In this paper,we consider the maximal positive definite solution of the nonlinear matrix equation.By using the idea of Algorithm 2.1 in ZHANG(2013),a new inversion-free method with a stepsize parameter is proposed to ...In this paper,we consider the maximal positive definite solution of the nonlinear matrix equation.By using the idea of Algorithm 2.1 in ZHANG(2013),a new inversion-free method with a stepsize parameter is proposed to obtain the maximal positive definite solution of nonlinear matrix equation X+A^(*)X|^(-α)A=Q with the case 0<α≤1.Based on this method,a new iterative algorithm is developed,and its convergence proof is given.Finally,two numerical examples are provided to show the effectiveness of the proposed method.展开更多
糖基化在植物天然产物的结构多样化中起着重要作用,鉴定高效的糖基转移酶是合成糖苷产物的关键步骤。该研究从短管兔耳草中克隆得到一条新的糖基转移酶基因UGT74DU1,借助伴侣蛋白质粒pGro7在大肠杆菌中实现可溶性高表达,并通过体外酶促...糖基化在植物天然产物的结构多样化中起着重要作用,鉴定高效的糖基转移酶是合成糖苷产物的关键步骤。该研究从短管兔耳草中克隆得到一条新的糖基转移酶基因UGT74DU1,借助伴侣蛋白质粒pGro7在大肠杆菌中实现可溶性高表达,并通过体外酶促反应验证了其功能。UGT74DU1全长1413 bp,编码470个氨基酸,蛋白质分子质量约为52.6 kDa,理论等电点为5.53。氨基酸序列比对及系统发育分析显示,UGT74DU1与CrUGT74AN3亲缘关系最近,序列相似度仅46.86%。通过LC-MS分析及核磁共振(nuclear magnetic resonance,NMR)结构鉴定发现UGT74DU1可以优先识别槲皮素、山奈酚、芦丁、异槲皮苷等黄酮类化合物C-7-OH,反应生成黄酮-7-O-葡萄糖苷,进一步识别C-4′-OH生成黄酮-4′,7-O-双葡萄糖苷;同时也可以催化苯乙醇苷类化合物毛蕊花糖苷羟基肉桂酰基的C-3″-OH糖基化,生成毛蕊花糖苷-3″-O-β-葡萄糖苷,具有一定的底物宽泛性。展开更多
A semiclassical particle moving near the horizon of a Schwarzschild black hole is chaotic,and its Lyapunov exponent saturates the chaos bound proposed by Maldacena,Shenker,and Stanford,with the temperature being the H...A semiclassical particle moving near the horizon of a Schwarzschild black hole is chaotic,and its Lyapunov exponent saturates the chaos bound proposed by Maldacena,Shenker,and Stanford,with the temperature being the Hawking temperature.Motivated by this,we consider the Lyapunov exponents of scalar and spinor fields in Schwarzschild spacetime by calculating their out-of-time-ordered commutators along the radial direction.Numerically,we find that the Lyapunov exponent of the scalar field is smaller than that of the spinor field.They are mainly contributed by the bound states near the horizon and lie below the chaos bound.展开更多
This paper investigates the in uence of local SS-quasinormal maximal subgroups of Sylow subgroups on the structure of nite groups.We present several new criteria on p-nilpotency of nite groups by utilizing a small qua...This paper investigates the in uence of local SS-quasinormal maximal subgroups of Sylow subgroups on the structure of nite groups.We present several new criteria on p-nilpotency of nite groups by utilizing a small quantity of local SS-quasinormal maximal subgroups of Sylow p-subgroups.As applications,we obtain some sucient conditions for a nite group to be in a saturated formation containing the class of supersolvable groups.展开更多
Let G be a finite group and H a subgroup of G.The normal index of H in G is defined as the order of K/H_(G),where K is a normal supplement of H in G such that|K|is minimal and H_(G)≤K■G.Let p be a prime which divide...Let G be a finite group and H a subgroup of G.The normal index of H in G is defined as the order of K/H_(G),where K is a normal supplement of H in G such that|K|is minimal and H_(G)≤K■G.Let p be a prime which divides the order of a group G.In this paper,some characterizations of G being p-solvable or p-supersolvable were obtained by analyzing the normal index of certain subgroups of G.These results can be viewed as local version of recent results in the literature.展开更多
Human activities have significantly impacted the land surface temperature(LST),endangering human health;however,the relationship between these two factors has not been adequately quantified.This study comprehensively ...Human activities have significantly impacted the land surface temperature(LST),endangering human health;however,the relationship between these two factors has not been adequately quantified.This study comprehensively constructs a Human Activity Intensity(HAI)index and employs the Maximal Information Coefficient,four-quadrant model,and XGBoostSHAP model to investigate the spatiotemporal relationship and influencing factors of HAI-LST in the Yellow River Basin(YRB)from 2000 to 2020.The results indicated that from 2000 to 2020,as HAI and LST increased,the static HAI-LST relationship in the YRB showed a positive correlation that continued to strengthen.This dynamic relationship exhibited conflicting development,with the proportion of coordinated to conflicting regions shifting from 1:4 to 1:2,indicating a reduction in conflict intensity.Notably,only the degree of conflict in the source area decreased significantly,whereas it intensified in the upper and lower reaches.The key factors influencing the HAI-LST relationship include fractional vegetation cover,slope,precipitation,and evapotranspiration,along with region-specific factors such as PM_(2.5),biodiversity,and elevation.Based on these findings,region-specific ecological management strategies have been proposed to mitigate conflict-prone areas and alleviate thermal stress,thereby providing important guidance for promoting harmonious development between humans and nature.展开更多
This paper presents new estimations for all parameters(amplitude,frequency,quality factor,and initial phase)of the_(0)S_(0)Earth fundamental mode,which was triggered by the 2004 Sumatra-Andaman earthquake with a magni...This paper presents new estimations for all parameters(amplitude,frequency,quality factor,and initial phase)of the_(0)S_(0)Earth fundamental mode,which was triggered by the 2004 Sumatra-Andaman earthquake with a magnitude of Mw9.1.Sixteen records from the IGETS superconducting gravimeters have been analyzed.Using the maximum likelihood method algorithm,frequency,initial phase,and amplitude estimates have been acquired with remarkable accuracy.The values of frequency(814.6568±0.0002μHz)and quality factor(5455±17)obtained in this study differ slightly from those of the PREM model,and the amplitude variations qualitatively correspond to those of the SKS12WM13model.The estimated time delay between the onset of the earthquake and the excitation of the mode(290 s)is consistent with the moment tensor analysis from the USGS National Earthquake Information Center.展开更多
目的现有数据浓缩后门攻击方法将含有触发器的中毒样本和干净样本浓缩为小的数据集,中毒数据中真实数据的强信号掩盖触发器的弱信号,并且未考虑将非目标类浓缩数据与中毒数据特征分离,非目标类浓缩数据残留触发器特征。因此,提出分离触...目的现有数据浓缩后门攻击方法将含有触发器的中毒样本和干净样本浓缩为小的数据集,中毒数据中真实数据的强信号掩盖触发器的弱信号,并且未考虑将非目标类浓缩数据与中毒数据特征分离,非目标类浓缩数据残留触发器特征。因此,提出分离触发器和多重对比的数据浓缩后门攻击。方法首先将触发器与真实数据进行分离。分离的触发器作为样本与真实数据并行嵌入浓缩数据,减少真实数据对触发器的干扰。然后,对分离的触发器进行优化,将触发器接近目标类真实数据的特征,提高触发器的嵌入效果,同时对触发器进行了分区放大预处理来增加触发器像素的数量,使其在优化过程获取大量的梯度用于指导学习。在数据浓缩阶段,通过多重对比将目标类浓缩数据与触发器特征投影在同一空间,将非目标类浓缩数据与触发器特征分离,进一步提高后门攻击的成功率。结果为了验证所提出方法的有效性,将所提出方法在FashionMNIST(Fashion Modified National Institute of Standards and Technology database)、CIFAR10(Canadian Institute for Advances Research’s ten categories dataset)、STL10(Stanford letter-10)、SVHN(street view house numbers)与其他4种方法进行对比实验。所提出的方法在5个数据集和6个不同的模型上均达到100%的攻击成功率,同时未降低干净样本在模型上的准确率。结论所提出的方法通过解决现有方法存在的问题,实现了性能的显著提高。本文方法具体代码见:https://github.com/tfuy/STMC。展开更多
基金Supported in part by Natural Science Foundation of Guangxi(2023GXNSFAA026246)in part by the Central Government's Guide to Local Science and Technology Development Fund(GuikeZY23055044)in part by the National Natural Science Foundation of China(62363003)。
文摘In this paper,we consider the maximal positive definite solution of the nonlinear matrix equation.By using the idea of Algorithm 2.1 in ZHANG(2013),a new inversion-free method with a stepsize parameter is proposed to obtain the maximal positive definite solution of nonlinear matrix equation X+A^(*)X|^(-α)A=Q with the case 0<α≤1.Based on this method,a new iterative algorithm is developed,and its convergence proof is given.Finally,two numerical examples are provided to show the effectiveness of the proposed method.
文摘糖基化在植物天然产物的结构多样化中起着重要作用,鉴定高效的糖基转移酶是合成糖苷产物的关键步骤。该研究从短管兔耳草中克隆得到一条新的糖基转移酶基因UGT74DU1,借助伴侣蛋白质粒pGro7在大肠杆菌中实现可溶性高表达,并通过体外酶促反应验证了其功能。UGT74DU1全长1413 bp,编码470个氨基酸,蛋白质分子质量约为52.6 kDa,理论等电点为5.53。氨基酸序列比对及系统发育分析显示,UGT74DU1与CrUGT74AN3亲缘关系最近,序列相似度仅46.86%。通过LC-MS分析及核磁共振(nuclear magnetic resonance,NMR)结构鉴定发现UGT74DU1可以优先识别槲皮素、山奈酚、芦丁、异槲皮苷等黄酮类化合物C-7-OH,反应生成黄酮-7-O-葡萄糖苷,进一步识别C-4′-OH生成黄酮-4′,7-O-双葡萄糖苷;同时也可以催化苯乙醇苷类化合物毛蕊花糖苷羟基肉桂酰基的C-3″-OH糖基化,生成毛蕊花糖苷-3″-O-β-葡萄糖苷,具有一定的底物宽泛性。
基金supported by the National Natural Science Foundation of China with Grants No.12174067 and No.11804223。
文摘A semiclassical particle moving near the horizon of a Schwarzschild black hole is chaotic,and its Lyapunov exponent saturates the chaos bound proposed by Maldacena,Shenker,and Stanford,with the temperature being the Hawking temperature.Motivated by this,we consider the Lyapunov exponents of scalar and spinor fields in Schwarzschild spacetime by calculating their out-of-time-ordered commutators along the radial direction.Numerically,we find that the Lyapunov exponent of the scalar field is smaller than that of the spinor field.They are mainly contributed by the bound states near the horizon and lie below the chaos bound.
基金Supported by NSF of China(12061011)NSF of Guangxi(2023GXN-SFAA026333)。
文摘This paper investigates the in uence of local SS-quasinormal maximal subgroups of Sylow subgroups on the structure of nite groups.We present several new criteria on p-nilpotency of nite groups by utilizing a small quantity of local SS-quasinormal maximal subgroups of Sylow p-subgroups.As applications,we obtain some sucient conditions for a nite group to be in a saturated formation containing the class of supersolvable groups.
基金Supported by the National Natural Science Foundation of China(Grant No.12071092)Guangdong Basic and Applied Basic Research Foundation(Grant No.2025A1515012072)+1 种基金the Natural Science Research Project of Anhui Educational Committee(Grant No.2024AH051298)the Scientific Research Foundation of Bozhou University(Grant No.BYKQ202419).
文摘Let G be a finite group and H a subgroup of G.The normal index of H in G is defined as the order of K/H_(G),where K is a normal supplement of H in G such that|K|is minimal and H_(G)≤K■G.Let p be a prime which divides the order of a group G.In this paper,some characterizations of G being p-solvable or p-supersolvable were obtained by analyzing the normal index of certain subgroups of G.These results can be viewed as local version of recent results in the literature.
基金Shanxi Province Graduate Research Practice Innovation Project,No.2023KY465Project on the Reform of Graduate Education and Teaching in Shanxi Province,No.2021YJJG146+1 种基金Research Project of Shanxi Provincial Cultural Relics Bureau,No.22-8-14-1400-119National Key R&D Program of China,No.2021YFB3901300。
文摘Human activities have significantly impacted the land surface temperature(LST),endangering human health;however,the relationship between these two factors has not been adequately quantified.This study comprehensively constructs a Human Activity Intensity(HAI)index and employs the Maximal Information Coefficient,four-quadrant model,and XGBoostSHAP model to investigate the spatiotemporal relationship and influencing factors of HAI-LST in the Yellow River Basin(YRB)from 2000 to 2020.The results indicated that from 2000 to 2020,as HAI and LST increased,the static HAI-LST relationship in the YRB showed a positive correlation that continued to strengthen.This dynamic relationship exhibited conflicting development,with the proportion of coordinated to conflicting regions shifting from 1:4 to 1:2,indicating a reduction in conflict intensity.Notably,only the degree of conflict in the source area decreased significantly,whereas it intensified in the upper and lower reaches.The key factors influencing the HAI-LST relationship include fractional vegetation cover,slope,precipitation,and evapotranspiration,along with region-specific factors such as PM_(2.5),biodiversity,and elevation.Based on these findings,region-specific ecological management strategies have been proposed to mitigate conflict-prone areas and alleviate thermal stress,thereby providing important guidance for promoting harmonious development between humans and nature.
基金conducted under the state assignment of Lomonosov Moscow State University。
文摘This paper presents new estimations for all parameters(amplitude,frequency,quality factor,and initial phase)of the_(0)S_(0)Earth fundamental mode,which was triggered by the 2004 Sumatra-Andaman earthquake with a magnitude of Mw9.1.Sixteen records from the IGETS superconducting gravimeters have been analyzed.Using the maximum likelihood method algorithm,frequency,initial phase,and amplitude estimates have been acquired with remarkable accuracy.The values of frequency(814.6568±0.0002μHz)and quality factor(5455±17)obtained in this study differ slightly from those of the PREM model,and the amplitude variations qualitatively correspond to those of the SKS12WM13model.The estimated time delay between the onset of the earthquake and the excitation of the mode(290 s)is consistent with the moment tensor analysis from the USGS National Earthquake Information Center.
文摘目的现有数据浓缩后门攻击方法将含有触发器的中毒样本和干净样本浓缩为小的数据集,中毒数据中真实数据的强信号掩盖触发器的弱信号,并且未考虑将非目标类浓缩数据与中毒数据特征分离,非目标类浓缩数据残留触发器特征。因此,提出分离触发器和多重对比的数据浓缩后门攻击。方法首先将触发器与真实数据进行分离。分离的触发器作为样本与真实数据并行嵌入浓缩数据,减少真实数据对触发器的干扰。然后,对分离的触发器进行优化,将触发器接近目标类真实数据的特征,提高触发器的嵌入效果,同时对触发器进行了分区放大预处理来增加触发器像素的数量,使其在优化过程获取大量的梯度用于指导学习。在数据浓缩阶段,通过多重对比将目标类浓缩数据与触发器特征投影在同一空间,将非目标类浓缩数据与触发器特征分离,进一步提高后门攻击的成功率。结果为了验证所提出方法的有效性,将所提出方法在FashionMNIST(Fashion Modified National Institute of Standards and Technology database)、CIFAR10(Canadian Institute for Advances Research’s ten categories dataset)、STL10(Stanford letter-10)、SVHN(street view house numbers)与其他4种方法进行对比实验。所提出的方法在5个数据集和6个不同的模型上均达到100%的攻击成功率,同时未降低干净样本在模型上的准确率。结论所提出的方法通过解决现有方法存在的问题,实现了性能的显著提高。本文方法具体代码见:https://github.com/tfuy/STMC。
