglion neurons, macula of saccule and inferior vestibular ganglion neurons, cochlear modiolus, endolymphatic duct and endolymphatic sac, and finally the crista ampullaris of the posterior semicircular canal. Moreover, technical details of preparing for temporal bone sectioning including fixation,decalcification, whole temporal bone staining, embedding penetration, and embedding orientation are also discussed.

Coalition Game Based Full-Duplex Concurrent Scheduling in Millimeter Wave Wireless Backhaul Network

With the development of self-interference(SI) cancelation technology, full-duplex(FD) communication becomes possible. FD communication can theoretically double the spectral efficiency. When the time slot(TS) resources are limited and the number of flows is large, the scheduling mechanism of the flows becomes more important. Therefore, the effectiveness of FD scheduling mechanism for the flows is studied in millimeter wave wireless backhaul network with the limited TS resources. We proposed a full duplex concurrent scheduling algorithm based on coalition game(FDCG) to maximize the number of flows with their QoS requirements satisfied. We transformed the problem of maximizing the number of flows with their QoS requirements satisfied into the problem of maximizing sum rate of concurrently scheduled flows in each slot. We obtained the scheduled flows with maximum sum rate in first slot by using coalition game.And then with certain restrictions, the maximum sum rate of concurrently scheduled flows can also be achieved in subsequent time slots. The simulation results show that the proposed FDCG algorithm canachieve superior performance in terms of the number of flows that meet their QoS requirements and system throughput compared with other three algorithms.

The effect of protic ionic liquids incorporation on CO_(2) separation performance of Pebax-based membranes

The separation of carbon dioxide(CO_(2))is of great importance for environment protection and gas resource purification.The ionic liquids(ILs)-based gas separation membrane provides a new chance for efficient CO_(2)separation,while high permeability and selectivity of membranes is a great challenge.In this study,the influence of two protic ILs with different anion([TMGH][Im]and[TMGH][PhO])on the CO_(2)separation performance of the prepared ILs/Pebax blended membranes were systematically investigated at different temperature.The results showed the CO_(2)permeability exhibits the rising trend for ILs/Pebax blended membranes with the increment of IL content.Especially,the[TMGH][Im]with low viscosity and high CO_(2)absorption capacity leads to the blended membranes showing better CO_(2)permeability and ideal CO_(2)selectivity than that of membranes with[TMGH][PhO]at high IL content.Besides,with operating temperature increasing,the gas permeability of 20%(mass)[TMGH][Im]/Pebax blended membrane increases due to the decreasing viscosity of IL and the rising chain mobility of polymer.Inversely,the gas selectivity shows decreasing trend because CO_(2)absorption capacity obviously decreased at higher temperature.

Experimental Study on Afforestation in the Engineering Treatment Areas in the Hydro-fluctuation Zone of the Three Gorges Reservoir:A Case Study on the Engineering Treatment Area in the Wuxi Section of the Daning River

Through the Betula nigra afforestation test in the engineering treatment area of the Wuxi Section of the Daning River in Chongqing,the feasibility of arbor vegetation restoration in the comprehensive management of the engineering treatment areas of the Three Gorges Reservoir was explored.The results showed that:(1)before the flooding in the project area,the survival rate of B.nigra seedlings was high,over 95%,and(2)in 2021,after a water storage period,affected by factors such as seedling specifications,flood and flooding time,the survival rate of the seedlings planted in 2020 was low,and the one-year-old seedlings were greatly competed by weeds and grew less.Two-year-old B.nigra seedlings were replanted in 2021,and the survival rate of the B.nigra seedlings was 100%in 2022.Two-year-old B.nigra seedlings have strong adaptability and have little impact on the stability of the engineering treatment area,and can be used as afforestation tree species in engineering treatment areas of hydro-fluctuation zones.

Seedling Raising of Moringa oleifera in Chongqing

The tests of raising seedlings of Moringa oleifera were carried out in autumn and spring in Chongqing.The results showed that in the case of container seedling raising,the seedling emergence rate in autumn was 90%.Due to the large humidity and extreme weather,and the limited management conditions such as ventilation,the seedlings suffered from serious diseases,and the preservation rate was only 30%.The emergence rate was 91% in the spring of 2017,and the seedlings had unanimous growth.However,the seedling preservation rate dropped to 75% due to hail.In the spring of 2018,the emergence rate was 93%,and the seedlings also had unanimous growth.By the end of May,the seedlings had grown to 15 cm high.In addition,in the field seedling raising in 2017 and 2018,the seedlings showed unanimous growth with the emergence rate of 88% and 90%,respectively,and the seedlings grew into 30 cm high with good growth conditions in May.

Study on Vegetation Restoration in Chongqing Bashan Lake National Wetland Park

The vegetation restoration experiment was carried out by selecting the arbor-shrub-grass plants with strong stress resistances in the drawdown area of the reservoir of Chongqing Bashan Lake National Wetland Park.The results showed that the survival rate of Taxodium distichum was only 33% in August since the completion of the planting in May 2017,while the survival rates of other plant species were all 100%.After the rising and falling of water levels from September 2017 to February 2018,the investigations conducted in April 2018 showed that the flooding lasted for 130 d at the altitude of 668-672 m,where the preserving rate of Betula nigra was very low of only 25%.The flooding lasted for 120 d at the altitude of 672-675 m,where B.nigra,Pontederia cordata,and Thalia dealbata showed good preserving conditions with the preserving rates over 55%,while Canna indica,Cyperus alternifolius and Iris tectorum had poor preserving conditions with the rates below 50%.The drawdown area with the altitude of 675-678 m had the flooding lasted for 84 d,and good preserving conditions were found in B.nigra,T.distichum,Pterocarya stenoptera,Distylium chinense,Rosa multiflora,P.cordata,T.dealbata and Iris tectorum,which had the preserving rates reach up to 65%,and the preserving rate of B.nigra was as high as 76.2%,but the preserving rates of C.indica and C.alternifolius were low.

Hydrothermal fabrication and visible-light-driven photocatalytic properties of bismuth vanadate with multiple morphologies and/or porous structures for Methyl Orange degradation

Monoclinic BiVO4 with multiple morphologies and/or porous structures were fabricated using the hydrothermal strategy. The materials were characterized by means of the XRD, Raman, TGA/DSC, SEM, XPS, and UV-Vis techniques. The photocatalytic activities of the BiVO4 materials were evaluated for the degradation of Methyl Orange under visible-light irradiation. It is observed that pH value and surfactant exerted a great effect on the morphology and pore structure of the BiVO4 product. Spherical BiVO4 with porous structures, flower-cluster-like BiVO4, and flower-bundle-like BiVO4 were generated hydrothermally at 100°C with poly(vinyl pyrrolidone) (PVP) and urea (pH = 2) and at 160°C with NaHCO3 (pH = 7 and 8), respectively. The PVP-derived BiVO4 showed much higher surface areas (5.0-8.4 m2/g) and narrower bandgap energies (2.45-2.49 eV). The best photocatalytic performance of the spherical BiVO4 material with a surface area of 8.4 m2/g was associated with its higher surface area, narrower bandgap energy, higher surface oxygen vacancy density, and unique porous architecture.

Microstructure, tensile properties and creep behavior of Al-12Si-3.5Cu-2Ni-0.8Mg alloy produced by different casting technologies

The relationship between the as-cast microstructure and mechanical properties of the Al-12 Si-3.5 Cu-2 Ni-0.8 Mg alloys produced by permanent mold casting(PMC) and high pressure die casting(HPDC)is investigated. The alloys in both PMC and HPDC consist of Al, Si, Al_5 Cu_2 Mg_8 Si_6, Al_3 Cu Ni, and Al_7 Cu_4 Ni phase. However, the microstructure of the HPDC alloy is significantly refined. Compared to the PMC alloy,the ultimate tensile strength of the HPDC alloy is significantly increased from 244 MPa to 310 MPa, while the elongation shows a reverse trend at room temperature. At low stress and temperature range, slight variations of stress exponent and activation energy indicate that the minimum creep rate is controlled by the grain boundary creep. Then the minimum creep rate is higher for the specimen with the smaller grain size, where grain boundary creep is the dominant creep mechanism. At high stress region, the stress exponent for the PMC alloy and HPDC alloy is 5.18 and 3.07, respectively. The different stress exponents and activation energies measured at high stress and high temperature range indicates that the creep mechanism varies with the casting technologies.

A Day-ahead Economic Dispatch Method Considering Extreme Scenarios Based on Wind Power Uncertainty

As the intermittency of wind power is a growing concern in the day-ahead economic dispatch,this paper proposes a day-ahead economic dispatch method considering extreme scenarios of wind power by using an uncertainty set.The uncertainty set inspired by robust optimization is used to describe wind power intermittency in this paper.Four extreme scenarios based on the uncertainty set are formulated to represent the worst cases of wind power fluctuation.An economic dispatch method considering the costs of both load shedding and wind curtailment is proposed.The economic dispatch model can be easily solved by a quadratic programming method owing to the introduction of four extreme scenarios and the uncertainty set of wind power.Simulation is done using the IEEE 30-bus system and the results verify the effectiveness of the proposed method.

Effects of Zr,Ti and Sc additions on the microstructure and mechanical properties of Al-0.4Cu-0.14Si-0.05Mg-0.2Fe alloys

The evolution of microstructure and mechanical properties of Al-0.4 Cu-0.14 Si-0.05 Mg-0.2 Fe(wt.%)alloys, micro-alloyed with Zr, Ti and Sc, were investigated. The addition of 0.2%Zr to base alloy accelerates the precipitation of Si-rich nano-phase in α-Al matrix, which plays an important role in improving the mechanical properties of an alloy. The tensile strength increases from 102 MPa for the base alloy to 113 MPa for the Zr-modified alloy. Adding 0.2%Zr + 0.2%Ti to base alloy effectively refines a-Al grain size and accelerates the precipitation of Si and Cu elements, leading to heavy segregation at grain boundary.By further adding 0.2%Sc to Zr + Ti modified alloy, the segregation of Si and Cu elements is suppressed and more Si and Cu precipitates appeared in α-Al matrix. Accompanied with the formation of coherent Al_3Sc phase, the tensile strength increases from 108 MPa for the Zr + Ti modified alloy to 152 MPa for the Sc-modified alloy. Due to excellent thermal stability of Al_3Sc phase, the Sc-modified alloy exhibits obvious precipitation hardening behavior at 350℃, and the tensile strength increases to 203 MPa after holding at 350 ℃ for 200 h.

Effects of Gd Addition on the Microstructure and Tensile Properties of Mg–4Al–5RE Alloy Produced by Three Different Casting Methods

This work deals with the effect of 0.67 wt%Gd addition on the microstructure and tensile properties of Mg–4 Al–5 RE(where RE represents La–Ce mischmetal)alloy produced by sand casting(SC),permanent mold casting(PMC),and high-pressure die casting(HPDC).The results show that Gd addition could refine the grains,but its efficiency decreases by increasing the cooling rate due to the shifting from SC to PMC and finally to the HPDC method.Meanwhile,the acicular Al11 RE3 phase is modified into the short-rod or granular-like shape under the three casting conditions.Such refined and modified microstructures are due to the Al2(Gd,RE)phases,which act as the nucleation sites in both theα-Mg matrix and Al11 RE3 phase.Also,the weakening grain refinement effect in the increased cooling rates can be attributed to the narrow constitutional undercooling zone.After Gd addition,the 0.2%proof strength of the SC and PMC alloys increases by about 16.9%and 12.7%,respectively,while in the HPDC alloy,it decreases by about 5.9%.The main factor in the strength increment of the SC and PMC alloys is the grain boundary strengthening due to grain refinement which is proved by modeling the related mechanisms,whereas weak secondary phases and grain boundary strengthening mechanisms in the HPDC alloy lead to strength reduction.After Gd addition,the elongation to failure of the SC,PMC,and HPDC alloys is significantly enhanced by about 34.8%,20.2%,and 12.3%,respectively,due to the crack resistance nature of the modified short-rod/granular Al11(RE,Gd)3 phase compared to the acicular one.

MULTI-SCALE METHODS FOR INVERSE MODELING IN 1-D MOS CAPACITOR

In this paper,we investigate multi-scale methods for the inverse modeling in 1-D Metal-Oxide-Silicon(MOS) capactior,First,the mathematical model of the device is given and the numerical simulation for the forward problem of the model is implemented using finite element method with adaptive moving mesh. Then numerical analysis of these parameters in the model for the inverse problems is presented .Some matrix analysis tools are applied to explore the parameters' sensitivities,And thired,the parameters are extracted using Levenberg-Marquardt optimization method.The essential difficulty arises from the effect of multi-scale physical differeence of the parameters.We explore the relationship between the parameters' sensitivitites and the sequencs for optimization,which can seriously affect the final inverse modeling results.An optimal sequence can efficiently overcome the multip-scale problem of these parameters,Numerical experiments show the efficiency of the proposed methods.