期刊文献+
共找到577篇文章
< 1 2 29 >
每页显示 20 50 100
Study on the optimal test parameters for vibration compaction based on the control of physical-mechanical indicators
1
作者 Zhongrui Chen Yanxi Xiong +3 位作者 Ronghui Yan Zhibo Cheng Taifeng Li Hongfu Tan 《Railway Sciences》 2025年第3期388-409,共22页
Purpose-The indoor vibration compaction test(IVCT)was a key step in controlling the compaction quality for high-speed railway graded aggregate(HRGA),which currently had a research gap on the assessment indicators and ... Purpose-The indoor vibration compaction test(IVCT)was a key step in controlling the compaction quality for high-speed railway graded aggregate(HRGA),which currently had a research gap on the assessment indicators and compaction parameters.Design/methodology/approach-To address these issues,a novel multi-indicator IVCT method was proposed,including physical indicator dry density(ρd)and mechanical indicators dynamic stiffness(Krb)and bearing capacity coefficient(K20).Then,a series of IVCTs on HRGA under different compaction parameters were conducted with an improved vibration compactor,which could monitor the physical-mechanical indicators in real-time.Finally,the optimal vibration compaction parameters,including the moisture content(ω),the diameter-to-maximum particle size ratio(Rd),the thickness-to-maximum particle size ratio(Rh),the vibration frequency(f),the vibration mass(Mc)and the eccentric distance(re),were determined based on the evolution characteristics for the physical-mechanical indicators during compaction.Findings-All results indicated that theρd gradually increased and then stabilized,and the Krb initially increased and then decreased.Moreover,the inflection time of the Krb was present as the optimal compaction time(Tlp)during compaction.Additionally,optimal compaction was achieved whenωwas the water-holding content after mud pumping,Rd was 3.4,Rh was 3.5,f was the resonance frequency,and the ratio between the excitation force and the Mc was 1.8.Originality/value-The findings of this paper were significant for the quality control of HRGA compaction. 展开更多
关键词 High-speed railway subgrade Graded aggregates Vibratory compaction test Optimal vibration compaction parameters Physical-mechanical indicator
在线阅读 下载PDF
Selection Method of Evaluation Indicators with Three-Parameter Interval Grey Number 被引量:1
2
作者 Fanlin Meng Na Wang Bingjun Li 《Open Journal of Applied Sciences》 2015年第12期833-840,共8页
The evaluation problem with three-parameter interval grey number (T-PIGN) widely exists in real world. To select effective evaluation indicators of the problem, this paper puts forward evaluation index system selectio... The evaluation problem with three-parameter interval grey number (T-PIGN) widely exists in real world. To select effective evaluation indicators of the problem, this paper puts forward evaluation index system selection principle of T-PIGN based on distance entropy model, and gives out evaluation index system selection judgment criterion of T-PIGN. Furthermore, for the redundancy of evaluation index system with T-PIGN, a selection method of evaluation index system with T-PIGN is proposed. Finally, the applicability of the proposed method is verified by concrete examples. 展开更多
关键词 Evaluation indicatorS Selection Three-parameter INTERVAL GREY NUMBER GREY DISTANCE ENTROPY
暂未订购
Assessment of active tectonics from geomorphic indices and morphometric parameters in part of Ganga basin 被引量:5
3
作者 Aditya Kumar ANAND Sarada Prasad PRADHAN 《Journal of Mountain Science》 SCIE CSCD 2019年第8期1943-1961,共19页
Ganga river basins exposed to active erosional and deformational processes. The recurrence of landslides, floods, and seismic activities makes it more susceptible to deformational activities. The tectonic analysis usi... Ganga river basins exposed to active erosional and deformational processes. The recurrence of landslides, floods, and seismic activities makes it more susceptible to deformational activities. The tectonic analysis using geomorphic indices and morphometric parameters will help in determining the hazard-prone area of the river basin. Geomorphic indices and morphometric parameters are calculated to investigate the role of neotectonic activities, as it acts as a controlling factor in the development of landforms in the tectonically active terrains. Neotectonic activities influence the terrain topography, which significantly affects the drainage system and geomorphological setup of the area. In this study, the assessment of active tectonics of study area was determined using Advanced Spaceborne Thermal Emission and Reflection Radiometer(ASTER) Global Digital Elevation Model(GDEM) based on Geomorphic Indices(Stream Length Gradient index, Hypsometric integral, Asymmetry factor, Basin shape, Valley floor width to Valley height ratio, Mountain front sinuosity index) cumulatively with Linear, Areal and Relief morphometric parameters on 27 delineated basins of the study area. The combined classification of Relative Tectonic Activity Index(Iat) and morphometric parameters of 27 basins categorized all the zones into four different classes:Class 1 – Very High(<1.97;410 km^2);Class 2 – High(1.97 – 2.05;275 km^2);Class 3 – Moderate(2.05 – 2.21;273 km^2),and Class 4 – Low(>2.21;299 km^2). The basins with tectonic activities have a consistent relationship with structural disturbances, basin geometry, and field studies. The tectonically active zonation of a part of Ganga basin using geomorphic indices and morphometric parameters suggest that it has significant influence of neotectonic activities in a part of Ganga basin. 展开更多
关键词 Linear parameterS Areal parameterS RELIEF parameterS Geomorphic indices RELATIVE TECTONIC Activity Index Ganga river BASINS
原文传递
Comprehensive early warning of rock burst utilizing microseismic multi-parameter indices 被引量:21
4
作者 Linming Dou Wu Cai +1 位作者 Anye Cao Wenhao Guo 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2018年第5期767-774,共8页
Rock bursts have become one of the most severe risks in underground coal mining and its early warning is an important component in the safety management. Microseismic(MS) monitoring is considered potentially as a powe... Rock bursts have become one of the most severe risks in underground coal mining and its early warning is an important component in the safety management. Microseismic(MS) monitoring is considered potentially as a powerful tool for the early warning of rock burst. In this study, an MS multi-parameter index system was established and the critical values of each index were estimated based on the normalized multi-information warning model of coal-rock dynamic failure. This index system includes bursting strain energy(BSE) index, time-space-magnitude independent information(TSMII) indices and timespace-magnitude compound information(TSMCI) indices. On the basis of this multi-parameter index system, a comprehensive analysis was conducted via introducing the R-value scoring method to calculate the weights of each index. To calibrate the multi-parameter index system and the associated comprehensive analysis, the weights of each index were first confirmed using historical MS data occurred in LW402102 of Hujiahe Coal Mine(China) over a period of four months. This calibrated comprehensive analysis of MS multi-parameter index system was then applied to pre-warn the occurrence of a subsequent rock burst incident in LW 402103. The results demonstrate that this multi-parameter index system combined with the comprehensive analysis are capable of quantitatively pre-warning rock burst risk. 展开更多
关键词 ROCK BURST Microseismic(MS)monitoring MULTI-parameter indices COMPREHENSIVE EARLY WARNING
在线阅读 下载PDF
Screening of Rice Accessions for Tolerance to Drought and Salt Stress Using Morphological and Physiological Parameters 被引量:3
5
作者 Chukwudi Umego Valentine Otang Ntui +2 位作者 Effiom Eyo Ita Charles Opara Edak Aniedi Uyoh 《American Journal of Plant Sciences》 2020年第12期2080-2102,共23页
Drought and salinity are the most widespread soil problems, posing a big threat to food security in rice growing regions. The present study evaluated the performance of eleven rice genotypes using morphological and ph... Drought and salinity are the most widespread soil problems, posing a big threat to food security in rice growing regions. The present study evaluated the performance of eleven rice genotypes using morphological and physiological parameters, under induced drought and salinity conditions. The seedlings were raised in 5 kg of homogenous soil in plastic bags in the </span><span style="font-family:Verdana;">greenhouse</span><span style="font-family:""><span style="font-family:Verdana;">. For the drought experiment, each bag was watered with 200 ml of water twice daily until plants reached the five-leaf stage when watering was suspended for 2 weeks for the drought stressed plants but not suspended for the control plants. The experiment was a 2 × 11 factorial and the set up was arranged using the completely randomized design with three replications. Data were taken on Plant height, Number of tillers, leaf length, Number of green leaves, Number of dead leaves, Leaf rolling score (LRS) and Rate of water loss. The salinity experiment was set up in a similar manner except that the plants were irrigated twice a day for 2 weeks with 200 ml of treatment solution containing either 0 mM NaCl or 75 mM and data were collected on plant height, number of tillers, shoot fresh weight, shoot dry weight, Na</span><sup><span style="font-family:Verdana;">+</span></sup><span style="font-family:Verdana;"> and K</span><sup><span style="font-family:Verdana;">+</span></sup><span style="font-family:Verdana;"> concentrations, relative water content and chlorophyll content. Data from both experiments were subjected to Analysis of variance test using the GenStat software 10</span><sup><span style="font-family:Verdana;">th</span></sup><span style="font-family:Verdana;"> edition and the means separated using least significant difference test. Individual stress response index (ISRI) was calculated for each parameter and the means used in grouping the varieties. Of the genotypes evaluated, four (FARO 44, NERICA 2, NERICA 8 and NERICA 5) were identified as tolerant, two (NERICA 4 and FARO 57) as moderately tolerant, while the rest were found to be sensitive to drought. Equally, two varieties (FARO 44 and RAM 137) stood out in the salinity screening as tolerant varieties, five were moderately tolerant while four (FARO 64, FARO 52, NERICA 2 and FARO 55) were clearly susceptible. FARO 44 is the only genotype that </span><span style="font-family:Verdana;">showed </span></span><span style="font-family:Verdana;">tolerance</span><span style="font-family:""> </span><span style="font-family:Verdana;">to both drought and salinity. The identified drought and salinity tolerant rice genotypes from this study can be recommended as genetic sources for future breeding programs for drought and salinity </span><span style="font-family:Verdana;">tolerance</span><span style="font-family:""> </span><span style="font-family:Verdana;">in rice. 展开更多
关键词 Oryza sativa Salinity Tolerance Drought Tolerance Morpho-Physiological parameters Stress Response indices
在线阅读 下载PDF
Coverage-optimization based guidance of mobile agents for improved control of distributed parameter systems
6
作者 ZHUANG Bo CUI Baotong +1 位作者 WU Wei JIANG Zhengxian 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2019年第3期601-612,共12页
The control problem of a class of parabolic distributed parameter systems (DPSs) is investigated by using mobile agents with capabilities of sensing and actuating. The guidance strategies of mobile agents based on cov... The control problem of a class of parabolic distributed parameter systems (DPSs) is investigated by using mobile agents with capabilities of sensing and actuating. The guidance strategies of mobile agents based on coverage optimization methods are proposed to improve the control performance of the system and make the state norm of the system converge to zero faster. The coverage optimization problems are constructed based on the measurement of each agent. By solving the coverage optimization problems, the local optimal moving direction of each agent can be obtained. Then the gradient-based agent motion control laws are established. With the indicator function and the surface delta function, this method is generalized to n-dimensional space, and suitable for any sensing region with piecewise smooth boundaries. The stability and control performance of the system are analyzed. Numerical simulations show the effectiveness of the proposed methods. 展开更多
关键词 distributed parameter systems (DPSs) mobile AGENTS COVERAGE OPTIMIZATION indicator function
在线阅读 下载PDF
Effects of coat colour genes on body measurements, heat tolerance traits and haematological parameters in West African Dwarf sheep
7
作者 John S. Decampos Christian O. N. Ikeobi +10 位作者 Olajide Olowofeso Olusiji F. Smith Matthew A. Adeleke Mathew Wheto David O. Ogunlakin Abubakar A. Mohammed Timothy M. Sanni Babatunde A. Ogunfuye Raman A. Lawal Adeyemi S. Adenaike Samuel A. Amusan 《Open Journal of Genetics》 2013年第4期280-284,共5页
With 178 West African Dwarf sheep aged 1 to 3 years, a study was conducted to investigate the effects of coat colour genes on body measurements, heat tolerance traits and haematological parameters. Body measurements c... With 178 West African Dwarf sheep aged 1 to 3 years, a study was conducted to investigate the effects of coat colour genes on body measurements, heat tolerance traits and haematological parameters. Body measurements considered included body length, hair length, ear length, hip width, tail length, height at withers, rump height, fore cannon bone length, chest depth, heart girth and body weight. Heat tolerance traits considered were skin temperature, rectal temperature, pulse rate and respiratory rate. Blood samples were collected for the evaluation of white blood cell (WBC), red blood cell (RBC), haemoglobin (HGB), haematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin cell (MCHC), red cell distribution width (RDW), platelets (PLT), mean platelets volume (MPV), platelets distribution width (PDW) and plateletcrits (PCT). Results showed that coat colour gene (CCG) had significant (P < 0.01) effect on rump height and tail length. Animals with black (BB) coat colour had the highest mean value for rump height (57.80 ± 1.29 cm) and tail length (22.10 ± 0.89 cm), while brown (Bb) coat colour had the least value of 53.00 ± 6.00 cm for rump height and 17.50 ± 0.50 cm for tail length. The CCG had significant (P < 0.01) effect on body temperature and pulse rate, with the grey/mouflon (Ag) colour possessing the highest body temperature (38.90°C ± 0.22°C), and Bb having the least value of 37.20°C ± 0.35°C. White/tan (Awt) had the highest pulse rate of 28.90 ± 0.66 beats/min and Bb had the least value of 20.00 ± 2.00 beats/min. The CCG had significant (P < 0.01) effect on RBC and MPV with brown (Bb) colour having the highest RBC counts (18.20 ± 0.00 L) and badgerface (Ab) having the least value (11.50 ± 0.62 L). The Bb had the highest value (5.60 ± 0.00 fL) for MPV and Ab had the least value (4.70 ± 0.15 fL). Sheep with Bb and Ab were found to withstand heat stress better than others. 展开更多
关键词 COAT Colour Gene Haematological parameters MORPHOLOGICAL indices SHEEP
暂未订购
Evaluation of the Influence of Thermooxidation of an Unconventional Scyphocephalium ochocoa Oil on Its Quality and on the Biological Parameters of Wistar Rats
8
作者 Michel Elenga Thérésia Ibara Beah Inianga +4 位作者 Stephane Wossolo Lingomo Gedellevie Ryssie Miantoko Zebita Stève Moulengo Massamba Yvon Simplice Itoua Okouango Vital Mananga 《Food and Nutrition Sciences》 2024年第12期1201-1217,共17页
The aim of this study was to evaluate the effects of thermooxidation of S. ochocoa oil on its quality and on the biochemical and anthropometric parameters of Wistar rats. S. ochocoa seeds from the Lekoumou department ... The aim of this study was to evaluate the effects of thermooxidation of S. ochocoa oil on its quality and on the biochemical and anthropometric parameters of Wistar rats. S. ochocoa seeds from the Lekoumou department were used for oil extraction at the press. The parameters measured were oil content and chemical indices, determined for samples of oil unheated and heated to 220˚C as a function of the number of heatings and the environment (open air, freezer). Two diets were created: the control diet and the treated diet, in which 10% oil was substituted for the control diet. These diets were fed to the rats for 28 days. Biochemical, anthropometric and atherogenicity parameters were measured. The results show that S. ochocoa oil has a saturated character and a blackish color, and it solidifies or coagulates rapidly. Unheated oil samples placed in a freezer and unheated samples placed in a simple freezer have relatively lower acid values (0.860 and 0.703 mg KOH/g respectively) than other samples. Acid index values for heated samples increase progressively with the number of heatings (1.063 ± 0.005 for 1st heating, 1.290 ± 0.010 for 2nd heating and 1.890 ± 0.006 for 3rd heating). The oil’s peroxide value increased with temperature and oxidation (65.6 ± 0.03 for unheated oil vs. 97.9 ± 003 for oil heated to 220˚C). The diet supplemented with this oil resulted in a significant increase in plasma cholesterol levels, and a significant decrease in triglyceride levels. The plasma atherogenicity index reveals the risk of cardiovascular disease associated with this food. 展开更多
关键词 THERMOOXIDATION OIL S. Ochocoa Chemical indices Biological parameters Wistar Rats Plasma Atherogenicity Index CONGO
在线阅读 下载PDF
Analysis on the Value of Erythrocyte Parameters in Blood Test in the Differential Diagnosis of Anemia
9
作者 CHEN Lingjuan 《外文科技期刊数据库(文摘版)医药卫生》 2021年第9期524-526,共5页
Objective: to analyze the results and application value of erythrocyte parameters in blood test in the differential diagnosis of anemia. Methods: 138 cases of anemia patients admitted to our hospital in May 2020 (01-3... Objective: to analyze the results and application value of erythrocyte parameters in blood test in the differential diagnosis of anemia. Methods: 138 cases of anemia patients admitted to our hospital in May 2020 (01-30) were taken as the research object, and set as the observation group. A total of 138 healthy subjects who underwent physical examination in our hospital during the same period were selected as the reference group. In the blood test of all subjects, the red blood cell analyzer is used to measure and record the parameters. Results: after examination, 138 cases of anemia in the observation group were identified as iron deficiency anemia, hemolytic anemia, megaloblastic anemia, aplastic anemia, liver and kidney disease and blood loss. There was significant difference between the observation group and the control group in the RBC parameters of the two groups (P < 0.05). Among them, Hb and RBC of hemolytic anemia and megaloblastic anemia patients were lower than those of the control group, while MCV, RDW and MCH were higher than those of the control group (P < 0.05). Compared with the reference group, the Hb and RBC of other anemia patients were lower (P < 0.05). Conclusion: the blood test for anemia patients can determine the parameters of red blood cells, and identify the type of anemia according to the level of each index, which provides reliable basis for the formulation of treatment plan and has strong possibility of popularization. 展开更多
关键词 ANEMIA blood test erythrocyte parameters relevant indicators
暂未订购
Effective palynological diversity indices for reconstructing angiosperm diversity in China
10
作者 Yuxuan Jiang Fuli Wu +3 位作者 Xiaomin Fang Haitao Wang Yulong Xie Cuirong Yu 《Plant Diversity》 2025年第2期244-254,共11页
The utilization of palynological data for plant diversity reconstructions offers notable advantages in addressing the discontinuity of plant fossils in the stratigraphic record. However, additional studies of modern p... The utilization of palynological data for plant diversity reconstructions offers notable advantages in addressing the discontinuity of plant fossils in the stratigraphic record. However, additional studies of modern processes are required to validate or refine the accuracy of diversity results obtained from palynological data. In this study, we used a modern pollen dataset of China to compare the accuracy of plant diversity reconstructions using five different palynological diversity indices(i.e., the pollen species number, Berger-Parker index, Simpson diversity index, Hill index, and Shannon-Wiener index) over a large spatial scale. We then identified climate factors that are most strongly correlated with these patterns of plant diversity. We found that the index that most accurately reflects plant diversity is the Shannon-Wiener index. Our analyses indicated that the most effective indices at reflecting plant diversity are the Shannon-Wiener index and Berger-Parker index. Numerical analysis revealed that palynological diversity(measured using the Shannon-Wiener index) was strongly correlated with climatic parameters, in particular average temperature in the coldest month and annual precipitation,suggesting these factors may be primary determinants of plant diversity distribution. We also found that a threshold value of the normalized Shannon-Wiener index(NH = 0.4) approximately aligns with the contour line specifying 400 mm annual precipitation, serving as a rudimentary indicator for assessing plant diversity in arid versus humid climates. This study suggests that pollen diversity indices have remarkable potential for quantitatively reconstructing paleoclimatic parameters. 展开更多
关键词 Angiosperm diversity POLLEN Diversity indices Climatic parameters
在线阅读 下载PDF
布尔山羊、河谷型藏山羊及其杂交F1代的血液生理生化、抗氧化及免疫指标的比较分析
11
作者 许会芬 雷菊婷 +8 位作者 平措次仁 索朗多吉 阿旺林珠 次仁 边巴 德吉 索朗达 仁青措姆 吴玉江 《黑龙江畜牧兽医》 北大核心 2026年第2期8-14,共7页
为了研究布尔山羊、河谷型藏山羊及其杂交F1代的血液生理生化、抗氧化及免疫指标的变化,试验选择布尔山羊、河谷型藏山羊、布尔山羊(父本)×河谷型藏山羊(母本)杂交F1代各10只,分别采集血样后测定血液生理生化指标、血清抗氧化指标... 为了研究布尔山羊、河谷型藏山羊及其杂交F1代的血液生理生化、抗氧化及免疫指标的变化,试验选择布尔山羊、河谷型藏山羊、布尔山羊(父本)×河谷型藏山羊(母本)杂交F1代各10只,分别采集血样后测定血液生理生化指标、血清抗氧化指标及血清免疫指标,并进行比较分析。结果表明:杂交F1代白细胞数(WBC)显著低于布尔山羊(P<0.05),与河谷型藏山羊差异不显著(P>0.05);红细胞数(RBC)和血细胞比容(HCT)极显著低于河谷型藏山羊(P<0.01),与布尔山羊差异不显著(P>0.05);血红蛋白浓度(HGB)和平均红细胞体积(MCV)均显著高于河谷型藏山羊(P<0.05);平均红细胞血红蛋白含量(MCH)显著或极显著高于布尔山羊和河谷型藏山羊(P<0.05或P<0.01);平均红细胞血红蛋白浓度(MCHC)极显著高于布尔山羊和河谷型藏山羊(P<0.01)。杂交F1代血清总蛋白(TP)、球蛋白(GLB)质量浓度,谷草谷丙比(GOT/GPT),尿素氮/肌酐比(BUN/CRE),钙磷乘积(Ca×P),γ-谷氨酰转移酶(GGT)活性,总胆红素(TBIL)、肌酐(CRE)、尿素氮(BUN)、无机磷(P)浓度均极显著低于布尔山羊(P<0.01),与河谷型藏山羊差异不显著(P>0.05);镁(Mg)浓度显著或极显著低于河谷型藏山羊和布尔山羊(P<0.05或P<0.01);白球比(A/G)、谷草转氨酶(GOT)活性及葡萄糖(GLU)浓度均极显著高于布尔山羊(P<0.01),与河谷型藏山羊差异不显著(P>0.05);谷丙转氨酶(GPT)活性显著或极显著高于河谷型藏山羊和布尔山羊(P<0.05或P<0.01);碱性磷酸酶(ALP)活性显著低于河谷型藏山羊(P<0.05),三酰甘油(TG)浓度显著高于河谷型藏羊(P<0.05),且均与布尔山羊差异不显著(P>0.05);肌酸激酶(CK)活性和钙(Ca)浓度与河谷型藏山羊和布尔山羊均差异不显著(P>0.05)。杂交F1代丙二醛(MDA)浓度显著或极显著高于布尔山羊和河谷型藏山羊(P<0.05或P<0.01);超氧化物歧化酶(SOD)活性极显著高于布尔山羊(P<0.01),与河谷型藏山羊差异不显著(P>0.05);总抗氧化能力(T-AOC)极显著低于布尔山羊和河谷型藏山羊(P<0.01);谷胱甘肽过氧化物酶(GSH-Px)浓度显著或极显著低于河谷型藏山羊和布尔山羊(P<0.05或P<0.01)。杂交F1代白细胞介素-4(IL-4)、白细胞介素-17(IL-17)、免疫球蛋白M(IgM)质量浓度均极显著高于布尔山羊和河谷型藏山羊(P<0.01);白细胞介素-8(IL-8)、白细胞介素-12(IL-12)质量浓度均极显著低于布尔山羊(P<0.01);白细胞介素-1β(IL-1β)、γ干扰素(IFN-γ)、免疫球蛋白G(IgG)质量浓度均极显著低于布尔山羊和河谷型藏山羊(P<0.01);白细胞介素-6(IL-6)、白细胞介素-13(IL-13)质量浓度均极显著低于河谷型藏山羊(P<0.01);转化生长因子-β(TGF-β)、肿瘤坏死因子α(TNF-α)质量浓度均极显著高于河谷型藏山羊(P<0.01)。说明与河谷型藏山羊相比,杂交F1代的血液运氧能力、免疫机能、抗氧化能力均有所提高,布尔山羊对河谷型藏山羊具有良好的改良效果。 展开更多
关键词 布尔山羊 藏山羊 血液生理生化指标 抗氧化指标 免疫指标
原文传递
妊娠中后期添加酵母培养物对母羊生产性能、产后血清指标及瘤胃发酵参数的影响
12
作者 杨振祥 李林贵 +5 位作者 李昌昌 马文彬 刘艳丰 杨会国 王文奇 李长青 《中国畜牧兽医》 北大核心 2026年第2期810-818,共9页
【目的】探讨妊娠中后期添加酵母培养物(YC)对初产母羊生产性能及产后血清生化指标和瘤胃发酵参数的影响。【方法】选取36只妊娠51 d、体重为(37.72±1.91)kg的健康湖羊,按体重相近原则随机分成2组,每组6个重复,每个重复3只羊。试验... 【目的】探讨妊娠中后期添加酵母培养物(YC)对初产母羊生产性能及产后血清生化指标和瘤胃发酵参数的影响。【方法】选取36只妊娠51 d、体重为(37.72±1.91)kg的健康湖羊,按体重相近原则随机分成2组,每组6个重复,每个重复3只羊。试验经9 d预饲,于妊娠60~150 d进行分组饲喂,其中对照组(CK组)提供全混合饲粮;试验组(YC组)在全混合饲粮中添加5%的YC。母羊分娩后,2组均饲喂相同的对照组饲粮。于产后第20天采集母羊血液和瘤胃液样本,测定血清生化、免疫、抗氧化指标及瘤胃发酵参数;同时测定母羊与羔羊的生产性能,以评估YC的持续性效应。【结果】与CK组相比,(1)YC组羔羊初生重显著升高(P<0.05),羔羊20 d体重也有升高的趋势(0.05<P<0.10);(2)YC组母羊血清中皮质醇(COR)含量极显著升高(P<0.01),总蛋白(TP)含量显著升高(P<0.05),白蛋白(ALB)含量有升高的趋势(0.05<P<0.10);(3)YC组母羊血清中白细胞介素-2(IL-2)和肿瘤坏死因子-α(TNF-α)含量极显著升高(P<0.01),免疫球蛋白G(IgG)含量显著升高(P<0.05);(4)YC组母羊血清中谷胱甘肽过氧化物酶(GSH-Px)活性极显著升高(P<0.01),总抗氧化能力(T-AOC)显著升高(P<0.05),超氧化物歧化酶(SOD)活性有升高的趋势(0.05<P<0.10),丙二醛(MDA)含量则呈降低的趋势(0.05<P<0.10);(5)YC组瘤胃液中微生物蛋白(MCP)含量和丙酸浓度均有升高的趋势(0.05<P<0.10)。【结论】妊娠中后期添加YC可提高初产母羊生产性能,改善母羊机体免疫功能和抗氧化能力。 展开更多
关键词 初产湖羊 酵母培养物 生产性能 血清指标 瘤胃发酵参数
在线阅读 下载PDF
外源三十烷醇对干旱胁迫下红豆草生长和生理特性的影响
13
作者 郭佳雨 南丽丽 +4 位作者 王利群 何蓉 任孟雨 马香香 田戈 《草地学报》 北大核心 2026年第1期142-153,共12页
为探究外源三十烷醇(Triacontanol,TA)对干旱胁迫下红豆草(Onobrychis viciifolia)幼苗生长和生理特性的影响,以‘甘肃’红豆草(GS)、新品系P1及2049为材料,采用营养液砂培法,以-1.0 MPa聚乙二醇6000(T1)模拟干旱胁迫,同时对红豆草叶面... 为探究外源三十烷醇(Triacontanol,TA)对干旱胁迫下红豆草(Onobrychis viciifolia)幼苗生长和生理特性的影响,以‘甘肃’红豆草(GS)、新品系P1及2049为材料,采用营养液砂培法,以-1.0 MPa聚乙二醇6000(T1)模拟干旱胁迫,同时对红豆草叶面喷施0(CK),2.5(T_(2)),5.0(T_(3)),7.5(T_(4)),10.0(T_(5))和12.5(T_(6))μmol·L^(-1) TA,测定21项形态与生理指标,筛选TA最佳缓解浓度。结果表明,不同浓度TA均能缓解红豆草干旱胁迫,其中10.0μmol·L^(-1) TA(T_(5))效果最佳。TA处理下各品种地上部株高、生物量及光合参数等指标较T1提升19%~454%;根冠比、渗透调节物质及相关抗氧化酶活性降低15%~89%。此外,主成分分析表明气孔导度、叶绿素a和类胡萝卜素这3个指标为关键调控指标;对红豆草抗旱性进行综合评价,其排名为T_(5)>T_(6)>T_(4)>T_(3)>T_(2)>T1;品种响应差异表现为GS>P1>2049。表明TA通过调节生理生化特性增强红豆草的抗旱性,其中10.0μmol·L^(-1)(T_(5))处理最佳,本研究为合理利用TA解决红豆草栽培中的干旱问题提供了参考。 展开更多
关键词 三十烷醇 红豆草 干旱胁迫 生理指标 光合参数
在线阅读 下载PDF
公路螺旋隧道驾驶认知负荷评价试验研究
14
作者 张磊刚 朱旺 +3 位作者 黄婷 牟星宇 韩磊 杜志刚 《现代隧道技术》 北大核心 2026年第1期76-86,115,共12页
为探究公路螺旋隧道几何特征(长度、半径)及行进方向(上行、下行)对驾驶人认知负荷的影响机制,基于自然驾驶试验,通过眼动追踪技术与问卷调查采集驾驶人眼动行为指标和主观评价数据,分析不同几何参数螺旋隧道中驾驶人的认知负荷。结果表... 为探究公路螺旋隧道几何特征(长度、半径)及行进方向(上行、下行)对驾驶人认知负荷的影响机制,基于自然驾驶试验,通过眼动追踪技术与问卷调查采集驾驶人眼动行为指标和主观评价数据,分析不同几何参数螺旋隧道中驾驶人的认知负荷。结果表明:在长距离、小半径螺旋隧道(如韩口隧道)中,与短距离、大半径隧道(如南坪隧道)相比,驾驶人平均注视持续时间增加12.9%,平均瞳孔直径扩大7.7%,平均扫视持续时间延长34%,平均扫视幅度减小14%,说明复杂几何特征会显著增加认知负荷;在螺旋隧道上行过程中,驾驶人平均注视持续时间增加10.2%,平均瞳孔直径扩大4%,平均扫视持续时间增加10.6%,平均扫视幅度减小5.5%,且其与隧道几何参数的影响相互独立;在长距离、小半径螺旋隧道上行时,驾驶人任务负荷主观评价综合指数较短距离、大半径螺旋隧道下行高出11.3%,弯坡错觉程度高出40.4%;明确了“长隧道、小半径、上行”是公路螺旋隧道驾驶认知负荷的关键影响因素。 展开更多
关键词 公路螺旋隧道 驾驶认知负荷 自然驾驶试验 眼动指标 隧道几何参数
在线阅读 下载PDF
诱导轮离心泵速度系数水力设计方法及其实验研究
15
作者 沙毅 曹玉华 +3 位作者 李林 李彦霞 周金伟 陈秋帆 《机电工程》 北大核心 2026年第1期159-167,共9页
针对如何简明扼要设计出诱导轮离心泵,并揭示其与同比转数普通离心泵在结构和性能上的主要差别的问题,在离心泵速度系数水力设计基础上,进一步拟合出了诱导轮离心泵容积效率和叶轮进口速度系数改型计算公式,总结出了诱导轮离心泵的简明... 针对如何简明扼要设计出诱导轮离心泵,并揭示其与同比转数普通离心泵在结构和性能上的主要差别的问题,在离心泵速度系数水力设计基础上,进一步拟合出了诱导轮离心泵容积效率和叶轮进口速度系数改型计算公式,总结出了诱导轮离心泵的简明设计方法。首先,阐述了普通离心泵叶轮的水力几何计算过程和诱导轮离心泵速度系数水力设计过程,成功地开发出了比转数n_(s)=70型CB250-140-330普通离心泵和YCB120-85-260诱导轮离心泵产品,以此验证该设计方法的实用性、简要性、优化性和准确性;然后,通过普通离心泵和诱导轮离心泵性能试验,对泵性能试验曲线进行了对比分析,阐述了诱导轮离心泵在泵效率、汽蚀余量(NPSH)等方面的技术指标和主要特性;最后,运用汽蚀基本方程式进行了分析,阐明了诱导轮离心泵抗汽蚀原理。研究结果表明:加装诱导轮可以使离心泵的汽蚀余量(NPSH)下降到1 m及以下,但比同类型普通离心泵效率降低了2.6%。该研究阐述了一个完整、全面的诱导轮离心泵研发案例,可为今后诱导轮离心泵的优化设计提供科学依据。 展开更多
关键词 诱导轮离心泵 结构和性能分析 容积效率 叶轮进口直径计算公式 技术指标参数 汽蚀余量
在线阅读 下载PDF
海菖蒲形态和生理特征及其关键环境影响因素
16
作者 韩秋影 罗宇峰 +3 位作者 白昕竹 谢艳芳 史云峰 赵牧秋 《生态学杂志》 北大核心 2026年第1期129-141,共13页
海菖蒲是海南陵水新村湾和黎安港的海草优势种,近年来衰退趋势明显。2021—2022年,对新村湾和黎安港海菖蒲海草床进行了6次采样调查,研究了海菖蒲形态和生理特征,分析了环境因素对海菖蒲相关指标的影响。结果表明,新村湾海草床海水温度... 海菖蒲是海南陵水新村湾和黎安港的海草优势种,近年来衰退趋势明显。2021—2022年,对新村湾和黎安港海菖蒲海草床进行了6次采样调查,研究了海菖蒲形态和生理特征,分析了环境因素对海菖蒲相关指标的影响。结果表明,新村湾海草床海水温度、pH、铵氮、DIN、磷酸盐以及海菖蒲叶长、地下组织C/N比值均显著高于黎安港,而海水盐度、硝酸盐、海菖蒲叶宽、地下组织N含量均显著低于黎安港。新村湾海菖蒲主要受到海水盐度、海水pH及沉积物粒径的影响,其叶长与海水盐度、海水pH和沉积物粒径呈显著正相关,地上、地下和总生物量均与沉积物粒径和海水盐度呈显著正相关。而黎安港海菖蒲则受海水盐度、海水pH、硝酸盐浓度、磷酸盐浓度和沉积物有机碳影响较大,其地上、地下和总生物量与沉积物有机碳、海水铵氮浓度呈显著负相关,与海水pH、硝酸盐浓度呈显著正相关。与历史数据相比,海草组织氮含量显著升高(>2.45%),未来应严格控制养殖污水向新村湾和黎安港海草床排放,设立专项资金进行海草床健康状况长期监测,加强受损海草床衰退机制研究。本研究为理解海水温度、盐度以及氮磷营养盐对海菖蒲的协同影响提供科学依据。 展开更多
关键词 海菖蒲 形态指标 生理指标 营养盐 环境参数
原文传递
声景分类的生理效应区分度研究:声源类型、主观感知与声学参数的对比
17
作者 李忠哲 巴美慧 康健 《声学学报》 北大核心 2026年第2期345-359,共15页
本研究旨在检验并比较不同声景分类方法在解释声景生理效应方面的能力。选取20种典型城市公共开放空间声景样本,对62名参与者进行生理测量和主观评价;采用分类主成分法提取生理维度,运用K-means聚类算法对声学参数和主观评价数据进行分... 本研究旨在检验并比较不同声景分类方法在解释声景生理效应方面的能力。选取20种典型城市公共开放空间声景样本,对62名参与者进行生理测量和主观评价;采用分类主成分法提取生理维度,运用K-means聚类算法对声学参数和主观评价数据进行分类,并比较了三种分类方法(声源类型分类、声学参数分类和主观感知分类)对生理维度的解释效力。结果显示:1)生理维度1(“舒适–不舒适”维度)具有显著区分效度,能有效区分各分类下的声景差异;2)三种分类方法在生理维度2上的区分效果均较弱,其中仅主观评价分类对“活力型”声景表现出一定的区分能力。总体而言,声景生理效应的可区分信息主要集中在舒适性相关反应上,其他生理信息对分类方式的敏感性总体较弱。 展开更多
关键词 声景分类 生理指标 主观评价 声学参数
原文传递
姜黄素对断奶湖羊生长性能、腹泻率及腹泻频率、养分表观消化率、瘤胃液发酵参数和血清指标的影响
18
作者 金振华 张备 +9 位作者 王丽坤 李红宇 张国华 李烨 刘昊 薛沾枚 董正德 张艳 张蕾 王洪宝 《中国饲料》 北大核心 2026年第5期80-86,共7页
为研究基础饲粮中添加姜黄素对断奶湖羊生长性能、腹泻率及腹泻频率、养分表观消化率、瘤胃液发酵参数和血清指标的影响,采用单因子完全随机试验设计,将180头体况良好、体重相近的45日龄断奶湖羊均分成4组,分别为对照组(基础日粮)、试... 为研究基础饲粮中添加姜黄素对断奶湖羊生长性能、腹泻率及腹泻频率、养分表观消化率、瘤胃液发酵参数和血清指标的影响,采用单因子完全随机试验设计,将180头体况良好、体重相近的45日龄断奶湖羊均分成4组,分别为对照组(基础日粮)、试验Ⅰ组(基础饲粮+200 mg/kg姜黄素)、试验Ⅱ组(基础饲粮+400 mg/kg姜黄素)和试验Ⅲ组(基础饲粮+600 mg/kg姜黄素),每组设置3个重复,每个重复15头。预试期为7 d,正式期为60 d。试验结果显示:(1)与对照组相比,试验Ⅱ、Ⅲ组的末重和平均日增重均显著升高(P<0.05),料重比均显著降低(P<0.05);(2)与对照组相比,试验Ⅰ、Ⅱ、Ⅲ组的腹泻率和腹泻频率均显著降低(P<0.05);(3)与对照组相比,试验Ⅱ、Ⅲ组的粗纤维、中性洗涤纤维和钙的表观消化率均显著升高(P<0.05);(4)与对照组相比,试验Ⅱ、Ⅲ组的IgA、IgM、IL-10、CD4+和CD4/CD8的含量均显著升高(P<0.05),TNF-α和IL-6的含量均显著降低(P<0.05);(5)与对照组相比,试验Ⅱ、Ⅲ组的总蛋白和白蛋白的含量均显著升高(P<0.05),尿素氮、总胆固醇和碱性磷酸酶的含量均显著降低(P<0.05);(6)与对照组相比,试验Ⅰ、Ⅱ、Ⅲ组谷胱甘肽过氧化物酶(GSH-Px)的含量均显著升高(P<0.05);试验Ⅱ、Ⅲ组的总抗氧化能力(T-AOC)和总超氧化物歧化酶(T-SOD)的含量均显著升高(P<0.05),丙二醛(MDA)的含量均显著降低(P<0.05)。试验结果表明,基础饲粮中添加姜黄素能够改善断奶湖羊的生长性能、腹泻率及腹泻频率、养分表观消化率、血清生化指标、免疫功能和抗氧化功能,其中姜黄素最佳使用量为600 mg/kg。 展开更多
关键词 姜黄素 断奶湖羊 生长性能 腹泻率 养分表观消化率 瘤胃液发酵参数 血清指标
在线阅读 下载PDF
CT定量参数联合肝功能指标预测肝癌动脉栓塞术患者预后的价值
19
作者 杨永丽 张庆辉 《临床医学工程》 2026年第1期111-115,共5页
目的探讨CT定量参数联合肝功能指标预测肝癌动脉栓塞术(TACE)患者预后的价值。方法回顾性分析2022年5月至2024年4月许昌北海医院收治的100例肝癌患者的临床资料,患者均接受CT扫描。对肝癌患者进行随访,根据预后情况分为预后不良组(n=25... 目的探讨CT定量参数联合肝功能指标预测肝癌动脉栓塞术(TACE)患者预后的价值。方法回顾性分析2022年5月至2024年4月许昌北海医院收治的100例肝癌患者的临床资料,患者均接受CT扫描。对肝癌患者进行随访,根据预后情况分为预后不良组(n=25)和预后良好组(n=75)。分析影响肝癌TACE患者预后的危险因素以及CT定量参数、肝功能指标评估患者预后的价值。结果两组的TNM分期、包膜不完整占比以及AFP、HBF、HAP、HAI、MTT比较,差异显著(P<0.05)。Logistic多因素分析显示,包膜不完整(OR=1.840)、AFP(OR=1.723)、HBF(OR=1.893)、HAP(OR=1.818)、HAI(OR=1.846)、MTT(OR=1.863)与肝癌TACE患者预后关系密切(P<0.05)。AFP、HBF、HAP、HAI、MTT单独及联合检测预测肝癌TACE患者预后的AUC分别为0.748(95%CI:0.652~0.830)、0.812(95%CI:0.722~0.883)、0.818(95%CI:0.728~0.888)、0.811(95%CI:0.720~0.882)、0.829(95%CI:0.741~0.897)、0.981(95%CI:0.931~0.998);联合检测预测肝癌TACE患者预后的AUC高于AFP、HBF、HAP、HAI、MTT单独检测(P<0.05)。结论CT定量参数HBF、HAP、HAI、MTT及肝功能指标AFP与肝癌TACE患者预后关系密切,联合预测可提高对肝癌TACE患者预后评估的价值。 展开更多
关键词 CT定量参数 肝功能指标 肝癌 动脉栓塞术 预后
暂未订购
Toxicity profile of ethanolic extract of Azadirachta indica stem bark in male Wistar rats 被引量:4
20
作者 Anofi Omotayo Tom Ashafal Latifat Olubukola Orekoya Musa Toyin Yakubu 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2012年第10期811-817,共7页
Objective:To investigate the loxic implications of ethanolic stem bark extract of Azadirachta indica(A-indica)at 50,100,200 and 300 mg/kg body weight in Wistar rats.Methods:Fifty male rats of Wistar strains were rando... Objective:To investigate the loxic implications of ethanolic stem bark extract of Azadirachta indica(A-indica)at 50,100,200 and 300 mg/kg body weight in Wistar rats.Methods:Fifty male rats of Wistar strains were randomly grouped into five(A-F.)of ten animals each.Animals in Group A(control)were orally administered 1 mL of distilled water on daily basis for 21 days while those in Groups B-E received same volume of the extract corresponding to 50,100,200 and 300mg/kg body weight.Results:The extract did not significantly(P>0.05)alter the levels of albumin,total protein,red blood cells and factors relating to it whereas the white blood cell,platelets,serum triacylglycerol and high-density lipoprotein cholesterol decreased significantly(P<0.05).In contrast,the final body weights,absolute weights of the liver,kidney,lungs and heart as well as their organ-body weight ratios,serum globulins,total and conjugated bilirubin,serum cholesterol,low-density lipoprotein cholesterol and computed atherogenic index increased significantly.The spleen-body weight ratio,alkaline phosphatase,alanine and aspartate transaminases,sodium,potassium,calcium,feed and water intake were altered at specific doses.Conclusions:Overall,the alterations in the biochemical parameters of toxicity have consequential effects on the normal functioning of the organs of the animals.Therefore,the ethanolic extract of A.indica stem bark at the doses of 50,100,200 and 300 mg/kg body weight may not be completely safe as an oral remedy and should be taken with caution if absolutely necessary. 展开更多
关键词 AZADIRACHTA indicA Feed INTAKE Functional indices Haematological parameters LIPID PROFILE MELIACEAE
暂未订购
上一页 1 2 29 下一页 到第
使用帮助 返回顶部