Subjects: Library Science，Information Science >> Library Science submitted time 2023-08-26 Cooperative journals: 《图书情报工作》
Abstract： [Purpose/significance] The discovery of core patents is an important part in technological innovation, which is of great significance to the technological improvement and the patent strategy layout.[Method/process] This paper firstly defined the concept of core patent. Then, by introducing the original PageRank algorithm model, the improved PageRank——PatentRank (referred to as PTR) was put forward, which combining the cited times of patents and the patent age. Finally, we applied the new model to the field of OLED to identify the core patents.[Result/conclusion] We find that compared with the cited times, PTR can not only identify the core patents but also some basic important patents which provide the research ideas for the research of OLED technology. Besides, compared with the original PageRank algorithm, the values of PTR have higher degree of differentiation, and it can improve the PR results on the local scale.
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2020-04-26 Cooperative journals: 《干旱区研究》
Abstract：为探究东祁连山河谷高寒草地植被群落特征与土壤性状的关系，根据研究区河谷地形地貌及河谷高寒草地分布特征，选取了分布在河谷山地阳坡上部和下部、河谷山地阴坡上部和下部及河谷水平阶地的5类不同植被类型的高寒草地为研究对象。研究草地植被群落和土壤性状特征及相关关系。结果表明：河谷中不同坡向、坡位高寒草地植被群落优势种不同，河谷阳坡高寒草地以嵩草属植物为主，阴坡以蓼属植物为主；阴坡植被总盖度高，阳坡低；河谷阴坡下部草层高度最高，而水平阶地最小；植被群落总科数、总属数和总种数均表现为坡下部高于上部，阴坡高于阳坡；地上生物量依次为：阴坡下部>阳坡上部>阴坡上部>阳坡下部>水平阶地；0～60 cm土层地下生物量依次为：阴坡下部>阳坡下部>阴坡上部>水平阶地>阳坡上部。不同高寒草地土壤性状之间有显著差异（P<0.05）。相关分析表明，土壤含水量、容重、孔隙度和全氮等指标与植被总盖度、地上生物量、总科数、草地平均高度有显著的相关关系。可见，研究区河谷高寒草地植被与土壤之间的影响主要表现为土壤含水量、容重、孔隙度和全氮与植被总盖度、地上生物量、总科数、草地平均高度间的相互作用。
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-18 Cooperative journals: 《材料研究学报》
Abstract： The spinel cobalt chromium zinc ferrites (Co0.7Cr0.1Zn0.2Fe2O4) and composites of polyaniline (PANI)- Co0.7Cr0.1Zn0.2Fe2O4 were prepared by polyacrylamide gel and in situ polymerization method, respectively, and then the synthesized materials were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectrometer (FT-IR), their magnetic properties were measured using vibrating sample magnetometer (VSM) and their microwave absorbing capability was investigated by wave-guide method. The results show that the spinel Co0.7Cr0.1Zn0.2Fe2O4 ferrites and the composites PANI-Co0.7Cr0.1Zn0.2Fe2O4 are acquired. Because a small amount Co2+ ion of the octahedron ferrite is replaced by Cr3+ ions, the lattice constant of the Co0.8Zn0.2Fe2O4 ferrite reduces from 0.8409 nm to 0.8377 nm. The saturation magnetization (Ms), remanent magnetization (Mr) and coercive force (Hc) of the PPy-Co0.7Cr0.1Zn0.2Fe2O4 composites are 8.80 emu穏- 1, 3.14 emu穏- 1 and 37.22 kA穖- 1, respectively, which are smaller than that of the Co0.7Cr0.1Zn0.2Fe2O4 ferrite. In a measuring frequency range of 5.0-20.0 GHz, two peak values of reflection loss for the composites PPy-Co0.7Cr0.1Zn0.2Fe2O4 appear at 14.1 GHz and 17.9 GHz with -13.17 dB and -15.36 dB, respectively, which is obviously higher than those of the Co0.7Cr0.1Zn0.2Fe2O4 ferrite.
Subjects: Biology >> Ecology submitted time 2023-03-13 Cooperative journals: 《干旱区研究》
Abstract： The understanding of the evolution process of barchan dune and its movement rate is an important prerequisite for wind prevention and sand fixation and ecological construction in Minqin oasis. Based on field measurement and high- resolution remote sensing image analysis, The study discusses the relationship between the morphological parameters of barchan dune and its movement rate in the upwind edge of Minqin oasis. The results show that: (1) The aspect ratio of the dunes remains a constant value of 16 in 16 years. (2) The average annual moving distance of the tall dune is less than 3 m, which is a medium moving speed. The shape of the tall dune is basically unchanged, and the change is obvious only at the baseline, ridge line, and wing Angle of the windward slope. Low dunes move fast, with an average annual distance of more than 10 m, which is an extremely fast-moving speed. (3) The downwind velocity of the dune is inversely proportional to its width, and the proportionality constant is 718.52 m2 ·a-1. In this area, the barchan dune is dominated by fast-moving speed, which is greater than 5 m·a-1, accounting for 52.63%. (4) During the process of sand erosion on the windward slope and deposition on the leeward slope, large dunes maintain stable morphology and move slowly. Small dunes change dramatically and move rapidly, and the dunes tend to shrink in development.
Subjects: Biology >> Zoology submitted time 2018-12-25 Cooperative journals: 《动物营养学报》
Abstract：本试验旨在研究发酵饲料对育肥猪生长性能、胴体性状、肉品质、血清生化指标和代谢产物的影响。试验选取体重约60 kg的三元杂交健康猪24头，随机分为2组，分别为基础饲粮组（对照组）和发酵饲料组（试验组），每组4个重复，每个重复3头猪。对照组饲喂基础饲粮，试验组饲喂80%基础饲粮和20%发酵饲料。预试期6 d，正试期29 d。结果表明，与对照组相比：1）试验组育肥猪的生长性能和胴体性状指标无显著差异（P>0.05）；2）试验组育肥猪背最长肌的pH45 min、红度值、肉色评分和粗脂肪含量显著提高（P<0.05），背最长肌肉剪切力显著降低（P<0.05）；3）试验组育肥猪的血清中总蛋白和尿素氮含量显著升高（P<0.05）；4）试验组育肥猪的血清中L-焦谷氨酸含量显著降低（P<0.05），但血清中黄嘌呤、丁子香酚、丙烯酰胺和对-香豆酸的含量均显著升高（P<0.05）。由此可见，饲喂发酵饲料可改变机体代谢，增加育肥猪背最长肌肉色评分及嫩度，改善肉品质。
Subjects: Mechanics >> Applied Mechanics submitted time 2023-03-20 Cooperative journals: 《应用力学学报》
Abstract： The changes of peak flexion and extension moments , peak power, joint work , joint impulsemoments , and cumulative joint impulse moments per unit distance of knee and ankle joints at different nun-ning speeds were compared to explore the effects of different running speeds on the single touchdown loadand cumulative load characteristics of lower limb joints. 'Twelve young male college students were recruitedas subjects , and the kinetic parameters of their knee and ankle joints were collected simultaneously using VICON infrared high-speed motion capture system and Bertec Fit 3D ergometer at four speeds of 8 km/ h,10 km/h,12 km/h and 14 km/ h. The peak flexion and extension moments , peak power , joint work , impulsemoments and joint cumulative impulse moments per unit distance of knee and ankle joints were analyzed.'The results show that the plantarflexion peak moment of the ankle during the support period , the peak pow-er during the landing cushion period and the off-ground pedal extension period and the joint work by theankle joint all increase significantly ( P<0.05) with the increase of speed. But , the peak extension mo-ment , peak power and joint work of knee during the support period do not change significantly (P>0.05)with the increase of speed. The cumulative impulse moments of the knee and ankle joints during the 1 kmrun decreased significantly (P<0.05) with the increase of speed , and the single step impulse moments ofthe knee and ankle joints do not change significantly (P>0.05 ). The increase of running speed do notaffect the single touchdown impulse moments of the ankle and knee in male college students , but it canreduce the cumulative impulse moments per unit distance of the knee and ankle joints. The plantarflexionpeak moment , peak power , and joint work in the ankle joint in male college students increase significantlywith the increase of running speed.Therefore , within a certain speed range , the increase in nunning speeddoes not increase the risk of knee , while the effect of running speed on the ankle needs further study.
Subjects: Geosciences >> Geography submitted time 2023-03-13 Cooperative journals: 《干旱区研究》
Abstract： This study aimed to study the shelter efficiency of Haloxylon ammodendron windbreak with different density and plant point distribution to provide scientific basis for optimizing the structure of windbreak in arid areas. With the field Haloxylon ammodendron as the prototype, windbreaks with three stand densities and four plant point distributions were designed, and their flow field and shelter efficiency were measured and analyzed by wind tunnel experiments. The corresponding label and“plant spacing × row spacing”of the windbreaks were as follows: A: 17 cm × 17 cm, B1: 34 cm × 17 cm, B2: 17 cm × 34 cm, and C: 34 cm × 34 cm. Results showed that (1) the area of wind speed deceleration region (U/U0 < 1) accounted for 78.06%, 70.41%, 74.36%, and 82.80% of the whole flow field of A, B1, B2, and C windbreaks, respectively; the area of weak wind speed region (U/U0 < 0.4) accounted for 22.46%, 0.73%, 5.91%, and 0%. (2) The higher the stand density, the lower the average wind speed under the canopy, but the faster the wind speed recovered at the leeside of windbreaks. The minimum wind speed was located at 11H, 15H, 15H, and 20H behind the A, B1, B2, and C windbreaks, respectively (H was the tree height). (3) The order of shelter efficiencies of the four windbreaks from large to small was A > B2 > B1 > C. The relationship between shelter efficiency and stand density was nonlinear. The ratio of wind reduction at the near surface was A:B:C≈6:3:2 behind the windbreaks. The density of afforestation should be determined based on the soil water carrying capacity in the practice of forestation. On this basis, the plant point distribution mode of“small plant spacing, large row spacing”should be preferred.
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Basic Disciplines of Agriculture submitted time 2017-11-10 Cooperative journals: 《中国生态农业学报》
Abstract：耐旱枸杞是西北干旱地区重要的经济作物, 为进一步明确枸杞水分运输特性, 提高农业生产潜力,在甘肃省古浪县农业示范基地(37.09oN, 102.79oE)以2 年生‘宁杞1 号’、‘宁杞5 号’和‘蒙杞1 号’3 个枸杞品种苗木为试验材料, 设计3 个处理[N: 正常水分; M: 中度干旱; S: 重度干旱], 研究干旱胁迫对光合速率、气孔导度、冠层和根系导水率的影响, 以及干旱胁迫后复水对枝条导水率的影响。结果表明: 随着干旱程度增加,枸杞冠层、枝条和根系导水率均下降, ‘宁杞5 号’在干旱胁迫后植株导水率的减小和根系导水阻力在整个植株中所占比例的增大最显著; 通过拟合木质部脆弱性曲线发现, ‘宁杞1 号’导水率损失50%时木质部水势显著高于‘宁杞5 号’和‘蒙杞1 号’。枸杞叶片净光合速率和气孔导度与植株叶片导水速率具有显著相关性。干旱胁迫复水后植物生长主要取决于根系恢复吸水的能力, 干旱胁迫复水4 d 后苗木导水率呈现不同程度的恢复, ‘蒙杞1 号’导水率恢复速度最快, 并出现显著补偿效应, 恢复速度最慢的为‘宁杞5 号’。综合分析表明, 枸杞耐旱特性与导水能力有关, 根系导水对干旱胁迫的敏感性可以反映植株持续抗旱能力, 干旱胁迫复水后根系导水率恢复能力和补偿效应对植株在逆境条件下土壤水分利用具有显著影响, 调控根系导水率对于提高土壤水分利用率具有重要意义。
Subjects: Biology >> Ecology submitted time 2017-06-29 Cooperative journals: 《生态学报》
Abstract：蜘蛛在茶园的生态控制和生物防治中起到重要的作用，为了解不同生境条件和管理方式的茶园蜘蛛群落结构差异和多样性变化，于2011年3月份-2011年10月份，运用振落承接和过筛法对3种不同类型茶园的蜘蛛群落组成与多样性进行了调查。结果表明：（1） 3种类型茶园蜘蛛群落组成：3种类型茶园蜘蛛群落在科、属、种的组成及个体数量上，均表现为有机茶园高，无公害茶园次之，普通茶园低，且在物种数和个体数存在显著差异。管巢蛛科和狼蛛科是3种类型茶园的优势类群，球蛛科、跳蛛科、狼蛛科、皿蛛科的物种优势度大于10%。（2）蜘蛛群落物种多样性的多重分析结果表明，有机茶园蜘蛛群落的个体数、物种数、物种多样性指数、物种丰富度指数和均匀度指数均高于无公害茶园和普通茶园，普通茶园最低，且达到显著水平（P < 0.05）。（3）多元数据分析结果表明，有机茶园蜘蛛群落组成与普通茶园差异较大，无公害茶园与普通茶园蜘蛛群落组成差异较小；3种类型茶园的茶丛蜘蛛群落个体数、物种数及物种多样性指数、丰富度指数和均匀度指数均高于地表，且表现为机茶园多，无公害茶园次之，普通茶园最少。蜘蛛的功能群采集发现，在3种茶园中结网蜘蛛少，而主要是游猎蜘蛛。（4）不使用化学农药的茶园，因其周边生境结构复杂（竹林、小灌木及杂草），植被丰富，形成植被缓冲带，改善了茶园小气候环境，增加了茶园土表覆盖度，可明显提高茶丛和地表游猎蜘蛛的物种数和个体数量。综合研究结果表明，在生态条件好、干扰少的有机茶园中的蜘蛛物种数量、群落多样性明显高于受损生态系统和人为干扰强的普通茶园。
Subjects: Geosciences >> Geography submitted time 2023-12-16 Cooperative journals: 《干旱区研究》
Abstract： In order to further explore the influence of precipitation and soil and water conservation measures on runoff sediment, and to gain an in-depth understanding of the driving factors of water and sand changes in small and medium-sized rivers of the Yellow River, M-K test, Morlet wavelet, linear regression and structural equation modeling were used to study the changes in precipitation and the area of soil and water conservation measures in the upper Guanchuan River from 1957-2021, as well as their the mechanism and process of action were studied. The results showed that annual precipitation showed a non-significant decreasing trend (P >0.05), runoff modulus and sand transport modulus showed a significant decreasing trend (P<0.05), and the area of soil and water conservation measures showed an increasing trend. The response of runoff modulus and sand transport modulus to precipitation got weakened, and the response to soil and water conservation measures was gradually strengthened; the key path of precipitation and soil and water conservation measures affecting the change of water and sand was“area of soil and water conservation measures→runoff modulus”, followed by“area of soil and water conservation measures→runoff→sand transport modulus”, then“precipitation→runoff modulus”, and finally“precipitation→runoff modulus→sand transport modulus”. The total effect of precipitation on water and sand change is 0.42 and 0.38 respectively, while the total effect of soil and water conservation measures on water and sand change is - 0.72 and - 0.65 respectively. The main factor affecting water and sand change in the watershed is the area of soil and water conservation measures, and the secondary factor is the amount of precipitation.
Subjects: Biology >> Ecology submitted time 2023-05-17 Cooperative journals: 《干旱区地理》
Abstract： In order to explore the influence of microtopography on the natural regeneration of Picea crassifolia seedlings in Qilian Mountains, Picea crassifolia forest was selected as the research object, and the topographic parameters (altitude, convexity and slope) of 15 fixed plots in the watershed were divided into four different microtopographic habitats by C-mean fuzzy clustering, and the effects of microtopographic habitats on the renewal characteristics (renewal seedling density, average crown width, mean base diameter and average plant height) of the regeneration seedlings were studied. The results show that: (1) The average crown width and mean base diameter of regenerated seedlings were in the order of low-altitude convex land>high-altitude slope>low-altitude concave land>high-altitude steep slope. The average plant height on high-altitude steep slopes was considerably lower than that in the other three microtopographies. Thus, different altitudes, slopes, aspects, and slope positions considerably affected the survival rate and growth process of regeneration seedlings. (2) The renewal seedling density and average plant height under different microtopographic conditions were as follows: low-altitude concave land, low-altitude convex land, high-altitude slope, and high-altitude steep slope. (3) Most of the regenerated seedlings showed an aggregated distribution under different microtopography in the order of high-altitude steep slope>low-altitude concave>low-altitude convex>high-altitude slope. (4) The results of the correlation analysis showed that there was a significant correlation between altitude, slope, slope position, and regenerated seedlings (P<0.05). In summary, the natural regeneration of Picea crassifolia forest was significantly affected by microtopographic habitat (P<0.05), and seedlings were more suitable for settlement and growth in low-altitude convex land and low-altitude concave land.
Subjects: Medicine, Pharmacy >> Clinical Medicine submitted time 2023-07-19 Cooperative journals: 《中国全科医学》
Abstract： Background As an objective index to evaluate chronic stress，allostatic load （AL） is associated with adverse pregnancy outcomes. At present，there are few longitudinal studies to analyze the influencing factors of AL among pregnant women. Objective To investigate the status of AL and its influencing factors in pregnant women at different trimesters. Methods This study was designed as a prospective study. Questionnaire survey，physical examination and laboratory examination were administered to 152 women in the first （≤ 14 weeks），second （23-27 weeks） and third （30-34 weeks） trimesters of pregnancy collected by using convenience sampling method. The Edinburgh Postpartum Depression Scale （EPDS） was used to assess the depression during pregnancy. Referring to previous studies，the relevant assessment indexes of metabolic system，cardiovascular system，and immune system were used to calculate the total score of AL，and AL ≥ 3 score was used as a criterion for determining high AL level at different trimesters of pregnancy. Multivariate logistic regression analysis was used to explore the influencing factors of AL in the first，second and third trimesters. Results Among 152 pregnant women，the mean total AL score was （2.06±1.68），（2.07±1.84） and （2.07±1.68） in the first，second and third trimesters；52 （34.0%），54 （35.3%） and 50 （32.7%） women were in high level of AL （total score of AL ≥ 3） in the first，seccond and third trimesters . The results of multivariate logistic regression analysis showed that occupations｛business service employees〔OR=0.229，95%CI（0.062，0.845），P=0.027〕，office staff〔OR=0.164，95%CI（0.051，0.528），P=0.002〕，professional and technical personnel〔OR=0.278，95%CI（0.099，0.784），P=0.015〕｝，unemployment〔OR=5.516，95%CI（1.044，29.144），P=0.044〕and depression〔OR=6.241，95%CI（1.403，27.757），P=0.016〕were the influencing factors of AL in the first trimester. Age〔OR=1.098，95%CI（1.002，1.202），P=0.045〕and AL in the first trimester〔OR=9.965，95%CI（4.402，22.561），P=0.000〕were the influencing factors of AL in the second trimester. Sleep duration in the third trimester〔≥ 9 h/d：OR=0.176，95%CI（0.044，0.703），P=0.014〕，AL in the first trimester〔OR=4.697，95%CI（1.852，11.908），P<0.001〕and AL in the second trimester〔OR=9.426，95%CI（3.728，23.834），P<0.001〕 were the influencing factors of AL in the third trimester. Conclusion More than 30% of women are at high levels of AL at different trimesters and the influencing factors of AL at different trimesters are different. Occupation，unemployment status，and depression are the influencing factors of AL in the first trimester；age and AL in the first trimester are the influencing factors of AL in the second trimester；sleep duration in the third trimester and AL in the first and second trimesters are the influencing factors of AL in the third trimester. Earlier attention and timely intervention of AL during pregnancy will help reduce the risk of high AL as pregnancy progresses.
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