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Robustness of the octupole collectivity in 144Ba within the cranking covariant density functional theory in 3D lattice
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作者 Ze‑Kai Li Yuan‑Yuan Wang 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第8期124-131,共8页
The octupole deformation and collectivity in octupole double-magic nucleus 144Ba are investigated using the Cranking covariant density functional theory in a three-dimensional lattice space.The reduced B(E3)transition... The octupole deformation and collectivity in octupole double-magic nucleus 144Ba are investigated using the Cranking covariant density functional theory in a three-dimensional lattice space.The reduced B(E3)transition probability is implemented for the first time in semiclassical approximation based on the microscopically calculated electric octupole moments.The available data,including the I-ωrelation and electric transitional probabilities B(E2)and B(E3)are well reproduced.Furthermore,it is shown that the ground state of 144Ba exhibits axial octupole and quadrupole deformations that persist up to high spins(I≈24h). 展开更多
关键词 Octupole collectivity Cranking covariant density functional theory Rotational spectrum Electric transitional probabilities
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Moments of inertia of triaxial nuclei in covariant density functional theory
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作者 Yu-Meng Wang Qi-Bo Chen 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第10期197-207,共11页
The covariant density functional theory(CDFT)and five-dimensional collective Hamiltonian(5DCH)are used to analyze the experimental deformation parameters and moments of inertia(MoIs)of 12 triaxial nuclei as extracted ... The covariant density functional theory(CDFT)and five-dimensional collective Hamiltonian(5DCH)are used to analyze the experimental deformation parameters and moments of inertia(MoIs)of 12 triaxial nuclei as extracted by Allmond and Wood[J.M.Allmond and J.L.Wood,Phys.Lett.B 767,226(2017)].We find that the CDFT MoIs are generally smaller than the experimental values but exhibit qualitative consistency with the irrotational flow and experimental data for the relative MoIs,indicating that the intermediate axis exhibites the largest MoI.Additionally,it is found that the pairing interaction collapse could result in nuclei behaving as a rigid-body flow,as exhibited in the^(186-192)Os case.Furthermore,by incorporating enhanced CDFT MoIs(factor of f≈1.55)into the 5DCH,the experimental low-lying energy spectra and deformation parameters are reproduced successfully.Compared with both CDFT and the triaxial rotor model,the 5DCH demonstrates superior agreement with the experimental deformation parameters and low-lying energy spectra,respectively,emphasizing the importance of considering shape fluctuations. 展开更多
关键词 Moment of inertia Trixial nucleus covariant density functional theory Five-dimensional collective Hamiltonian Low-lying energy spectrum
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Calculation of microscopic nuclear level densities based on covariant density functional theory 被引量:2
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作者 Kun-Peng Geng Peng-Xiang Du +1 位作者 Jian Li Dong-Liang Fang 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2023年第9期118-127,共10页
In this study,a microscopic method for calculating the nuclear level density(NLD)based on the covariant density functional theory(CDFT)is developed.The particle-hole state density is calculated by a combinatorial meth... In this study,a microscopic method for calculating the nuclear level density(NLD)based on the covariant density functional theory(CDFT)is developed.The particle-hole state density is calculated by a combinatorial method using single-particle level schemes obtained from the CDFT,and the level densities are then obtained by considering collective effects such as vibration and rotation.Our results are compared with those of other NLD models,including phenomenological,microstatisti-cal and nonrelativistic Hartree–Fock–Bogoliubov combinatorial models.This comparison suggests that the general trends among these models are essentially the same,except for some deviations among the different NLD models.In addition,the NLDs obtained using the CDFT combinatorial method with normalization are compared with experimental data,including the observed cumulative number of levels at low excitation energies and the measured NLDs.The CDFT combinatorial method yields results that are in reasonable agreement with the existing experimental data. 展开更多
关键词 Nuclear level density covariant density functional theory Combinatorial method
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Model Selection in Estimation of Covariance Functions for Growth of Angora Goats 被引量:2
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作者 LIU Wen-zhong ZHANG Yuan ZHOU Zhong-xiao 《Agricultural Sciences in China》 CAS CSCD 2010年第7期1041-1049,共9页
Covariance functions have been proposed as an alternative to model longitudinal data in animal breeding because of their various merits in comparison to the classical analytical methods.In practical estimation,differe... Covariance functions have been proposed as an alternative to model longitudinal data in animal breeding because of their various merits in comparison to the classical analytical methods.In practical estimation,different models and polynomial orders fitted can influence the estimates of covariance functions and thus genetic parameters.The objective of this study was to select model for estimation of covariance functions for body weights of Angora goats at 7 time points.Covariance functions were estimated by fitting 6 random regression models with birth year,birth month,sex,age of dam,birth type,and relative birth date as fixed effects.Random effects involved were direct and maternal additive genetic,and animal and maternal permanent environmental effects with different orders of fit.Selection of model and orders of fit were carried out by likelihood ratio test and 4 types of information criteria.The results showed that model with 6 orders of polynomial fit for direct additive genetic and animal permanent environmental effects and 4 and 5 orders for maternal genetic and permanent environmental effects,respectively,were preferable for estimation of covariance functions.Models with and without maternal effects influenced the estimates of covariance functions greatly.Maternal permanent environmental effect does not explain the variation of all permanent environments,well suggesting different sources of permanent environmental effects also has large influence on covariance function estimates. 展开更多
关键词 Angora goats GROWTH covariance function model selection random regression model
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Recent efficacy and long-term survival of Astragalus polysaccharide combined with gemcitabine and S-1 in pancreatic cancer
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作者 Guang-Yu Li Jing Jiang 《World Journal of Clinical Oncology》 2024年第11期1404-1411,共8页
BACKGROUND Pancreatic cancer is a highly malignant tumor with a rapid progression rate and a high susceptibility to infiltration and metastasis.Astragalus polysaccharide(APS),a pure Chinese medicine preparation primar... BACKGROUND Pancreatic cancer is a highly malignant tumor with a rapid progression rate and a high susceptibility to infiltration and metastasis.Astragalus polysaccharide(APS),a pure Chinese medicine preparation primarily made from the traditional Chinese herb Astragalus,plays a positive role in the treatment of many malignant tumors.AIM To explore the recent efficacy of APS combined with gemcitabine plus tegafur gimeracil oteracil potassium capsule(S-1)(GS)regimen in the treatment of pancreatic cancer and assess its effect on the immune function and long-term survival of patients.METHODS A total of 97 patients who were diagnosed with pancreatic cancer and received GS chemotherapy at The First Affiliated Hospital of Zhejiang Chinese Medical University(Zhejiang Provincial Hospital of Chinese Medicine)from March 2021 to December 2021 were included in the retrospective analysis.Among them,41 patients received APS combined with GS chemotherapy,and 56 patients received GS chemotherapy only.The recent efficacy,immune function,adverse reactions,and long-term survival were compared among these patients.RESULTS After 4 cycles of treatment,the objective response rate of patients receiving the combined therapy of APS and GS was 51.22%,and the disease control rate(DCR)was 56.10%,higher than those of patients receiving the monotherapy with GS alone(30.36%and 35.71%,respectively).Besides,the percentages of CD3+T cells(50.18%±9.57%)and CD4+T cells(31.52%±5.33%)in the peripheral blood of patients receiving the combined therapy of APS and GS were higher compared with those treated with GS regimen alone[(44.06%±8.55%)and(26.01%±7.83%),respectively].Additionally,the incidences of leukopenia,thrombocytopenia,and fatigue in patients receiving the combined therapy of APS and GS were significantly lower than those in patients receiving the monotherapy of GS alone(17.07%,9.76%,31.71%vs 37.50%,28.57%,60.71%).Moreover,the median survival time of patients receiving the combined therapy of APS and GS was 394 days,significantly longer than that of patients receiving the mono-therapy of GS alone(339 days)(hazard ratio:0.66;95%CI:0.45-0.99;P=0.036).All these differences were statistically si-gnificant(P<0.05).CONCLUSION The combined therapy of APS and GS improved the recent efficacy and long-term survival of patients with pancreatic cancer and alleviated chemotherapy-induced immune suppression and adverse reactions. 展开更多
关键词 Pancreatic cancer Astragalus polysaccharide long-term survival Immune function Traditional Chinese medicine
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Safety and Quality of Care Evaluation in Japanese Long-Term Facilities Focused on the Activity Condition and Cognitive Function of Residents 被引量:1
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作者 Sayuri Kaneko 《Open Journal of Nursing》 2020年第2期131-142,共12页
Objective: Currently, standards for evaluating long-term care facilities do not exist in Japan. This study aimed to evaluate the quality of healthcare services in Japan’s long-term care facilities and identify the st... Objective: Currently, standards for evaluating long-term care facilities do not exist in Japan. This study aimed to evaluate the quality of healthcare services in Japan’s long-term care facilities and identify the structural and process indicators associated with the facilities’ outcome indicators. Methods: This retrospective study assessed changes in residents’ abilities to participate in physical activities, their cognitive function, and their vulnerability to injuries. From 2012 to 2013, we collected information on the healthcare services at 1067 long-term care facilities registered with Japan’s Welfare, Health and Medical Care Information Network in the Welfare and Medical Service Agency. We examined 12 structural indicators, 26 process indicators, and 7 outcome indicators. We used multivariate linear regression models adjusted to analyze relationships between outcome indicators and structural or process indicators. Results: Residents’ activity and cognitive function indicators either improved by 80% - 90% or were maintained for one year. The Geriatric Functional Independence Measures, the Barthel Index, and holding conferences related to care were all considered activities of daily living. Three adverse events—tumbles and falls, behavioral problems, and aimless wandering or leaving the facility without permission—were factors that restricted residents’ behavior and number of residents per care staff member. Conclusions: Maintaining or improving levels of independence and cognition in daily living requires a care process system that enables ongoing monitoring of residents’ activities of daily living and cognitive functioning. Ensuring the safety of residents and improving the quality of care in long-term care facilities without securing adequate care staff are not possible. 展开更多
关键词 Activity CONDITION Cognitive function long-term CARE Facility SAFETY Quality of CARE
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Tilted Axis Rotation of ^(57)Mn in Covariant Density Functional Theory
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作者 彭婧 徐文强 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第1期23-26,共4页
The self-consistent tilted axis cranking covariant density functional theory based on the point-coupling interaction is applied to investigate the tilted axis rotation in ^57 Mn. The observed data for band C are repro... The self-consistent tilted axis cranking covariant density functional theory based on the point-coupling interaction is applied to investigate the tilted axis rotation in ^57 Mn. The observed data for band C are reproduced well with the assigned configuration eonfig 1. The shears mechanism for magnetic rotation is examined by investigating microscopically the orientation of angular momentum and the corresponding contributions. It is found that config 1 and config 3 correspond to a rotation of high-K character. Config 2 corresponds to a rotation of magnetic character. However, due to the presence of electromagnetic transition B(M1) and B(E2), collective rotation plays an essential role in the competition with magnetic rotation. 展开更多
关键词 Tilted Axis Rotation of on IS AS IT in Mn in covariant Density functional Theory for been
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Long-term renal function, complications and life expectancy in living kidney donors
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作者 Masahiko Okamoto 《World Journal of Transplantation》 2012年第1期5-8,共4页
Living kidney transplantation is now a widely accepted treatment for end stage renal disease(ESRD) because it provides excellent outcomes for recipients. However, long-term outcomes of living kidney donors have not be... Living kidney transplantation is now a widely accepted treatment for end stage renal disease(ESRD) because it provides excellent outcomes for recipients. However, long-term outcomes of living kidney donors have not been well understood. Because securing the safety of the donor is essential to the continued success of this procedure, we reviewed articles discussing long-term outcomes of living kidney donors. Most studies found no decrease in long-term survival or progressive renal dysfunction in previous kidney donors. Moreover, the prevalence of hypertension was comparable to that expected in the general population, although some did report otherwise. Urinary protein showed small increases in this population and was associated with hypertension and a lower glomerular filtration rate. Quality of life following living kidney donation seems to be better than the national norm. We also encountered several reports of ESRD in previous living kidney donors. Regular follow-up of kidney donors is recommended and future controlled, prospective studies will better delineate risk factors which cause health problems following living kidney donation. 展开更多
关键词 Living kidney DONOR long-term survival Hypertension PROTEINURIA RENAL function Quality of LIFE
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Clinical Significance of Pulmonary Function Tests in Long-Term Survivors after Myeloablative Allogeneic Hematopoietic Stem Cell Transplantation
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作者 Kenji Matsumoto Satomi Ito +4 位作者 Wataru Yamamoto Eriko Ogusa Atsuo Maruta Yoshiaki Ishigatsubo Heiwa Kanamori 《Open Journal of Blood Diseases》 2013年第1期6-12,共7页
We retrospectively assessed long-term pulmonary function in adults surviving for ≥5 years after myeloablative allogeneic hematopoietic stem cell transplantation and identified risk factors for late-onset noninfectiou... We retrospectively assessed long-term pulmonary function in adults surviving for ≥5 years after myeloablative allogeneic hematopoietic stem cell transplantation and identified risk factors for late-onset noninfectious pulmonary complications. Among 174 patients undergoing transplantation for hematologic malignancies between May 1994 and December 2004, 81 long-term survivors were evaluated. Pulmonary function tests (PFTs) were performed before conditioning, 3 months and 1 year after transplantation, and then annually. Eight patients (10%) had abnormal pulmonary function before transplantation, but this was not associated with late changes in PFTs. Patients with chronic graft-versus-host disease (GVHD) showed a significant decline of lung function after 3 years when compared with patients without chronic GVHD. Abnormal pretransplantation lung function was associated with pulmonary chronic GVHD according to National Institutes of Health criteria (score 0, n = 58;score 1, n = 14;score 2, n = 6;score 3, n = 3). Five patients with late-onset noninfectious pulmonary complications showed a decline of lung function at 1 year after transplantation. Only chronic GVHD was significantly related to late-onset noninfectious pulmonary complications. In conclusion, abnormal lung function before transplantation may be associated with a decline in pulmonary function within 1 year after transplantation, but late-onset noninfectious pulmonary complications could not be predicted from pretransplantation lung function. 展开更多
关键词 long-term SURVIVOR PULMONARY function Tests LATE-ONSET Noninfectious PULMONARY COMPLICATIONS MYELOABLATIVE ALLOGENEIC Stem Cell Transplantation
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Evaluation of Care Quality Related to Dietary Intake and Swallowing Functions of Residents at Long-Term Facilities in Japan
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作者 Sayuri Kaneko 《Open Journal of Nursing》 2021年第7期610-619,共10页
This study aimed to evaluate the quality of healthcare services pertaining to the dietary intake and swallowing functions of residents, nutrition management practices, and performance of residents at long-term care fa... This study aimed to evaluate the quality of healthcare services pertaining to the dietary intake and swallowing functions of residents, nutrition management practices, and performance of residents at long-term care facilities. We investigated outcome indicators, such as changes in dietary intake and swallowing function levels of residents, and clarified which structural and process indicators were associated with the outcome indicators. This was a retrospective study, analyzing information on healthcare services from 1067 long-term care facilities during the fiscal year 2012, sampled from among those registered with the Welfare, Health and Medical Care Information Network of the Welfare and Medical Service Agency in Japan. Five outcome indicators were identified. Next, we examined the relationships between the outcome indicators and structural or process indicators using a multivariate linear regression model, adjusting for facility type. The findings showed how the five outcome indicators were used in long-term care facilities over a period of one year and determined the independent predictors of these outcome indicators. The amplification of dietary function 1 was associated with “assessment of oral functions using a feeding and swallowing assessment checklist every three months”, “holding care conferences related to ingestion and swallowing every three months”, and “maintaining a 1:2 ratio for meal-time assistants to residents”. To improve the quality of care, it is necessary to increase the number of staff (e.g., to provide meal assistance to residents) and to understand changes in the residents’ status through accurate assessment and monitoring. 展开更多
关键词 Dietary Intake long-term Care Facility Nutrient Intake Quality Indicators Swallowing functions
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Long-term feeding of sand rice(Agriophyllum squarrosum seed)can improve the antioxidant capacity of mice
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作者 PengShu Zhao Liang Shi +9 位作者 Xia Yan ChaoJu Qian WeiJia Zhao Yan Chang XiaoYue Yin XingKe Fan TingZhou Fang YuQiu Liao ShanShan Zhou XiaoFei Ma 《Research in Cold and Arid Regions》 CSCD 2023年第2期105-112,共8页
Unhealthy eating habits with sugar-rich and high-fat foods can bring nutritional imbalance and other chronic diseases. At present, there is an increasing demand in regulating human sub-health through functional foods.... Unhealthy eating habits with sugar-rich and high-fat foods can bring nutritional imbalance and other chronic diseases. At present, there is an increasing demand in regulating human sub-health through functional foods. Agriophyllum squarrosum(L.) Moq., a pioneer plant native to sand dunes with ecological restoration function, is a traditional food plant of sand regions and Mongolian folk medicine. Numerous studies have confirmed that A. squarrosum seed, also called sand rice, has high nutritional value. However, the long-term health effects of eating sand rice remain unclear. To better explore and evaluate its long-term effects, hereby, ICR mice were fed with sand rice flour at different ratios(control, 60% and 95%) for 100 days. Results show that the growth and blood glucose level curve of these experimental mice were lower and more stable than that of the control. In addition, mice fed pure sand rice ingredient(95%) gained more stable body weight and blood glucose after 28 days, which revealed that sand rice is a food with comprehensive nutritional value and rarely negatively impacts the body growth performance. Our data also demonstrates that, the content of triglyceride(TG), total cholesterol(TC), low-density lipoprotein cholesterol(LDL-C) and high-density lipoprotein cholesterol(HDL-C) provided the lowest level in the blood of mice with a diet of pure sand rice ingredient, 0.48, 4.14, 0.91, 3.03 mmol/L, respectively. Also, T-SOD and GSH-PX activity provided a high level in mice with pure sand rice gradient, which significantly increased by 36%(T-SOD)and 19%(GSH-PX) compared to the control. These results suggest that long term intake of the pure sand rice ingredients is more helpful for stabilizing blood lipid and improve antioxidant capacity and beneficial to people suffering from chronic disease. This study supplies the first animal evidence to support the claim that sand rice is a promising functional food with comprehensive nutrition in the future. We are confident that, with increasing demands of daily sand rice usage, planting A. squarrosum in the vast desert regions will further increase the local economy and ecological restoration when coping with global warming. 展开更多
关键词 Sand rice functional food long-term effects Health evaluation Antioxidant capacity
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A comparative study of pancreatic endocrine function and related metabolism after long-term survival between the patients with combined kidneypancreas transplantation vs those with combined en bloc ' liver-pancreas transplantation
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作者 朱晓峰 《外科研究与新技术》 2011年第4期292-292,共1页
Objective To compare the effects of combined en bloc liver - pancreas transplantation ( LPT) with portal vein drainage and simultaneous combined kidney - pancreas transplantation ( KPT) with systemic venous drainage o... Objective To compare the effects of combined en bloc liver - pancreas transplantation ( LPT) with portal vein drainage and simultaneous combined kidney - pancreas transplantation ( KPT) with systemic venous drainage on the pancreatic endocrine function and related me- 展开更多
关键词 LPT A comparative study of pancreatic endocrine function and related metabolism after long-term survival between the patients with combined kidneypancreas transplantation vs those with combined en bloc liver-pancreas transplantation KPT
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基于二次分数低阶协方差的时延估计方法 被引量:1
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作者 刘小松 徐再祥 +2 位作者 单泽彪 徐恩达 吕悦 《电子测量与仪器学报》 CSCD 北大核心 2024年第2期112-119,共8页
针对强脉冲噪声背景下基于分数低阶统计量时延估计方法性能退化且需要噪声先验知识的问题,提出了一种基于二次分数低阶协方差的时延估计新方法。所提方法首先利用有界非线性Sigmoid函数对含有脉冲噪声的信号进行预处理,使其在不影响有... 针对强脉冲噪声背景下基于分数低阶统计量时延估计方法性能退化且需要噪声先验知识的问题,提出了一种基于二次分数低阶协方差的时延估计新方法。所提方法首先利用有界非线性Sigmoid函数对含有脉冲噪声的信号进行预处理,使其在不影响有用信号时延信息的基础上对附加脉冲噪声进行充分压缩;然后对处理后的收发信号进行二次分数低阶协方差运算,即求得发射信号的自分数低阶协方差和收发信号的互分数低阶协方差之后,再次计算二者的互分数低阶协方差,以期更大程度上抑制脉冲噪声的影响。通过模拟仿真实验对所提方法进行了有效性验证,结果表明所提方法突破了分数低阶矩阶次需小于Alpha稳定分布噪声特征指数的限制,并且比分数低阶协方差方法具有更高的估计精度。仿真实验结果表明在广义信噪比-10 dB情况下,时延估计用时为0.0560 s,准确率达到97.76%。 展开更多
关键词 时延估计 脉冲噪声 二次分数低阶协方差 有界非线性函数
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协方差分析描述函数法的通用化数值算法
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作者 王汉平 柳洋鑫 张宝振 《北京理工大学学报》 EI CAS CSCD 北大核心 2024年第5期439-446,共8页
协方差分析描述函数法(covariance analysis describing function technique,CADET)在处理系统的随机响应问题上具有求解迅速、仿真精度高等优点.但对于复杂系统,其理论推导过程、求解系统解析响应方程较为复杂繁琐.为进一步推广CADET... 协方差分析描述函数法(covariance analysis describing function technique,CADET)在处理系统的随机响应问题上具有求解迅速、仿真精度高等优点.但对于复杂系统,其理论推导过程、求解系统解析响应方程较为复杂繁琐.为进一步推广CADET的应用,依托高斯–埃尔米特积分法,提出了一种通用化的CADET数值算法.作为算法验证,以车辆行驶过程中的随机振动为例,建立了几种不同非线性悬架车辆的二自由度动力学模型,并将CADET通用化数值算法与传统CADET算法及蒙特卡罗法进行了对比分析.仿真结果表明,CADET的通用化数值算法可以达到满足应用要求的计算精度,这验证了所提数值算法的有效性,且具有更强的泛化应用于复杂非线性动力系统的价值. 展开更多
关键词 车辆悬架系统 协方差分析描述函数法 随机振动 数值算法 非线性系统
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不同微生境毛尖紫萼藓形态结构性状差异性与协变特征
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作者 代玲 张梦玉 +1 位作者 邱东 马晓东 《江西农业大学学报》 CAS CSCD 北大核心 2024年第3期726-735,共10页
【目的】毛尖紫萼藓(Grimmia pilifera)是典型的石生耐旱藓类,广布于我国南北各省,其生长往往受到干旱和贫瘠生长环境的限制,是自然界的拓荒者之一。研究不同微生境中毛尖紫萼藓形态结构性状的差异性与协变特征,为开展藓类植物耐旱机理... 【目的】毛尖紫萼藓(Grimmia pilifera)是典型的石生耐旱藓类,广布于我国南北各省,其生长往往受到干旱和贫瘠生长环境的限制,是自然界的拓荒者之一。研究不同微生境中毛尖紫萼藓形态结构性状的差异性与协变特征,为开展藓类植物耐旱机理研究及深入揭示石生耐旱藓类在不同微环境的适应机制提供基础数据。【方法】以3种不同遮荫程度微生境(竹林开放式遮蔽岩石S_(1)、向阳裸岩E、薜荔完全遮蔽岩石S_(2))下的毛尖紫萼藓为研究对象,通过测定15个形态结构性状,即7个单株性状(中部叶片夹角、中部叶长度、中部毛尖长度、上部毛尖长度、植株高度、带毛尖的植株宽度、不带毛尖的植株宽度)和8个茎叶微结构性状(茎横截面长、茎横截面宽、茎中部细胞长、茎中部细胞宽、茎细胞密度、叶中肋宽、叶细胞长、叶细胞宽),计算各性状的变异系数,探究其形态结构性状在不同微生境间的差异性与协变特征。【结果】在单株性状中,株高、植株宽度、植株宽度(带毛尖)、叶片夹角和中部叶长最大值均出现在S_(1)生境,最小值多出现在E生境,而中部毛尖长为S_(2)>E>S_(1)。无论何种微生境,毛尖长度的变异性均较高。在茎叶微结构性状中,茎细胞长、叶细胞长及叶细胞宽均表现为S_(1)生境显著高于E生境,其他5个茎叶微结构性状在3个微生境间无显著差异(P>0.05)。叶细胞在S_(1)生境中最大,S_(2)生境中次之,E生境中最小。所有性状均属于中等以下程度变异,具有一定的可塑性。主成分分析表明,不同微生境下毛尖紫萼藓15个性状间的协变特征不完全一致,且呈现较明显的分异特征,其中S_(1)生境的毛尖紫萼藓综合生长性能相对较好。【结论】在3种不同微生境下,毛尖紫萼藓形态结构性状所反映的生长性能表现为:S_(1)>S_(2)>E。毛尖紫萼藓功能性状间具有一定的协变趋势,但出现了微生境间的差异化,这是对不同微环境长期响应和适应的结果。该研究结果可为进一步探讨藓类植物这类特殊植物类群对不同微生境的响应与适应提供理论依据。 展开更多
关键词 毛尖紫萼藓 微生境 功能性状 协变
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A Cautionary Note on the Application of GIS in Spatial Optimization Modeling
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作者 Bin Zhou 《Journal of Geographic Information System》 2024年第1期89-113,共25页
Spatial optimization as part of spatial modeling has been facilitated significantly by integration with GIS techniques. However, for certain research topics, applying standard GIS techniques may create problems which ... Spatial optimization as part of spatial modeling has been facilitated significantly by integration with GIS techniques. However, for certain research topics, applying standard GIS techniques may create problems which require attention. This paper serves as a cautionary note to demonstrate two problems associated with applying GIS in spatial optimization, using a capacitated p-median facility location optimization problem as an example. The first problem involves errors in interpolating spatial variations of travel costs from using kriging, a common set of techniques for raster files. The second problem is inaccuracy in routing performed on a graph directly created from polyline shapefiles, a common vector file type. While revealing these problems, the paper also suggests remedies. Specifically, interpolation errors can be eliminated by using agent-based spatial modeling while the inaccuracy in routing can be improved through altering the graph topology by splitting the long edges of the shapefile. These issues suggest the need for caution in applying GIS in spatial optimization study. 展开更多
关键词 Spatial Optimization GIS Agent-Based Model covariance function INTERPOLATION
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基于航迹概率假设密度的多传感器多目标跟踪
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作者 王志伟 刘永祥 +1 位作者 杨威 卢哲俊 《系统工程与电子技术》 EI CSCD 北大核心 2024年第2期526-533,共8页
针对基于概率假设密度(probability hypothesis density,PHD)的分布式多传感器多目标跟踪(distributed multi-sensor multi-target tracking,DMMT)存在无法形成航迹、计算复杂度高、目标漏检等问题。本文基于航迹PHD后验估计提出了一种D... 针对基于概率假设密度(probability hypothesis density,PHD)的分布式多传感器多目标跟踪(distributed multi-sensor multi-target tracking,DMMT)存在无法形成航迹、计算复杂度高、目标漏检等问题。本文基于航迹PHD后验估计提出了一种DMMT方法。为此,首先构建了各节点估计航迹间相似性度量矩阵,并采用匈牙利算法实现最优航迹匹配;其次采用协方差逆准则对关联航迹实现并行融合;最后基于概率生成泛函推导了一种鲁棒的DMMT方法。仿真实验验证了所提算法在目标状态估计精度、计算有效性和实时性方面的优势。 展开更多
关键词 航迹概率假设密度 最优航迹匹配 广义协方差逆 概率生成泛函
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均值函数相等检验及在高频股指收益率中应用
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作者 李气芳 黄宝坤 《佳木斯大学学报(自然科学版)》 CAS 2024年第6期176-180,共5页
针对具有相依特征的函数型数据样本,提出利用经典的Newey-West估计式对它们的长期协方差函数进行估计,从而可以得到更加准确的函数主成分,进而对独立同分布条件下的均值函数相等检验统计量进行改进,并通过模特卡罗模拟和实例分析与现有... 针对具有相依特征的函数型数据样本,提出利用经典的Newey-West估计式对它们的长期协方差函数进行估计,从而可以得到更加准确的函数主成分,进而对独立同分布条件下的均值函数相等检验统计量进行改进,并通过模特卡罗模拟和实例分析与现有独立同分布和相依条件下的检验方法进行比较。模特卡罗模拟结果表明,相比于现有检验方法,文中所提改进方法的检验水平与显著性水平更接近,而检验功效更高。实例分析结果表明,2018年沪深300和上证180股指1分钟和5分钟累积收益率的均值函数相等,即这两个金融市场的投资收益水平相当。 展开更多
关键词 相依函数型数据 均值函数相等检验 长期协方差函数 累积收益率
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Karhunen-Loeve展开在Abaqus中的实现
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作者 胡烨之 张雅琪 《计算机辅助工程》 2024年第2期44-49,60,共7页
基于数值分析理论,提出一种Karhunen-Loeve展开的数值算法,采用Python和Fortran混合编码的方式将其内嵌至Abaqus的计算内核中,分析程序编制的关键要素并开展误差分析。结果表明:编制的程序可行,随机场展开合理,数值算法精度较高,特征值... 基于数值分析理论,提出一种Karhunen-Loeve展开的数值算法,采用Python和Fortran混合编码的方式将其内嵌至Abaqus的计算内核中,分析程序编制的关键要素并开展误差分析。结果表明:编制的程序可行,随机场展开合理,数值算法精度较高,特征值、特征函数以及协方差函数的计算结果与理论解一致。 展开更多
关键词 随机场 ABAQUS Karhunen-Loeve展开 协方差函数 第二类Fredholm积分
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小波辅助的最小二乘配置在板块运动中的应用
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作者 赵旭坤 王东东 徐欢 《办公自动化》 2024年第17期87-90,共4页
在块体运动监测中,同一区域块体运动整体上表现出趋势性,局部区域又表现出随机性和不规则性。基于此,文章采用最小二乘配置模型确定我国大陆主要块体运动模型。针对速度场数据被污染的情况,采用小波变换对其进行处理,减少数据污染的影... 在块体运动监测中,同一区域块体运动整体上表现出趋势性,局部区域又表现出随机性和不规则性。基于此,文章采用最小二乘配置模型确定我国大陆主要块体运动模型。针对速度场数据被污染的情况,采用小波变换对其进行处理,减少数据污染的影响。实验结果表明,运动参数的精度有一定的提高。 展开更多
关键词 最小二乘配置 小波变换 协方差函数 板块运动
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