Synthetic bandwidth technique is used to increase frequency bandwidth of the system and provides an effective way to achieve the ultra high resolution in the field of Synthetic Aperture Radar (SAR). But in the actual ...
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Synthetic bandwidth technique is used to increase frequency bandwidth of the system and provides an effective way to achieve the ultra high resolution in the field of Synthetic Aperture Radar (SAR). But in the actual SAR system, the synthesis result will be seriously deteriorated by the inner-channel and inter-channel phase error. A frequency domain synthetic bandwidth method based on transfer function extracting technique is proposed in an actual SAR system which consists of single wideband transmit channel and 8-way down-conversion receive sub-channels. The method can accurately get the amplitude and phase characteristics of the sub-channel and compensate the amplitude-phase errors. The final experimental results demonstrate the validity and feasibility of the method and the range resolution down to 0.1 m is obtained.
A central Pacific(CP)El Niño event occurred in 2018/*** studies have shown that different mechanisms are responsible for different subtypes of CP El Niño events(CP-I El Niño and CP-II El Niño).By comparing the evoluti...
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A central Pacific(CP)El Niño event occurred in 2018/*** studies have shown that different mechanisms are responsible for different subtypes of CP El Niño events(CP-I El Niño and CP-II El Niño).By comparing the evolutions of surface winds,ocean temperatures,and heat budgets of the CP-I El Niño,CP-II El Niño,and 2018/19 El Niño,it is illustrated that the subtropical westerly anomalies in the North Pacific,which led to anomalous convergence of Ekman flow and surface warming in the central equatorial Pacific,played an important role in the 2018/19 El Niño event as well as in the CP-II El Niñ*** the off-equatorial forcing played a vital role,it is found that the equatorial forcing acted as a driving(damping)term in boreal spring(summer)of the 2018/19 El Niñ*** 2018/19 El Niño provides a timely and vivid example that helps illustrate the proposed mechanism of the CP El Niño,which could be leveraged to improve El Niño predictability.
BACKGROUND Although substantial evidence supports the advantages of cold snare polypectomy(CSP)in terms of polypectomy efficacy and reduced postoperative adverse events,few studies have examined the cost differences b...
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BACKGROUND Although substantial evidence supports the advantages of cold snare polypectomy(CSP)in terms of polypectomy efficacy and reduced postoperative adverse events,few studies have examined the cost differences between CSP and traditional endoscopic mucosal resection(EMR)for the treatment of intestinal *** To compare the efficacy-cost of EMR and CSP in the treatment of intestinal *** A total of 100 patients with intestinal polyps were included in the retrospective data of our hospital from April 2022 to May *** to the treatment methods,they were divided into EMR(n=46)group and CSP(n=54)*** baseline data of the two groups were balanced by 1:1 propensity score matching(PSM),and the cost-effectiveness analysis was performed on the two groups after *** recurrence rate of the two groups of patients was followed up for 1 year,and they were divided into recurrence group and non-recurrence group according to whether they *** logistic regression analysis was used to screen out the influencing factors affecting the recurrence of intestinal polyps after endoscopic *** Significant disparities were observed in the number of polyps and smoking background between the two groups before PSM(P<0.05).Following PSM,the number of polyps and smoking history were well balanced between the EMR and CSP *** direct cost incurred by the CSP group was markedly higher than that incurred by the EMR ***,the cost-effectiveness ratio in the CSP group was substantially reduced when juxtaposed with that in the EMR group(P<0.05).Upon completion of the 1-year follow-up,the rate of recurrence after endoscopic intestinal polypectomy was 38.00%.Multivariate methods revealed that age≥60 years,male sex,number of polyps≥3,and pathological type of adenoma were risk factors for recurrence after endoscopic intestinal polypectomy(all P<0.05).CONCLUSION CSP was more cost-effective for the treatment of intestinal
This study examined the effectiveness for degradation of hydrophobic (HPO),transphilic(TPI) and hydrophilic (HPI) fractions of natural organic matter (NOM) during UV/H_(2)O_(2),UV/TiO_(2)and UV/K2S2O8(UV/PS) advanced ...
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This study examined the effectiveness for degradation of hydrophobic (HPO),transphilic(TPI) and hydrophilic (HPI) fractions of natural organic matter (NOM) during UV/H_(2)O_(2),UV/TiO_(2)and UV/K2S2O8(UV/PS) advanced oxidation processes (AOPs).The changing characteristics of NOM were evaluated by dissolved organic carbon (DOC),the specific UV absorbance (SUVA),trihalomethanes formation potential (THMFP),organic halogen adsorbable on activated carbon formation potential (AOXFP) and parallel factor analysis of excitation–emission matrices (PARAFAC-EEMs).In the three UV-based AOPs,HPI fraction with low molecular weight and aromaticity was more likely to degradate than HPO and TPI,and the removal efficiency of SUVA for HPO was much higher than TPI and HPI *** terms of the specific THMFP of HPO,TPI and HPI,a reduction was achieved in the UV/H_(2)O_(2)process,and the higest removal rate even reached to 83%.UV/TiO_(2)and UV/PS processes can only decrease the specific THMFP of *** specific AOXFP of HPO,TPI and HPI fractions were all able to be degraded by the three UV-based AOPs,and HPO content is more susceptible to decompose than TPI and HPI ***/H_(2)O_(2)was found to be the most effective treatment for the removal of THMFP and AOXFP under given conditions.C1 (microbial or marine derived humic-like substances),C_(2) (terrestrially derived humic-like substances)and C_(3) (tryptophan-like proteins) fluorescent components of HPO fraction were fairly labile across the UV-based AOPs treatment.C_(3) of each fraction of NOM was the most resistant to degrade upon the UV-based *** from this study may provide the prediction about the consequence of UV-based AOPs for the degradation of different fractions of NOM with varied characteristics.
Nanostructured electrodes with surface effect show a distinct advantage in prolonging the lifetime of lithium-ion(Li-ion)*** order to characterize the surface and chemical diffusion effects in a cylindrical nanowire e...
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Nanostructured electrodes with surface effect show a distinct advantage in prolonging the lifetime of lithium-ion(Li-ion)*** order to characterize the surface and chemical diffusion effects in a cylindrical nanowire electrode,a new theoretical model is proposed based on a combination of the diffusion theory and a surface energy density-based elastic *** the reformulation of the stress boundary condition in terms of a surface-induced traction,the bulk surface energy density and surface relaxation parameter are introduced as two simple parameters characterizing the surface effect in nanowire electrodes,instead of the surface elastic constants always used in existing ***-form solutions of the diffusion-induced elastic fields under potentiostatic operation are *** is found that the radial expansion and tensile stress in nanowire electrodes become smaller than the classical predictions without surface effect and decrease monotonically with a decreasing nanowire radius when the surface effect is *** phenomena can be basically attributed to the action of surface-induced traction on the nanowire *** results demonstrate the convenience and effectiveness of the present model in predicting the chemo-mechanical behavior of nanowire electrodes,which should be of guidance value for the optimal design of durable electrodes.
Summary of main observation and conclusion Heteroatom-doped carbon materials have been widely used in energy storage and conversion such as supercapacitors and *** this work,L-asparagine(Asn),an amino acid derivative,...
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Summary of main observation and conclusion Heteroatom-doped carbon materials have been widely used in energy storage and conversion such as supercapacitors and *** this work,L-asparagine(Asn),an amino acid derivative,has been used as a doping agent to prepare nitrogen-doped reduced graphene oxide gels(N-GAs).The 3D interconnected structure gives rise to the superior electrochemical properties for supercapacitor and electrocatalytic oxygen reduction reaction(ORR).The N-GA-4(the mass ratio of Asn to graphene oxide(GO)is 4:1 by hydrothermal method)electrode shows the capacitance of 291.6 F.g 1 at 0.5 Ag。Meanwhile,the assembled symmetric supercapacitor achieves a maximum energy density of 23.8 *** when the power density is 451.2 W-kg,and demonstrates an ultralong cycling life that the retention of capacitance is 99.3%after 80000 ***'s more,the annealed aerogel N-GA-4.900 exhibits an onset potential(Eonse)of 0.95 V,half wave potential(Eyz)of 0.84 V(***)and the oxygen reduction current density of 5.5 ***2 at 0.1 V with nearly four-electron transfer,which are superior to commercial Pt/*** work offers a new insight into the synthesis and applications of N-GAS materials towards high performance in supercapacitors and ORR.
The network is a major platform for implementing new cyber-telecom ***,it is important to carry out monitoring and early warning research on new cyber-telecom crime platforms,which will lay the foundation for the esta...
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The network is a major platform for implementing new cyber-telecom ***,it is important to carry out monitoring and early warning research on new cyber-telecom crime platforms,which will lay the foundation for the establishment of prevention and control systems to protect citizens’***,the deep-learning methods applied in the monitoring and early warning of new cyber-telecom crime platforms have some apparent *** instance,the methods suffer from data-distribution differences and tremendous manual efforts spent on data ***,a monitoring and early warning method for new cyber-telecom crime platforms based on the BERT migration learning model is *** method first identifies the text data and their tags,and then performs migration training based on a pre-training ***,the method uses the fine-tuned model to predict and classify new cyber-telecom *** analysis on the crime data collected by public security organizations shows that higher classification accuracy can be achieved using the proposed method,compared with the deep-learning method.
Compressed gas is usually used for the pressure compensation of the deep-sea pressure-maintaining *** pressure and volume of the recovered fluid sample are highly related to the precharged gas. To better understand th...
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Compressed gas is usually used for the pressure compensation of the deep-sea pressure-maintaining *** pressure and volume of the recovered fluid sample are highly related to the precharged gas. To better understand the behavior of the gas under high pressure, we present a new real gas state equation based on the compression factor Z which was derived from experimental data. Then theoretical calculation method of the pressure and volume of the sample was introduced based on this empirical gas state equation. Finally, the proposed calculation method was well verified by the high-pressure vessel experiment of the sampler under 115 MPa.
The precipitation and age hardening response of the solid-soluted Mg–10Gd–1Er–1Zn–0.6Zr(wt.%)alloy performed by water-quenching(QC),air-cooling(AC)and furnace-cooling(FC)in terms of the volume fraction of precipit...
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The precipitation and age hardening response of the solid-soluted Mg–10Gd–1Er–1Zn–0.6Zr(wt.%)alloy performed by water-quenching(QC),air-cooling(AC)and furnace-cooling(FC)in terms of the volume fraction of precipitates and tensile properties were investigated in present *** indicated the solid-soluted alloy contained stacking faults(SFs)and long period stacking ordered(LPSO)phase on the basal planes regardless of the cooling rate,but a larger volume fraction of the LPSO phase was formed with decreasing in the cooling *** aging,βandβ1 phases precipitated on the prismatic planes,and their number density decreased but mean particle size increased with decreasing in the cooling *** solid-soluted alloys(QC,AC and FC samples)showed no apparent difference in yield strength(YS),but their correspondent peak-aged alloys exhibited sharp difference in hardening *** strongest hardening response took place in the QC sample and showed 82MPa enhancement in YS,which was much larger than that of AC(+26MPa)and FC samples(+5MPa).The reason lies in that the higher cooling rate promotes the precipitation and reduces the average size ofβprecipitate.A novel cooling-rate controlled precipitation model with respect to the correlation of precipitates on basal and prismatic planes was *** this model,the basal precipitates showed a restrictive effect on the growth and/or coarsening ofβprecipitate,and composite precipitates containing theβphase with fine size as well as high area-number density and lower volume fraction of the LPSO phase are preferred to strengthen the Mg–10Gd–1Er–1Zn–0.6Zr alloy.
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