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Treadmill exercise in combination with acousto-optic and olfactory stimulation improves cognitive function in APP/PS1 mice through the brain-derived neurotrophic factor-and Cygb-associated signaling pathways
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作者 Biao Xiao Chaoyang Chu +6 位作者 Zhicheng lin Tianyuan Fang Yuyu Zhou Chuxia Zhang Jianghui Shan Shiyu Chen liping li 《Neural Regeneration Research》 SCIE CAS 2025年第9期2706-2726,共21页
A reduction in adult neurogenesis is associated with behavioral abnormalities in patients with Alzheimer's disease.Consequently,enhancing adult neurogenesis represents a promising therapeutic approach for mitigati... A reduction in adult neurogenesis is associated with behavioral abnormalities in patients with Alzheimer's disease.Consequently,enhancing adult neurogenesis represents a promising therapeutic approach for mitigating disease symptoms and progression.Nonetheless,nonpharmacological interventions aimed at inducing adult neurogenesis are currently limited.Although individual non-pharmacological interventions,such as aerobic exercise,acousto-optic stimulation,and olfactory stimulation,have shown limited capacity to improve neurogenesis and cognitive function in patients with Alzheimer's disease,the therapeutic effect of a strategy that combines these interventions has not been fully explored.In this study,we observed an age-dependent decrease in adult neurogenesis and a concurrent increase in amyloid-beta accumulation in the hippocampus of amyloid precursor protein/presenilin 1 mice aged 2-8 months.Amyloid deposition became evident at 4 months,while neurogenesis declined by 6 months,further deteriorating as the disease progressed.However,following a 4-week multifactor stimulation protocol,which encompassed treadmill running(46 min/d,10 m/min,6 days per week),40 Hz acousto-optic stimulation(1 hour/day,6 days/week),and olfactory stimulation(1 hour/day,6 days/week),we found a significant increase in the number of newborn cells(5'-bromo-2'-deoxyuridine-positive cells),immature neurons(doublecortin-positive cells),newborn immature neurons(5'-bromo-2'-deoxyuridine-positive/doublecortin-positive cells),and newborn astrocytes(5'-bromo-2'-deoxyuridine-positive/glial fibrillary acidic protein-positive cells).Additionally,the amyloid-beta load in the hippocampus decreased.These findings suggest that multifactor stimulation can enhance adult hippocampal neurogenesis and mitigate amyloid-beta neuropathology in amyloid precursor protein/presenilin 1 mice.Furthermore,cognitive abilities were improved,and depressive symptoms were alleviated in amyloid precursor protein/presenilin 1 mice following multifactor stimulation,as evidenced by Morris water maze,novel object recognition,forced swimming test,and tail suspension test results.Notably,the efficacy of multifactor stimulation in consolidating immature neurons persisted for at least 2weeks after treatment cessation.At the molecular level,multifactor stimulation upregulated the expression of neuron-related proteins(NeuN,doublecortin,postsynaptic density protein-95,and synaptophysin),anti-apoptosis-related proteins(Bcl-2 and PARP),and an autophagyassociated protein(LC3B),while decreasing the expression of apoptosis-related proteins(BAX and caspase-9),in the hippocampus of amyloid precursor protein/presenilin 1 mice.These observations might be attributable to both the brain-derived neurotrophic factor-mediated signaling pathway and antioxidant pathways.Furthermore,serum metabolomics analysis indicated that multifactor stimulation regulated differentially expressed metabolites associated with cell apoptosis,oxidative damage,and cognition.Collectively,these findings suggest that multifactor stimulation is a novel non-invasive approach for the prevention and treatment of Alzheimer's disease. 展开更多
关键词 acousto-optic stimulation adult neurogenesis Alzheimer's disease amyloid precursor protein/presenilin 1 mice amyloid-beta deposition brain cell apoptosis cognitive impairment depression-like behavior involuntary treadmill exercise olfactory stimulation serum metabolites
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Chemical bonding of perovskite LaFeO_(3) with Li_(1.2)Mn_(0.6)Ni_(0.2)O_(2) to moderate anion redox for achieving high cycling stability
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作者 Xin Zhang Chaochao Fu +5 位作者 Dong Luo Xiaoqing liu Qiao Wang Baoyun li Guangshe li liping li 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第4期330-339,共10页
Oxygen anion redox reaction provides a high theoretical capacity for Li-rich manganese-based cathodes.However,irreversible surface oxygen release often results in further oxygen loss and exacerbates the decomposition ... Oxygen anion redox reaction provides a high theoretical capacity for Li-rich manganese-based cathodes.However,irreversible surface oxygen release often results in further oxygen loss and exacerbates the decomposition of the electrolyte,which could reduce the capacity contribution from the anionic redox and produce more acidic substances to corrode the surface of the material.In this paper,the surface oxygen release is suppressed by moderating oxygen anion redox activity via constructing chemical bonds between M(M=Fe and La)in LaFeO_(3)and surface oxygen anions of Li_(1.2)Mn_(0.6)Ni_(0.2)O_(2).The constructed interface layer stabilizes the surface lattice oxygen and retards the electrolyte from being attacked by the nucleophilic oxygen generated in the process of oxygen release,as evidenced by Differential Electrochemical Mass Spectrometry(DEMS)and X-ray Photoelectron Spectroscopy(XPS)detections.Moreover,in the charge and discharge process,the formed FeF_(3),located at the cathode electrolyte interfacial layer,is conducive to the stability of the cathode surface.The modified Li_(1.2)Mn_(0.6)Ni_(0.2)O_(2)electrode with 3 wt%LaFeO_(13)exhibits a high specific capacity of 189.5 mA h g-at 1C(200 mA g^(-1))after 150 cycles with capacity retentions of 96.6%,and 112.6 mA h g^(-1)(84.7%)at 5C after 200 cycles higher than the pristine sample.This study provides a rational design chemical bonding method to suppress the oxygen release from the cathode surface and enhance cyclic stability. 展开更多
关键词 Lithium battery Li_(1.2)Mn_(0.6)Ni_(0.2)O_(2) Oxygen release Interface chemical bond Electrolyte decomposition
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新冠疫情后传统校园欺凌的流行率是否增加--一项来自两阶段横断面研究的证据
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作者 陈月亮 周家俊 +2 位作者 宋子翊 达清琛(摘译) 李丽萍(审校) 《伤害医学(电子版)》 2024年第1期51-55,共5页
新型冠状病毒感染(COVID-19)疫情对全球青少年的日常生活产生巨大影响,包括隔离、停课和社交娱乐活动限制等。此外,新冠疫情还对学生的行为、心理和生理健康造成一系列不良影响,如久坐时间增长和体力活动水平下降、网络使用时间增长、... 新型冠状病毒感染(COVID-19)疫情对全球青少年的日常生活产生巨大影响,包括隔离、停课和社交娱乐活动限制等。此外,新冠疫情还对学生的行为、心理和生理健康造成一系列不良影响,如久坐时间增长和体力活动水平下降、网络使用时间增长、药物滥用、自我效能降低、压力增加、肥胖、睡眠障碍、自伤抑郁、焦虑、自伤和自杀意念增加等。 展开更多
关键词 药物滥用 流行率 横断面研究 自我效能 睡眠障碍 生理健康 冠状病毒感染 疫情
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Multi-scale Cyclone Activity in the Changjiang River–Huaihe River Valleys during Spring and Its Relationship with Rainfall Anomalies 被引量:10
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作者 Yujing QIN Chuhan LU liping li 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2017年第2期246-257,共12页
Based on the recognition framework of the outermost closed contours of cyclones, an automated identification algorithm capable of identifying the multi-scale cyclones that occur during spring in the Changjiang River-H... Based on the recognition framework of the outermost closed contours of cyclones, an automated identification algorithm capable of identifying the multi-scale cyclones that occur during spring in the Changjiang River-Huaihe River valleys (CHV) were developed. We studied the characteristics of the multi-scale cyclone activity that affects CHV and its relationship with rainfall during spring since 1979. The results indicated that the automated identification algorithm for cyclones proposed in this paper could intuitively identify multi-scale cyclones that affect CHV. The algorithm allows for effectively describing the shape and coverage area of the closed contours around the periphery of cyclones. We found that, compared to the meso- and sub-synoptic scale cyclone activities, the synoptic-scale cyclone activity showed more intimate correlation with the overall activity intensity of multi-scale CHV cyclones during spring. However, the frequency of occurrence of sub-synoptic scale cyclones was the highest, and their effect on changes in CHV cyclone activity could not be ignored. Based on the area of impact and the depth of the cyclones, the sub-synoptic scale, synoptic scale and comprehensive cyclone intensity indices were further defined, which showed a positive correlation with rainfall in CHV during spring. Additionally, the comprehensive cyclone intensity index was a good indicator of strong rainfall events. 展开更多
关键词 cyclone activity multi-scale cyclone extreme precipitation CHV area
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A multifunctional rock testing system for rock failure analysis under different stress states: Development and application 被引量:3
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作者 Shucai li Jie Hu +4 位作者 Florian Amann liping li Hongliang liu Shaoshuai Shi Pooya Hamdi 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2022年第5期1531-1544,共14页
The stress state in a rock mass is complex. Stress redistribution around underground excavation may lead to various failure modes, including compressive-shear, tensile-shear, and tensile failures. The ability to perfo... The stress state in a rock mass is complex. Stress redistribution around underground excavation may lead to various failure modes, including compressive-shear, tensile-shear, and tensile failures. The ability to perform laboratory tests with these complex stress states is significant for establishing new strength criteria. The present paper introduces a new rock testing system with “tensile-compressive-shear”loading functions. The device includes bi-directional and double-range hydraulic cylinders, auxiliary loading equipment, and roller rows that can perform direct compressive-shear tests, direct tensile tests,and direct tensile-shear tests. The testing system provides maximum vertical and lateral loading forces of2000 k N and allows testing cubical rock specimens with dimensions of 0.5 m × 0.5 m × 0.5 m. The performance of the testing machine was evaluated by testing a rock-like material based on cement mortar under compressive-shear, tensile, and tensile-shear stress states. The failure process and deformation characteristics were monitored during loading using acoustic emission(AE) transient recorder,piezoelectric AE sensors, a high-speed camera, and a thermal infrared camera. The failure mechanism was investigated by analyzing AE counts, AE amplitude, strain, and temperature changes on the rock specimen surface. The test results confirmed that the testing system could successfully simulate the abovementioned stress path. The AE counts and amplitude responses were influenced by different failure modes. The temperature response during the compressive-shear test indicated the development of a high-temperature band on the rock specimen surface. In contrast, a negligible temperature change was observed during the tensile and tensile-shear tests. The newly developed multifunctional rock testing system allows laboratory tests under various failure modes. The monitoring results of multiple variables during rock failure tests provide valuable information on failure characteristics. 展开更多
关键词 Rock testing system Compressive-shear test Tensile test Tensile-shear test Failure behavior Multiple variable evolutions
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Multi-dimensional blind separation method for STBC systems 被引量:3
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作者 Minggang Luo liping li +1 位作者 Guobing Qian Huaguo Zhang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2013年第6期912-918,共7页
Intercepted signal blind separation is a research topic with high importance for both military and civilian communication systems. A blind separation method for space-time block code (STBC) systems is proposed by us... Intercepted signal blind separation is a research topic with high importance for both military and civilian communication systems. A blind separation method for space-time block code (STBC) systems is proposed by using the ordinary independent component analysis (ICA). This method cannot work when specific complex modulations are employed since the assumption of mutual independence cannot be satisfied. The analysis shows that source signals, which are group-wise independent and use multi-dimensional ICA (MICA) instead of ordinary ICA, can be applied in this case. Utilizing the block-diagonal structure of the cumulant matrices, the JADE algorithm is generalized to the multidimensional case to separate the received data into mutually independent groups. Compared with ordinary ICA algorithms, the proposed method does not introduce additional ambiguities. Simulations show that the proposed method overcomes the drawback and achieves a better performance without utilizing coding information than channel estimation based algorithms. 展开更多
关键词 multiple input multiple output (MIMO) space-time block code (STBC) multi-dimensional independent component analysis (MICA) blind separation
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Using self-location to calibrate the errors of observer positions for source localization 被引量:2
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作者 Wanchun li Wanyi Zhang liping li 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2014年第2期194-202,共9页
The uncertainty of observers' positions can lead to significantly degrading in source localization accuracy. This pa-per proposes a method of using self-location for calibrating the positions of observer stations in ... The uncertainty of observers' positions can lead to significantly degrading in source localization accuracy. This pa-per proposes a method of using self-location for calibrating the positions of observer stations in source localization to reduce the errors of the observer positions and improve the accuracy of the source localization. The relative distance measurements of the two coordinative observers are used for the linear minimum mean square error (LMMSE) estimator. The results of computer si-mulations prove the feasibility and effectiveness of the proposed method. With the general estimation errors of observers' positions, the MSE of the source localization with self-location calibration, which is significantly lower than that without self-location calibra-tion, is approximating to the Cramer-Rao lower bound (CRLB). 展开更多
关键词 self-location errors of the observer positions linearminimum mean square error (LMMSE) estimator accuracy of thesource localization Cramer-Rao lower bound (CRLB).
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Research on the Reform and Practice of “Basic Nursing Skills Practice” Course Assessment
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作者 Zhuoqing Wu Hong Zhou +2 位作者 Aiping Gong liping li Fang Peng 《Open Journal of Applied Sciences》 2023年第6期823-831,共9页
Objective: “Basic Nursing Skills Practice” is a key course connecting classroom and clinical teaching in nursing specialty teaching. Nursing practice ability is one of the core abilities of nurse practitioners. Ther... Objective: “Basic Nursing Skills Practice” is a key course connecting classroom and clinical teaching in nursing specialty teaching. Nursing practice ability is one of the core abilities of nurse practitioners. Therefore, the teaching quality of this course is directly related to the quality of nursing work. To improve the teaching quality of practical course, the assessment reform of the “Basic Nursing Skills Practice” course was carried out among the nursing undergraduates to explore a reasonable and fair assessment mechanism. Method: In the assessment of “Basic Nursing Skills Practice” course, the assessment included individual skill operation assessment, virtual simulation assessment and team comprehensive skill assessment. The assessment proportion was adjusted from 100% for the final examination to 50% for the middle and final examinations respectively. The assessment method was changed from individual skills assessment at the end of the term to a combination of individual skills assessment at the midterm and virtual simulation assessment and team skills assessment at the end of the term. The method has changed from summative evaluation to a combination of formative evaluation and summative evaluation, and self-made questionnaire was used to investigate the effect. Results: After implementing the assessment reform, 86.84% of the students were satisfied with the assessment reform, and the percentage of students with scores above 80 reached 100%. The highest score is 93.0, while the lowest score is 83.0, and the average score was 88.0. Conclusions: High satisfaction of students with basic nursing skills examination reform promoted the learning effectiveness and professional emotions, cultivated comprehensive quality and ability, promoted the realization of talent training objectives. 展开更多
关键词 Basic Nursing Skills Nursing Education Assessment Mechanism REFORM CURRICULUM
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Differentially Expressed Genes Related to Fertility Conversion in Thermo-sensitive Genic Male Sterile(TGMS) Lines of Brassica juncea
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作者 libo SUI Haiyang ZHAO +5 位作者 lijun AI liping li Chuanli ZHANG Chao SUN Tianxiang TANG liangbin liN 《Agricultural Science & Technology》 CAS 2017年第10期1795-1799,1804,共6页
[Objective] This study was performed to screen functional genes related to the fertility conversion of thermo-sensitive genic male sterile (TGMS) lines of Brassica juncea L. [Method] A B. juncea TGMS line K121S was ... [Objective] This study was performed to screen functional genes related to the fertility conversion of thermo-sensitive genic male sterile (TGMS) lines of Brassica juncea L. [Method] A B. juncea TGMS line K121S was selected as the experimental material. The total RNAs were isolated from fertile and sterile pollens at different development stages, including mother cell stage, tetrad stage, tricellular pollen stage and maturity stage. DDRT-PCR was carried out to identify differentially expressed genes. [Result] A total of 44 differentially expressed cDNA fragments were identified with Dot blot. And seven candidate genes related to fertility conversion of K121S were screened out by BLASTN, including callose synthase gene, aldehyde dehydrogenase gene and RNA polymerase I transcription factor RRN3 gene which were differentially expressed at the transcriptional level, H'-ATPase gene, fructose diphosphate aldolase -class I gene, teucine-rich repeat receptor-Jike serine/threonine- protein kinase gene and alkaline/neutral invertase gene, which were differentially expressed at the post-transcriptional level. [Conclusion] The results of this study will help to explain the molecular mechanism of thermo-sensitive genic male sterility of B. juncea. 展开更多
关键词 Brassica juncea L. Thermo-sensitive male genic sterility DDRT-PCR Fertility conversion related genes
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卤化物固态电解质研究进展
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作者 陈帅 余创 +5 位作者 罗启悦 魏超超 李莉萍 李广社 程时杰 谢佳 《物理化学学报》 SCIE CAS CSCD 北大核心 2023年第8期1-18,共18页
全固态电池因其高能量密度和高安全性而成为具有发展前景的下一代储能技术。开发具有高室温离子电导率、优异化学/电化学稳定性、良好正/负极兼容性的固态电解质是实现全固态电池实用化的关键。卤化物固态电解质因其优异的电化学窗口、... 全固态电池因其高能量密度和高安全性而成为具有发展前景的下一代储能技术。开发具有高室温离子电导率、优异化学/电化学稳定性、良好正/负极兼容性的固态电解质是实现全固态电池实用化的关键。卤化物固态电解质因其优异的电化学窗口、高正极稳定性、可接受的室温锂离子电导率等优势,受到了广泛的关注。本文通过对近年来卤化物电解质的相关研究进行总结,综述了该类电解质的组成、结构、离子传导路径及制备方法,并分析了金属卤化物电解质的电导率、稳定性特点,归纳了近年来该电解质在全固态电池中具有代表性的应用,并基于以上总结和分析,指出了卤化物固态电解质的研究难点及发展方向。 展开更多
关键词 金属卤化物电解质 结构 传导机理 合成路径 改性 电化学性能
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Automated Pavement Crack Detection Using Deep Feature Selection and Whale Optimization Algorithm
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作者 Shorouq Alshawabkeh li Wu +3 位作者 Daojun Dong Yao Cheng liping li Mohammad Alanaqreh 《Computers, Materials & Continua》 SCIE EI 2023年第10期63-77,共15页
Pavement crack detection plays a crucial role in ensuring road safety and reducing maintenance expenses.Recent advancements in deep learning(DL)techniques have shown promising results in detecting pavement cracks;howe... Pavement crack detection plays a crucial role in ensuring road safety and reducing maintenance expenses.Recent advancements in deep learning(DL)techniques have shown promising results in detecting pavement cracks;however,the selection of relevant features for classification remains challenging.In this study,we propose a new approach for pavement crack detection that integrates deep learning for feature extraction,the whale optimization algorithm(WOA)for feature selection,and random forest(RF)for classification.The performance of the models was evaluated using accuracy,recall,precision,F1 score,and area under the receiver operating characteristic curve(AUC).Our findings reveal that Model 2,which incorporates RF into the ResNet-18 architecture,outperforms baseline Model 1 across all evaluation metrics.Nevertheless,our proposed model,which combines ResNet-18 with both WOA and RF,achieves significantly higher accuracy,recall,precision,and F1 score compared to the other two models.These results underscore the effectiveness of integrating RF and WOA into ResNet-18 for pavement crack detection applications.We applied the proposed approach to a dataset of pavement images,achieving an accuracy of 97.16%and an AUC of 0.984.Our results demonstrate that the proposed approach surpasses existing methods for pavement crack detection,offering a promising solution for the automatic identification of pavement cracks.By leveraging this approach,potential safety hazards can be identified more effectively,enabling timely repairs and maintenance measures.Lastly,the findings of this study also emphasize the potential of integrating RF and WOA with deep learning for pavement crack detection,providing road authorities with the necessary tools to make informed decisions regarding road infrastructure maintenance. 展开更多
关键词 Pavement crack detection deep learning feature selection whale optimization algorithm civil engineering
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聚乳酸基层状纳米复合材料的研究进展 被引量:9
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作者 龚勇吉 张道海 +3 位作者 何敏 宋位华 李莉萍 于杰 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2018年第6期184-190,共7页
聚乳酸由于其良好的生物降解性、力学性能以及可加工性,具有极大的应用潜力,但是却面临脆性大、耐热温度低、阻燃性能差等缺点。而层状纳米材料是一类具有层状纳米结构,颗粒尺度为纳米或亚微米的纳米材料,具有优异的力学性能、热稳定性... 聚乳酸由于其良好的生物降解性、力学性能以及可加工性,具有极大的应用潜力,但是却面临脆性大、耐热温度低、阻燃性能差等缺点。而层状纳米材料是一类具有层状纳米结构,颗粒尺度为纳米或亚微米的纳米材料,具有优异的力学性能、热稳定性能、气体阻隔性能、电性能及化学性能。因此,使用层状纳米材料对聚乳酸进行改性,可以制备出具有优异性能的聚乳酸基纳米复合材料。文中重点综述了聚乳酸基层状硅酸盐、聚乳酸基层状双氢氧化物、聚乳酸基石墨烯及其衍生物3类纳米复合材料最新研究进展。 展开更多
关键词 聚乳酸 层状硅酸盐 层状双氢氧化物 石墨烯及其衍生物 纳米复合材料
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Altitudinal patterns of stand structure and herb layer diversity of Picea schrenkiana forests in the central Tianshan Mountains,Northwest China 被引量:3
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作者 liping li XiangPing WANG +2 位作者 Stefan ZERBE liYun ZHANG JingYun FANG 《Journal of Arid Land》 SCIE 2011年第4期254-260,共7页
Altitude is a useful indicator to examine patterns of forest structure and species diversity in relation to environmental factors.In this study,the altitude patterns of forest stand structure and species diversity wer... Altitude is a useful indicator to examine patterns of forest structure and species diversity in relation to environmental factors.In this study,the altitude patterns of forest stand structure and species diversity were analyzed across 20 plots in the Tianchi Nature Reserve,Northwest China.The results showed that mean stem height(Hm),maximum stem height(Hmax) and mean stem diameter at breast height(Dm) of Picea schrenkiana trees all decreased significantly with increasing altitude.Potential tree height(H*) decreased while stem taper increased significantly as altitude increased,suggesting remarkable altitudinal changes in biomass allocation between the diameter and height growth of Picea schrenkiana.Understory herbaceous richness increased significantly with increasing altitude,or with decreasing total basal area(TBA),Hm and stand volume(Volume).High light availability for understory herbs might account for the higher species richness at high altitude.Sorensen Index decreased significantly with the increase in altitude intervals,while the Cody Index demonstrated a converse pattern,suggesting greater differences in species composition with larger distances. 展开更多
关键词 ALLOMETRY beta diversity species richness Picea schrenkiana Tianshan Mountains XINJIANG
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LLR Processing of Polar Codes in Concatenation Systems 被引量:2
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作者 Ya Meng Yi Fang +1 位作者 Chuan Zhang liping li 《China Communications》 SCIE CSCD 2019年第9期201-208,共8页
This paper studies the decoding performance of low-density parity-check(LDPC)codes in a serial concatenation system with polar codes employing the successive cancellation(SC)decoding.It is known that the absolute inco... This paper studies the decoding performance of low-density parity-check(LDPC)codes in a serial concatenation system with polar codes employing the successive cancellation(SC)decoding.It is known that the absolute incorrect log-likelihood ratio(LLR)values from the SC decoding can be very large.This phenomenon dramatically deteriorates the error correcting performance of the outer LDPC codes.In this paper,the LLR values of polar codes are regulated by a log processing before being sent to the LDPC decoder.Simulation results show that the log processing is an efficient approach with a low optimization complexity compared with the existing procedures to improve the performance of the serial concatenation systems. 展开更多
关键词 POLAR CODES SC DECODING LDPCcodes CONCATENATION
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Influence of stress wave-induced disturbance on ultra-low friction in broken blocks 被引量:1
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作者 liping li Haitao Zhang +3 位作者 Yishan Pan Xiangyu Ju Lei Tang Minghui li 《International Journal of Coal Science & Technology》 EI CAS CSCD 2022年第2期107-123,共17页
Deep rock mass tends to be broken into blocks when mining for materials deep below the surface.The rock layer of the roof of the mine can be regarded as a system of blocks of fractured rock mass.When subjected to high... Deep rock mass tends to be broken into blocks when mining for materials deep below the surface.The rock layer of the roof of the mine can be regarded as a system of blocks of fractured rock mass.When subjected to high ground stress and mining-induced disturbance,the efect of the ultra-low friction of the block system easily becomes apparent,and can induce rock burst and other accidents.By taking the block of rock mass as research object,this study developed a test system for ultra-low friction to experimentally examine its efects on the broken blocks under stress wave-induced disturbance.We used the horizontal displacement of the working block as the characteristic parameter refecting the efect of ultra-low friction,and examine its characteristic laws of horizontal displacement,acceleration,and energy when subjected to the efects of ultra-low friction by changing the frequency and amplitude of the stress wave-induced disturbance.The results show that the frequency of stress wave-induced disturbance is related to the generation of ultra-low friction in the broken block.The frequency of disturbance of the stress wave is within 1–3 Hz,and signifcantly increases the maximum acceleration and horizontal displacement of the broken blocks.The greater the intensity of the stress wave-induced disturbance is,the higher is the degree of block fragmentation,and the more likely are efects of ultra-low friction to occur between the blocks.The greater the intensity of the horizontal impact load is,the higher is the degree of fragmentation of the rock mass,and the easier it is for the efects of ultra-low friction to occur.Stress wave-induced disturbance and horizontal impact are the main causes of sliding instability of the broken blocks.When the dominant frequency of the kinetic energy of the broken block is within 20 Hz,the efects of ultra-low friction are more likely. 展开更多
关键词 Rock burst Block rock mass Ultra-low friction efect Stress wave-induced disturbance Horizontal displacement
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Evolution characteristics of precursor information of coal and gas outburst in deep rock cross‑cut coal uncovering 被引量:1
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作者 Jupeng Tang Xin Zhang +2 位作者 Shengjie Sun Yishan Pan liping li 《International Journal of Coal Science & Technology》 EI CAS CSCD 2022年第1期138-150,共13页
As mines become deeper,the potential for coal and gas outbursts in deep rock cross-cut coal uncovering is enhanced.The outburst precursors are unclear,which restricts the effectiveness and reliability of warning syste... As mines become deeper,the potential for coal and gas outbursts in deep rock cross-cut coal uncovering is enhanced.The outburst precursors are unclear,which restricts the effectiveness and reliability of warning systems.To reveal the evolution characteristics of coal and gas outburst precursor information in deep rock cross-cut coal uncovering,briquette specimens are constructed and experiments are conducted using a self-developed true triaxial outburst test system.Using acoustic emission monitoring technology,the dynamic failure of coal is monitored,and variations in the root mean square(RMS)of the acoustic emissions allow the effective cracking time and effective cracking gas pressure to be defined.These characteristics are obviously different in deep and shallow coal.The characteristic parameters of gas outburst exhibit stepwise variations at different depths.The RMS and cumulative RMS have stepped failure characteristics with respect to changes in gas pressure.The characteristic parameters of coal failure are negatively correlated with the average in-situ stress and effective stress,but positively correlated with the lateral pressure coefficient of in-situ stress and the critical gas pressure.The transition characteristics are highly sensitive in all cases.The critical depth between deep and shallow coal and gas outbursts is 1700 m.The expansion multiple of acoustic emission intensity from the microfracture stage to the sharp-fracture stage of coal is defined as the outburst risk index,N1.For depths of 1100–1700 m,N1≥7 denotes a higher risk of outburst,whereas at depths of 1700–2500 m,N1≥3 indicates enhanced risk. 展开更多
关键词 Deep coal and gas outburst Rock cross-cut coal uncovering Acoustic emission Critical gas pressure Risk index
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Anesthesia Management at Fuwai Hospital:Practice,Evidence and Outcomes 被引量:1
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作者 Yuntai Yao lixian He liping li 《Chinese Medical Sciences Journal》 CAS CSCD 2021年第3期234-251,共18页
Fuwai Hospital was established in 1956 and the Anesthesia Department of Fuwai Hospital was one of the earliest anesthesia departments then in China.Under the leadership of several department directors and with the con... Fuwai Hospital was established in 1956 and the Anesthesia Department of Fuwai Hospital was one of the earliest anesthesia departments then in China.Under the leadership of several department directors and with the concerted efforts of all generations of colleagues,the Anesthesia Department of Fuwai Hospital has dramatically transformed,upgraded and modernized.For more than six decades,the Anesthesia Department has been providing high-quality peri-operative anesthesia care for cardiovascular surgeries,conducting innovative experimental and clinical researches,and offering comprehensive training on cardiovascular anesthesiology for professionals across China.Currently,Fuwai Hospital is the National Center for Cardiovascular Diseases of China and one of the largest cardiovascular centers in the world.The present review introduces the Anesthesia Department of Fuwai Hospital,summarizes its current practice of anesthesia management,the outcomes of cardiovascular surgeries at Fuwai Hospital,accumulates relevant evidence,and provides prospects for future development of cardiovascular anesthesiology. 展开更多
关键词 ANESTHESIA management cardiac surgery OUTCOME
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Optimal Reservoir Operation Using Stochastic Dynamic Programming 被引量:1
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作者 Pan liu Jingfei Zhao +1 位作者 liping li Yan Shen 《Journal of Water Resource and Protection》 2012年第6期342-345,共4页
This paper focused on the applying stochastic dynamic programming (SDP) to reservoir operation. Based on the two stages decision procedure, we built an operation model for reservoir operation to derive operating rules... This paper focused on the applying stochastic dynamic programming (SDP) to reservoir operation. Based on the two stages decision procedure, we built an operation model for reservoir operation to derive operating rules. With a case study of the China’s Three Gorges Reservoir, long-term operating rules are obtained. Based on the derived operating rules, the reservoir is simulated with the inflow from 1882 to 2005, which the mean hydropower generation is 85.71 billion kWh. It is shown that the SDP works well in the reservoir operation. 展开更多
关键词 RESERVOIR Operation STOCHASTIC DYNAMIC PROGRAMMING Operating RULES
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Definition and analysis of the circulation indices of polar vortex at 10 hPa in the Northern Hemisphere 被引量:1
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作者 liping li ShuXuan Guan +1 位作者 PanXing Wang JuHui Ma 《Research in Cold and Arid Regions》 2009年第6期549-558,共10页
A set of circulation indices are defined and calculated to characterize monthly mean polar vortex at 10 hPa geopotential height chart in the Northern Hemisphere,including area–(S),intensity–(P) and center position (... A set of circulation indices are defined and calculated to characterize monthly mean polar vortex at 10 hPa geopotential height chart in the Northern Hemisphere,including area–(S),intensity–(P) and center position (λc,φc)–indices by use of 1948–2007 NCEP/NCAR 10 hPa monthly height data.These indices series are used to investigate the seasonal variation and interannual anomaly of polar vortex,along with the relations with global warming,ozone anomaly and Arctic Oscillation (AO).The results show that (1) there is anticyclonic (cyclonic) from Jun.to Aug.(from Sep.to Mar.).The change of spring circulation pattern is slower than that of autumn.(2) S can be replaced by P due to the interannual synchronal variations of the intensity and area for polar vortex.The interannual (interdecadal) variations of P are significant in Jan.(Jul.).(3) The anomalies of system center position in Jan.are more evident than that in Jul.(4) The variations of mean temperature at mid-stratosphere in the vicinity of pole zone in Jan.are different from that in Jul.,but they are synchronal with the corresponding P and not significant correlation with the trend of global warming.However,the relationship between P and total O3 in Jul.are obvious.(5) There is so notable correlation between P and AO that P can represent AO. 展开更多
关键词 polar vortex at 10 hPa circulation indices global warming ozone anomaly Arctic Oscillation
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构建青少年化学科普活动内容分级素材库
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作者 李丽萍 李雪丽 +1 位作者 刘文皓 杜泽朔 《大学化学》 CAS 2022年第9期302-312,共11页
在收集和分析常见化学类科普素材的基础上,通过整合素材内容与科学教育体系的对应关系,为化学教育和化学科普工作者搭建一个有实践参考价值的内容分级素材库。本研究着眼新时期社会发展的政策导向和现实需求,旨在为青少年化学类科普活... 在收集和分析常见化学类科普素材的基础上,通过整合素材内容与科学教育体系的对应关系,为化学教育和化学科普工作者搭建一个有实践参考价值的内容分级素材库。本研究着眼新时期社会发展的政策导向和现实需求,旨在为青少年化学类科普活动的具体实践提供一种框架性和建设性的新视角。 展开更多
关键词 青少年 科普素材 化学教育 化学科普
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