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Pure bending of simply supported circular plate of transversely isotropic functionally graded material 被引量:6
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作者 LI Xiang-yu DING Hao-jiang CHEN Wei-qiu 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第8期1324-1328,共5页
This paper considers the pure bending problem of simply supported transversely isotropic circular plates with elastic compliance coefficients being arbitrary functions of the thickness coordinate. First, the partial d... This paper considers the pure bending problem of simply supported transversely isotropic circular plates with elastic compliance coefficients being arbitrary functions of the thickness coordinate. First, the partial differential equation, which is satisfied by the stress functions for the axisymmetric deformation problem is derived. Then, stress functions are obtained by proper manipulation. The analytical expressions of axial force, bending moment and displacements are then deduced through integration. And then, stress functions are employed to solve problems of transversely isotropic functionally graded circular plate, with the integral constants completely determined from boundary conditions. An elasticity solution for pure bending problem, which coincides with the available solution when degenerated into the elasticity solutions for homogenous circular plate, is thus obtained. A numerical example is finally presented to show the effect of material inhomogeneity on the elastic field in a simply supported circular plate of transversely isotropic functionally graded material (FGM). 展开更多
关键词 Transversely isotropic functionally graded materials (FGMs) pure bending problem Simply supported circular plate Axisymmetric deformation
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Wigner Function:from Ensemble Average of Density Operator to Its Matrix Element in Entangled Pure States 被引量:2
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作者 FANHong-Yi 《Communications in Theoretical Physics》 SCIE CAS CSCD 2002年第5期533-536,共4页
We show that the Wigner function (an ensemble average of the density operator ρ, Δ is the Wigner operator) can be expressed as a matrix element of ρ in the entangled pure states. In doing so, converting from quant... We show that the Wigner function (an ensemble average of the density operator ρ, Δ is the Wigner operator) can be expressed as a matrix element of ρ in the entangled pure states. In doing so, converting from quantum master equations to time-evolution equation of the Wigner functions seems direct and concise. The entangled states are defined in the enlarged Fock space with a fictitious freedom. 展开更多
关键词 Wigner function ensemble average of density operator matrix element in entangled pure states
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Wigner Function:from Ensemble Average of Density Operator to Its One Matrix Element in Entangled Pure States
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作者 FAN Hong-Yi 《Communications in Theoretical Physics》 SCIE CAS CSCD 2002年第11期533-536,共4页
We show that the Wigner function W = Tr(△ρ) (an ensemble average of the density operator ρ, △ is theWigner operator) can be expressed as a matrix element of ρ in the entangled pure states. In doing so, converting... We show that the Wigner function W = Tr(△ρ) (an ensemble average of the density operator ρ, △ is theWigner operator) can be expressed as a matrix element of ρ in the entangled pure states. In doing so, converting fromquantum master equations to time-evolution equation of the Wigner functions seems direct and concise. The entangledstates are defined in the enlarged Fock space with a fictitious freedom. 展开更多
关键词 WIGNER function ENSEMBLE AVERAGE of density operator matrix element in ENTANGLED pure STATES
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Evaluation of Kenyan Orange Fleshed Sweet Potato (Ipomoea batatas Lam,) Purees for Functional Food Production
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作者 Muchiri M. Njeri McCartney Anne L. 《Journal of Life Sciences》 2014年第2期128-133,共6页
Consumption of functional foods with health promoting benefits and/or disease prevention has been on the increase globally. The study aimed at evaluating the potential of utilizing Kenyan orange fleshed sweet potato ... Consumption of functional foods with health promoting benefits and/or disease prevention has been on the increase globally. The study aimed at evaluating the potential of utilizing Kenyan orange fleshed sweet potato (Ipomoea batatas Lam.) for functional food production with aesthetics benefits. Purees from three different varieties of orange fleshed sweet potato (OFSP) were analyzed for nutritional, physicochemical and microbial quality, The findings of the study show that the three purees were all microbiologically safe and of near neutral pH, but differed significantly (P 〈 0.05) in nutrient content (dry matter content, 12.76-28.23%; crude fiber, 1.37-2.90% fresh weight basis (FWB); 13-carotene, 0.94-9.27 mg/100g dry weight basis (DWB); starch, 10.20-18.30% FWB & total sugar 27.08-31.76% DWB). The purees had attractive appearance (ranging from yellow to dark orange), with varying significantly different spectrophotometer hunters color scale (P 〈 0.05), and flow ability. Conclusions from the findings show great potential of utilizing the varying properties of OFSP puree to produce enriched functional food products such as probiotic/prebiotic dairy, beverages, bakery and baby foods. 展开更多
关键词 Orange fleshed sweet potato puree functional foods sustainable nutrition.
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Fuzzy Prescribed-Time Control for Uncertain Nonlinear Pure Feedback Systems
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作者 Qidong Li Changchun Hua Kuo Li 《IEEE/CAA Journal of Automatica Sinica》 2025年第10期2162-2164,共3页
Dear Editor,This letter investigates the fuzzy prescribed-time control(PTC)problem for a class of uncertain pure feedback nonlinear systems.Firstly,a novel prescribed-time stability lemma is introduced,which plays a c... Dear Editor,This letter investigates the fuzzy prescribed-time control(PTC)problem for a class of uncertain pure feedback nonlinear systems.Firstly,a novel prescribed-time stability lemma is introduced,which plays a critical role in stability analysis.Unlike existing PTC algorithms,where the nonlinear functions are typically known or satisfy a linear growth condition,our approach does not require such assumptions.To address these unknown factors,fuzzy logic systems(FLSs)are employed.Based on the new prescribed-time stability lemma,it is proven that the controller and all system states converge to the origin within the prescribed time and remain there.Finally,the effectiveness of the proposed algorithm is validated through a simulation example. 展开更多
关键词 pure feedback nonlinear systemsfirstlya nonlinear functions pure feedback systems stability analysis logic systems flss prescribed time control nonlinear systems stability analysisunlike
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多孔MOFS负载Ni单原子催化剂电化学还原CO_(2)性能研究
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作者 郭凯 付乾 +3 位作者 汪洋 张敏 朱恂 廖强 《工程热物理学报》 北大核心 2026年第3期1019-1025,共7页
运用可再生电力驱动CO_(2)电化学还原定向转化为高附加值化学品是实现碳中和的一种经济有效的途径,将纯水作为电解质进行CO_(2)电解可有效缓解膜电极反应器中的盐结晶问题,但纯水体系中析氢反应竞争导致产物选择性大幅下降,严重制约其... 运用可再生电力驱动CO_(2)电化学还原定向转化为高附加值化学品是实现碳中和的一种经济有效的途径,将纯水作为电解质进行CO_(2)电解可有效缓解膜电极反应器中的盐结晶问题,但纯水体系中析氢反应竞争导致产物选择性大幅下降,严重制约其发展。本文成功制备了氨基官能团修饰的Ni单原子催化剂,氨基官能团修饰增强了催化剂对CO_(2)的吸附性能,同时进一步增强了催化剂的传荷能力,进而增强电化学还原CO_(2)性能。在膜电极反应器纯水体系测试中,在100 mA/cm^(2)的电流密度和60◦C的条件下,该催化剂实现了83.2%的CO法拉第效率,而未修饰处理的催化剂仅为57.3%。该研究提出的氨化策略为纯水体系中制备高效的CO_(2)电化学还原催化剂提供了新的思路。 展开更多
关键词 电化学还原CO_(2) 单原子催化剂 纯水体系 氨基官能团
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基于高通量测序和纯培养联用技术的红糟酸细菌多样性解析
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作者 舒娜 赵慧君 +2 位作者 侯强川 郭壮 王玉荣 《轻工学报》 北大核心 2026年第1期26-33,68,共9页
【目的】探究广西武宣地区红糟酸中细菌类群多样性,为红糟酸产品寻找菌种资源。【方法】采用MiSeq高通量测序技术对广西武宣地区12份红糟酸样品的细菌α多样性、群落结构及功能进行解析,并采用纯培养技术对乳酸菌进行分离鉴定。【结果... 【目的】探究广西武宣地区红糟酸中细菌类群多样性,为红糟酸产品寻找菌种资源。【方法】采用MiSeq高通量测序技术对广西武宣地区12份红糟酸样品的细菌α多样性、群落结构及功能进行解析,并采用纯培养技术对乳酸菌进行分离鉴定。【结果】红糟酸样品的优势细菌门是厚壁菌门(Firmicutes)和变形菌门(Proteobacteria),平均相对含量分别为90.17%和9.17%;优势细菌属是乳酸杆菌属(Lactobacillus)、片球菌属(Pediococcus)和促生乳杆菌属(Levilactobacillus),平均相对含量分别为32.18%、20.54%和11.62%。红糟酸样品在碳水化合物和氨基酸转运与代谢这2个功能上具有较高的丰度。12份红糟酸样品中共分离出29株乳酸菌,隶属于5个属下的6个种,其中优势可培养乳酸菌为戊糖乳植物杆菌(Lactiplantibacillus pentosus)和乳酸片球菌(Pediococcus acidilactici),分别占乳酸菌分离株总数的44.83%和24.14%。【结论】武宣地区红糟酸中细菌多样性较高,乳酸菌资源丰富,可作为产业化红糟酸的菌种资源。 展开更多
关键词 红糟酸 高通量测序 纯培养 细菌多样性 基因功能预测 乳酸菌
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基于UK-EVF耦合算法的瓦斯含量分布场预测与重构
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作者 何健 廖巍 《工矿自动化》 北大核心 2026年第3期43-51,共9页
针对计算资源有限场景中矿井瓦斯含量分布场精确重构的技术难题,提出了一种基于泛克里金(UK)插值与经验变差函数(EVF)的耦合算法(UK-EVF),旨在以轻量化计算实现高精度的瓦斯含量空间分布表征。首先,通过现场实测采集目标区域不同位置的... 针对计算资源有限场景中矿井瓦斯含量分布场精确重构的技术难题,提出了一种基于泛克里金(UK)插值与经验变差函数(EVF)的耦合算法(UK-EVF),旨在以轻量化计算实现高精度的瓦斯含量空间分布表征。首先,通过现场实测采集目标区域不同位置的瓦斯含量数据,构建涵盖测点空间坐标与对应瓦斯含量的数据集;其次,引入UK插值算法,以EVF获取的空间参数为约束,利用EVF模型对瓦斯含量分布的空间结构特征进行定量分析,精准提取变程、块金效应、基台值等关键空间相关性参数;在此基础上,对未采样区域的瓦斯含量进行空间插值预测,最终实现预测区域瓦斯含量分布场重构。选取4种经典空间插值算法与5种主流机器学习及神经网络模型进行对比分析,结果表明:UK-EVF耦合算法在所有对比算法中表现最优,瓦斯含量预测结果的平均相对误差绝对值稳定控制在5.1%以内,分布场重构运行耗时不超过10 s,在小样本、低算力场景下,实现了瓦斯含量分布场高精度重构。 展开更多
关键词 瓦斯含量预测 分布场重构 空间插值算法 经验变差函数 UK-EVF耦合算法
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Rare-Earth Functional Films Prepared by Ion Beam Epitaxy
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作者 Yang Shaoyan Chai Chunlin Zhou Jianping Liu Zhikai Chen Yonghai Chen Nuofu Wang Zhanguo 《Journal of Rare Earths》 SCIE EI CAS CSCD 2005年第5期536-536,共1页
Ion beam epitaxy (IBE) technology is a significant method for preparing high pure and high quality rare-earth functional films at low growth temperatue. A new method of preparing rare-earth functional films by ion b... Ion beam epitaxy (IBE) technology is a significant method for preparing high pure and high quality rare-earth functional films at low growth temperatue. A new method of preparing rare-earth functional films by ion beam epitaxy was reviewed in details. The recent developments and application of IBE on rare-earth functional films is focused, particularly for high-K materials CeO2, photoluminescence materials Gd2O3 and magnetic semiconductor materials Si1-x Gdx. 展开更多
关键词 rare-earth functional films IBE technology high pure growth low temperature epitaxy
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Study on Surface Properties for Non-polar Fluids with Density Functional Theory
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作者 吴畏 陆九芳 +2 位作者 付东 刘金晨 李以圭 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2004年第2期256-262,共7页
The density functional theory, simplified by the local density approximation and mean-field approxi-mation, is applied to study the surface properties of pure non-polar fluids. A reasonable long rang correction is ado... The density functional theory, simplified by the local density approximation and mean-field approxi-mation, is applied to study the surface properties of pure non-polar fluids. A reasonable long rang correction is adopted to avoid the truncation of the potential. The perturbation theory is applied to establish the equation for the phase equilibrium, in which the hard-core chain fluid is as the reference fluid and the Yukawa potential is used as the perturbation term. Three parameters, ε/κ, d and ms, are regressed frorn the vapor-liquid equilibria, and the surface properties, including density profile, surface tension and local surface tension profile are predicted with these parameters. 展开更多
关键词 density functional theory surface tension density profile pure non-polar fluids
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Wear Characteristics of Functionally Graded Tubes Reinforced with Silicon Carbide and Alumina: A Comparative Study
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作者 SALEH Bassiouny Ibrahim AHMED Mahmoud Hamed 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2021年第S01期76-83,共8页
In the current study,an effort has been taken to manufacture and compare the characteristics of functionally graded tubes. Two samples have been produced with a commercially pure aluminium matrix reinforced by 10%(in ... In the current study,an effort has been taken to manufacture and compare the characteristics of functionally graded tubes. Two samples have been produced with a commercially pure aluminium matrix reinforced by 10%(in weight) SiC and Al_(2)O_(3)with a 16 μm average size via horizontal centrifugal casting. In addition to microstructure analysis,the mechanical and wear characteristics have been investigated across the thickness of the produced tubes.The results showed that the addition of SiC and Al_(2)O_(3)particles relative to the unreinforced matrix(pure Al)significantly enhance the mechanical properties and wear resistance of the produced tubes. Thus,these tubes are the best choice for automobile applications. 展开更多
关键词 functionally graded materials centrifugal casting pure aluminium wear characteristics
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The solution of minimum reliability index for modified weak point of arbitrary curved beam under pure bending
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作者 WU Xiang-guo AN Wei-guang LI Hong-liang 《Journal of Marine Science and Application》 2005年第4期29-33,共5页
This paper is based on the fundamental loading model of pure bending and the analytical model of a circular beam element with arbitrary initial deflection. The L.W. Guo solution is modified and generalized according t... This paper is based on the fundamental loading model of pure bending and the analytical model of a circular beam element with arbitrary initial deflection. The L.W. Guo solution is modified and generalized according to the elastic theory, and the analytical solution for the stress of the beam element with arbitrary initial deflection under pure bending is derived. Using yield theory of edge strength, an expression for the safety margin of one point in the arbitrary curved beam under pure bending (ACPB) is built. This paper modifies the model for weak points of service structures and establishes a foundation for safe design and inspection of imperfect structures. Also, according to the theory of the method of advanced first-order second-moment(AFOSM) , this paper derives an expression for the reliability index of one point in ACPB. Lastly, it modifies the solution for weak points by solving the minimal reliability index. 展开更多
关键词 arhitrary curved beam pure bending reliability index function geometrical imperfection
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应用咽鼓管功能声测法和阶跃式纯音线谱信号对健康成人咽鼓管开放功能的研究 被引量:1
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作者 金蕾 郑阳阳 +1 位作者 倪坤 李晓艳 《听力学及言语疾病杂志》 北大核心 2025年第2期145-149,共5页
目的探究咽鼓管功能声测法合理的纯音声源信号频率区间,并初步建立正常值范围。方法选取31例健康成人受试者,分段采用3~6 kHz频带上间隔100 Hz的阶跃式纯音线谱信号作为声源进行咽鼓管功能声测法测试,分析结果。结果本研究发现3.5、4.3... 目的探究咽鼓管功能声测法合理的纯音声源信号频率区间,并初步建立正常值范围。方法选取31例健康成人受试者,分段采用3~6 kHz频带上间隔100 Hz的阶跃式纯音线谱信号作为声源进行咽鼓管功能声测法测试,分析结果。结果本研究发现3.5、4.3、4.35、4.5、4.65、4.8、5.0、5.15 kHz 8个频点通过率均较高,是较为合适的纯音信号频点;将这8个频率点上的线谱数据汇总后统计分析,计算出LVc值的95%可信区间,即95%的LVc值>5.5 dB,取整数后将6 dB设为LVc门限阈值。结论本研究发现咽鼓管功能声测法较合适的纯音线谱声源频率为3.5、4.3、4.35、4.5、4.65、4.8、5.0、5.15 kHz 8个频点,声源信号在吞咽动作发生前后约0.5~1秒范围内相对声压级超过6 dB幅值变化可作为咽鼓管有效开放指标。 展开更多
关键词 咽鼓管功能 纯音信号 声测法
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红柄病羊肚菌子实体细菌多样性研究 被引量:1
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作者 曹乐 兰阿峰 +3 位作者 郭素芬 李玲义 陈翠翠 彭浩 《北方园艺》 北大核心 2025年第12期100-110,共11页
以汉中市采集的红柄病羊肚菌为试材,采用高通量测序法与纯培养相结合的方法,并运用多种生物信息学方法进行数据分析,研究了感染红柄病的羊肚菌子实体细菌群落的多样性及功能,以期为羊肚菌红柄病害的科学防治提供参考依据。结果表明:感... 以汉中市采集的红柄病羊肚菌为试材,采用高通量测序法与纯培养相结合的方法,并运用多种生物信息学方法进行数据分析,研究了感染红柄病的羊肚菌子实体细菌群落的多样性及功能,以期为羊肚菌红柄病害的科学防治提供参考依据。结果表明:感病组和CK内细菌群落均以变形菌门(Proteobacteria)和拟杆菌门(Bacteroidota)为主,拟杆菌门丰度高于变形菌门30%。假单胞菌属(Pseudomonas sp.)、土地杆菌属(Pedobacter sp.)和黄杆菌属(Flavobacterium sp.)在健康羊肚菌子实体中作为优势菌属存在。感病组中黄杆菌属(Flavobacterium sp.)、类芽孢杆菌属(Paenibacillus sp.)和詹氏杆菌属(Janthinobacterium sp.)多于CK。由LEfSe结果可知,CK的潜在共同细菌为土地杆菌属(Pedobacter sp.)。羊肚菌内细菌代谢途径丰富,大多集中在代谢与合成中,其中一级分类水平人类疾病相关功能占0.279%~0.320%。纯培养结果归纳到2门11属,共计50株菌,以芽孢杆菌属(Bacillus sp.)和假单胞菌属(Pseudomonas sp.)为主。 展开更多
关键词 羊肚菌红柄病 高通量测序 纯培养 细菌多样性 功能预测
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赋范*代数与局部紧群的GNS表示 被引量:1
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作者 许沁轩 黄书棋 《南开大学学报(自然科学版)》 北大核心 2025年第4期84-89,共6页
讨论了赋范*代数的态与纯态之间的关系,证明了在满足一定条件下,纯态集恰好为态集的端点集,并且纯态集的凸包在态集中弱*稠密.然后定义了一般*代数的GNS表示,证明了一般*代数的GNS表示是唯一的.最后利用赋范*代数的GNS表示理论给出了局... 讨论了赋范*代数的态与纯态之间的关系,证明了在满足一定条件下,纯态集恰好为态集的端点集,并且纯态集的凸包在态集中弱*稠密.然后定义了一般*代数的GNS表示,证明了一般*代数的GNS表示是唯一的.最后利用赋范*代数的GNS表示理论给出了局部紧群的正型函数及其GNS表示相关结论的简洁证明. 展开更多
关键词 纯态 GNS表示 局部紧群 正型函数
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法向圆弧齿廓纯滚动圆柱齿轮设计
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作者 杨辉 肖小平 +3 位作者 唐万和 陈祯 陈扬枝 FUENTES Alfonso 《机械传动》 北大核心 2025年第4期64-70,共7页
【目的】为了研究基于啮合线方程主动设计的法向圆弧齿廓纯滚动圆柱齿轮设计方法,深入了解该新型齿轮的啮合特性,包括接触斑痕和非承载传动误差,同时为了更好地掌握中心距误差、交叉轴误差和交错轴误差对螺旋线修形的法向圆弧齿廓纯滚... 【目的】为了研究基于啮合线方程主动设计的法向圆弧齿廓纯滚动圆柱齿轮设计方法,深入了解该新型齿轮的啮合特性,包括接触斑痕和非承载传动误差,同时为了更好地掌握中心距误差、交叉轴误差和交错轴误差对螺旋线修形的法向圆弧齿廓纯滚动圆柱齿轮啮合特性的影响,开展了一系列研究工作。【方法】由法向截面的圆弧齿廓推导大轮(从动轮)和小轮(主动轮)端面工作齿廓,端面全齿廓由端面工作齿廓与Hermite曲线构造的根部过渡曲线组合而成,二者在连接点光滑连接;轮齿全齿面由端面全齿廓分别沿小轮和大轮的纯滚动接触线扫掠而成。建立了用于轮齿接触分析的基本设计参数、齿面方程和数学模型,同时,对小轮进行螺旋线抛物线修形来对比齿面啮合特性。【结果】无论是否采取螺旋线抛物线修形,其轮齿接触分析结果充分验证了纯滚动啮合设计思路:所有接触斑痕的中心均位于齿面节线,可以实现纯滚动啮合传动;抛物线形的非承载传动误差曲线由小轮螺旋线修形实现,可以吸收由于错位安装所引发的噪声和振动。该法向圆弧齿廓纯滚动圆柱齿轮具备中心距可分性,但是它对交错轴安装误差更加敏感。本文为后续的应力分析和承载传动误差的深入研究奠定了基础。 展开更多
关键词 纯滚动啮合 啮合线方程 圆弧齿廓 啮合性能
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基于XGBoost方法的甘肃庆阳苹果天气指数农业保险定价 被引量:2
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作者 李金蓉 肖鸿民 《中国农业气象》 2025年第5期715-724,共10页
基于机器学习算法的天气指数保险是农业保险创新研究的有益尝试。农作物产量受气象灾害影响严重,构建能准确反映产量损失与气象灾害关系的数据分析模型,对农作物天气指数保险的定价十分重要。本文以甘肃庆阳苹果为研究对象,基于1996-202... 基于机器学习算法的天气指数保险是农业保险创新研究的有益尝试。农作物产量受气象灾害影响严重,构建能准确反映产量损失与气象灾害关系的数据分析模型,对农作物天气指数保险的定价十分重要。本文以甘肃庆阳苹果为研究对象,基于1996-2020年庆阳市5个县(区)苹果生长期(4-10月)逐日降水量、逐日气温数据以及苹果产量数据,构建低温冻害指数、干旱指数和连阴雨指数,利用XGBoost算法建立与苹果气象减产率的回归模型,结合核函数密度估计法厘定庆阳市苹果天气指数保险纯费率。结果表明:(1)庆阳市各县(区)苹果气象减产率受气象灾害影响波动明显,7种苹果灾害天气指数与苹果气象减产率存在非线性关系;(2)基于XGBoost算法建立1996-2020年宁县、庆城县、正宁县、环县和西峰区苹果气象减产率-天气指数回归模型,其拟合精准度高于多元逐步回归模型,决定系数R2分别高出0.157、0.125、0.190、0.115和0.117,均方根误差RMSE分别降低0.045、0.026、0.335、0.126和0.039个百分点;(3)宁县、庆城县、正宁县、环县和西峰区的苹果天气指数保险的气象减产率赔付触发值分别为11.88%、3.37%、4.33%、9.21%和17.70%,苹果天气指数保险纯费率分别为4.00%、3.64%、4.91%、1.94%和4.98%。 展开更多
关键词 天气指数保险 XGBoost算法 核函数 纯费率厘定
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纯生物防晒产品研发中的功能强化路径与工艺创新进展
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作者 赵永斌 李雨彤 +3 位作者 甄佳雪 宗舒馨 魏银梦 李伟 《中国化妆品科学》 2025年第6期2-8,共7页
聚焦纯生物防晒产品研发核心,以“全成分(涵盖功效成分及生物基辅料/助剂)源于生物资源,且无化学合成类、物理类防晒剂添加”为界定标准,系统梳理其功能强化关键路径与工艺创新方向。从天然生物活性成分定向挖掘、分子结构生物法修饰、... 聚焦纯生物防晒产品研发核心,以“全成分(涵盖功效成分及生物基辅料/助剂)源于生物资源,且无化学合成类、物理类防晒剂添加”为界定标准,系统梳理其功能强化关键路径与工艺创新方向。从天然生物活性成分定向挖掘、分子结构生物法修饰、多生物组分协同体系构建3个维度,阐述防晒功能强化策略;详解适配纯生物体系的绿色提取纯化、生物基载体包埋、生物基缓释及智能响应型制备等工艺创新成果。分析当前研发面临的活性成分稳定性、功效量化及产业化成本挑战,展望未来发展趋势,为高安全性、高效能纯生物防晒产品的研发与产业化提供参考。 展开更多
关键词 纯生物防晒产品 功能强化 工艺创新 生物活性成分 研发进展
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听力正常成人窄带Chirp听性脑干反应与40 Hz听觉相关电位比较
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作者 高妍 刘霞 +5 位作者 陈芳 杨小萍 王泽宇 孙亚宁 盛延良 夏文涛 《法医学杂志》 北大核心 2025年第6期559-565,共7页
目的探讨在不同频率声刺激下听力正常成人窄带Chirp听性脑干反应(narrow band Chirp auditory brainstem response,NB Chirp ABR)、40 Hz听觉相关电位(40 Hz auditory event related potential,40 Hz AERP)反应阈与纯音测听(pure-tone a... 目的探讨在不同频率声刺激下听力正常成人窄带Chirp听性脑干反应(narrow band Chirp auditory brainstem response,NB Chirp ABR)、40 Hz听觉相关电位(40 Hz auditory event related potential,40 Hz AERP)反应阈与纯音测听(pure-tone audiometry,PTA)阈值之间的关系。方法选取听力正常成年受试者50名(100耳)作为实验组,在不同言语频率(0.5、1、2、4 kHz)下分别进行PTA、NB Chirp ABR及40 Hz AERP测试,对NB Chirp ABR及40 Hz AERP反应阈与PTA阈值之间的关系进行配对t检验、Pearson相关系数及散点图分析,并将各频率反应阈与PTA阈值的平均差值作为本实验室校正值。另选取听力正常成年受试者11名(22耳)作为验证组,评估单独应用NB Chirp ABR、40 Hz AERP及两者联合应用推测行为听阈的准确性,以MAE、MSE、RMSE及相关系数作为评估指标。结果在0.5、1、2、4 kHz频率下,NB Chirp ABR反应阈与PTA阈值的相关系数依次为0.601、0.672、0.805、0.931,40 Hz AERP反应阈与PTA阈值的相关系数依次为0.763、0.737、0.643、0.580。基于本研究得到的实验室校正值,联合应用NB Chirp ABR与40 Hz AERP推测行为听阈的MAE、MSE、RMSE和相关系数分别为2.216 dB nHL、7.509 dB nHL、2.740 dB nHL和0.906。结论NB Chirp ABR在听觉功能评估中具有应用价值,与40 Hz AERP联合应用(0.5、1 kHz下采用40 Hz AERP,2、4 kHz下采用NB Chirp ABR)可提高听觉功能评估的准确性。 展开更多
关键词 法医学 窄带Chirp听性脑干反应 40 Hz听觉相关电位 纯音测听 听觉功能评估
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