To interpret the common symmetric peaks caused by the large-scale structure in the complex S(f)spectrum from the heterodyne Doppler reflectometry(DR)measurement in EAST,a 2D circular-shaped O-mode full-wave model base...To interpret the common symmetric peaks caused by the large-scale structure in the complex S(f)spectrum from the heterodyne Doppler reflectometry(DR)measurement in EAST,a 2D circular-shaped O-mode full-wave model based on the finite-difference time-domain method is built.The scattering characteristics and the influences on the DR signal from various scales are investigated.When the structure is located around the cutoff layer,a moving radial or poloidal large-scale structure k_(θ)k_(θ),match(k_(θ),match is the theoretic wavenumber of Bragg scattering)could both generate an oscillation phase term called‘phase modulation’,and symmetrical peaks in the complex S(f)spectrum.It was found that the image-rejection ratio A_(−1)/A_(+1)(A_(±1)represents the amplitudes of±1 order modulation peaks)could be a feasible indicator for experiment comparison.In the case when the structure is near the cutoff layer with the same arrangement as the experiment for the edge DR channel,the curve of A_(−1)/A_(+1)versus kθcan be divided into three regions,weak asymmetrical range with k_(θ)/k_(0)0.15(k_(0)is the vacuum wavenumber),harmonics range with 0.15k_(θ)/k_(0)0.4,and Bragg scattering range of 0.4k_(θ)/k_(0)0.7.In the case when the structure is located away from the cutoff layer,the final complex S(f)spectrum is the simple superimposing of modulation and Bragg scattering,and the modulation peaks have an amplitude response nearly proportional to the local density fluctuation,called the‘propagationroute effect’.Under the H-mode experiment arrangement for the core DR,a critical fluctuation amplitude Amp(n_(e,Mod.@route))/Amp(n_(e,Tur.@MSA)∼1.3–4.1(Amp(n_(e,Mod.@route))refers to the pedestal large-scale structure amplitude and Amp(ne,Tur.@MSA)refers to turbulence amplitude at the main scattering area)is needed for the structure in the pedestal to be observed by the core DR measurement.The simulations are well consistent with the experimental results.These effects need to be carefully considered during the DR signal analyses as the injecting beam passes through the plasma region with large-scale structures.展开更多
Federated Learning(FL),a burgeoning technology,has received increasing attention due to its privacy protection capability.However,the base algorithm FedAvg is vulnerable when it suffers from so-called backdoor attacks...Federated Learning(FL),a burgeoning technology,has received increasing attention due to its privacy protection capability.However,the base algorithm FedAvg is vulnerable when it suffers from so-called backdoor attacks.Former researchers proposed several robust aggregation methods.Unfortunately,due to the hidden characteristic of backdoor attacks,many of these aggregation methods are unable to defend against backdoor attacks.What's more,the attackers recently have proposed some hiding methods that further improve backdoor attacks'stealthiness,making all the existing robust aggregation methods fail.To tackle the threat of backdoor attacks,we propose a new aggregation method,X-raying Models with A Matrix(XMAM),to reveal the malicious local model updates submitted by the backdoor attackers.Since we observe that the output of the Softmax layer exhibits distinguishable patterns between malicious and benign updates,unlike the existing aggregation algorithms,we focus on the Softmax layer's output in which the backdoor attackers are difficult to hide their malicious behavior.Specifically,like medical X-ray examinations,we investigate the collected local model updates by using a matrix as an input to get their Softmax layer's outputs.Then,we preclude updates whose outputs are abnormal by clustering.Without any training dataset in the server,the extensive evaluations show that our XMAM can effectively distinguish malicious local model updates from benign ones.For instance,when other methods fail to defend against the backdoor attacks at no more than 20%malicious clients,our method can tolerate 45%malicious clients in the black-box mode and about 30%in Projected Gradient Descent(PGD)mode.Besides,under adaptive attacks,the results demonstrate that XMAM can still complete the global model training task even when there are 40%malicious clients.Finally,we analyze our method's screening complexity and compare the real screening time with other methods.The results show that XMAM is about 10–10000 times faster than the existing methods.展开更多
背景与目的气腔扩散(spread through air spaces,STAS)作为一种新发现的肺癌侵袭方式,其生物学特点及分子特征尚存在争议。本研究旨在探讨STAS与肺浸润性腺癌临床病理学特征及基因改变的关系。方法选取广州医科大学附属第一医院2019年7...背景与目的气腔扩散(spread through air spaces,STAS)作为一种新发现的肺癌侵袭方式,其生物学特点及分子特征尚存在争议。本研究旨在探讨STAS与肺浸润性腺癌临床病理学特征及基因改变的关系。方法选取广州医科大学附属第一医院2019年7月至2021年3月确诊的肺非黏液性浸润性腺癌手术切除标本694例,分析STAS与临床病理因素之间的关系。应用免疫组织化学方法检测间变性淋巴瘤激酶(anaplastic lymphoma kinase,ALK)蛋白表达;应用扩增阻滞突变系统-聚合酶链反应(amplification refractory mutation system-polymerase chain reaction,ARMS-PCR)技术检测表皮生长因子受体(epidermal growth factor receptor,EGFR)基因突变;应用反转录-PCR(reverse transcription-PCR,RT-PCR)技术检测肉瘤致癌因子受体(ROS proto-oncogene 1-receptor,ROS1)基因融合。结果STAS阳性病例共344例,STAS阴性病例共350例。STAS阳性与肿瘤最大径(P<0.001)、胸膜侵犯(P<0.001)、脉管侵犯(P<0.001)、神经束侵犯(P=0.013)、淋巴结转移(P<0.001)、临床分期(P<0.001)及组织学分型(P<0.001)相关;STAS与ALK蛋白表达(P<0.001)相关。多因素分析表明,STAS阳性与胸膜侵犯(P=0.001)、脉管侵犯(P<0.001)、淋巴结转移(P=0.005)及ALK蛋白表达(P=0.032)相关。结论STAS阳性与肺腺癌高侵袭性生物学行为有关,提示不良预后。展开更多
A quasi-coherent(QC)mode was observed in the core region of low-density ohmic plasmas in Sino-UNIted Spherical Tokamak.In experiments on the QC mode,two sets of moveable Langmuir probes(LPs)were used to measure the lo...A quasi-coherent(QC)mode was observed in the core region of low-density ohmic plasmas in Sino-UNIted Spherical Tokamak.In experiments on the QC mode,two sets of moveable Langmuir probes(LPs)were used to measure the local parameters including floating potential,electron temperature,electron density,and so on,as well as their profiles.To monitor the magnetohydrodynamic activities,a Mirnov probe was used to measure the poloidal magnetic fluctuation.The QC mode can be seen in the spectra of floating potential,but there is no similar peak in the spectra of magnetic fluctuation.Thus,the QC mode is probably electrostatic.By analyzing the electrostatic potential fluctuations from the LPs,the features of the QC mode including frequency,wavenumber,propagation direction,and dependence on collisionality are identified,which are consistent with the characteristics of dissipative trapped electron mode.展开更多
The high-voltage battery has now become a goal in order to meet the demands for high energy density.However,the severe side reactions between Li metal and carbonate-based electrolytes in this system result in unstable...The high-voltage battery has now become a goal in order to meet the demands for high energy density.However,the severe side reactions between Li metal and carbonate-based electrolytes in this system result in unstable interphase,leading to non-uniform Li-ion flux and thus aggravating the dendrite growth of Li.The protect interphase,traditional solid electrolyte interface(SEI),is a loose solid layer consisted of many components,which generally does not possess the function of preventing the lithium budding.Herein,based on polysulfide solubility in ester,we proposed a strategy to eliminate the dendrite by constructing a unique SEI in which the dynamic polysulfides were in situ formed and encapsuled.For this purpose,a 2-fluorophenylsulfur pentafluoride(2-FSPF)was employed as an additive in carbonate-based electrolyte that can be decomposed electrochemically during battery operation to form such a polysulfide-rich interphase.These polysulfides with certain fluidity can adhere to dynamically the budding tip of Li metal,as a so-called tip-inhibitor,when the local current density of the tip rising,thus to hinder Li^(+)diffusion toward the tip,resulting in inhibiting the further growth of Li dendrites and leveling the Li deposition.At the current density of 1 mA cm^(-2),the average Coulombic efficiency of Li//Cu cells is as high as 98.39%during 600 cycles,and the stable cycling of Li//Li symmetric cell reaches 3500 h.Furthermore,due to the high anodic stability,the Li//high-voltage LiCoO_(2)(LCO)full cells and Li–O_(2)battery achieve excellent cycle performance with lean electrolyte.展开更多
A novel electromagnetic probe array(EMPA) diagnostic, which consists of a magnetic probe array and an electrostatic probe array, has recently been developed on EAST. The EMPA is fixed near the first wall at horizontal...A novel electromagnetic probe array(EMPA) diagnostic, which consists of a magnetic probe array and an electrostatic probe array, has recently been developed on EAST. The EMPA is fixed near the first wall at horizontal port P. The magnetic probe array of the EMPA consists of 24 identical magnetic probes, each of them capable of measuring toroidal, poloidal and radial magnetic fluctuations simultaneously, providing additional toroidal magnetic fluctuation measurements compared with the regular magnetic probes on EAST. With a higher sampling rate and self-resonant frequency, the EMPA magnetic probes can provide higher frequency magnetic fluctuation measurements. The magnetic probe array of the EMPA is composed of two parallel layers of magnetic probes with a radial distance of 63 mm, and each layer of magnetic probes is arranged in four poloidal rows and three toroidal columns. The compact arrangement of the EMPA magnetic probe array largely improves the toroidal mode number measurement ability from-8≤ n≤ 8 to-112≤ n≤ 112, and also improves the high poloidal wave number measurement ability of magnetic fluctuations compared with the regular high frequency magnetic probes on EAST. The electrostatic probe array of the EMPA consists of two sets of four-tip probes and a single-tip probe array with three poloidal rows and four toroidal columns. It complements the electrostatic parameter measurements behind the main limiter and near the first wall in EAST. The engineering details of the EMPA diagnostic, including the mechanical system, the electrical system, the acquisition and control system, and the effective area calibration, are presented. The preliminary applications of the EMPA in L-mode and H-mode discharges on EAST have demonstrated that the EMPA works well for providing information on the magnetic and electrostatic fluctuations and can contribute to deeper physical analysis in future EAST experiments.展开更多
Lithium-oxygen(Li-O) battery is considered as one of the most promising alternatives because of its ultrahigh theoretical energy density. However, their cycling stability is severely restricted by the uncontrollable d...Lithium-oxygen(Li-O) battery is considered as one of the most promising alternatives because of its ultrahigh theoretical energy density. However, their cycling stability is severely restricted by the uncontrollable dendrite growth and serious oxygen corrosion issue on Li surface. Herein, a sulfur-modified Li surface can be successfully constructed via chemical reaction of guanylthiourea(GTU) molecule on Li,which can induce the selectively fast decomposition of lithium bis(trifluoromethanesulfonyl)imide(LiTFSI) to form a smooth and stable inorganics-rich solid-electrolyte interphase(IR-SEI) during the subsequent electrochemical process. Such an IR-SEI cannot only offer a highly reversible and stable Li plating/stripping chemistry with dendrite-free property(10 mA cm^(-2)-10 mAh cm^(-2), > 0.5 years;3 mA cm^(-2)-3 m Ah cm^(-2), > 1 year) but also endows the Li metal an anti-oxygen corrosion function, thereby significantly improving the cycling stability of Li-Obatteries. This work provides a new idea for constructing functional solid-electrolyte interphase(SEI) to achieve highly stable Li metal anode.展开更多
The effect of externally applied resonant magnetic perturbation(RMP)on carbon impurity behavior is investigated in the J-TEXT tokamak.It is found that the m/n=3/1 islands have an impurity screening effect,which become...The effect of externally applied resonant magnetic perturbation(RMP)on carbon impurity behavior is investigated in the J-TEXT tokamak.It is found that the m/n=3/1 islands have an impurity screening effect,which becomes obvious while the edge magnetic island is generated via RMP field penetration.The impurity screening effect shows a dependence on the RMP phase with the field penetration,which is strongest if the O point of the magnetic island is near the low-field-side(LFS)limiter plate.By combining a methane injection experimental study and STRAHL impurity transport analysis,we found that the variation of the impurity transport dominates the impurity screening effect.The impurity diffusion at the inner plasma region(r/a<0.8)is enhanced with a significant increase in outward convection velocity at the edge region in the case of the magnetic island’s O point near the LFS limiter plate.The impurity transport coefficient varies by a much lower level for the case with the magnetic island’s X point near the LFS limiter plate.The interaction of the magnetic island and the LFS limiter plate is thought to contribute to the impurity transport variation with the dependence on the RMP phase.A possible reason is the interaction between the magnetic island and the LFS limiter.展开更多
In the harsh service environment of high temperature and intense neutron irradiation in water-cooled nuclear reactors,the austenitic stainless steel weld overlay cladding on the inner surface of the reactor pressure v...In the harsh service environment of high temperature and intense neutron irradiation in water-cooled nuclear reactors,the austenitic stainless steel weld overlay cladding on the inner surface of the reactor pressure vessel suffers from thermal aging and irradiation damage simultaneously,which can induce microstructural evolution and hardening of the material.Since it is quite difficult to achieve this simul-taneous process out of the pile,two kinds of combined experiments,i.e.,post-irradiation thermal aging and post-aging irradiation were performed on 308 L stainless steel weld metals in this work.The interactive effect of thermal aging and proton irradiation on microstructural evolution and hardening ofδ-ferrite in 308 L weld metal was investigated by combining atom probe tomography,transmission elec-tron microscopy and nanoindentation tests.The results revealed that thermal aging could eliminate the dislocation loops induced by irradiation and affect the phase transition process by accelerating spinodal decomposition and G-phase precipitation,thus enhancing hardening of irradiatedδ-ferrite.For the effect of irradiation on the microstructure and hardening of thermally agedδ-ferrite,however,intensive collision cascades can intensify G-phase precipitation and dislocation loop formation but decrease spinodal decomposition,leading to a limited effect on hardening of thermally agedδ-ferrite.Furthermore,the interaction of thermal aging and irradiation can promote G-phase precipitation.Meanwhile,the interaction can causeδ-ferrite hardening,which is mainly influenced by spinodal decomposition,followed by G-phase and dislocation loops,where spinodal decomposition and G-phase cause hardening by inducing strain fields.展开更多
A manganese superoxide dismutase （Mn-SOD） gene, NnMSD1, was identified from embryonic axes of the sacred lotus （Nelumbo nucifera Gaertn.）. The NnMSD1 protein contains all conserved residues of the Mn-SOD protein f...A manganese superoxide dismutase （Mn-SOD） gene, NnMSD1, was identified from embryonic axes of the sacred lotus （Nelumbo nucifera Gaertn.）. The NnMSD1 protein contains all conserved residues of the Mn-SOD protein family, including four consensus metal binding domains and a signal peptide for mitochondrial targeting. Southern blot analysis suggests the existence of two Mn.SOD genes in sacred lotus. NnMSD1 was highly expressed in developing embryonic axes during seed development, but appeared in cotyledons only at the early stage of development and became undetectable in the cotyledons during late embryogenesis. The expression of the NnMSD1 gene in germinating embryonic axes, in response to various stresses such as heat shock, chilling, and exposure to stress-related chemicals, was also studied. Heat shock strongly inhibited the expression of the NnMSD1 gene, whereas the NnMSD1 transcript level increased strongly in chilling stress treatment. An increase in expression was also highly induced by H2O2 in germinating embryonic axes. The results suggest that the expression pattern of the NnMSD1 gene differed between developing axes and cotyledons, and that the NnMSD1 gene expression responds strongly to chilling and oxidative stress.展开更多
Perovskite nanocrystals （NCs） have strong nonlinear optical responses with a number of potential applications, ranging from upconverted blue-lasing to the tagging of specific cellular components in multicolor fluore...Perovskite nanocrystals （NCs） have strong nonlinear optical responses with a number of potential applications, ranging from upconverted blue-lasing to the tagging of specific cellular components in multicolor fluorescence microscopy. Here, we determine the one-photon linear absorption cross section of two kinds of blue-emitting perovskite NCs, i.e., CsPbCl3 and CsPb（C10.53Br0.47）3, by utilizing femtosecond transient absorption spectroscopy. The wavelength-dependent nonlinear refraction and two-photon absorption have been measured at wavelengths from 620 to 720 nm by performing Z-scan measurements. The nonlinear optical responses of CsPb（C10.53Br0.47）3 are much more pronounced than those of CsPbCl3 due to the larger structural destahilization of the former.展开更多
In this work,one kind of typeⅡZnSe/CdS/ZnS core/shell/shell nanocrystals(NCs)is synthesized,and their linear and nonlinear photophysical properties are investigated.Through measurements of the temperaturedependent ph...In this work,one kind of typeⅡZnSe/CdS/ZnS core/shell/shell nanocrystals(NCs)is synthesized,and their linear and nonlinear photophysical properties are investigated.Through measurements of the temperaturedependent photoluminescence spectra of NCs,their excitonic properties,including the coefficient of the bandgap change,coupling strength of the exciton acoustic phonons,exciton longitudinal optical(LO)phonons,and LO–phonon energy are revealed.Femtosecond transient absorption spectroscopy was employed to obtain insight into ultrafast processes occurring at the interface of ZnSe and CdS,such as those involving the injection of photoinduced electrons into the CdS shell,interfacial state bleaching,and charge separation time.At the end,their multiphoton absorption spectra were determined by using the z-scan technique,which yielded a maximum twophoton absorption cross section of 3717 GM at 820 nm and three-photon absorption cross section up to 3.9×10^-77cm^6·s^2·photon^-2at 1220 nm,respectively.The photophysical properties presented here may be important for exploiting their relevant applications in optoelectronic devices and deep-tissue bioimaging.展开更多
Lamb Wave(LW) simulation under time-varying conditions is an effective and low cost way to study the problem of the low reliability of the structural health monitoring methods based on the LW and Piezoelectric Transdu...Lamb Wave(LW) simulation under time-varying conditions is an effective and low cost way to study the problem of the low reliability of the structural health monitoring methods based on the LW and Piezoelectric Transducer(PT). In this paper, a multiphysics simulation method of the LW propagation with the PTs under load condition is proposed. With this method, two key mechanisms of the load influence on the LW propagation are considered and coupled with each other. The first mechanism is the acoustoelastic effect which is the main reason of the LW velocity change. The second key mechanism is the load influence on piezoelectric materials, which results in a change of the amplitude. Based on the computational platform of the COMSOL Multiphysics, a multiphysics simulation model of the LW propagation with the PTs under load condition is established. The simulation model includes two physical phenomena. The first one is called solid mechanics, which is used to simulate the acoustoelastic effect being combined with the hyperelastic material properties of the structure in which the LW propagates. The second one is called electromechanical coupling, which considers the simulation of the piezoelectric effect of the PTs for the LW excitation and sensing. To simulate the load influence on piezoelectric materials, a non-linear numerical model of the relationship between the load and the piezoelectric coefficient d31 is established based on an experiment of the load influence on the LW. The simulation results under uniaxial tensile load condition are obtained and are compared with the data obtained from the experiment. It shows that the variations of the phase velocity and amplitude of the LW obtained from the simulation model match the experimental results well.展开更多
The proton-irradiated 308L stainless steel weld metal was strained by using constant extension rate tensile testing in simulated PWR primary water, and its deformation microstructures and irradiation assisted stress c...The proton-irradiated 308L stainless steel weld metal was strained by using constant extension rate tensile testing in simulated PWR primary water, and its deformation microstructures and irradiation assisted stress corrosion cracking(IASCC) behavior were investigated. The results suggest that the irradiation significantly increases the SCC susceptibility of 308L weld metal and causes various deformation microstructures including lathy faulted planes, dislocation channels and deformation twins in austenite and atomic plane rotation in δ-ferrite. The propagation of intergranular IASCC cracks is closely related to the location of the crack tip. For the crack tip in the specimen matrix interior, localized deformation is likely the key factor responsible for the crack growth. For the crack tip close to the specimen surface, however, localized corrosion along the grain boundary rather than the localized deformation appears to dominate the crack propagation. Unlike the intergranular cracks, the IASCC cracks along the δ-ferrite/austenite phase boundary can initiate either by crack initiation at the phase boundary or by crack propagation from the grain boundary. In both cases, the cracked phase boundaries contain a large number of carbides and are severely corroded, but no deformation microstructures are observed, which implies that the localized corrosion may play an important role in the IASCC along the phase boundary. In addition, δ-ferrite can retard the IASCC crack propagation along the grain boundary, which is probably related to the reduction of localized deformation by δ-ferrite.展开更多
As a widely-used machine-learning classifier,a decision tree model can be trained and deployed at a service provider to provide classification services for clients,e.g.,remote diagnostics.To address privacy concerns r...As a widely-used machine-learning classifier,a decision tree model can be trained and deployed at a service provider to provide classification services for clients,e.g.,remote diagnostics.To address privacy concerns regarding the sensitive information in these services(i.e.,the clients’inputs,model parameters,and classification results),we propose a privacy-preserving decision tree classification scheme(PDTC)in this paper.Specifically,we first tailor an additively homomorphic encryption primitive and a secret sharing technique to design a new secure two-party comparison protocol,where the numeric inputs of each party can be privately compared as a whole instead of doing that in a bit-by-bit manner.Then,based on the comparison protocol,we exploit the structure of the decision tree to construct PDTC,where the input of a client and the model parameters of a service provider are concealed from the counterparty and the classification result is only revealed to the client.A formal simulation-based security model and the security proof demonstrate that PDTC achieves desirable security properties.In addition,performance evaluation shows that PDTC achieves a lower communication and computation overhead compared with existing schemes.展开更多
The corrosion of unaged and 7000-h thermally aged 308 L stainless steel weld metals in simulated PWR primary water under aerated and deaerated conditions was investigated,involving the corrosion of austenite,δ-ferrit...The corrosion of unaged and 7000-h thermally aged 308 L stainless steel weld metals in simulated PWR primary water under aerated and deaerated conditions was investigated,involving the corrosion of austenite,δ-ferrite andδ-ferrite/austenite phase boundary.The results revealed that thermal ageing for 7000 h had a limited effect on the corrosion behavior of 308 L weld metal as it only increased the inner oxide thickness ofδ-ferrite slightly under the deaerated condition.No obvious corrosion enhancement of 308 L weld metal under the aerated condition was found compared to the deaerated condition regardless of the thermal ageing.Nevertheless,Cr-enrichment on the surface of oxide particles,dissolved regions at the metal/oxide interface and localized corrosion along theδ-ferrite/austenite phase boundary occurred under the aerated condition.展开更多
Lithium metal anodes have received tremendous attention in recent years and are considered as the most promising anode material for the next-generation high-energy-density batteries[1].However,the commercial adoption ...Lithium metal anodes have received tremendous attention in recent years and are considered as the most promising anode material for the next-generation high-energy-density batteries[1].However,the commercial adoption of such anodes is severely hindered by poor electrochemical reversibility and insufficient cycle-life[2].展开更多
We have studied the two-and three-photon absorption(2PA and 3PA) properties of Mn-doped CsPbCl_3 twodimensional nanoplatelets(2D NPs) and cubic nanocrystals. Compared with their cubic counterparts, the Mn-doped 2D NPs...We have studied the two-and three-photon absorption(2PA and 3PA) properties of Mn-doped CsPbCl_3 twodimensional nanoplatelets(2D NPs) and cubic nanocrystals. Compared with their cubic counterparts, the Mn-doped 2D NPs exhibit stronger quantum confinement effects that can more efficiently enhance their dopantcarrier exchange interactions and multiphoton absorption. More specifically, the maximum volume-normalized 2PA and 3PA cross sections of the 2D NPs were 6.8 and 7.2 times greater than those of their cubic counterparts,respectively, reaching up to 1237 GM∕nm^3 in the visible light band and 2.24 × 10^(-78) cm^6· s^2· photon^(-2)∕nm^3 in the second biological window, respectively.展开更多
The major cause of pediatric anterior urethral injuries(AUIs)is blunt trauma.12 Penetrating injuries caused by explosive trauma are rare in pediatric patients.Both early and delayed urethral repairs are optional strat...The major cause of pediatric anterior urethral injuries(AUIs)is blunt trauma.12 Penetrating injuries caused by explosive trauma are rare in pediatric patients.Both early and delayed urethral repairs are optional strategies to manage AUIs.Studies from clinical manage-ment of blunt trauma have concluded rich experiences.However,poor experiences can be used to manage explosive AUIs.In this case,a 7-year old boy threw a detonator into the fire.His external genitalia and bilateral medial region of the thigh were injured in a sudden explosion.Corpus spongiosum penis was covered by incomplete prepuce.Splintered glans penis with high-degree edema concealed the urethral meatus.The swollen testis was detected in the tattered scrotum.Muscular layer was included in explosive inju-ries of the bilateral thigh(figure 1).Surgical debridement was performed urgently.展开更多
Professor Xiaodong Lin believes the ability to tackle struggles is similar to the human body's immune system,which is a natural defense that can be activated when the body is infected or damaged.Thus,Lin aims to b...Professor Xiaodong Lin believes the ability to tackle struggles is similar to the human body's immune system,which is a natural defense that can be activated when the body is infected or damaged.Thus,Lin aims to build a similar,psychological mechanism to enhance children's ability to deal with problems in life.展开更多
基金supported by Shenzhen Clean Energy Research Institute,the National MCF Energy R&D Program of China(Nos.2018YFE0311200 and 2022YFE03070004)National Natural Science Foundation of China(Nos.U1967206 and 12075155)+1 种基金the China Postdoctoral Science Foundation(No.2021M702270)the Fundamental Research Funds for the Central Universities(No.WK3420000018)。
文摘To interpret the common symmetric peaks caused by the large-scale structure in the complex S(f)spectrum from the heterodyne Doppler reflectometry(DR)measurement in EAST,a 2D circular-shaped O-mode full-wave model based on the finite-difference time-domain method is built.The scattering characteristics and the influences on the DR signal from various scales are investigated.When the structure is located around the cutoff layer,a moving radial or poloidal large-scale structure k_(θ)k_(θ),match(k_(θ),match is the theoretic wavenumber of Bragg scattering)could both generate an oscillation phase term called‘phase modulation’,and symmetrical peaks in the complex S(f)spectrum.It was found that the image-rejection ratio A_(−1)/A_(+1)(A_(±1)represents the amplitudes of±1 order modulation peaks)could be a feasible indicator for experiment comparison.In the case when the structure is near the cutoff layer with the same arrangement as the experiment for the edge DR channel,the curve of A_(−1)/A_(+1)versus kθcan be divided into three regions,weak asymmetrical range with k_(θ)/k_(0)0.15(k_(0)is the vacuum wavenumber),harmonics range with 0.15k_(θ)/k_(0)0.4,and Bragg scattering range of 0.4k_(θ)/k_(0)0.7.In the case when the structure is located away from the cutoff layer,the final complex S(f)spectrum is the simple superimposing of modulation and Bragg scattering,and the modulation peaks have an amplitude response nearly proportional to the local density fluctuation,called the‘propagationroute effect’.Under the H-mode experiment arrangement for the core DR,a critical fluctuation amplitude Amp(n_(e,Mod.@route))/Amp(n_(e,Tur.@MSA)∼1.3–4.1(Amp(n_(e,Mod.@route))refers to the pedestal large-scale structure amplitude and Amp(ne,Tur.@MSA)refers to turbulence amplitude at the main scattering area)is needed for the structure in the pedestal to be observed by the core DR measurement.The simulations are well consistent with the experimental results.These effects need to be carefully considered during the DR signal analyses as the injecting beam passes through the plasma region with large-scale structures.
基金Supported by the Fundamental Research Funds for the Central Universities(328202204)。
文摘Federated Learning(FL),a burgeoning technology,has received increasing attention due to its privacy protection capability.However,the base algorithm FedAvg is vulnerable when it suffers from so-called backdoor attacks.Former researchers proposed several robust aggregation methods.Unfortunately,due to the hidden characteristic of backdoor attacks,many of these aggregation methods are unable to defend against backdoor attacks.What's more,the attackers recently have proposed some hiding methods that further improve backdoor attacks'stealthiness,making all the existing robust aggregation methods fail.To tackle the threat of backdoor attacks,we propose a new aggregation method,X-raying Models with A Matrix(XMAM),to reveal the malicious local model updates submitted by the backdoor attackers.Since we observe that the output of the Softmax layer exhibits distinguishable patterns between malicious and benign updates,unlike the existing aggregation algorithms,we focus on the Softmax layer's output in which the backdoor attackers are difficult to hide their malicious behavior.Specifically,like medical X-ray examinations,we investigate the collected local model updates by using a matrix as an input to get their Softmax layer's outputs.Then,we preclude updates whose outputs are abnormal by clustering.Without any training dataset in the server,the extensive evaluations show that our XMAM can effectively distinguish malicious local model updates from benign ones.For instance,when other methods fail to defend against the backdoor attacks at no more than 20%malicious clients,our method can tolerate 45%malicious clients in the black-box mode and about 30%in Projected Gradient Descent(PGD)mode.Besides,under adaptive attacks,the results demonstrate that XMAM can still complete the global model training task even when there are 40%malicious clients.Finally,we analyze our method's screening complexity and compare the real screening time with other methods.The results show that XMAM is about 10–10000 times faster than the existing methods.
基金National Natural Science Foundation of China(Nos.11827810,11875177,12105189 and 12075155)International Atomic Energy Agency Research(No.22733)National Magnetic Confinement Fusion Program of China(No.2019YFE03010001)。
文摘A quasi-coherent(QC)mode was observed in the core region of low-density ohmic plasmas in Sino-UNIted Spherical Tokamak.In experiments on the QC mode,two sets of moveable Langmuir probes(LPs)were used to measure the local parameters including floating potential,electron temperature,electron density,and so on,as well as their profiles.To monitor the magnetohydrodynamic activities,a Mirnov probe was used to measure the poloidal magnetic fluctuation.The QC mode can be seen in the spectra of floating potential,but there is no similar peak in the spectra of magnetic fluctuation.Thus,the QC mode is probably electrostatic.By analyzing the electrostatic potential fluctuations from the LPs,the features of the QC mode including frequency,wavenumber,propagation direction,and dependence on collisionality are identified,which are consistent with the characteristics of dissipative trapped electron mode.
基金financial support from the NSFC projects(U1805254,21773192,22072117,and 22179112)
文摘The high-voltage battery has now become a goal in order to meet the demands for high energy density.However,the severe side reactions between Li metal and carbonate-based electrolytes in this system result in unstable interphase,leading to non-uniform Li-ion flux and thus aggravating the dendrite growth of Li.The protect interphase,traditional solid electrolyte interface(SEI),is a loose solid layer consisted of many components,which generally does not possess the function of preventing the lithium budding.Herein,based on polysulfide solubility in ester,we proposed a strategy to eliminate the dendrite by constructing a unique SEI in which the dynamic polysulfides were in situ formed and encapsuled.For this purpose,a 2-fluorophenylsulfur pentafluoride(2-FSPF)was employed as an additive in carbonate-based electrolyte that can be decomposed electrochemically during battery operation to form such a polysulfide-rich interphase.These polysulfides with certain fluidity can adhere to dynamically the budding tip of Li metal,as a so-called tip-inhibitor,when the local current density of the tip rising,thus to hinder Li^(+)diffusion toward the tip,resulting in inhibiting the further growth of Li dendrites and leveling the Li deposition.At the current density of 1 mA cm^(-2),the average Coulombic efficiency of Li//Cu cells is as high as 98.39%during 600 cycles,and the stable cycling of Li//Li symmetric cell reaches 3500 h.Furthermore,due to the high anodic stability,the Li//high-voltage LiCoO_(2)(LCO)full cells and Li–O_(2)battery achieve excellent cycle performance with lean electrolyte.
基金supported by the National Magnetic Confinement Fusion Energy R&D Program of China (Nos. 2019YFE03030000 and 2022YFE03020004)National Natural Science Foundation of China (Nos. 12105187, 11905250 and 11975275)+1 种基金the China Postdoctoral Science Foundation (No. 2021M702245)the Users with Excellence Program of Hefei Science Center, CAS (No. 2021HSC-UE014)。
文摘A novel electromagnetic probe array(EMPA) diagnostic, which consists of a magnetic probe array and an electrostatic probe array, has recently been developed on EAST. The EMPA is fixed near the first wall at horizontal port P. The magnetic probe array of the EMPA consists of 24 identical magnetic probes, each of them capable of measuring toroidal, poloidal and radial magnetic fluctuations simultaneously, providing additional toroidal magnetic fluctuation measurements compared with the regular magnetic probes on EAST. With a higher sampling rate and self-resonant frequency, the EMPA magnetic probes can provide higher frequency magnetic fluctuation measurements. The magnetic probe array of the EMPA is composed of two parallel layers of magnetic probes with a radial distance of 63 mm, and each layer of magnetic probes is arranged in four poloidal rows and three toroidal columns. The compact arrangement of the EMPA magnetic probe array largely improves the toroidal mode number measurement ability from-8≤ n≤ 8 to-112≤ n≤ 112, and also improves the high poloidal wave number measurement ability of magnetic fluctuations compared with the regular high frequency magnetic probes on EAST. The electrostatic probe array of the EMPA consists of two sets of four-tip probes and a single-tip probe array with three poloidal rows and four toroidal columns. It complements the electrostatic parameter measurements behind the main limiter and near the first wall in EAST. The engineering details of the EMPA diagnostic, including the mechanical system, the electrical system, the acquisition and control system, and the effective area calibration, are presented. The preliminary applications of the EMPA in L-mode and H-mode discharges on EAST have demonstrated that the EMPA works well for providing information on the magnetic and electrostatic fluctuations and can contribute to deeper physical analysis in future EAST experiments.
基金the financial support from the National Natural Science Foundation of China(U1805254,21773192,22072117,22179112)。
文摘Lithium-oxygen(Li-O) battery is considered as one of the most promising alternatives because of its ultrahigh theoretical energy density. However, their cycling stability is severely restricted by the uncontrollable dendrite growth and serious oxygen corrosion issue on Li surface. Herein, a sulfur-modified Li surface can be successfully constructed via chemical reaction of guanylthiourea(GTU) molecule on Li,which can induce the selectively fast decomposition of lithium bis(trifluoromethanesulfonyl)imide(LiTFSI) to form a smooth and stable inorganics-rich solid-electrolyte interphase(IR-SEI) during the subsequent electrochemical process. Such an IR-SEI cannot only offer a highly reversible and stable Li plating/stripping chemistry with dendrite-free property(10 mA cm^(-2)-10 mAh cm^(-2), > 0.5 years;3 mA cm^(-2)-3 m Ah cm^(-2), > 1 year) but also endows the Li metal an anti-oxygen corrosion function, thereby significantly improving the cycling stability of Li-Obatteries. This work provides a new idea for constructing functional solid-electrolyte interphase(SEI) to achieve highly stable Li metal anode.
基金supported by the National Key R&D Program of China(Nos.2017YFE0301301 and 2017YFE0302000)National Natural Science Foundation of China(Nos.11805135 and 11805131)the Ministry of Science and Technology(No.2015GB103001).
文摘The effect of externally applied resonant magnetic perturbation(RMP)on carbon impurity behavior is investigated in the J-TEXT tokamak.It is found that the m/n=3/1 islands have an impurity screening effect,which becomes obvious while the edge magnetic island is generated via RMP field penetration.The impurity screening effect shows a dependence on the RMP phase with the field penetration,which is strongest if the O point of the magnetic island is near the low-field-side(LFS)limiter plate.By combining a methane injection experimental study and STRAHL impurity transport analysis,we found that the variation of the impurity transport dominates the impurity screening effect.The impurity diffusion at the inner plasma region(r/a<0.8)is enhanced with a significant increase in outward convection velocity at the edge region in the case of the magnetic island’s O point near the LFS limiter plate.The impurity transport coefficient varies by a much lower level for the case with the magnetic island’s X point near the LFS limiter plate.The interaction of the magnetic island and the LFS limiter plate is thought to contribute to the impurity transport variation with the dependence on the RMP phase.A possible reason is the interaction between the magnetic island and the LFS limiter.
基金supported by the National Natural Science Foundation of China(No.52071018).
文摘In the harsh service environment of high temperature and intense neutron irradiation in water-cooled nuclear reactors,the austenitic stainless steel weld overlay cladding on the inner surface of the reactor pressure vessel suffers from thermal aging and irradiation damage simultaneously,which can induce microstructural evolution and hardening of the material.Since it is quite difficult to achieve this simul-taneous process out of the pile,two kinds of combined experiments,i.e.,post-irradiation thermal aging and post-aging irradiation were performed on 308 L stainless steel weld metals in this work.The interactive effect of thermal aging and proton irradiation on microstructural evolution and hardening ofδ-ferrite in 308 L weld metal was investigated by combining atom probe tomography,transmission elec-tron microscopy and nanoindentation tests.The results revealed that thermal aging could eliminate the dislocation loops induced by irradiation and affect the phase transition process by accelerating spinodal decomposition and G-phase precipitation,thus enhancing hardening of irradiatedδ-ferrite.For the effect of irradiation on the microstructure and hardening of thermally agedδ-ferrite,however,intensive collision cascades can intensify G-phase precipitation and dislocation loop formation but decrease spinodal decomposition,leading to a limited effect on hardening of thermally agedδ-ferrite.Furthermore,the interaction of thermal aging and irradiation can promote G-phase precipitation.Meanwhile,the interaction can causeδ-ferrite hardening,which is mainly influenced by spinodal decomposition,followed by G-phase and dislocation loops,where spinodal decomposition and G-phase cause hardening by inducing strain fields.
基金Supported by the National Natural Science Foundation of China (30370912)the Natural Science Foundation of Guangdong Province (04009773 and 2006B20101010).
文摘A manganese superoxide dismutase （Mn-SOD） gene, NnMSD1, was identified from embryonic axes of the sacred lotus （Nelumbo nucifera Gaertn.）. The NnMSD1 protein contains all conserved residues of the Mn-SOD protein family, including four consensus metal binding domains and a signal peptide for mitochondrial targeting. Southern blot analysis suggests the existence of two Mn.SOD genes in sacred lotus. NnMSD1 was highly expressed in developing embryonic axes during seed development, but appeared in cotyledons only at the early stage of development and became undetectable in the cotyledons during late embryogenesis. The expression of the NnMSD1 gene in germinating embryonic axes, in response to various stresses such as heat shock, chilling, and exposure to stress-related chemicals, was also studied. Heat shock strongly inhibited the expression of the NnMSD1 gene, whereas the NnMSD1 transcript level increased strongly in chilling stress treatment. An increase in expression was also highly induced by H2O2 in germinating embryonic axes. The results suggest that the expression pattern of the NnMSD1 gene differed between developing axes and cotyledons, and that the NnMSD1 gene expression responds strongly to chilling and oxidative stress.
基金Shenzhen Basic Research Project of Science and Technology(JCYJ2015032414171163,JCYJ20170302142433007)National Natural Science Foundation of China(NSFC)(11404092,11404219,11574130)
文摘Perovskite nanocrystals （NCs） have strong nonlinear optical responses with a number of potential applications, ranging from upconverted blue-lasing to the tagging of specific cellular components in multicolor fluorescence microscopy. Here, we determine the one-photon linear absorption cross section of two kinds of blue-emitting perovskite NCs, i.e., CsPbCl3 and CsPb（C10.53Br0.47）3, by utilizing femtosecond transient absorption spectroscopy. The wavelength-dependent nonlinear refraction and two-photon absorption have been measured at wavelengths from 620 to 720 nm by performing Z-scan measurements. The nonlinear optical responses of CsPb（C10.53Br0.47）3 are much more pronounced than those of CsPbCl3 due to the larger structural destahilization of the former.
基金Natural Science Foundation of Guangdong Province(2018A030310637,2019A1515012094)Department of Education of Guangdong Province(2018KTSCX19)。
文摘In this work,one kind of typeⅡZnSe/CdS/ZnS core/shell/shell nanocrystals(NCs)is synthesized,and their linear and nonlinear photophysical properties are investigated.Through measurements of the temperaturedependent photoluminescence spectra of NCs,their excitonic properties,including the coefficient of the bandgap change,coupling strength of the exciton acoustic phonons,exciton longitudinal optical(LO)phonons,and LO–phonon energy are revealed.Femtosecond transient absorption spectroscopy was employed to obtain insight into ultrafast processes occurring at the interface of ZnSe and CdS,such as those involving the injection of photoinduced electrons into the CdS shell,interfacial state bleaching,and charge separation time.At the end,their multiphoton absorption spectra were determined by using the z-scan technique,which yielded a maximum twophoton absorption cross section of 3717 GM at 820 nm and three-photon absorption cross section up to 3.9×10^-77cm^6·s^2·photon^-2at 1220 nm,respectively.The photophysical properties presented here may be important for exploiting their relevant applications in optoelectronic devices and deep-tissue bioimaging.
基金supported by the National Natural Science Foundation of China(Nos.51635008 and 51575263)the Fok Ying Tung Education Foundation of China(No.161048)+1 种基金the Program for Distinguished Talents of Six Domains in Jiangsu Province of China(No.GDZB-035)the Priority Academic Program Development of Jiangsu Higher Education Institutions of China
文摘Lamb Wave(LW) simulation under time-varying conditions is an effective and low cost way to study the problem of the low reliability of the structural health monitoring methods based on the LW and Piezoelectric Transducer(PT). In this paper, a multiphysics simulation method of the LW propagation with the PTs under load condition is proposed. With this method, two key mechanisms of the load influence on the LW propagation are considered and coupled with each other. The first mechanism is the acoustoelastic effect which is the main reason of the LW velocity change. The second key mechanism is the load influence on piezoelectric materials, which results in a change of the amplitude. Based on the computational platform of the COMSOL Multiphysics, a multiphysics simulation model of the LW propagation with the PTs under load condition is established. The simulation model includes two physical phenomena. The first one is called solid mechanics, which is used to simulate the acoustoelastic effect being combined with the hyperelastic material properties of the structure in which the LW propagates. The second one is called electromechanical coupling, which considers the simulation of the piezoelectric effect of the PTs for the LW excitation and sensing. To simulate the load influence on piezoelectric materials, a non-linear numerical model of the relationship between the load and the piezoelectric coefficient d31 is established based on an experiment of the load influence on the LW. The simulation results under uniaxial tensile load condition are obtained and are compared with the data obtained from the experiment. It shows that the variations of the phase velocity and amplitude of the LW obtained from the simulation model match the experimental results well.
基金financially supported by the Jiangsu Natural Science Foundation (No. BK20191178)the National Natural Science Foundation of China (No. 52071018)the China Postdoctoral Science Foundation (No. 2021M692018)。
文摘The proton-irradiated 308L stainless steel weld metal was strained by using constant extension rate tensile testing in simulated PWR primary water, and its deformation microstructures and irradiation assisted stress corrosion cracking(IASCC) behavior were investigated. The results suggest that the irradiation significantly increases the SCC susceptibility of 308L weld metal and causes various deformation microstructures including lathy faulted planes, dislocation channels and deformation twins in austenite and atomic plane rotation in δ-ferrite. The propagation of intergranular IASCC cracks is closely related to the location of the crack tip. For the crack tip in the specimen matrix interior, localized deformation is likely the key factor responsible for the crack growth. For the crack tip close to the specimen surface, however, localized corrosion along the grain boundary rather than the localized deformation appears to dominate the crack propagation. Unlike the intergranular cracks, the IASCC cracks along the δ-ferrite/austenite phase boundary can initiate either by crack initiation at the phase boundary or by crack propagation from the grain boundary. In both cases, the cracked phase boundaries contain a large number of carbides and are severely corroded, but no deformation microstructures are observed, which implies that the localized corrosion may play an important role in the IASCC along the phase boundary. In addition, δ-ferrite can retard the IASCC crack propagation along the grain boundary, which is probably related to the reduction of localized deformation by δ-ferrite.
基金The associate editor coordinating the review of this paper and approving it for publication was X.Cheng。
文摘As a widely-used machine-learning classifier,a decision tree model can be trained and deployed at a service provider to provide classification services for clients,e.g.,remote diagnostics.To address privacy concerns regarding the sensitive information in these services(i.e.,the clients’inputs,model parameters,and classification results),we propose a privacy-preserving decision tree classification scheme(PDTC)in this paper.Specifically,we first tailor an additively homomorphic encryption primitive and a secret sharing technique to design a new secure two-party comparison protocol,where the numeric inputs of each party can be privately compared as a whole instead of doing that in a bit-by-bit manner.Then,based on the comparison protocol,we exploit the structure of the decision tree to construct PDTC,where the input of a client and the model parameters of a service provider are concealed from the counterparty and the classification result is only revealed to the client.A formal simulation-based security model and the security proof demonstrate that PDTC achieves desirable security properties.In addition,performance evaluation shows that PDTC achieves a lower communication and computation overhead compared with existing schemes.
基金financially supported by the National Natural Science Foundation of China(No.52071018)the Gusu Innovation Leader Talents Program(ZXL2017112)。
文摘The corrosion of unaged and 7000-h thermally aged 308 L stainless steel weld metals in simulated PWR primary water under aerated and deaerated conditions was investigated,involving the corrosion of austenite,δ-ferrite andδ-ferrite/austenite phase boundary.The results revealed that thermal ageing for 7000 h had a limited effect on the corrosion behavior of 308 L weld metal as it only increased the inner oxide thickness ofδ-ferrite slightly under the deaerated condition.No obvious corrosion enhancement of 308 L weld metal under the aerated condition was found compared to the deaerated condition regardless of the thermal ageing.Nevertheless,Cr-enrichment on the surface of oxide particles,dissolved regions at the metal/oxide interface and localized corrosion along theδ-ferrite/austenite phase boundary occurred under the aerated condition.
文摘Lithium metal anodes have received tremendous attention in recent years and are considered as the most promising anode material for the next-generation high-energy-density batteries[1].However,the commercial adoption of such anodes is severely hindered by poor electrochemical reversibility and insufficient cycle-life[2].
基金Shenzhen Basic Research Project of Science and Technology(JCYJ20150324141711581,JCYJ20170302142433007)Postgraduate Innovation Development Fund Project of Shenzhen University(PIDFPZR2018007)
文摘We have studied the two-and three-photon absorption(2PA and 3PA) properties of Mn-doped CsPbCl_3 twodimensional nanoplatelets(2D NPs) and cubic nanocrystals. Compared with their cubic counterparts, the Mn-doped 2D NPs exhibit stronger quantum confinement effects that can more efficiently enhance their dopantcarrier exchange interactions and multiphoton absorption. More specifically, the maximum volume-normalized 2PA and 3PA cross sections of the 2D NPs were 6.8 and 7.2 times greater than those of their cubic counterparts,respectively, reaching up to 1237 GM∕nm^3 in the visible light band and 2.24 × 10^(-78) cm^6· s^2· photon^(-2)∕nm^3 in the second biological window, respectively.
基金The authors received financial support from the Yunnan Provincial Department of Education(2019J0780).
文摘The major cause of pediatric anterior urethral injuries(AUIs)is blunt trauma.12 Penetrating injuries caused by explosive trauma are rare in pediatric patients.Both early and delayed urethral repairs are optional strategies to manage AUIs.Studies from clinical manage-ment of blunt trauma have concluded rich experiences.However,poor experiences can be used to manage explosive AUIs.In this case,a 7-year old boy threw a detonator into the fire.His external genitalia and bilateral medial region of the thigh were injured in a sudden explosion.Corpus spongiosum penis was covered by incomplete prepuce.Splintered glans penis with high-degree edema concealed the urethral meatus.The swollen testis was detected in the tattered scrotum.Muscular layer was included in explosive inju-ries of the bilateral thigh(figure 1).Surgical debridement was performed urgently.
文摘Professor Xiaodong Lin believes the ability to tackle struggles is similar to the human body's immune system,which is a natural defense that can be activated when the body is infected or damaged.Thus,Lin aims to build a similar,psychological mechanism to enhance children's ability to deal with problems in life.
