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ANALYSIS ON GRAY NODES AND GRAYNESS DEGREE IN COMPLEX NETWORK 被引量:1
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作者 崔博 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2012年第2期125-130,共6页
Based on the theory of complex network and gray system, the sugesstion that there exist two types of gray nodes in complex networks, Gray Node I and Gray Node II, is concluded. The first one refers to the existent unk... Based on the theory of complex network and gray system, the sugesstion that there exist two types of gray nodes in complex networks, Gray Node I and Gray Node II, is concluded. The first one refers to the existent unknown gray nodes, and the second the evolution gray nodes. The relevant definitions are also given. Further- more, grayness degree in complex networks is described and divided into two forms--the relative grayness degree (RGD) and the absolute grayness degree (AGD), which are proved respectively. 展开更多
关键词 gray system complex network gray nodes grayness degree
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Persistent alterations in gray matter in COVID-19 patients experiencing sleep disturbances:a 3-month longitudinal study
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作者 Kaixuan Zhou Gaoxiong Duan +19 位作者 Ying Liu Bei Peng Xiaoyan Zhou Lixia Qin Lingyan Liang Yichen Wei Qingping Zhang Xiaocheng Li Haixia Qin Yinqi Lai Yian Lu Yan Zhang Jiazhu Huang Jinli Huang Yinfei Ouyang Bolin Bin Mingming Zhao Jun Liu Jianrong Yang Demao Deng 《Neural Regeneration Research》 SCIE CAS 2025年第10期3013-3024,共12页
Sleep disturbances are among the most prevalent neuropsychiatric symptoms in individuals who have recovered from severe acute respiratory syndrome coronavirus 2 infections.Previous studies have demonstrated abnormal b... Sleep disturbances are among the most prevalent neuropsychiatric symptoms in individuals who have recovered from severe acute respiratory syndrome coronavirus 2 infections.Previous studies have demonstrated abnormal brain structures in patients with sleep disturbances who have recovered from coronavirus disease 2019(COVID-19).However,neuroimaging studies on sleep disturbances caused by COVID-19 are scarce,and existing studies have primarily focused on the long-term effects of the virus,with minimal acute phase data.As a result,little is known about the pathophysiology of sleep disturbances in the acute phase of COVID-19.To address this issue,we designed a longitudinal study to investigate whether alterations in brain structure occur during the acute phase of infection,and verified the results using 3-month follow-up data.A total of 26 COVID-19 patients with sleep disturbances(aged 51.5±13.57 years,8 women and 18 men),27 COVID-19 patients without sleep disturbances(aged 47.33±15.98 years,9 women and 18 men),and 31 age-and gender-matched healthy controls(aged 49.19±17.51 years,9 women and 22 men)were included in this study.Eleven COVID-19 patients with sleep disturbances were included in a longitudinal analysis.We found that COVID-19 patients with sleep disturbances exhibited brain structural changes in almost all brain lobes.The cortical thicknesses of the left pars opercularis and left precuneus were significantly negatively correlated with Pittsburgh Sleep Quality Index scores.Additionally,we observed changes in the volume of the hippocampus and its subfield regions in COVID-19 patients compared with the healthy controls.The 3-month follow-up data revealed indices of altered cerebral structure(cortical thickness,cortical grey matter volume,and cortical surface area)in the frontal-parietal cortex compared with the baseline in COVID-19 patients with sleep disturbances.Our findings indicate that the sleep disturbances patients had altered morphology in the cortical and hippocampal structures during the acute phase of infection and persistent changes in cortical regions at 3 months post-infection.These data improve our understanding of the pathophysiology of sleep disturbances caused by COVID-19. 展开更多
关键词 brain structure cortical gray matter volume cortical surface area cortical thickness HIPPOCAMPUS magnetic resonance imaging Pittsburgh Sleep Quality Index severe acute respiratory syndrome coronavirus 2 infections sleep disturbances sub-cortical volume
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中国近海栉江珧属分类与地理分布研究进展
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作者 薛东秀 王海艳 +1 位作者 马兴浩 张涛 《海洋科学》 CAS CSCD 北大核心 2024年第4期122-129,共8页
本文收集了涉及中国栉江珧属(Atrina Gray,1842)分类和分布的文献,结合近年来栉江珧属分子生物学的研究结果以及野外调查情况,对栉江珧属种类和地理分布情况进行了系统的梳理,确定了中国共有7种栉江珧属贝类,并对其分类分歧进行了讨论;... 本文收集了涉及中国栉江珧属(Atrina Gray,1842)分类和分布的文献,结合近年来栉江珧属分子生物学的研究结果以及野外调查情况,对栉江珧属种类和地理分布情况进行了系统的梳理,确定了中国共有7种栉江珧属贝类,并对其分类分歧进行了讨论;概括各栉江珧属种类的地理分布,广东是中国近海栉江珧属物种多样性最丰富的省份,其次为广西壮族自治区。根据目前中国栉江属种类的资源现状,对栉江珧属种类的开发利用与保护提出了建议,以期为深入开展全国范围的栉江珧属生物多样性保护和可持续利用提供科学依据。 展开更多
关键词 栉江珧属(Atrina Gray 1842) 物种分类 地理分布 资源保护
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深层页岩气井井筒压力模型研究
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作者 苏正远 王坤 倪杰 《当代化工研究》 2024年第24期137-139,共3页
为优选出适用于威远、永川区块气井的井筒压力模型,利用现场40井次测压数据,分别对Duns-Ros、Gray、Hagedorn-Brown等6种压力模型进行了评价。结果显示Gray模型误差最小,为13%,但这一误差依然较大。基于Gray模型,选取YY1-4HF井17组测压... 为优选出适用于威远、永川区块气井的井筒压力模型,利用现场40井次测压数据,分别对Duns-Ros、Gray、Hagedorn-Brown等6种压力模型进行了评价。结果显示Gray模型误差最小,为13%,但这一误差依然较大。基于Gray模型,选取YY1-4HF井17组测压数据对Gray模型的摩擦阻力系数、持液率进行修正,修正后的Gray模型的摩阻因子为4.6911,持液率因子为1.3888。利用16口气井的测压数据对修正后的Gray模型进行验证,结果显示新模型的误差仅为8.46%。新模型的建立可为威远、永川区块气井高效生产提供理论支撑。 展开更多
关键词 井筒压力 Gray模型 威远、永川区块 摩阻因子
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扩频通信领域一种新的偶周期四元序列偶的构造研究
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作者 石妍 崔云 +1 位作者 李晶 刘海妹 《信息技术与信息化》 2024年第8期152-155,共4页
提出了一种新的利用四阶分圆类构造新的四元序列偶的方法。假设N是一个奇素数,满足N=4f+1=x2+4y2,f、x和y均是整数且f为奇数。首先,选择4个周期为N的四阶分圆序列sa、sb、sc、sd,其中a,b,c,d∈{1,2,3,4,5,6};然后,对以上4个序列运用逆G... 提出了一种新的利用四阶分圆类构造新的四元序列偶的方法。假设N是一个奇素数,满足N=4f+1=x2+4y2,f、x和y均是整数且f为奇数。首先,选择4个周期为N的四阶分圆序列sa、sb、sc、sd,其中a,b,c,d∈{1,2,3,4,5,6};然后,对以上4个序列运用逆Gray映射得到周期为N的4个四元序列u、v、p、q;最后,对构造得到的4个四元序列分组采用交织运算,得到两个周期为2N的四元序列偶。当x和y,以及a、b、c、d的取值不同时,构造得到的四元序列偶的自相关特性也各不相同。 展开更多
关键词 四元序列偶 四阶分圆类 逆Gray映射 自相关特性 交织法
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周期为2N的四元序列偶的构造方法
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作者 石妍 王悦 +1 位作者 王会 郝丽霞 《信息技术与信息化》 2024年第9期74-77,82,共5页
自相关特性和平衡性良好的四元序列偶广泛应用于扩频通信领域。虽然已经被发现的四元序列偶很多,但自相关特性良好的四元序列偶还有很大的研究空间。为了进一步获取到更多可用的四元序列偶,基于四阶分圆理论、逆Gray映射和交织运算,对... 自相关特性和平衡性良好的四元序列偶广泛应用于扩频通信领域。虽然已经被发现的四元序列偶很多,但自相关特性良好的四元序列偶还有很大的研究空间。为了进一步获取到更多可用的四元序列偶,基于四阶分圆理论、逆Gray映射和交织运算,对周期为2N(N=4f+1=x^(2)+4y^(2)奇素数,x≡1(mod 4),f为偶数、y是非零整数)的四元序列偶展开了研究。假设s_(a)、s_(b)、s_(c)、s_(d)是有限域Z_(N)上的4个周期为N的四阶分圆序列,其中a,b,c,d∈{1,2,3,4,5,6}。当y、a、b、c、d的取值不同时,构造得到旁瓣为{0,2}、{2,4,-4}、{0,2,-2}以及{4,2-2}的自相关特性良好的四元序列偶。 展开更多
关键词 四元序列偶 四阶分圆类 逆Gray映射 自相关特性 交织法
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Gray code based gradient-free optimization algorithm for parameterized quantum circuit
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作者 张安琪 武春辉 赵生妹 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第2期189-194,共6页
A Gray code based gradient-free optimization(GCO)algorithm is proposed to update the parameters of parameterized quantum circuits(PQCs)in this work.Each parameter of PQCs is encoded as a binary string,named as a gene,... A Gray code based gradient-free optimization(GCO)algorithm is proposed to update the parameters of parameterized quantum circuits(PQCs)in this work.Each parameter of PQCs is encoded as a binary string,named as a gene,and a genetic-based method is adopted to select the offsprings.The individuals in the offspring are decoded in Gray code way to keep Hamming distance,and then are evaluated to obtain the best one with the lowest cost value in each iteration.The algorithm is performed iteratively for all parameters one by one until the cost value satisfies the stop condition or the number of iterations is reached.The GCO algorithm is demonstrated for classification tasks in Iris and MNIST datasets,and their performance are compared by those with the Bayesian optimization algorithm and binary code based optimization algorithm.The simulation results show that the GCO algorithm can reach high accuracies steadily for quantum classification tasks.Importantly,the GCO algorithm has a robust performance in the noise environment. 展开更多
关键词 gradient-free optimization Gray code genetic-based method
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Prediction of high-embankment settlement combining joint denoising technique and enhanced GWO-v-SVR method
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作者 Qi Zhang Qian Su +2 位作者 Zongyu Zhang Zhixing Deng De Chen 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第1期317-332,共16页
Reliable long-term settlement prediction of a high embankment relates to mountain infrastructure safety.This study developed a novel hybrid model(NHM)that combines a joint denoising technique with an enhanced gray wol... Reliable long-term settlement prediction of a high embankment relates to mountain infrastructure safety.This study developed a novel hybrid model(NHM)that combines a joint denoising technique with an enhanced gray wolf optimizer(EGWO)-n-support vector regression(n-SVR)method.High-embankment field measurements were preprocessed using the joint denoising technique,which in-cludes complete ensemble empirical mode decomposition,singular value decomposition,and wavelet packet transform.Furthermore,high-embankment settlements were predicted using the EGWO-n-SVR method.In this method,the standard gray wolf optimizer(GWO)was improved to obtain the EGWO to better tune the n-SVR model hyperparameters.The proposed NHM was then tested in two case studies.Finally,the influences of the data division ratio and kernel function on the EGWO-n-SVR forecasting performance and prediction efficiency were investigated.The results indicate that the NHM suppresses noise and restores details in high-embankment field measurements.Simultaneously,the NHM out-performs other alternative prediction methods in prediction accuracy and robustness.This demonstrates that the proposed NHM is effective in predicting high-embankment settlements with noisy field mea-surements.Moreover,the appropriate data division ratio and kernel function for EGWO-n-SVR are 7:3 and radial basis function,respectively. 展开更多
关键词 High embankment Settlement prediction Joint denoising technique Enhanced gray wolf optimizer Support vector regression
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Depositional process of hyperpycnal flow deposits:A case study on Lower Cretaceous Sangyuan outcrop in the Luanping Basin,Northeast China
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作者 De-zhi Yan Ru-kai Zhu +8 位作者 Hao Shou Zhao-hui Xu Wei-hong Liu Si-cheng Zhu Zhi-cheng Lei Jing-ya Zhang Chang Liu Yi Cai Huai-min Xu 《China Geology》 CAS CSCD 2024年第3期505-516,共12页
Sedimentary process research is of great significance for understanding the distribution and characteristics of sediments.Through the detailed observation and measurement of the Sangyuan outcrop in Luanping Basin,this... Sedimentary process research is of great significance for understanding the distribution and characteristics of sediments.Through the detailed observation and measurement of the Sangyuan outcrop in Luanping Basin,this paper studies the depositional process of the hyperpycnal flow deposits,and divides their depositional process into three phases,namely,acceleration,erosion and deceleration.In the acceleration phase,hyperpycnal flow begins to enter the basin nearby,and then speeds up gradually.Deposits developed in the acceleration phase are reverse.In addition,the original deposits become unstable and are taken away by hyperpycnal flows under the eroding force.As a result,there are a lot of mixture of red mud pebbles outside the basin and gray mud pebbles within the basin.In the erosion phase,the reverse deposits are eroded and become thinner or even disappear.Therefore,no reverse grading characteristic is found in the proximal major channel that is closer to the source,but it is still preserved in the middle branch channel that is far from the source.After entering the deceleration phase,normally grading deposits appear and cover previous deposits.The final deposits in the basin are special.Some are reverse,and others are normal.They are superimposed with each other under the action of hyperpycnal flow.The analysis of the Sangyuan outcrop demonstrates the sedimentary process and distribution of hyperpycnites,and reasonably explain the sedimentary characteristics of hyperpycnites.It is helpful to the prediction of oil and gas exploration targets in gravity flow deposits. 展开更多
关键词 Hyperpycnal flow Sedimentary characteristics Depositional process Gravity flow deposit Hyperpycnite Red mud pebble Gray mud pebble Oil and gas exploration engineering Luanping Basin
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Carbon efficiency evaluation method for urban energy system with multiple energy complementary
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作者 Xianan Jiao Jiekang Wu +1 位作者 Yunshou Mao Mengxuan Yan 《Global Energy Interconnection》 EI CSCD 2024年第2期142-154,共13页
Urban energy systems(UESs)play a pivotal role in the consumption of clean energy and the promotion of energy cascade utilization.In the context of the construction and operation strategy of UESs with multiple compleme... Urban energy systems(UESs)play a pivotal role in the consumption of clean energy and the promotion of energy cascade utilization.In the context of the construction and operation strategy of UESs with multiple complementary energy resources,a comprehensive assessment of the energy efficiency is of paramount importance.First,a multi-dimensional evaluation system with four primary indexes of energy utilization,environmental protection,system operation,and economic efficiency and 21 secondary indexes is constructed to comprehensively portray the UES.Considering that the evaluation system may contain a large number of indexes and that there is overlapping information among them,an energy efficiency evaluation method based on data processing,dimensionality reduction,integration of combined weights,and gray correlation analysis is proposed.This method can effectively reduce the number of calculations and improve the accuracy of energy efficiency assessments.Third,a demonstration project for a UES in China is presented.The energy efficiency of each scenario is assessed using six operational scenarios.The results show that Scenario 5,in which parks operate independently and investors build shared energy-storage equipment,has the best results and is best suited for green and low-carbon development.The results of the comparative assessment methods show that the proposed method provides a good energy efficiency assessment.This study provides a reference for the optimal planning,construction,and operation of UESs with multiple energy sources. 展开更多
关键词 Urban energy systems(UESs) Multiple energy complementary system Carbon efficiency evaluation Data downscaling Subjective and objective weight Gray correlation analysis
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Curcuminoids Inhibit Botrytis cinerea and Colletotrichum gloeosporioides
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作者 ZHOU Li-ting HE Yan-biao +2 位作者 GUO Kai-fa LI Yi-cheng LIU Xiu 《Agricultural Science & Technology》 CAS 2024年第2期33-37,共5页
The growth rate method was adopted to measure the inhibitory effect of curcumin,tetrahydrocurcumin,demethoxycurcumin,and bisdemethoxycurcumin on the mycelial growth of Botrytis cinerea and Colletotrichum gloeosporioid... The growth rate method was adopted to measure the inhibitory effect of curcumin,tetrahydrocurcumin,demethoxycurcumin,and bisdemethoxycurcumin on the mycelial growth of Botrytis cinerea and Colletotrichum gloeosporioides.The results showed that the four curcuminoids inhibited the mycelial growth of the two pathogens in a concentration-dependent manner.Bisdemethoxycurcumin at 600 mg/L exerted the strongest inhibitory effect on the mycelial growth of B.cinerea and C.gloeosporioides,with the relative inhibition rates of 98.19%and 100%,respectively;followed by demethoxycurcumin;curcumin exerted the worst inhibitory effect.Toxicity test results also showed that four curcuminoids all had a certain toxicity to B.cinerea and C.gloeosporioides,among which,bisdemethoxycurcumin exhibited the strongest toxicity,with the EC_(50)of 131.125 and 122.235 mg/L,respectively;while curcumin had the lowest toxicity,with the EC_(50)of 273.143 and 194.943 mg/L,respectively. 展开更多
关键词 CURCUMIN CURCUMINOIDS Tomato gray mold Mango anthracnose Antifungal activity
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Optimization of short-circuit transition parameters of Q235B steel GMAW based on orthogonal gray relational analysis
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作者 陈昌荣 唐宝林 +2 位作者 叶宇杰 练国富 黄旭 《China Welding》 CAS 2024年第2期39-49,共11页
In gas metal arc welding(GMAW)process,the short-circuit transition was the most typical transition observed in molten metal droplets.This paper used orthogonal tests to explore the coupling effect law of welding proce... In gas metal arc welding(GMAW)process,the short-circuit transition was the most typical transition observed in molten metal droplets.This paper used orthogonal tests to explore the coupling effect law of welding process parameters on the quality of weld forming under short-circuit transition,the design of 3 factors and 3 levels of a total of 9 groups of orthogonal tests,welding current,welding voltage,welding speed as input parameters:effective area ratio,humps,actual linear power density,aspect ratio,Vickers hardness as output paramet-ers(response targets).Using range analysis and trend charts,we can visually depict the relationship between input parameters and a single output parameter,ultimately determining the optimal process parameters that impact the single output index.Then combined with gray the-ory to transform the three response targets into a single gray relational grade(GRG)for analysis,the optimal combination of the weld mor-phology parameters as follows:welding current 100 A,welding voltage 25 V,welding speed 30 cm/min.Finally,validation experiments were conducted,and the results showed that the error between the gray relational grade and the predicted value was 2.74%.It was observed that the effective area ratio of the response target significantly improved,validating the reliability of the orthogonal gray relational method. 展开更多
关键词 short-circuit transition orthogonal test gray relational forming quality
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Application of proton magnetic resonance spectroscopy in metabolic alterations of prefrontal white and gray matter in depression adolescents
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作者 Ying Zou Yu-Qin Wu +2 位作者 Yao-Jing Han Xiao-Ming He Jiang Zhao 《World Journal of Psychiatry》 SCIE 2024年第11期1652-1660,共9页
BACKGROUND Cases of depression among adolescents are gradually increasing.The study of the physiological basis of cognitive function from a biochemical perspective has therefore been garnering increasing attention.Dep... BACKGROUND Cases of depression among adolescents are gradually increasing.The study of the physiological basis of cognitive function from a biochemical perspective has therefore been garnering increasing attention.Depression has been hypothesized to be associated with the brain biochemical metabolism of the anterior cingulate gyrus,frontal lobe white matter,and the thalamus.AIM To explore the application of proton magnetic resonance spectroscopy(1H-MRS)in the metabolic alterations in the prefrontal white matter(PWM)and gray matter(GM)in adolescents with depression.METHODS 1H-MRS was performed for semi-quantitative analysis of the biochemical metabolites N-acetylaspartate(NAA),choline(Cho)complexes,creatine(Cr),and myoinositol(mI)in bilateral PWM,anterior cingulate GM,and thalami of 31 adolescent patients with depression(research group)and 35 healthy adolescents(control group),and the NAA/Cr,Cho/Cr,and mI/Cr ratios were calculated.Meanwhile,Hamilton Depression Scale(HAMD)and Wechsler Memory Scale were used to assess the degree of depression and memory function in all adolescents.The correlation of brain metabolite levels with scale scores was also analyzed.RESULTS The research group had markedly higher HAMD-24 scores and lower memory quotient(MQ)compared with the control group(P<0.05).Adolescents with depression were found to have lower bilateral PWM NAA/Cr and Cho/Cr ratios compared with healthy adolescents(P<0.05).The mI/Cr ratios were found to be similar in both groups(P>0.05).The bilateral anterior cingulate GM NAA/Cr,Cho/Cr,and mI/Cr also did not demonstrate marked differences(P>0.05).No statistical inter-group difference was determined in NAA/Cr of the bilateral thalami(P>0.05),while bilateral thalamic Cho/Cr and mI/Cr were reduced in teenagers with depression compared with healthy adolescents(P<0.05).A significant negative correlation was observed between the HAMD-24 scores in adolescents with depression with bilateral PWM NAA/Cr and Cho/Cr and were inversely linked to bilateral thalamic Cho/Cr and mI/Cr(P<0.05).In adolescents with depressions,MQ positively correlated with right PWH NAA/Cr,left PWH Cho/Cr,and bilateral thalamic Cho/Cr and mI/Cr.CONCLUSION PWM and thalamic metabolic abnormalities might influence teen depression,and the reduction in bilateral PWM NAA/Cr and Cho/Cr could be related to the neuropathology of adolescents with depression suffering from memory impairment.There exists a possibility of dysfunction of nerve cell membrane phospholipids in the thalami of adolescent patients with depression. 展开更多
关键词 Proton magnetic resonance spectroscopy Adolescent depression Prefrontal white matter Anterior cingulate gray matter METABOLISM
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Research on Grid-Connected Control Strategy of Distributed Generator Based on Improved Linear Active Disturbance Rejection Control
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作者 Xin Mao Hongsheng Su Jingxiu Li 《Energy Engineering》 EI 2024年第12期3929-3951,共23页
The virtual synchronous generator(VSG)technology has been proposed to address the problem of system frequency and active power oscillation caused by grid-connected new energy power sources.However,the traditional volt... The virtual synchronous generator(VSG)technology has been proposed to address the problem of system frequency and active power oscillation caused by grid-connected new energy power sources.However,the traditional voltage-current double-closed-loop control used in VSG has the disadvantages of poor disturbance immunity and insufficient dynamic response.In light of the issues above,a virtual synchronous generator voltage outer-loop control strategy based on improved linear autonomous disturbance rejection control(ILADRC)is put forth for consideration.Firstly,an improved first-order linear self-immunity control structure is established for the characteristics of the voltage outer loop;then,the effects of two key control parameters-observer bandwidthω_(0)and controller bandwidthω_(c)on the control system are analyzed,and the key parameters of ILADRC are optimally tuned online using improved gray wolf optimizer-radial basis function(IGWO-RBF)neural network.A simulationmodel is developed using MATLAB to simulate,analyze,and compare the method introduced in this paper.Simulations are performed with the traditional control strategy for comparison,and the results demonstrate that the proposed control method offers superior anti-interference performance.It effectively addresses power and frequency oscillation issues and enhances the stability of the VSG during grid-connected operation. 展开更多
关键词 Virtual synchronous generator(VSG) active power improved linear active disturbance rejection control(ILADRC) radial basis function(RBF)neural networks improved gray wolf optimizer(IGWO)
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顺应论视域下The Picture of Dorian Gray中译本的对比研究
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作者 滕璐 《现代语言学》 2024年第6期265-271,共7页
The Picture of Dorian Gray是王尔德唯一一部长篇小说,小说语言唯美自然。本文从顺应论的角度出发,从语境顺应、结构顺应以及动态顺应三个方面分析孙宜学译本与荣如德译本的差异。文章发现,两译者对于自己的定位不同,即前者是源语文化... The Picture of Dorian Gray是王尔德唯一一部长篇小说,小说语言唯美自然。本文从顺应论的角度出发,从语境顺应、结构顺应以及动态顺应三个方面分析孙宜学译本与荣如德译本的差异。文章发现,两译者对于自己的定位不同,即前者是源语文化的传播者,后者则是文学作品的传播者,译者的意识程度以及自身定位影响着译者采取的翻译方法,只有找准定位才能更好地翻译,获得更大的阅读价值以及参考价值。 展开更多
关键词 The Picture of Dorian Gray 英汉对比 顺应论 翻译对比
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Later-Life Marital Dissolution in Italy:An Emerging Phenomenon?
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作者 Laura Arosio 《Sociology Study》 2024年第2期98-106,共9页
The phenomenon of marital dissolution in later life,also referred to as“gray divorce”,is described on the rise in contemporary Western societies.This article contributes to the study of marriage breakdown in older a... The phenomenon of marital dissolution in later life,also referred to as“gray divorce”,is described on the rise in contemporary Western societies.This article contributes to the study of marriage breakdown in older age,with a specific focus on Italian society.First,the temporal trends of this phenomenon are reconstructed using official statistics.The data reveal that,although still relatively rare,the dissolution of marriage in later life is expanding in Italy.The analysis of the period from 1974 to 2015 indicates a rise in the average age at separation,a higher percentage of spouses over 50 years on the total number of couples obtaining legal separation,and an increase in the proportion of Italian spouses separating after many years of marriage.Furthermore,data from the national survey“Family and Social Subjects”,conducted in 2016 by the Italian National Institute of Statistics,are utilized to explore the relationship between specific traits of those who separated and their tendency to dissolve marriages before or after the age of 50.The data suggest that individuals with characteristics such as lower educational attainment,residence in the South and Islands,and adherence to more traditional family models are more likely to experience separation in later life. 展开更多
关键词 marital dissolution later life gray divorce social inequality ITALY
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基于Gray近似的弹性波阻抗方程及反演 被引量:66
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作者 王保丽 印兴耀 张繁昌 《石油地球物理勘探》 EI CSCD 北大核心 2007年第4期435-439,共5页
为得到更准确的岩石物理参数数据体,减小计算误差的累积效应,人们希望通过某种方法直接提取岩石物理参数。用Connolly的弹性阻抗(EI)公式进行反演只能直接得到纵、横波速度和密度的信息,再通过计算得到相应的弹性参数,而且不同角度的弹... 为得到更准确的岩石物理参数数据体,减小计算误差的累积效应,人们希望通过某种方法直接提取岩石物理参数。用Connolly的弹性阻抗(EI)公式进行反演只能直接得到纵、横波速度和密度的信息,再通过计算得到相应的弹性参数,而且不同角度的弹性阻抗的量纲不统一。本文针对Connolly方法的不足,通过Gray近似把佐普里兹方程表示为反射系数是剪切模量μ、拉梅系数λ和密度ρ的函数,提出了以Gray的AVO近似方程为基础的一种新的弹性波阻抗反演公式,并对该公式进行了标准化以实现不同角度的弹性波阻抗间量纲的统一。文中用标准化后的弹性波阻抗反演公式对A地区的实际地震数据进行了反演,从反演得到的弹性阻抗数据体中可直接提取剪切模量μ、拉梅系数λ,表明用文中方法提取弹性参数更加稳定、准确。 展开更多
关键词 Gray近似 弹性阻抗反演 标准化 拉梅参数
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基于弹性阻抗贝叶斯反演的拉梅参数提取方法研究 被引量:31
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作者 宗兆云 印兴耀 张繁昌 《石油地球物理勘探》 EI CSCD 北大核心 2011年第4期598-604,609,共8页
在储层预测和油气直接检测方面,储层介质拉梅参数比传统的纵横波速度及密度参数更有应用价值。叠前弹性波阻抗反演具有信息量丰富、分辨率高、运算速度快等特点。本文在贝叶斯理论框架下,假设待反演参数服从改进Cauchy分布,采用稀疏脉... 在储层预测和油气直接检测方面,储层介质拉梅参数比传统的纵横波速度及密度参数更有应用价值。叠前弹性波阻抗反演具有信息量丰富、分辨率高、运算速度快等特点。本文在贝叶斯理论框架下,假设待反演参数服从改进Cauchy分布,采用稀疏脉冲反演方法实现了基于Gray近似的叠前弹性波阻抗反演,并在此基础上提取到地下介质的拉梅参数信息。该方法可以较好地恢复待反演参数的稀疏性,减少对弱信号的压制并实现拉梅参数直接提取,减少传统方法带来的累积误差。模型试算表明,基于弹性阻抗贝叶斯反演的拉梅参数直接提取方法具有较好的稳定性和可靠性。实际应用表明,该方法适用于非均质性强的缝洞型碳酸盐岩储层,结果准确可靠。 展开更多
关键词 拉梅参数 弹性阻抗Gray近似 贝叶斯理论 非均匀介质
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广义Gray码及其在数字图像置乱中的应用 被引量:74
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作者 邹建成 李国富 齐东旭 《高校应用数学学报(A辑)》 CSCD 北大核心 2002年第3期363-370,共8页
以图像信息安全问题为背景 ,讨论了广义 Gray码及其在数字图像中的置乱作用 ,推广了丁玮等人 ( 1 999年 )的相关结果 .给出了图像置乱变换的周期 。
关键词 广义Gray码 数字图像 信息安全 置乱变换 周期性
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红树植物甲醇提取物的抑菌活性研究 被引量:20
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作者 阳振 邓业成 陈新华 《热带海洋学报》 CAS CSCD 北大核心 2007年第1期78-80,共3页
采用生长率法测定了15种红树植物甲醇提取物对西瓜枯萎病菌Fusarium oxysporumf.sp. Niveum、芒果叶枯病菌Pestalotia calabae Westond、甘蔗凤梨病菌Thielaviopsis paradoxa(de Seynes)V.Hohnel、香蕉炭疽病菌Glorosprium musarum Cook... 采用生长率法测定了15种红树植物甲醇提取物对西瓜枯萎病菌Fusarium oxysporumf.sp. Niveum、芒果叶枯病菌Pestalotia calabae Westond、甘蔗凤梨病菌Thielaviopsis paradoxa(de Seynes)V.Hohnel、香蕉炭疽病菌Glorosprium musarum Cookeet Mass、梨黑斑病菌Alternaria kikuchiana(Fr)Keissl、梨褐斑病菌Mycosphae-rella sentina(Fr.)Schroeter、柑桔疮痂病菌Sphaceloma fawcettiiJenkins和柑桔溃疡病菌Xanthomonas axonopo-dis pv. citri(Hasse)Dye 8种病原菌的抑菌活性。结果表明,水黄皮Pongamia pinnata(L.)Merr.、苦蓝盘Clerodendron inerme(L.)Gaertn.、桐花树Aegiceras corniculatum(Linn.)Blanco、海漆Excoecaria agallochaLinn.、榄李Lumnitzera racemosa Willd.、苦槛蓝Myoporum bontioides(Sieb.et Zucc.)A.Gray、海杧果Cerberamanghas L.对供试病原真菌有明显的抑菌活性,其中以苦槛蓝的抑菌活性最为显著,其甲醇提取物对上述7种病原真菌的EC50分别为3.32、1.04、2.57、1.44、1.63、2.66和1.25 mg.ml-1。 展开更多
关键词 红树植物 抑菌活性 苦槛蓝 Myoporum bontioides(Sieb.Et Zucc.)A.Gray
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