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101.
China is rising and gradually developing into an innovation-oriented economy. This transition is fueled by public and private investment in education and by increasing inputs into science and technology. Little attention, however, has been paid to the great differences in China-specific context peculiarity. Hence, the paper assesses Chinese innovation networks using a comprehensive analytical model that includes network configuration, regional environment, government interference and firm attributes. The empirical analysis examines China’s machinery manufacturing industry to test the determinants of the spatial character of Chinese innovation networks based on questionnaire surveys and illustrative cases. Our study finds that Chinese innovation networks are affected not only by innovation resource endowments and firm attributes, but also by government interference and regional culture. Regarding the influence of regional culture, the typical Northern culture with the importance of guanxi plays an important role in the process of searching for partners and makes the innovation network and interpersonal network interwoven. Firms’ ownership and innovation ability are the two essential variables to determine whether any of the regional elements are of significance. 相似文献
102.
豫西崤山北部沟壑纵横,第四系黄土广泛覆盖,地表植被发育。为探讨地电化学法在豫西崤山黄土覆盖区寻找金矿的有效性,选择了隐伏于黄土下的石寨沟金矿开展找矿可行性试验,并在其邻区石龙山金多金属矿预查区南部开展地电化学找矿研究。研究发现,石寨沟Au矿床上部发育地电化学综合异常,异常规律明显,元素相关性较好,具有很好的套合和分带关系。对石龙山预查区地电提取的微量元素含量特征(分形、变异系数、地电提取比)进行分析,发现其与石寨沟Au矿床具有相近的地电异常规律。进一步利用Surfer软件绘制等值线异常图,结合前人研究成果在异常套合较好的02号线45～47测点初步经过地表工程验证,确定了一条品位较好的工业金矿体,侧面证明实测、推测断层F1-1和F20确实存在。该成果为石龙山地区深部及石寨沟矿床外围找矿提供地电化学理论基础,也为崤山黄土覆盖区找矿提供了新的思路。 相似文献
103.
Pulse-like ground motion observed during the 6 February 2023 MW7.8 Pazarcık Earthquake (Kahramanmaraş, SE Türkiye) 
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下载免费PDF全文 Fan Wu Junju Xie Zhao An Chenghao Lyu Tuncay Taymaz Tahir Serkan Irmak Xiaojun Li Zengping Wen Baofeng Zhou 《地震科学（英文版）》2023,36(4):328-339
In this study, we analyzed 100 three-component strong ground motion records observed within 200 km of the causative fault of the 6 February 2023 MW7.8 Pazarcık (Kahramanmaraş) Earthquake in SE Türkiye. The wavelet method was utilized to identify and analyze the characteristics of pulse-like ground motions in the near-fault region, while considering the uncertainty of the pulse orientation during the analysis. Our investigation focused on the effects of the focal mechanism and rupture process on the spatial distribution, pulse orientation, and maximum pulse direction of the observed pulse-like ground motion. We also analyzed the amplitude and period of the observed ground pulses and the effect of long-period amplification on the ground motion response spectra. Our results indicated the following: (1) A total of 21 typical ground velocity pulses were observed during this earthquake, exhibiting complex characteristics due to the influence of the strike-slip mechanism and rupture directivity. Most ground pulses (17 out of 21) were recorded within 20 km of the fault, in a wide range of orientations, including normal and parallel to the fault direction. The waveforms exhibited unidirectional features, indicating the effects of left-lateral fault slip. Distinct pulses observed more than 20 km from the fault were mainly oriented normal to the fault. The waveforms were bidirectional with double- or multi-round trips as a result of rupture directivity. (2) The amplitudes of the observed pulses ranged from 30.5 to 220.0 cm/s, with the largest peak velocity of 220.0 cm/s observed at Station 3138. The pulse periods ranged from 2.3 to 14.5 s, with the longest pulse period of 14.5 s observed at Station 3116. The amplitude and period of the pulses observed during this earthquake were comparable to those of similar-magnitude global earthquakes. The amplitude of the pulses decreased significantly with increasing fault distance, whereas the pulse period was not significantly affected by the fault distance. (3) Compared with non-pulse records, the velocity pulse records had a pronounced amplification effect on the acceleration response spectra near the pulse period, with factors ranging from 2.1 to 5.8. The larger velocity pulses also significantly amplified the velocity response spectra, particularly over the long periods. This significant amplification effect of the pulses on the response spectra leads to empirical models underestimating the long-period earthquake ground motion. 相似文献
104.
An introduced turbot population was used to establish families and to estimate genetic parameters of the offspring. However, there is a lack of pedigree information, and common environmental effects can be introduced when each full-sib family is raised in a single tank. Therefore, in the genetic evaluation, SSRs(simple sequence repeats) were used to reconstruct the pedigree and to calculate molecular relatedness between individuals, and the early mixed-family culture model was used to remove the impact of the common environmental effects. After100 d of early mixed culture, twenty SSRs were used to cluster 20 families and to calculate paired molecular relationships(n=880). Additive genetic matrices were constructed using molecular relatedness(MR) and pedigree reconstruction(PR) and were then applied to the same animal model to estimate genetic parameters. Based on PR, the heritabilities for body weight and body length were 0.214±0.124 and 0.117±0.141, and based on MR they were 0.101±0.031 and 0.102±0.034, respectively. Cross validation showed that the accuracies of the estimated breeding values based on MR(body weight and body length of 0.717±0.045 and 0.629±0.141, respectively) were higher than those of PR(body weight and body length of 0.692±0.052 and 0.615±0.060, respectively). The MR method ensure availability of all genotyped selection candidates, thereby improving the accuracy of the breeding value estimation. 相似文献
105.
The migration of groundwater in rock and soil can appear as abnormalities in geoelectric fields. It is therefore important to study the characteristics of seepage in porous media by measuring the geoelectric field signatures. In this study, a physical model with layers of sand and clay was constructed and an electrical resistivity meter was used to examine the changes in the geoelectric field parameters during the infiltration process. The results show that the infiltration could be detected based on the geoelectric signatures including temporal changes through the spontaneous potential, excitation currents, and apparent resistivity. Specifically, the spontaneous potential was reduced by 100 to 200 mV when the water reaches an electrode. During the second water injection in the experiment, the measured spontaneous potential of all the electrodes recovered to the previous extreme values that range from −200 to −550 mV, thus indicating a “memory” effect. With stepwise changes in the excitation current, it was possible to determine the seepage velocity in sand and clay layer. The apparent resistivity is reduced to less than 400 Ωm when the infiltration reaches the electrodes. These results indicate the potential for real-time monitoring of water flow. 相似文献
106.
Soil freeze-thaw process is closely related to surface energy budget,hydrological activity,and terrestrial ecosystems.In this study,two numerical experiments(including and excluding soil freeze-thaw process)were designed to examine the effect of soil freeze-thaw process on surface hydrologic and thermal fluxes in frozen ground region in the Northern Hemisphere based on the state-of-the-art Community Earth System Model version 1.0.5.Results show that in response to soil freeze-thaw process,the area averaged soil temperature in the shallow layer(0.0175?0.0451 m)decreases by 0.35℃in the TP(Tibetan Plateau),0.69℃in CES(Central and Eastern Siberia),and 0.6℃in NA(North America)during summer,and increases by 1.93℃in the TP,2.28℃in CES and 1.61℃in NA during winter,respectively.Meanwhile,in response to soil freeze-thaw process,the area averaged soil liquid water content increases in summer and decrease in winter.For surface heat flux components,the ground heat flux is most significantly affected by the freeze-thaw process in both summer and winter,followed by sensible heat flux and latent heat flux in summer.In the TP area,the ground heat flux increases by 2.82 W/m2(28.5%)in summer and decreases by 3.63 W/m2(40%)in winter.Meanwhile,in CES,the ground heat flux increases by 1.89 W/m2(11.3%)in summer and decreases by 1.41 W/m2(18.6%)in winter.The heat fluxes in the Tibetan Plateau are more susceptible to the freeze-thaw process compared with the high-latitude frozen soil regions.Soil freeze-thaw process can induce significant warming in the Tibetan Plateau in winter.Also,this process induces significant cooling in high-latitude regions in summer.The frozen ground can prevent soil liquid water from infiltrating to deep soil layers at the beginning of thawing;however,as the frozen ground thaws continuously,the infiltration of the liquid water increases and the deep soil can store water like a sponge,accompanied by decreasing surface runoff.The influence of the soil freeze-thaw process on surface hydrologic and thermal fluxes varies seasonally and spatially. 相似文献
107.
Zhenshan Xue Xianguo Lyu Zhike Chen Zhongsheng Zhang Ming Jiang Kun Zhang Yonglei Lyu 《中国地理科学(英文版)》2018,28(6):935-945
Wetlands on the Qinghai-Tibetan Plateau (QTP) perform a dazzling array of vital ecological functions and are one of the most fragile ecosystems in the world. Timely and accurate information describing wetland resources and their changes over time is becoming more important in their protection and conservation. By using remote sensing data, this study intended to investigate spatial distribution and temporal variations of wetlands on the QTP at different watershed scales from 1970s to 2010s. Results show that wetlands on the QTP have undergone widespread degradation from 1970s to 2010s, with nearly 6.4% of their area being lost. Areas of freshwater marsh, salt marsh and wet meadow declined by 46.6%, 53.9% and 15.6%, respectively, while lake area increased by 14.6%. The most extensive losses of natural wetlands have occurred in endorheic basins, such as in the Kunlun-Altun-Qilian Drainage Basin and Qiangtang Basin, which shrank by 44.5% and 33.1%, respectively. A pronounced increase in temperature tends to facilitate the evaporation process and reduce water availability for wetlands. One-third of the wetlands on the QTP are under threat of being submerged due to lakes rising in recent years. More research is needed to gain insight into the interaction mechanisms behind observed variations and potential impacts from further warming in the future. 相似文献
108.
黄土高原地区乡村性空间特征及其与可达性格局关系 总被引：1，自引：0，他引：1
在乡村转型重构的关键时期以及城乡融合背景下,可达性作为驱动乡村地域特征改变的直接媒介,对乡村减贫及可持续发展产生重要影响。以县域为基本空间单元,构建了刻画乡村性和可达性的指标体系,定量测度了1990年、2000年、2010年、2015年黄土高原地区243个县域乡村性与可达性指数,探索黄土高原地区县域乡村性和可达性的时空演变特征,采用探索性空间数据方法,引入空间计量经济模型,对乡村性与可达性的集聚特征及关系进行计量分析。结果显示：① 研究区乡村性整体呈减弱态势、差异不断增大,呈现“西高东低”分布格局;可达性整体呈增强趋势、差异不断缩小,“东高西低”的分布格局基本不变。② 乡村性与可达性空间分布均呈较强的正空间自相关,以“榆林-庆阳”一线为界分布,但集聚态势总体不断减弱;其次,可达性的提升对乡村性呈负向影响且波动增强,低可达性-高乡村性类型主要分布在西北的青海、甘肃、宁夏境内,高可达性-低乡村性类型主要分布在东部经济发展水平较高的地级市周边县市。③ 乡村性的空间溢出效应显著,表现出显著的空间滞后和空间误差溢出效应,区域乡村性会受到周边地区乡村性的显著影响;可达性的提升会使得乡村人口变化率、一产产值比重降低;使农业劳动生产率、农村人均纯收入、农业土地生产率提高,且可达性对农业土地生产率的影响最大,而对农村居民人均纯收入的影响提升最大。 相似文献
109.
通过分析2011年8月的出海调查数据,绘制了不同断面上的温度分布图及调查海域底部的温度分布图,基本了解了黄海冷水团西边界的空间分布特征;根据热力学及流体力学的基本理论,在忽略热量传递次要项的前提下,通过计算海水在输运过程中的"冷量"损失,得到了黄海冷水在输运过程中的温度变化情况;进一步结合青岛地区海水源热泵技术的具体应用情况,分析探讨了黄海冷水团的开发利用前景。结果表明:黄海冷水团边缘距离岸边较近,约20~40km,在冷水输运过程中"冷量"损失较小,管道内部末端水温仅升高5℃~6℃,并且青岛地区已经具备相对成熟的海水温差能利用技术,这些都为黄海冷水团的开发利用提供了理论与现实基础。 相似文献
110.
Ying Wang Jiang Feng Qianxin Lin Xianguo Lyu Xiaoyu Wang Guoping Wang 《中国地理科学(英文版)》2013,23(6):708-715
Large oilfields are often coincidentally located in major river deltas and wetlands, and potentially damage the structure, function and ecosystem service values of wetlands during oil exploration. In the present study, the effects of crude oil contamination during oil exploration on soil physical and chemical properties were investigated in marshes of the Momoge National Nature Reserve in Jilin Province, China. The concentrations of total petroleum hydrocarbons in the marsh soil near the oil wells are significantly higher than those in the adjacent control marsh. Soil water contents in oil-contaminated marshes are negatively correlated with soil temperature and are significantly lower than those in the control area, especially in fall. Crude oil contamination significantly increases the soil pH up to 8.0, and reduces available phosphorus concentrations in the soil. The concentrations of total organic carbon are significantly different among sampling sites. Therefore, crude oil contamination could potentially alkalinize marsh soils, adversely affect soil fertility and physical properties, and cause deterioration of the marshes in the Momoge National Nature Reserve. Phyto-remediation by planting Calamagrostis angustifolia has the potential to simultaneously restore and remediate the petroleum hydrocarbon-contaminated wetlands. Crude oil contamination affects the soil physical and chemical properties, so developing an effective restoration program in the Momoge wetland is neccesary. 相似文献