The problem of cavity stability widely exists in deep underground engineering and energy exploitation.First,the stress field of the surrounding rock under the uniform stress field is deduced based on a post-peak stren...The problem of cavity stability widely exists in deep underground engineering and energy exploitation.First,the stress field of the surrounding rock under the uniform stress field is deduced based on a post-peak strength drop model considering the rock’s characteristics of constant modulus and double moduli.Then,the orthogonal non-associative flow rule is used to establish the displacement of the surrounding rock under constant modulus and double moduli,respectively,considering the stiffness degradation and dilatancy effects in the plastic region and assuming that the elastic strain in the plastic region satisfies the elastic constitutive relationship.Finally,the evolution of the displacement in the surrounding rock is analyzed under the effects of the double modulus characteristics,the strength drop,the stiffness degradation,and the dilatancy.The results show that the displacement solutions of the surrounding rock under constant modulus and double moduli have a unified expression.The coefficients of the expression are related to the stress field of the original rock,the elastic constant of the surrounding rock,the strength parameters,and the dilatancy angle.The strength drop,the stiffness degradation,and the dilatancy effects all have effects on the displacement.The effects can be characterized by quantitative relationships.展开更多
Sulfamethoxazole(SMX)is a significant environmental concern due to its adverse effects and ecological risks.SMX elimination in aquatic environments via photocatalysis presents a viable solution,given its high oxidatio...Sulfamethoxazole(SMX)is a significant environmental concern due to its adverse effects and ecological risks.SMX elimination in aquatic environments via photocatalysis presents a viable solution,given its high oxidation potential.However,such a solution remains controversial,primarily due to a lack of selectivity.Here we introduce a molecularly imprinted TiO2@Fe_(2)O_(3)@g-C_(3)N_(4)(MFTC)photocatalyst designed for the selective degradation of SMX.To assess MFTC's selectivity,we applied it to degrade synthetic wastewater containing SMX alongside interfering species sulfadiazine(SDZ),ibuprofen(IBU),and bisphenol A(BPA).The results demonstrated a selective degradation efficiency rate of 96.8%,nearly twice that of competing pollutants.The molecularly imprinted sites within the catalyst played a crucial role by selectively capturing SMX and enhancing its adsorption,thereby improving catalytic efficiency.The degradation process involvedOH and·O_(2)^(-)free radicals,with a newly proposed double Z-scheme mechanism and potential pathway for SMX degradation by the MFTC photocatalytic system.This study enriches the application of photocatalysis using molecularly imprinted nanocomposite materials for treating complex pollutant mixtures in water.展开更多
ZnO/NiO/ZnAl2O4 mixed-metal oxides were successfully synthesized through a hydrotalcite-like precursor route, in which appropriate amounts of metal salts solutions were mixed to obtain a new series of ZnNiAl layered d...ZnO/NiO/ZnAl2O4 mixed-metal oxides were successfully synthesized through a hydrotalcite-like precursor route, in which appropriate amounts of metal salts solutions were mixed to obtain a new series of ZnNiAl layered double hydroxides（LDHs） as precursors, followed by calcination under different temperatures. The as-obtained samples were characterized by SEM, HRTEM, TEM, XRD, BET, TG-DTA, and UV-Vis spectra techniques. The photocatalytic activities of the samples were evaluated by degradation of methyl orange（MO） under the simulated sunlight irradiation. The effects of Zn/Ni/Al mole ratio and calcination temperature on the composition, morphology and photocatalytic activity of the samples were investigated in detail. The results indicated that compared with ZnNiAl-LDHs, the mixed-metal oxide showed superior photocatalytic performance for the degradation of MO. A maximum of 97.3% photocatalytic decoloration rate within 60 min was achieved from the LDH with the Zn/Ni/Al mole ratio of 2：1：1 and the calcination temperature of 500 ℃, which much exceeded that of Degussa P25 under the same conditions. The possible mechanism of photocatalytic degradation over ZnO/NiO/ZnAl2O4 was discussed.展开更多
In order to minimize the hot-carrier effect（HCE）and maintain on-state performance in the high voltage N-type lateral double diffused MOS（N-LDMOS）, an optimized device structure with step gate oxide is proposed. Co...In order to minimize the hot-carrier effect（HCE）and maintain on-state performance in the high voltage N-type lateral double diffused MOS（N-LDMOS）, an optimized device structure with step gate oxide is proposed. Compared with the conventional configuration, the electric field under the gate along the Si-SiO2 interface in the presented N-LDMOS can be greatly reduced, which favors reducing the hot-carrier degradation. The step gate oxide can be achieved by double gate oxide growth, which is commonly used in some smart power ICs. The differences in hot-carrier degradations between the novel structure and the conventional structure are investigated and analyzed by 2D technology computer-aided design（TCAD）numerical simulations, and the optimal length of the thick gate oxide part in the novel N-LDMOS device can also be acquired on the basis of maintaining the characteristic parameters of the conventional device. Finally, the practical degradation measurements of some characteristic parameters can also be carried out. It is found that the hot-carrier degradation of the novel N-LDMOS device can be improved greatly.展开更多
Residual enrofloxacin(ENR)exposed in aqueous environments is challenging to the ecosphere.In this work,a layered double hydroxide CoAl-LDH was used to activate the common oxidizing agent persulfate(PS)for photodegrada...Residual enrofloxacin(ENR)exposed in aqueous environments is challenging to the ecosphere.In this work,a layered double hydroxide CoAl-LDH was used to activate the common oxidizing agent persulfate(PS)for photodegradation of ENR,and the degradation pathways of ENR were scrutinized and elucidated.The results indicated that,under the optimal conditions obtained through orthogonal experiments,even though the degradation rate of ENR was as high as 97.72%,the removal of total organic carbon(TOC)from the system was only about 30%.Eleven probable reaction pathways were categorized,and thirty-one types of intermediates were identified in participating in the complex degradation process.The major products of ENR were P4(C_(17)H_(20)FN_(3)O_(3)),P22(C_(19)H_(22)FN_(3)O_(4)),P19(C_(17)H_(18)FN_(3)O_(3)),which are mainly derived from the cleavage of the piperazine groups and quinolone rings.Density functional theory(DFT)calculations of the Fukui index for ENR revealed that the two N atoms in the piperazine ring were the core reactive sites in triggering the degradation chains,which were sensitive for electrophilic attack by the dominant radicals(·OH and SO_(4)·^(-))generated from the composite PS-UV-CoAl-LDH system.展开更多
A new restoration algorithm based on double loops and alternant iterations is proposed to restore the object image effectively from a few frames of turbulence-degraded images, Based on the double loops, the iterative ...A new restoration algorithm based on double loops and alternant iterations is proposed to restore the object image effectively from a few frames of turbulence-degraded images, Based on the double loops, the iterative relations for estimating the turbulent point spread function PSF and object image alternately are derived. The restoration experiments have been made on computers, showing that the proposed algorithm can obtain the optimal estimations of the object and the point spread function, with the feasibility and practicality of the proposed algorithm being convincing.展开更多
目的挖掘呕吐毒素(deoxynivalenol,DON)降解酶,应用双酶体系实现呕吐毒素的高效降解。方法利用生物信息学技术从国家生物技术信息中心(National Center for Biotechnology Information,NCBI)数据库筛选潜在DON降解酶AKR18A2,在大肠杆菌E...目的挖掘呕吐毒素(deoxynivalenol,DON)降解酶,应用双酶体系实现呕吐毒素的高效降解。方法利用生物信息学技术从国家生物技术信息中心(National Center for Biotechnology Information,NCBI)数据库筛选潜在DON降解酶AKR18A2,在大肠杆菌EscherichiacoliBL21(DE3)中进行重组和异丙基-β-D-硫代半乳糖苷(isopropylβ-D-thiogalactoside,IPTG)诱导表达,经镍亲和层析纯化并鉴定AKR18A2的酶学性质,构建德沃斯氏菌(Devosiasp.)来源的DON降解酶QDDH和AKR18A2双酶作用体系,实现DON的高效降解。结果来自鞘氨醇单胞菌属(Sphingomonas sp.)的呕吐毒素降解酶(AKR18A2)由343个氨基酸组成。该酶属于醛酮还原酶超家族,45℃和pH7.0为最适反应条件。AKR18A2可在24h内降解15.42%DON,而双酶(QDDH和AKR18A2)协同作用4h后对DON的降解率可提高至98.02%。结论本研究鉴定了一种新型DON降解酶AKR18A2,并首次创新建立双酶联用体系进一步实现DON的高效降解。展开更多
基金Project supported by the National Natural Science Foundation of China and Shandong Province Joint Program(No.U1806209)the National Natural Science Foundation of China(Nos.51774196 and 51774194)and Shandong University of Science and Technology(SDUST)Research Fund(No.2019TDJH101)。
文摘The problem of cavity stability widely exists in deep underground engineering and energy exploitation.First,the stress field of the surrounding rock under the uniform stress field is deduced based on a post-peak strength drop model considering the rock’s characteristics of constant modulus and double moduli.Then,the orthogonal non-associative flow rule is used to establish the displacement of the surrounding rock under constant modulus and double moduli,respectively,considering the stiffness degradation and dilatancy effects in the plastic region and assuming that the elastic strain in the plastic region satisfies the elastic constitutive relationship.Finally,the evolution of the displacement in the surrounding rock is analyzed under the effects of the double modulus characteristics,the strength drop,the stiffness degradation,and the dilatancy.The results show that the displacement solutions of the surrounding rock under constant modulus and double moduli have a unified expression.The coefficients of the expression are related to the stress field of the original rock,the elastic constant of the surrounding rock,the strength parameters,and the dilatancy angle.The strength drop,the stiffness degradation,and the dilatancy effects all have effects on the displacement.The effects can be characterized by quantitative relationships.
文摘Sulfamethoxazole(SMX)is a significant environmental concern due to its adverse effects and ecological risks.SMX elimination in aquatic environments via photocatalysis presents a viable solution,given its high oxidation potential.However,such a solution remains controversial,primarily due to a lack of selectivity.Here we introduce a molecularly imprinted TiO2@Fe_(2)O_(3)@g-C_(3)N_(4)(MFTC)photocatalyst designed for the selective degradation of SMX.To assess MFTC's selectivity,we applied it to degrade synthetic wastewater containing SMX alongside interfering species sulfadiazine(SDZ),ibuprofen(IBU),and bisphenol A(BPA).The results demonstrated a selective degradation efficiency rate of 96.8%,nearly twice that of competing pollutants.The molecularly imprinted sites within the catalyst played a crucial role by selectively capturing SMX and enhancing its adsorption,thereby improving catalytic efficiency.The degradation process involvedOH and·O_(2)^(-)free radicals,with a newly proposed double Z-scheme mechanism and potential pathway for SMX degradation by the MFTC photocatalytic system.This study enriches the application of photocatalysis using molecularly imprinted nanocomposite materials for treating complex pollutant mixtures in water.
基金Project(21306041)supported by the National Natural Science Young Foundation of ChinaProject(21271071)supported by the National Natural Science Foundation of ChinaProject(15A076)supported by the Scientific Research Foundation of Hunan Provincial Education Department of China
文摘ZnO/NiO/ZnAl2O4 mixed-metal oxides were successfully synthesized through a hydrotalcite-like precursor route, in which appropriate amounts of metal salts solutions were mixed to obtain a new series of ZnNiAl layered double hydroxides（LDHs） as precursors, followed by calcination under different temperatures. The as-obtained samples were characterized by SEM, HRTEM, TEM, XRD, BET, TG-DTA, and UV-Vis spectra techniques. The photocatalytic activities of the samples were evaluated by degradation of methyl orange（MO） under the simulated sunlight irradiation. The effects of Zn/Ni/Al mole ratio and calcination temperature on the composition, morphology and photocatalytic activity of the samples were investigated in detail. The results indicated that compared with ZnNiAl-LDHs, the mixed-metal oxide showed superior photocatalytic performance for the degradation of MO. A maximum of 97.3% photocatalytic decoloration rate within 60 min was achieved from the LDH with the Zn/Ni/Al mole ratio of 2：1：1 and the calcination temperature of 500 ℃, which much exceeded that of Degussa P25 under the same conditions. The possible mechanism of photocatalytic degradation over ZnO/NiO/ZnAl2O4 was discussed.
基金The Natural Science Foundation of Jiangsu Province(No.BK2008287)the Preresearch Project of the National Natural Science Foundation of Southeast University(No.XJ2008312)
文摘In order to minimize the hot-carrier effect（HCE）and maintain on-state performance in the high voltage N-type lateral double diffused MOS（N-LDMOS）, an optimized device structure with step gate oxide is proposed. Compared with the conventional configuration, the electric field under the gate along the Si-SiO2 interface in the presented N-LDMOS can be greatly reduced, which favors reducing the hot-carrier degradation. The step gate oxide can be achieved by double gate oxide growth, which is commonly used in some smart power ICs. The differences in hot-carrier degradations between the novel structure and the conventional structure are investigated and analyzed by 2D technology computer-aided design（TCAD）numerical simulations, and the optimal length of the thick gate oxide part in the novel N-LDMOS device can also be acquired on the basis of maintaining the characteristic parameters of the conventional device. Finally, the practical degradation measurements of some characteristic parameters can also be carried out. It is found that the hot-carrier degradation of the novel N-LDMOS device can be improved greatly.
基金support from the National Key Research and Development Program of China(2022YFE0104900)Foshan Shunde District Core Technology Breakthrough Project(2230218004273)+1 种基金2022 Zhuhai Social Development Science and Technology Program Project(2220004000355)Guangdong Basic and Applied Basic Research Foundation(2023B1515040028).
文摘Residual enrofloxacin(ENR)exposed in aqueous environments is challenging to the ecosphere.In this work,a layered double hydroxide CoAl-LDH was used to activate the common oxidizing agent persulfate(PS)for photodegradation of ENR,and the degradation pathways of ENR were scrutinized and elucidated.The results indicated that,under the optimal conditions obtained through orthogonal experiments,even though the degradation rate of ENR was as high as 97.72%,the removal of total organic carbon(TOC)from the system was only about 30%.Eleven probable reaction pathways were categorized,and thirty-one types of intermediates were identified in participating in the complex degradation process.The major products of ENR were P4(C_(17)H_(20)FN_(3)O_(3)),P22(C_(19)H_(22)FN_(3)O_(4)),P19(C_(17)H_(18)FN_(3)O_(3)),which are mainly derived from the cleavage of the piperazine groups and quinolone rings.Density functional theory(DFT)calculations of the Fukui index for ENR revealed that the two N atoms in the piperazine ring were the core reactive sites in triggering the degradation chains,which were sensitive for electrophilic attack by the dominant radicals(·OH and SO_(4)·^(-))generated from the composite PS-UV-CoAl-LDH system.
文摘A new restoration algorithm based on double loops and alternant iterations is proposed to restore the object image effectively from a few frames of turbulence-degraded images, Based on the double loops, the iterative relations for estimating the turbulent point spread function PSF and object image alternately are derived. The restoration experiments have been made on computers, showing that the proposed algorithm can obtain the optimal estimations of the object and the point spread function, with the feasibility and practicality of the proposed algorithm being convincing.
文摘目的挖掘呕吐毒素(deoxynivalenol,DON)降解酶,应用双酶体系实现呕吐毒素的高效降解。方法利用生物信息学技术从国家生物技术信息中心(National Center for Biotechnology Information,NCBI)数据库筛选潜在DON降解酶AKR18A2,在大肠杆菌EscherichiacoliBL21(DE3)中进行重组和异丙基-β-D-硫代半乳糖苷(isopropylβ-D-thiogalactoside,IPTG)诱导表达,经镍亲和层析纯化并鉴定AKR18A2的酶学性质,构建德沃斯氏菌(Devosiasp.)来源的DON降解酶QDDH和AKR18A2双酶作用体系,实现DON的高效降解。结果来自鞘氨醇单胞菌属(Sphingomonas sp.)的呕吐毒素降解酶(AKR18A2)由343个氨基酸组成。该酶属于醛酮还原酶超家族,45℃和pH7.0为最适反应条件。AKR18A2可在24h内降解15.42%DON,而双酶(QDDH和AKR18A2)协同作用4h后对DON的降解率可提高至98.02%。结论本研究鉴定了一种新型DON降解酶AKR18A2,并首次创新建立双酶联用体系进一步实现DON的高效降解。
