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A Novel Reliable and Trust Objective Function for RPL-Based IoT Routing Protocol
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作者 Mariam A.Alotaibi Sami S.Alwakeel Aasem N.Alyahya 《Computers, Materials & Continua》 2025年第2期3467-3497,共31页
The Internet of Things (IoT) integrates diverse devices into the Internet infrastructure, including sensors, meters, and wearable devices. Designing efficient IoT networks with these heterogeneous devices requires the... The Internet of Things (IoT) integrates diverse devices into the Internet infrastructure, including sensors, meters, and wearable devices. Designing efficient IoT networks with these heterogeneous devices requires the selection of appropriate routing protocols, which is crucial for maintaining high Quality of Service (QoS). The Internet Engineering Task Force’s Routing Over Low Power and Lossy Networks (IETF ROLL) working group developed the IPv6 Routing Protocol for Low Power and Lossy Networks (RPL) to meet these needs. While the initial RPL standard focused on single-metric route selection, ongoing research explores enhancing RPL by incorporating multiple routing metrics and developing new Objective Functions (OFs). This paper introduces a novel Objective Function (OF), the Reliable and Secure Objective Function (RSOF), designed to enhance the reliability and trustworthiness of parent selection at both the node and link levels within IoT and RPL routing protocols. The RSOF employs an adaptive parent node selection mechanism that incorporates multiple metrics, including Residual Energy (RE), Expected Transmission Count (ETX), Extended RPL Node Trustworthiness (ERNT), and a novel metric that measures node failure rate (NFR). In this mechanism, nodes with a high NFR are excluded from the parent selection process to improve network reliability and stability. The proposed RSOF was evaluated using random and grid topologies in the Cooja Simulator, with tests conducted across small, medium, and large-scale networks to examine the impact of varying node densities. The simulation results indicate a significant improvement in network performance, particularly in terms of average latency, packet acknowledgment ratio (PAR), packet delivery ratio (PDR), and Control Message Overhead (CMO), compared to the standard Minimum Rank with Hysteresis Objective Function (MRHOF). 展开更多
关键词 IOT LLNs RPL objective function OF MRHOF OF0 routing metrics RELIABILITY trustworthiness
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带有P_0函数的非线性互补问题的一个新的非内点连续算法 被引量:1
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作者 房亮 贺国平 王永丽 《数学物理学报(A辑)》 CSCD 北大核心 2011年第1期229-238,共10页
研究带有P_0函数的非线性互补问题.基于一个新的光滑函数,把问题近似成参数化的光滑方程组,并且给出一个新的非内点连续算法.所给算法在每步迭代只需要求解一个线性方程组和执行一次Armijo类型的线搜索.在不需要严格互补条件的情况下,... 研究带有P_0函数的非线性互补问题.基于一个新的光滑函数,把问题近似成参数化的光滑方程组,并且给出一个新的非内点连续算法.所给算法在每步迭代只需要求解一个线性方程组和执行一次Armijo类型的线搜索.在不需要严格互补条件的情况下,证明了算法是全局收敛和超线性收敛的.并且,在一个较弱的条件下该算法具有局部二阶收敛性.数值实验证实了算法的可行性和有效性. 展开更多
关键词 非线性互补 非内点连续算法 P_0-函数 强制性 全局收敛
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P_(5)0_(7)功能化磁性颗粒吸附分离废水中的铒
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作者 李栋 刘杰 +3 位作者 李倩婷 芦星杰 薛志潇 张秋露 《有色金属(中英文)》 北大核心 2026年第1期50-61,共12页
稀土开采、冶炼及应用过程中,不可避免地产生大量含低浓度稀土离子的工业废水,将其中的有价稀土元素进行高效分离回收具有重要意义。本文成功制备了具有优异吸附性能的Fe_(3)O_(4)@SiO_(2)@P_(5)0_(7)磁性颗粒,系统探究了吸附时间、溶... 稀土开采、冶炼及应用过程中,不可避免地产生大量含低浓度稀土离子的工业废水,将其中的有价稀土元素进行高效分离回收具有重要意义。本文成功制备了具有优异吸附性能的Fe_(3)O_(4)@SiO_(2)@P_(5)0_(7)磁性颗粒,系统探究了吸附时间、溶液初始pH值、固液比、初始Er(Ⅲ)浓度及温度等因素对Fe_(3)O_(4)@SiO_(2)@P_(5)0_(7)磁性颗粒吸附性能的影响。结果表明,在吸附时间为120 min、初始pH值为6、固液比为2 g·L^(-1),初始Er(Ⅲ)浓度为100 mg·L^(-1),温度为298 K的条件下,Fe_(3)O_(4)@SiO_(2)@P_(5)0_(7)表现出最佳吸附性能,吸附容量可达40 mg·g^(-1)左右,且吸附率可达96%以上。以1.5 mol·L^(-1)HCl溶液为再生剂,对吸附铒饱和后的磁性材料进行再生处理,经过5次吸附再生循环实验后,Fe_(3)O_(4)@SiO_(2)@P_(5)0_(7)磁性材料仍具有较好的吸附性能,对Er(Ⅲ)的去除率仍能达到75%以上。通过FT-IR对吸附前后的材料进行了表征分析,并探究其吸附机理。研究发现,Fe_(3)O_(4)@SiO_(2)@P_(5)0_(7)对Er(Ⅲ)的吸附过程主要以P_(5)0_(7)的孔效应为主,静电吸附与化学吸附为辅。本研究为水溶液中低浓度稀土元素的高效分离与回收提供了新方法。 展开更多
关键词 Fe_(3)O_(4) P_(5)0_(7) 稀土 吸附 废水
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求解P_0函数互补问题的一种微分方程方法
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作者 周丽美 《运筹与管理》 CSCD 2003年第5期33-36,共4页
本文针对P0函数互补问题,给出了一种微方程方法,并且证明了P0函数互补问题的解是微分方程系统的渐进稳定平衡点。在适当的假设条件下,证明了所给出的算法具有二次收敛速度。几个数值例子表明了该算法的有效性。
关键词 P0函数 非线性互补问题 微分方程法 渐进稳定 平衡点 二次收敛速度
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0°鼻内镜下腺样体低温等离子射频消融术联合双侧扁桃体切除术治疗儿童重度OSAHS的疗效分析
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作者 赵有彪 梁好勇 《临床研究》 2026年第1期67-71,共5页
目的探讨0°鼻内镜下腺样体低温等离子射频消融术联合双侧扁桃体切除术治疗儿童重度阻塞性睡眠呼吸暂停低通气综合征(OSAHS)的临床疗效。方法采用回顾性研究方法,选择2022年1月至2024年1月新乡同盟医院收治的119例重度OSAHS患儿。... 目的探讨0°鼻内镜下腺样体低温等离子射频消融术联合双侧扁桃体切除术治疗儿童重度阻塞性睡眠呼吸暂停低通气综合征(OSAHS)的临床疗效。方法采用回顾性研究方法,选择2022年1月至2024年1月新乡同盟医院收治的119例重度OSAHS患儿。根据治疗方式不同分为观察组(59例)和对照组(60例)。对照组采用双侧扁桃体剥离术联合鼻动力系统腺样体切除术,观察组采用0°鼻内镜下腺样体低温等离子射频消融术联合双侧扁桃体切除术。两组均于术后3个月进行复查。比较两组术中出血量、手术时长、术后出血情况[包括术后出血例数、需要再次处置情况、出血时段(分为20:01—次日6:00及其他时段)、出血天数(分为术后6~7 d及其他日期)及出血部位(左侧或右侧)]、疼痛持续时间、症状缓解时间、住院时间、睡眠呼吸暂停低通气指数(AHI)、最低血氧饱和度(SpO_(2))及免疫球蛋白A(IgA)、免疫球蛋白G(IgG)和免疫球蛋白M(IgM)水平。结果观察组治疗有效率高于对照组,术中出血量、手术时长、疼痛持续时间、症状缓解时间和住院时间均少于对照组,差异有统计学意义(P<0.05)。两组术后出血例数、需要再次处置情况、出血时段、出血天数和出血部位比较,差异无统计学意义(P>0.05)。术后3个月,两组IgA、IgG和IgM水平均降低,但观察组高于对照组,差异有统计学意义(P<0.05)。术后3个月,两组AHI均降低,最低SpO_(2)升高,差异有统计学意义(P<0.05),但两组AHI和最低SpO_(2)比较,差异无统计学意义(P>0.05)。结论0°鼻内镜下腺样体低温等离子射频消融术联合双侧扁桃体切除术治疗儿童重度OSAHS,在改善AHI和最低SpO_(2)上与传统术式相当,但在围手术期指标(如术中出血、手术时间、疼痛恢复)和免疫功能保护方面更具优势。 展开更多
关键词 0°鼻内镜 低温等离子射频消融 儿童阻塞性睡眠呼吸暂停低通气综合征 治疗效果 免疫功能
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A MAXIMAL FUNCTION CHARACTERIZATION 0F HARDY SPACES ON SPACES OF HOMOGENEOUS TYPE 被引量:6
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作者 Li Wenming Zhongshan University, China 《Analysis in Theory and Applications》 1998年第2期12-27,共16页
A new maximal function is introduced in the dual spaces of test function spaces on spaces of homogeneous type. Using this maximal function, we get new characterization of atomic H^p spaces.
关键词 A MAXIMAL function CHARACTERIZATION 0F HARDY SPACES ON SPACES OF HOMOGENEOUS TYPE APPI 尸气
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The Non-standard Characteristics of Functional SpacesK(X) and C_0(X) 被引量:1
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作者 陈东立 《Chinese Quarterly Journal of Mathematics》 CSCD 1998年第4期7-9, ,共3页
In this paper,the non standard characteristics of functional spaces K(X) and C 0(X) are presented and proved.
关键词 functional space K(X) functional space C 0(X) near standard points remote points
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Thermodynamic Fit Functions of the Two-Phase Fluid and Critical Exponents 被引量:1
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作者 Albrecht Elsner 《Engineering(科研)》 2014年第12期789-826,共38页
Two-phase fluid properties such as entropy, internal energy, and heat capacity are given by thermodynamically defined fit functions. Each fit function is expressed as a temperature function in terms of a power series ... Two-phase fluid properties such as entropy, internal energy, and heat capacity are given by thermodynamically defined fit functions. Each fit function is expressed as a temperature function in terms of a power series expansion about the critical point. The leading term with the critical exponent dominates the temperature variation between the critical and triple points. With β being introduced as the critical exponent for the difference between liquid and vapor densities, it is shown that the critical exponent of each fit function depends (if at all) on β. In particular, the critical exponent of the reciprocal heat capacity c﹣1 is α=1-2β and those of the entropy s and internal energy u are?2β, while that of the reciprocal isothermal compressibility?κ﹣1T is γ=1. It is thus found that in the case of the two-phase fluid the Rushbrooke equation conjectured α +?2β + γ=2 combines the scaling laws resulting from the two relations c=du/dT and?κT=dlnρ/dp. In the context with c, the second temperature derivatives of the chemical potential μ and vapor pressure p are investigated. As the critical point is approached, ﹣d2μ/dT2 diverges as c, while?d2p/dT2 converges to a finite limit. This is explicitly pointed out for the two-phase fluid, water (with β=0.3155). The positive and almost vanishing internal energy of the one-phase fluid at temperatures above and close to the critical point causes conditions for large long-wavelength density fluctuations, which are observed as critical opalescence. For negative values of the internal energy, i.e. the two-phase fluid below the critical point, there are only microscopic density fluctuations. Similar critical phenomena occur when cooling a dilute gas to its Bose-Einstein condensate. 展开更多
关键词 CRITICAL Condition U = 0 CRITICAL OPALESCENCE Rushbrooke Equation THERMODYNAMIC FIT functionS for Saturated Water Vapor and Liquid Volumes Vapor Pressure Chemical Potential Entropy Internal ENERGY Free ENERGY Heat Capacity
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Enhancement of gaseous mercury(Hg^0) adsorption for the modified activated carbons by surface acid oxygen function groups
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作者 GUO Si-jia GUO Gui-ping 《Journal of Groundwater Science and Engineering》 2018年第2期104-114,共11页
This article discussed the benzoic acid activated carbons which have changed the types and content of acid oxygen-function groups on the surface of activated carbons and their effect on the adsorption for Hg^0 in simu... This article discussed the benzoic acid activated carbons which have changed the types and content of acid oxygen-function groups on the surface of activated carbons and their effect on the adsorption for Hg^0 in simulated flue gas at 140 ℃. These surface acid oxygen function groups were identified by Boehm titration, Fourier transformation infrared spectrum, temperature programmed desorption and X-ray photoelectron spectroscopy. It indicates that the carboxyl, lactone and phenolic were formed when the benzoic acid is loaded on the surface of activated carbons. Among the surface acid oxygen function groups, the carboxyl groups enhance the adsorption capacities of Hg^0 for activated carbons to a greater extent. 展开更多
关键词 Benzoic acid Modified activated carbon Surface acid oxygen function groups Characterization Adsorption for Hg^0
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A Density Functional Theory Study of the Hydrates of 2NH_3:H_2SO_4 and Its Implications for the Formation of Atmosphere Particles
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作者 赵亚英 曾永平 +2 位作者 张锡辉 马琳 陶福明 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2010年第4期525-534,共10页
Density functional theory was used at the B3LYP/6-311++G(d,p) level of theory to study the hydrates of 2NH3:H2SO4:nH2O for n = 0~4. Neutrals of the most stable clusters, when n = 0 and 1, spontaneously formed a... Density functional theory was used at the B3LYP/6-311++G(d,p) level of theory to study the hydrates of 2NH3:H2SO4:nH2O for n = 0~4. Neutrals of the most stable clusters, when n = 0 and 1, spontaneously formed and were determined to be hydrogen-bonded molecular complexes of monomeric species. Double ions (clusters containing a NH4+ cation and a HSO4- anion) or even ternary ions (clusters with two NH4+ cations and one SO42- anion) spontaneously formed in the most stable clusters of 2NH3:H2SO4:nH2O (n = 2, 3, 4). The energetics of binding and incremental association was also calculated. Double ions are not energetically favorable until 2NH3:H2SO4:2H2O because of the about equal free energies for forming the neutral (the most stable) and double ion (the second stable) isomers. The free energy of incremental association from free H2O and 2NH3:H2SO4:nH2O has a maximum at n = 2 at room temperature with ΔG ≈ –2 kcal/mol. The comparison of incremental association energies between 2NH3:H2SO4:nH2O, NH3:H2SO4:nH2O and H2SO4:nH2O clusters revealed that NH3 plays an important role in the atmospheric particle nucleation. 展开更多
关键词 2NH3:H2SO4:nH2O (n = 0~4) molecular complexes incremental association density functional theory
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Underwater Image Classification Based on EfficientnetB0 and Two-Hidden-Layer Random Vector Functional Link
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作者 ZHOU Zhiyu LIU Mingxuan +2 位作者 JI Haodong WANG Yaming ZHU Zefei 《Journal of Ocean University of China》 CAS CSCD 2024年第2期392-404,共13页
The ocean plays an important role in maintaining the equilibrium of Earth’s ecology and providing humans access to a wealth of resources.To obtain a high-precision underwater image classification model,we propose a c... The ocean plays an important role in maintaining the equilibrium of Earth’s ecology and providing humans access to a wealth of resources.To obtain a high-precision underwater image classification model,we propose a classification model that combines an EfficientnetB0 neural network and a two-hidden-layer random vector functional link network(EfficientnetB0-TRVFL).The features of underwater images were extracted using the EfficientnetB0 neural network pretrained via ImageNet,and a new fully connected layer was trained on the underwater image dataset using the transfer learning method.Transfer learning ensures the initial performance of the network and helps in the development of a high-precision classification model.Subsequently,a TRVFL was proposed to improve the classification property of the model.Net construction of the two hidden layers exhibited a high accuracy when the same hidden layer nodes were used.The parameters of the second hidden layer were obtained using a novel calculation method,which reduced the outcome error to improve the performance instability caused by the random generation of parameters of RVFL.Finally,the TRVFL classifier was used to classify features and obtain classification results.The proposed EfficientnetB0-TRVFL classification model achieved 87.28%,74.06%,and 99.59%accuracy on the MLC2008,MLC2009,and Fish-gres datasets,respectively.The best convolutional neural networks and existing methods were stacked up through box plots and Kolmogorov-Smirnov tests,respectively.The increases imply improved systematization properties in underwater image classification tasks.The image classification model offers important performance advantages and better stability compared with existing methods. 展开更多
关键词 underwater image classification EfficientnetB0 random vector functional link convolutional neural network
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Density Functional Theory Study on the Adsorption of CN on Transition Metal M(100) (M = Ni, Pd, Pt, Cu, Ag and Au) Surfaces
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作者 李奕 倪碧莲 +3 位作者 胡建明 章永凡 陈文凯 李俊篯 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2008年第8期1002-1008,共7页
The adsorption of cyanide on the top site of a series of transition metal M(100) (M = Cu, Ag, Au, Ni, Pd, Pt) surfaces via carbon and nitrogen atoms respectively, with the CN axis perpendicular to the surface, has... The adsorption of cyanide on the top site of a series of transition metal M(100) (M = Cu, Ag, Au, Ni, Pd, Pt) surfaces via carbon and nitrogen atoms respectively, with the CN axis perpendicular to the surface, has been studied by means of density functional theory and cluster model. Geometry, adsorption energy and vibrational frequencies have been determined, and the present calculations show that the adsorption of CN through C-end on metal surface is more favorable than that via N-end for the same surface. The vibrational frequencies of CN for C-down configuration on surface are blue-shifted with respect to the free CN, which is contrary to the change of vibrational frequencies when CN is adsorbed by N-down structure. Furthermore, the charge transfer from surface to CN causes the increase of surface work function. 展开更多
关键词 ADSORPTION density functional theory transition metal(lO0) surfaces CYANIDE
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Error Bound for the Generalized Complementarity Problem with Analytic Functions
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作者 Hong-Chun Sun 《International Journal of Automation and computing》 EI 2012年第3期288-291,共4页
In this paper,we consider the global error bound for the generalized complementarity problem(GCP)with analytic functions.Based on the new technique,we establish computable global error bound under milder conditions,wh... In this paper,we consider the global error bound for the generalized complementarity problem(GCP)with analytic functions.Based on the new technique,we establish computable global error bound under milder conditions,which refines the previously known results. 展开更多
关键词 Generalized complementarity problem(GCP) error bound analytic functions R0-function Lipschitz continuity.
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一种抗冲击噪声的高精度波达方向估计算法
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作者 单泽彪 姚瑞广 +2 位作者 刘小松 薛泓垚 刘云清 《西安交通大学学报》 北大核心 2025年第4期193-202,共10页
针对现有波达方向(DOA)估计算法在冲击噪声下估计精度较低的问题,提出了一种基于相控分数低阶矩和指数族分布函数的离格近似l_(0)范数DOA估计算法。首先,利用相控分数低阶矩抑制冲击噪声,构建稀疏DOA模型;其次,通过对平滑函数的平滑性... 针对现有波达方向(DOA)估计算法在冲击噪声下估计精度较低的问题,提出了一种基于相控分数低阶矩和指数族分布函数的离格近似l_(0)范数DOA估计算法。首先,利用相控分数低阶矩抑制冲击噪声,构建稀疏DOA模型;其次,通过对平滑函数的平滑性和陡峭性进行研究,构造了一类平滑性和陡峭性可变的函数族,并利用该函数族求解初始支撑集;然后,提出了一种前向展望和后向延拓策略,对初始支撑集进行扩展,并从中选择出可以使残差最小化的一组支撑集为最优支撑集,从而确定在格DOA估计;最后,为了解决网格失配效应,利用DOA粗估计与离格偏差之间的联合稀疏性,通过交替方向迭代联合求解DOA粗估计与离格偏差,获得离格DOA估计值。仿真结果表明:与正交匹配追踪算法相比,在信噪比为-8 dB时,所提算法的DOA估计精度提高了66.36%。此外,当冲击噪声特征指数大于0.6时,所提算法对目标DOA的估计误差可以控制在1°以内。仿真结果充分说明了所提算法可在冲击噪声下实现高精度的DOA估计。 展开更多
关键词 波达方向估计 近似l 0范数 冲击噪声 指数族分布函数 前向展望 后向延拓
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硫酸体系中V(Ⅳ)与V(Ⅴ)的离子形态分析及萃取性能对比
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作者 冯雪茹 《矿产综合利用》 2025年第6期100-106,共7页
为优化硫酸体系中钒的萃取工艺,提升钒资源回收效率,本文结合热力学平衡系统研究了硫酸体系中V(Ⅳ)和V(Ⅴ)离子的水解行为、存在形态及影响因素,分别绘制了25℃下浓度为0.02 mol/L V(Ⅳ)离子和V(Ⅴ)离子的组分优势区域图,以二(2-乙基己... 为优化硫酸体系中钒的萃取工艺,提升钒资源回收效率,本文结合热力学平衡系统研究了硫酸体系中V(Ⅳ)和V(Ⅴ)离子的水解行为、存在形态及影响因素,分别绘制了25℃下浓度为0.02 mol/L V(Ⅳ)离子和V(Ⅴ)离子的组分优势区域图,以二(2-乙基己基)磷酸酯(P_(2)0_(4))为萃取剂、自制磺化煤油为稀释剂,系统研究了水相初始pH值、P_(2)0_(4)用量、萃取相比(O/A)、振荡时间对V(Ⅳ)和V(Ⅴ)萃取性能的影响。结果表明,在pH<3的硫酸体系中,V(Ⅳ)与V(Ⅴ)分别主要以VO^(2+)、VO^(2+)形式存在;P_(2)0_(4)对V(Ⅳ)的萃取性能显著优于V(Ⅴ),V(Ⅳ)的最优萃取工艺条件为:水相初始pH=2.4、有机相含20%P_(2)0_(4)、萃取相比(O/A)=1:1、振荡时间6 min,此时V(Ⅳ)的单级萃取率高达96.39%,而相同条件下V(Ⅴ)的单级萃取率仅为88.41%。在无焙烧加压酸浸工艺中,将浸出液中的V(Ⅴ)预还原为V(Ⅳ)可有效提升总钒萃取率。 展开更多
关键词 P_(2)0_(4) 萃取 V(Ⅳ) V(Ⅴ) 硫酸体系
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Mn^(2+)掺杂聚阴离子型钠离子电池正极材料的制备及电化学性能
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作者 闫共芹 谢相飞 +3 位作者 蓝春波 赵卓凡 王晨 武桐 《精细化工》 北大核心 2025年第9期1951-1959,共9页
以FeSO_(4)·7H_(2)O、MnSO_(4)·H_(2)O、NH_(4)H_(2)PO_(4)、CH_(3)COONa、一水合柠檬酸和氧化石墨烯(GO)为原料,采用溶胶-凝胶法制备了Mn^(2+)掺杂、还原氧化石墨烯(rGO)包覆的聚阴离子型钠离子电池正极材料Na_(4)Fe_(3–x)M... 以FeSO_(4)·7H_(2)O、MnSO_(4)·H_(2)O、NH_(4)H_(2)PO_(4)、CH_(3)COONa、一水合柠檬酸和氧化石墨烯(GO)为原料,采用溶胶-凝胶法制备了Mn^(2+)掺杂、还原氧化石墨烯(rGO)包覆的聚阴离子型钠离子电池正极材料Na_(4)Fe_(3–x)Mn_(x)(PO_(4))_(2)(P_(2)O_(7))/rGO(Mn_(x)-NFPP/rGO,x为Mn掺杂量,即Mn取代Fe的物质的量)。采用SEM、XRD、EDS、XPS对Mn_(x)-NFPP/rGO的微观形貌和结构成分进行了表征。通过恒流充放电、循环伏安和电化学阻抗测试,考察了Mn^(2+)掺杂量对Mn_(x)-NFPP/rGO电化学性能的影响,采用密度泛函理论计算了Mn_(x)-NFPP/rGO的能带和态密度。结果表明,Mn^(2+)掺杂扩大了Na^(+)扩散通道,提高了Na^(+)扩散速率,但对材料的三维结构和形貌没有影响;Mn_(0.30)-NFPP/rGO表现出最优的循环稳定性和倍率性能,在0.05 C倍率下具有131.2 mA·h/g的初始放电比容量,在2 C倍率下的放电比容量为91.9 mA·h/g;Mn^(2+)掺杂和rGO包覆有效提高了材料的放电比容量和循环稳定性,在1 C倍率下循环100圈后的比容量保持率为94%。Mn^(2+)的掺杂降低了材料价带与导带之间的带隙(3.128 eV),使价带中的电子更容易跃迁到导带,从而有利于提高Na^(+)的扩散动力学和本征电导率。 展开更多
关键词 Mn^(2+)掺杂 Na_(4)Fe_(3)(PO_(4))_(2)P_(2)O_(7)/rGO 钠离子电池 正极材料 电化学性能 储能机理 功能材料
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基于SCN函数共轭梯度方向的稀疏支持向量机特征分块分解算法 被引量:1
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作者 潘阳 孟志青 +1 位作者 温国栋 蒋敏 《运筹与管理》 北大核心 2025年第5期89-96,I0022-I0027,共14页
随着机器学习分类算法在多模态大数据中的广泛应用,对高维数据进行准确分类变得迫切而重要。处理高维数据时,传统支持向量机模型常受冗余特征的影响,导致分类精度降低。因此,实现特征稀疏化的方法变得至关重要。虽然许多学者提出了使用... 随着机器学习分类算法在多模态大数据中的广泛应用,对高维数据进行准确分类变得迫切而重要。处理高维数据时,传统支持向量机模型常受冗余特征的影响,导致分类精度降低。因此,实现特征稀疏化的方法变得至关重要。虽然许多学者提出了使用添加正则化项的方法进行稀疏化,但其本质上都是构建一个近似于L_(0)范数的函数,与L_(0)范数在稀疏性方面仍存在差距。为了获得更好的稀疏分类结果,本文利用L_(0)范数构建稀疏支持向量机模型,并运用强可转化非凸函数将L_(0)范数转化为可微凸凹连续函数,进一步解决L_(0)范数导致的直接计算困难问题,从而可以使用梯度下降算法求解。本文在五个高维数据集上进行了CGDL-SVM算法与其他经典算法的对比实验,结果表明,在保持相近分类精度的前提下,CGDL-SVM算法在稀疏性方面显著优于其他算法。 展开更多
关键词 稀疏性 L_(0)范数 支持向量机 强可转化非凸函数
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两类损失函数下泊松差分布参数的Bayes估计 被引量:1
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作者 王德辉 李昕炎 《辽宁大学学报(自然科学版)》 2025年第1期86-96,共11页
本文研究在熵损失函数以及0-1损失函数下泊松差分布参数的Bayes估计问题.首先,以Bayes推断思想为基础,分别得出在两类损失函数下参数的Bayes估计.其次,通过随机模拟验证了两类损失函数下Bayes估计的相合性与渐近正态性,并且对这两类损... 本文研究在熵损失函数以及0-1损失函数下泊松差分布参数的Bayes估计问题.首先,以Bayes推断思想为基础,分别得出在两类损失函数下参数的Bayes估计.其次,通过随机模拟验证了两类损失函数下Bayes估计的相合性与渐近正态性,并且对这两类损失函数下的Bayes估计进行了比较.结果表明,两类损失函数下的Bayes估计均具有良好的估计效果,在相同样本下,熵损失函数下的Bayes估计要优于0-1损失函数下的Bayes估计.最后,利用泊松差分布对某医院每日使用床位数目的变化量进行实证分析,通过皮尔逊卡方检验,熵损失函数下的Bayes估计得到的泊松差分布与数据的拟合度较好. 展开更多
关键词 泊松差分布 BAYES估计 熵损失函数 0-1损失函数 随机模拟
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厦门地区0-4岁儿童功能性便秘的临床特点及危险因素分析
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作者 王梅 陈競芳 +3 位作者 王晓冬 苏莹 陈俊鸿 金翠 《四川生理科学杂志》 2025年第12期2613-2616,2778,共5页
目的:探讨厦门地区0~4岁儿童功能性便秘的临床特点,并分析其发生的危险因素。方法:选取2023年3月~2025年3月厦门地区4所社区卫生服务中心、3家幼儿园及厦门市儿童医院的1558名0~4岁儿童作为研究对象,分析其功能性便秘发生率。将确诊为... 目的:探讨厦门地区0~4岁儿童功能性便秘的临床特点,并分析其发生的危险因素。方法:选取2023年3月~2025年3月厦门地区4所社区卫生服务中心、3家幼儿园及厦门市儿童医院的1558名0~4岁儿童作为研究对象,分析其功能性便秘发生率。将确诊为功能便秘的240例患儿作为病例组,另选取240名健康儿童作为对照组,比较两组一般特征,采用Logistic回归法分析0~4岁儿童功能性便秘的危险因素。结果:确诊为功能性便秘的儿童240例,患病率为15.40%。各年龄段间功能性便秘发生率有差异,呈现出随年龄增长发生率逐渐上升的趋势(P<0.05)。排便间隔延长占比82.50%;排便困难76.67%;粪便性状异常71.25%;存在肛门疼痛或肛裂症状24.17%;出现食欲不振症状18.75%;存在腹胀症状15.42%;两组在便秘家族史、每日饮水量、喂养方式、户外活动时间、膳食纤维摄入、排便训练、添加辅食时间、饮食过精细、饮食不均衡、挑食频率及食欲不振频率情况比较差异显著(P<0.05);多因素Logistic回归分析显示饮水量不足、人工喂养、户外活动时间不足、膳食纤维摄入不足、未进行排便训练、辅食添加时间不当、饮食过精细以及经常挑食是独立危险因素(P均<0.05)。结论:厦门地区0-4岁儿童功能性便秘的发生率为15.40%,随年龄增长发生率上升,患儿多以排便间隔延长、排便困难、粪便性状异常为主。且饮水量不足、人工喂养、户外活动时间不足、膳食纤维摄入不足、未进行排便训练、辅食添加时间不当、饮食过精细以及经常挑食均为该年龄段儿童功能性便秘的危险因素。 展开更多
关键词 厦门地区 0~4岁 功能性便秘 临床特点 危险因素
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Laparoscopic surgical approaches for various locations of gastrointestinal stromal tumours
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作者 Li-Quan Chen Chu-Ying Wu +1 位作者 Si-Jia Wu Kai Ye 《World Journal of Clinical Cases》 2025年第21期16-24,共9页
Gastrointestinal stromal tumours(GISTs)are tumours that originate from mesenchymal tissue,are predominantly located in the stomach,and typically do not metastasize to the lymph nodes.Surgical intervention remains the ... Gastrointestinal stromal tumours(GISTs)are tumours that originate from mesenchymal tissue,are predominantly located in the stomach,and typically do not metastasize to the lymph nodes.Surgical intervention remains the primary treatment modality for GISTs.Historically,open surgery was the predominant approach;however,advancements in medical technology have led to laparoscopic surgery becoming the standard practice.Compared with traditional open surgical techniques,laparoscopic surgery is less invasive and facilitates more rapid postoperative recovery.Given that GISTs can arise at any location within the gas-trointestinal tract,the specific surgical methods employed vary according to both the tumour's anatomical site and its growth characteristics.The aim of this review is to examine laparoscopic surgical strategies for managing GISTs across different regions of the gastrointestinal tract by synthesizing recent research trends and relevant evidence-based medical literature. 展开更多
关键词 Gastrointestinal stromal tumour LAPAROSCOPY SURGERY R0 resection function preservation
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