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泊松方程离散系统的病态原理和通用预条件子

高等学校计算数学学报 2022年第4期44卷 344-363页

作者：张衡张宏游文杰湖南三一工业职业技术学院工程机械学院无损检测技术福建省高等学校重点实验室(福建技术师范学院) 福建技术师范学院大数据与人工智能学院

1引言泊松方程的数值求解问题,通常转化为如下离散系统一一线性方程组的求解问题[1],Ax=b (1.1)大规模求解时,方程组的病态(高条件数)问题凸显,并且求解规模越大,该方程组的条件数也越大,病态越严重[2],是影响求解效率和精度的瓶颈因素... 详细信息

1引言泊松方程的数值求解问题,通常转化为如下离散系统一一线性方程组的求解问题[1],Ax=b (1.1)大规模求解时,方程组的病态(高条件数)问题凸显,并且求解规模越大,该方程组的条件数也越大,病态越严重[2],是影响求解效率和精度的瓶颈因素,因此,在大规模求解过程中,使用预处理技术来降低方程组的条件数,减少病态,是成功求解的关键.

关键词：病态原理病态结构病态因子病态消除因子预处理子

Atomic-resolution Interfacial Microstructure and Thermo-electro-magnetic Energy Conversion Performance of Gd/Bi0.5Sb1.5Te3 Composites

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Energy & Environmental Materials 2024年第4期7卷 355-363页

作者： Chengshan Liu wenjie Xu Ping Wei Shaoqiu Ke Wenjun Cui Longzhou Li Dong Liang Xianfeng Ye Tiantian Chen Xiaolei Nie Wanting Zhu Wenyu Zhao Qingjie Zhang State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory

Thermo-electro-magnetic materials with simultaneously large magnetocaloric(MC) and thermoelectric (TE) effects are the core part for designing TE/MC all-solid-state cooling *** MC phase with TE material is an effective ***,the elemental diffusion and chemical reaction occurring at the two-phase interfaces could significantly impair the cooling performance.

关键词： interfacial reaction magnetocaloric performance thermoelectric performance thermo-electro-magnetic materials

Feasibility analysis of hypergravity experiment of density-driven convection of dissolved CO

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Journal of Earth Science 2024年

作者： Ruiqi Chen wenjie Xu Yingtao Hu Yunmin Chen Jinlong Li Duanyang Zhuang Center for Hypergravity Experimental and Interdisciplinary Research， Zhejiang University MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering， Zhejiang University School of Engineering， Hangzhou City University

Dissolution trapping is one of the most promising mechanisms for safe geological carbon storage. Density-driven convection substantially accelerates the conversion of free-phase CO2to the dissolved state， enhancing the sequestration safety. Since this process occurs on time scales of hundreds to thousands of years， reproducing it through conventional laboratory physical model tests is challenging. The hypergravity experiment reduces the model size and shortens the experimental time， enabling the modeling of gravity-driven flow processes at the field scale. However， it is uncertain whether the preferential flow effect caused by fractures can be reproduced in a hypergravity experiment. In this study， a three-dimensional discrete fracture-matrix model （3D-DFM） was used to evaluate the feasibility of hypergravity experiment of the transport of dissolved CO2in fractured *** hypergravity tests were performed to examine the feasibility of modeling density-driven convection in homogeneous and heterogeneous media at different centrifuge accelerations. The hypergravity experiment can be used to study density-driven convection of dissolved CO2at the field scale in homogeneous system. The numerical results show that the hypergravity experiment enables a faster breakthrough of plume and overestimates CO2migration in the matrix surrounding the fractures.

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Advancing oxygen separation:insights from experimental and computational analysis of La_(0.7)Ca_(0.3)Co_(0.3)Fe_(0.6)M_(0.1)O_(3-δ)(M=Cu,Zn)oxygen transport membranes

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Frontiers of Chemical Science and Engineering 2024年第6期18卷 17-29页

作者： Guoxing Chen Wenmei Liu Marc Widenmeyer Xiao Yu Zhijun Zhao Songhak Yoon Ruijuan Yan wenjie Xie Armin Feldhoff Gert Homm Emanuel Ionescu Maria Fyta Anke Weidenkaff Fraunhofer Research Institution for Materials Recycling and Resource Strategies IWKS Alzenau 63755Germany Electrochemistry Laboratory Paul Scherrer InstituteVilligen PSI 5232Switzerland Department of Materials and Earth Sciences Materials and ResourcesTechnical University of DarmstadtDarmstadt 64287Germany Institute of Physical Chemistry and Electrochemistry Leibniz University HannoverHannover 30167Germany Institute for Computational Physics University of StuttgartStuttgart 70569Germany Computational Biotechnology RWTH AachenAachen 52074Germany

In this study,perovskite-type La_(0.7)Ca_(0.3)Co_(0.3)Fe_(0.6)M_(0.1)O_(3-δ)(M=Cu,Zn)powders were synthesized using a scalable reverse co-precipitation method,presenting them as novel materials for oxygen transport *** comprehensive study covered various aspects including oxygen permeability,crystal structure,conductivity,morphology,CO_(2) tolerance,and long-term regenerative durability with a focus on phase structure and *** membrane La_(0.7)Ca_(0.3)Co_(0.3)Fe_(0.6)M_(0.1)O_(3-δ)exhibited high oxygen permeation fluxes,reaching up to 0.88 and 0.64 mL·min^(−1)·cm^(−2) under air/He and air/CO_(2) gradients at 1173 K,*** 1600 h of CO_(2) exposure,the perovskite structure remained intact,showcasing superior CO_(2) resistance.A combination of first principles simulations and experimental measurements was employed to deepen the understanding of Cu/Zn substitution effects on the structure,oxygen vacancy formation,and transport behavior of the *** findings underscore the potential of this highly CO_(2)-tolerant membrane for applications in high-temperature oxygen *** enhanced insights into the oxygen transport mechanism contribute to the advancement of next-generation membrane materials.

关键词： perovskite oxygen permeation membrane oxygennionsdiffusiono xygen vacancy formation energy energy barrier

Hardware-oriented algorithms for softmax and layer normalization of large language models

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Science China(Information Sciences) 2024年

作者： wenjie LI Dongxu LYU Gang WANG Aokun HU Ningyi XU Guanghui HE School of Electronic Information and Electrical Engineering Shanghai Jiao Tong University Department of Micro/Nano Electronics Shanghai Jiao Tong University MoE Key Laboratory of Artificial Intelligence Shanghai Jiao Tong University

While large language models (LLMs) have sparked a new revolution in the field of natural language processing (NLP), their hardware accelerators have garnered tremendous attention. However, softmax and layer normalization which are the most common non-linear operations in LLMs are frequently *** paper presents hardware-oriented algorithms for both softmax and layer normalization of LLMs. We propose an approximate approach to implementing division in softmax and extend it for simultaneously computing square root and performing division in layer normalization. It replaces the original computation by multiplication and shifting. For softmax, we further approximate the exponential function by truncating its exponent and then reuse the involved subtraction. For layer normalization, we additionally simplify the computation of denominator by directly removing the term regarding the square of the mean. Furthermore,hardware architectures are developed for the proposed algorithms of softmax and layer normalization. They can work as plug-and-play units for LLM accelerators, requiring no fine-tuning and introducing negligible performance loss. Compared with the state-of-the-art designs, the proposed softmax architecture can save up to 23.45%area cost and 17.39%power consumption, while the proposed layer normalization architecture can save up to 32.70%area cost and 14.29%power consumption.

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Therapy and mechanism of natural polysaccharides for atopic dermatitis treatment

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Food Science and Human Wellness 2024年

作者： wenjie Wang Lijun Shao Xiao Jiang Qiulu Chu Jian Xiao Shufang Wu College of Light Industry and Food Engineering， Nanjing Forestry University Department of Forest Biomaterials， North Carolina State University Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources， Nanjing Forestry University

Atopic dermatitis (AD) is a common multifactorial skin disease characterized by chronic inflammation， unbearable itching， and significant physical and mental burden on patients. In recent years， there has been extensive studied on the use of natural polysaccharides in anti-inflammatory therapy， due to their low toxicity and multi-target pharmacological activity. The unique biological activities of polysaccharides from natural sources as functional food additives and cosmeceuticals present a new option for the treatment of AD. This review aims to summarize the pathogenesis of AD， the therapeutic effects， and the mechanisms of natural polysaccharides， as well as discuss the limitations and prospects of these compounds in the treatment of AD. The insights provided in this review can serve as references and inspiration for the development of applications of natural polysaccharides in the treatment of AD.

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Optimized NPK fertilizer recommendations based on topsoil available nutrient criteria for wheat in drylands of China

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Journal of Integrative Agriculture 2024年第7期23卷 2421-2433页

作者： wenjie Yang Jie Yu Yanhang Li Bingli Jia Longgang Jiang Aijing Yuan Yue Ma Ming Huang Hanbing Cao Jinshan Liu Weihong Qiu Zhaohui Wang Key Laboratory of Plant Nutrition and Agri-environment in Northwest China Ministry of Agriculture and Rural Affairs/College of Natural Resources and EnvironmentNorthwest A&F UniversityYangling 712100China

The optimized management of crop fertilization is very important for improving crop yield and reducing the consumption of chemical *** nutrient values can be used for evaluating the nutritional status of a crop,and they reflect the nutrient concentrations above which the plant is sufficiently supplied for achieving the maximum potential *** on on-farm surveys of 504 farmers and 60 field experimental sites in the drylands of China,we proposed a recommended fertilization method to determine nitrogen(N),phosphorus(P),and potassium(K)fertilizer input rates for wheat production,and then validated the method by a field experiment at 66 different sites in northern *** results showed that wheat grain yield varied from 1.1 to 9.2 t ha^(-1),averaging 4.6 t ha^(-1),and it had a quadratic relationship with the topsoil(0-20 cm)nitrate N and soil available P contents at ***,yield was not correlated with the inputs of N,P,and K *** on the relationship(exponential decay model)between 95–105%of the relative yield and topsoil nitrate N,available P,and available K contents at wheat harvest from 60 field experiments,the topsoil critical nutrient values were determined as 34.6,15.6,and 150 mg kg^(-1)for soil nitrate N,available P,and available K,***,based on five groups of relative yield(>125%,115–125%,105–115%,95–105%,and<95%)and the model,the five groups of topsoil critical nutrient levels and fertilization coefficients(Fc)were ***,we proposed a new method for calculating the recommended fertilizer input rate as:Fr=Gy×Nr×Fc,where Fr is the recommended fertilizer(N/P/K)input rate;Gy is the potential grain yield;Nr is the N(N_(rN)),P(N_(rP)),and K(N_(rK))nutrient requirements for wheat to produce 1,000 kg of grain;and Fc is a coefficient for N(N_c)/P(P_c)/K(K_c)fertilizer.A 2-year validated experiment confirmed that the new method reduced N fertilizer input by 17.5%(38.5 kg N ha^(-1))and P fertilizer i

关键词： fertilization method dryland wheat soil nutrient critical value soil nitrogen topsoil nutrients

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Spatiotemporal characteristics of seed rain and soil seed bank of artificial Caragana korshinskii Kom. forest in the Tengger Desert, China

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Journal of Arid Land 2024年第4期16卷 550-566页

作者： SHEN Jianxiang WANG Xin WANG Lei WANG Jiahui QU wenjie ZHANG Xue CHANG Xuanxuan YANG Xinguo CHEN Lin QIN Weichun ZHANG Bo NIU Jinshuai College of Ecological Environment Ningxia UniversityYinchuan 750021China Key Laboratory of Restoration and Reconstruction of Degraded Ecosystems in Northwest China Ministry of EducationNingxia UniversityYinchuan 750021China College of Agriculture Ningxia UniversityYinchuan 750021China

Vegetation restoration and reconstruction are effective approaches to desertification control and achieving social and economic sustainability in desert ***,the self-succession ability of native plants during the later periods of vegetation restoration remains ***,this study was conducted to bridge the knowledge gap by investigating the regeneration dynamics of artificial forest under natural *** information of seed rain and soil seed bank was collected and quantified from an artificial Caragana korshinskii *** in the Tengger Desert,*** germination tests were conducted in a laboratory *** analysis of species quantity and diversity in seed rain and soil seed bank was conducted to assess the impact of different durations of sand fixation(60,40,and 20 a)on the progress of vegetation restoration and ecological conditions in artificial *** *** results showed that the top three dominant plant species in seed rain were Echinops gmelinii Turcz.,Eragrostis minor Host.,and Agropyron mongolicum Keng.,and the top three dominant plant species in soil seed bank were ***,Chloris virgata Sw.,and *** restoration period increased,the density of seed rain and soil seed bank increased first and then *** for species richness,as restoration period increased,it gradually increased in seed rain but decreased in soil seed *** was a positive correlation between seed rain density and soil seed bank density among all the three restoration *** species similarity between seed rain or soil seed bank and aboveground vegetation decreased with the extension of restoration *** shape of the seeds,specifically those with external appendages such as spines and crown hair,clearly had an effect on their dispersal,then resulting in lower seed density in soil seed *** addition,precipitation was a crucial factor in promoting rapid germination,also resulting in lower seed density in soi

关键词： ecological restoration soil seed bank seed rain artificial forest vegetation desertification Caragana korshinskii Tengger Desert

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基于SiC器件的高效光伏Boost电路

现代信息科技 2021年第12期5卷 44-46,50页

作者：张波尤文杰张恩苏州市职业大学电子信息工程学院江苏苏州215104

提高DC/DC变换器运行效率对实现MPPT和提高光伏系统的效率尤为重要。采用扰动观察法,通过Boost电路实现光伏电池的MPPT。用新型的SiC功率半导体器件替代Boost电路中的Si器件,结合所设计的适用于SiC MOSFET的驱动电路以提高Boost电路效... 详细信息

提高DC/DC变换器运行效率对实现MPPT和提高光伏系统的效率尤为重要。采用扰动观察法,通过Boost电路实现光伏电池的MPPT。用新型的SiC功率半导体器件替代Boost电路中的Si器件,结合所设计的适用于SiC MOSFET的驱动电路以提高Boost电路效率。实验结果表明,同样为2 kW的Boost电路,相同频率下,全SiC器件比全Si器件效率提高了2%左右;全SiC器件电路的频率高于全Si器件电路时,前者的效率高于后者,光伏系统的效率也相应提高。

关键词： SiC器件 MPPT 驱动电路高效率光伏发电

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