Subjects: Geosciences >> Geography submitted time 2024-04-01 Cooperative journals: 《干旱区地理》
Abstract：为客观评价新疆图木舒克市驱动因素对其生态环境质量的影响，选取图木舒克市2000、2011 年和2021 年3 期Landsat 影像数据，耦合归一化植被指数（NDVI）、土壤湿度（WET）、干度（NDSI）、地表温度（LST）4个指标，分析主成分构建遥感生态指数（RSEI），结合研究区自然因素和社会经济因素，对图木舒克市近22 a来生态环境质量进行动态监测与评价。结果表明：（1）图木舒克市近22 a来RSEI均值从0.406升至0.476，生态环境质量变好面积远大于变差面积，改善区域主要分布在研究区中部、东南、西北地区，近22 a生态环境质量得到有效改善。（2）通过对图木舒克市驱动因素进行分析，当地生态环境质量受人口、国内生产总值（GDP）、耕地面积、气候等因素影响，在驱动因素中社会经济因素对当地生态环境质量有显著影响。（3）通过构建RSEI并分析其驱动因素对生态环境质量的影响，可以高效、准确地对当地生态环境质量进行动态监测与客观评价。
Subjects: Geosciences >> Geography submitted time 2018-11-14 Cooperative journals: 《干旱区地理》
Abstract： 基于2000—2015年西安市能源消费量数据，采用碳排放模型和GFI模型，分析区域能源消费碳排放量的变化趋势及影响因素。探讨西安市能源消费碳排放的拉动与抑制要素的互动关系及影响。结果表明：(1)西安市能源消费碳排放量总体呈现上升趋势，煤炭、原油消费为主要碳源。（2）能源利用结构正在发生转变，低能耗低碳排的能源消费量逐年上升，传统能源利用量正日趋减少。（3）经济发展要素和人口要素是西安市能源消费碳排放的主要拉动因素，能源结构要素拉动效应不显著，短期内不易改变；能源强度对能源消费碳排放具有抑制作用，且呈现增强态势，但效果不明显。最后提出西安市能源消费碳排放减排建议。
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-08-13 Cooperative journals: 《计算机应用研究》
Abstract： When the traditional collaborative filtering algorithm is used for recommendation, the credibility based on similarity between users or items directly obtained is relatively low due to the sparsity of the user rating matrix. In order to solve this problem, this paper introduced the relevance between projects on the basis of traditional collaborative filtering. The association is established in a non- reciprocal condition by building a dynamic weighting factor between the project's category label and bipartite graph approach, and the user's rating of the project will be predicted. As a result, compared with the method of using the equivalent similarity and the fixed weight value in the traditional method, the method of using non-equivalent relationship formed by the dynamic weights is more in line with the reality of life and has a better recommendation effect.
Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-31 Cooperative journals: 《农业图书情报学报》
Abstract： [Purpose/Significance] As rural entrepreneurship advances continually, exploring the impact of agricultural information services on entrepreneurial performance is of great significance for accelerating the transformation of scientific and technological achievements and driving rural entrepreneurship. [Method/Process] Based on the theory of information and empirical data collected via "pilot work on the monitoring and investigation of the innovation and entrepreneurship of rural", this paper takes new professional farmers as the research object and constructs a panel threshold model with the level of agricultural information service supply as the threshold variable. With the model, the influence mechanism of agricultural information service supply level on entrepreneurial performance of new professional farmers is explored to reveal the relationships between agricultural information services and entrepreneurial performance. [Results/Conclusions] Results show that the impact of agricultural information services on the entrepreneurial performance of new professional farmers is not a simple linear relationship, but a non-linear one with a "single threshold" effect. When service supply crossed the "threshold level", the promotion effect was weakened by 43.6% . It confirms that information technology productivity paradox also existed in the development process of rural entrepreneurship. Therefore, strategies of agricultural information service supply can be formulated according to actual conditions to avoid excessive investment. At the same time, measures such as improving the quality of farmer education and accelerating the construction of rural entrepreneurship infrastructure can be combined to achieve an effective improvement on the quality of rural entrepreneurship.
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Other Disciplines of Agriculture, Forestry,Livestock & Aquatic Products Science submitted time 2023-02-17 Cooperative journals: 《智慧农业（中英文）》
Abstract： The wide application of advanced information technologies such as big data, Internet of Things and artificial intelligence in agriculture has promoted the modernization of agriculture in rural areas and the development of smart agriculture. This trend has also led to the boost of demands for technology and knowledge from a large amount of agricultural business entities. Faced with problems such as dispersiveness of knowledges, hysteric knowledge update, inadequate agricultural information service and prominent contradiction between supply and demand of knowledge, the agricultural knowledge service has become an important engine for the transformation, upgrading and high-quality development of agriculture. To better facilitate the agriculture modernization in China, the research and application perspectives of agricultural knowledge services were summarized and analyzed. According to the whole life cycle of agricultural data, based on the whole agricultural industry chain, a systematic framework for the construction of agricultural intelligent knowledge service systems towards the requirement of agricultural business entities was proposed. Three layers of techniques in necessity were designed, ranging from AIoT-based agricultural situation perception to big data aggregation and governance, and from agricultural knowledge organization to computation/mining based on knowledge graph and then to multi-scenario-based agricultural intelligent knowledge service. A wide range of key technologies with comprehensive discussion on their applications in agricultural intelligent knowledge service were summarized, including the aerial and ground integrated Artificial Intelligence & Internet-of-Things (AIoT) full-dimensional of agricultural condition perception, multi-source heterogeneous agricultural big data aggregation/governance, knowledge modeling, knowledge extraction, knowledge fusion, knowledge reasoning, cross-media retrieval, intelligent question answering, personalized recommendation, decision support. At the end, the future development trends and countermeasures were discussed, from the aspects of agricultural data acquisition, model construction, knowledge organization, intelligent knowledge service technology and application promotion. It can be concluded that the agricultural intelligent knowledge service is the key to resolve the contradiction between supply and demand of agricultural knowledge service, can provide support in the realization of the advance from agricultural cross-media data analytics to knowledge reasoning, and promote the upgrade of agricultural knowledge service to be more personalized, more precise and more intelligent. Agricultural knowledge service is also an important support for agricultural science and technologies to be more self-reliance, modernized, and facilitates substantial development and upgrading of them in a more effective manner.
Subjects: Materials Science >> Materials Science (General) submitted time 2017-03-31 Cooperative journals: 《材料研究学报》
Abstract：为了研究焊接工艺条件对焊缝金属组织性能的影响,采用不同热输入对1200 MPa级低合金高强钢进行熔化极气体保护焊,利用OM、SEM、TEM观察并分析不同焊接热输入对焊缝组织及力学性能的影响规律。结果显示,当热输入为16、20、25 kJ/cm时,焊缝组织主要以针状铁素体为主,并含有少量M-A组元以及粒状贝氏体。随焊接热输入增大,针状铁素体组织有所增多且板条宽度逐渐增大,而粒状贝氏体组织减少。焊缝内非金属夹杂物类型多为促进针状铁素体形核的Ti-Mn-Al-O-S系复合氧化物夹杂。焊缝金属硬度、冲击韧性及焊接接头强度随热输入增大基本呈下降趋势,并且各焊接热输入条件下焊缝金属具有良好的强韧性匹配。随热输入增大,焊缝金属断裂特征由韧性、脆性混合型断裂向脆性断裂转变。热输入为20 kJ/cm时,焊接接头综合性能最佳。
Subjects: Medicine, Pharmacy >> Clinical Medicine submitted time 2022-08-12 Cooperative journals: 《中国全科医学》
Abstract： Objective To investigate the risk factors for positive surgical margin after radical prostatectomy in Chinese population, and to provide reference for prevention and control. Methods We searched the PubMed, EMbase, The Cochrane Library, Web of Science, CNKI, WanFang Data, CBM and VIP databases to collect literature on risk factors for positive surgical margin after radical prostatectomy. Stata 16 software was used to perform meta-analysis. Results Twenty-one case-control studies, including 6782 patients, 2028 patients with positive surgical margin, were finally included. Meta-analysis results showed that preoperative PSA(OR=1.77, 95%CI: 1.18～2.65), percentage of positive puncture stitches(OR=1.83, 95%CI: 1.35～2.47), number of positive puncture stitches(OR=2.17, 95%CI:0.9～4.8), puncture Gleason score(OR=2.14, 95%CI:1.67～2.74), puncture perineural invasion(OR=5.83, 95%CI:2.05～16.59), preoperative clinical T stage(OR=2.17, 95%CI:1.06～4.42), postoperative pathological T stage(OR=4.30, 95%CI: 2.43～7.63), and postoperative Gleason score(OR= 2.33, 95%CI:1.80～3.01)were the risk factors for positive surgical margin after radical prostatectomy. Subgroup analysis of the different surgical approaches showed that in laparoscopic radical prostatectomy, preoperative PSA（OR=1.47, 95%CI: 0.42～5.09）, number of positive puncture stitches (OR=2.17, 95%CI:0.98～4.80), preoperative clinical T stage(OR=4.57, 95%CI:2.57～8.12), postoperative pathological T stage (OR=4.80, 95%CI: 2.20～10.48), and postoperative Gleason score(OR=2.46, 95%CI:1.57～3.86) were risk factors for positive margins; in robotic-assisted laparoscopic radical prostatectomy, the risk factors were preoperative PSA (OR=2.17, 95%CI:1.60～2.94), and preoperative clinical T stage (OR=1.19, 95%CI: 0.52～2.74). Conclusions positive surgical margin after radical prostatectomy involves multiple factors preoperatively and postoperatively, which should be identified early in clinical workup and interventions should be taken to prevent tumor recurrence and progression.
Subjects: Biology >> Zoology submitted time 2018-12-25 Cooperative journals: 《动物营养学报》
Abstract：本试验旨在研究米曲霉来源α-半乳糖苷酶基因gal A在毕赤酵母中的表达及其对豆浆中大豆寡糖的酶解效果。以NCBI数据库中米曲霉来源α-半乳糖苷酶基因gal A的mRNA序列（GenBank登录号：XP_001817311.1）为依据，利用PCR扩增得到gal A基因并根据毕赤酵母使用密码子的偏好性优化基因序列，构建野生型和优化型毕赤酵母工程菌株，摇瓶发酵 120 h，测定酶学性质。设置25和45 ℃2个温度，每个温度下各设置0.6、1.2和2.4 U 3个加酶量，用发酵得到的α-半乳糖苷酶酶解10 mL豆浆中的大豆寡糖。结果显示：该α-半乳糖苷酶基因gal A全长1 605 bp，不含内含子，编码534个氨基酸，诱导120 h后优化型工程菌株的α-半乳糖苷酶活性为1.952 U/mL，比野生型工程菌株提高了285%。发酵得到的α-半乳糖苷酶的最适pH为4.33，最适温度为55 ℃；在pH 3.00~8.00间稳定性良好，在55 ℃条件下保持40 min后残余α-半乳糖苷酶相对活性为60%；该酶对大部分金属离子具有抗性，但其被MnSO4抑制；以pNPG为底物时的酶动力学参数米氏常数（Km）为0.024 3 mol/L，最大反应速度（Vmax）为1.0×10-7 mol/(L·s)。酶解试验结果显示，45 ℃下加酶量为2.4 U反应12 h后，大豆寡糖中棉籽糖的降解率为50.0%，水苏糖的降解率为31.9%。由此可见，本试验中生产的α-半乳糖苷酶对豆浆中的大豆寡糖有一定的降解作用。
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2018-06-10 Cooperative journals: 《干旱区研究》
Abstract： 本文采用光镜与扫描电镜，对新疆一号冰川10种青藓科植物叶的微结构进行了研究，观察得出10种青藓科植物叶尖渐尖或为长毛尖，叶尖顶端细胞透明，短或狭长；叶片细胞壁加厚；导水主细胞少。植株的叶干燥时，细胞壁排列方式不同，表面具不同形状的纹饰及附属物，大多数种类的表面有小窝点分布，但这些微结构在青藓属（Brachythecium B.S.G.）、毛尖藓属（Cirriphyllum Grout.）、长喙藓属（Rhynchostegium B.S.G.）植物叶中均有明显差异。同属、不同属之间，由于生长环境不同，植物体叶也会呈现出不同的形态特征。这表明10种植物的微结构特征是与环境密切相关。
submitted time 2024-04-03 Cooperative journals: 《农业图书情报学报》
Abstract： [Purpose/Significance] In the era of big data, the volume of data is growing at an exponential rate. One of the most prominent areas affected by this growth is the field of agriculture. The use of agricultural knowledge graphs, which serve as key infrastructures for managing agricultural knowledge, has expanded significantly. However, as the number of nodes and relationships within these graphs increase, so too does their complexity. This complexity gives rise to new challenges in training and representing such large-scale knowledge graphs. It is therefore of great significance to investigate methods for speeding up the embedding process of agricultural knowledge graphs, while preserving their structural integrity and minimizing resource consumption. This research embarks on a novel exploration to address this issue. It stands out from previous studies by concentrating on a hierarchical representation model for agricultural knowledge graphs. The potential impacts of this research on propelling the advancement of the field and on addressing significant real-world problems are substantial. [Method/Process] To confront this challenge, we propose a hierarchical representation model for agricultural knowledge graphs rooted in the HARP framework. Our model leverages the inherent hierarchical features of the agricultural knowledge graph. It incorporates an improved random walk strategy based on relational paths to semantically model relationship objects within the agricultural knowledge graph. This innovative approach effectively retains the hierarchy and asymmetrical relationship structure of the nodes in the graph, setting our work apart from previous research. The validity of our proposed model is fortified by a strong foundation of theoretical and empirical evidence. [Results/Conclusions] Our experimental results reveal several key findings. First, the hierarchical random walk with path (HRWP) model using the LEIDEN algorithm can preserve the spatial structure more effectively and converge more quickly to the maximum modularity, in comparison to the HARP framework. Second, the fusion model employing HRWP takes less training time than the total training time of both models combined, without significantly affecting the time complexity of the original algorithm. Third, we observed that when traditional algorithms are integrated with HRWP, there is an average improvement of 2% across various indicators, with a substantial enhancement in non-neural network models. Therefore, our proposed model not only accurately represents the agricultural knowledge graph but also effectively reduces the training time. Despite the promising outcomes of our study, there remain areas of potential improvement. One such area is the need for a more detailed discussion on the hierarchical nature of relationship objects in future research. This provides potential avenues for future exploration in this field. The findings of this research carry profound implications for the development of agricultural knowledge management systems, offering an effective approach to handle the burgeoning complexity of knowledge graphs.
Subjects: Biology >> Botany >> Applied botany submitted time 2018-12-19 Cooperative journals: 《广西植物》
Abstract：以采自黑龙江省齐齐哈尔市的樟子松((Pinus sylvestris)针叶作为研究对象，采用溶剂提取法对樟子松针叶中的化学成分进行提取，应用硅胶柱色谱、制备薄层色谱和高效液相色谱等现代色谱技术对提取浸膏中的化学成分进行分离和纯化，运用质谱，核磁('H-NMR和‘3C-NMR)等波谱技术，鉴定了化合物结构，并对提取浸膏的抑菌活性进行了测试。结果表明:从樟子松针叶提取物中分离得到15个化合物，分别鉴定为松叶酸(1)、松叶酸甲酷(2), 18a-acetoxylabd-8(17)-en-l5-oic acid(3), 4-eplimbricataloic acid (4), 15一乙基一18一松叶酸甲酷(5), 15-acetoxy-labda-8(17) } 13E-then-l8-al (},邓一轻基脱氢极酸(7), 7a-轻基脱氢极酸(8), endo-peroxide (9), a一杜松醇(10) , /}一谷当醇(11)、邻苯二甲酸二丁酷(12), 7R } 11R-phytol (13)、正二十四烷醇(14), N-octacosan邓-of (15)。其中，化合物9} 13} 14和15为首次从该属植物中分离得到。抑菌活性实验结果表明，正己烷萃取浸膏在浓度为5100 mg } mL-‘时对大肠杆菌和枯草芽抱菌的抑菌率分别为53%}71%和56%}70%，在浓度为50 mg } mL-‘和100 mg } mL-‘时对金黄色葡萄球菌的抑菌率分别为51%和69%。该研究课题进一步明确了樟子松针叶中的化学成分，为其活性测试及应用研究提供依据。
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《腐蚀科学与防护技术》
Abstract： The microstructure，microhardness and corrosion resistance of S32101 lean duplex stainless steel after aging treatment at temperatures in a range from 300 ℃ to 900 ℃ were characterized by means of optical microscope (OM), microhardness testers, electrochemical potentiodynamic reactivation (EPR), electrochemical impedance spectroscopy (EIS). The result showed that with the increasing aging temperature, the hardness increased, the passivation film would become uneven and less dense, so the corrosion resistance relative declined. When the aging temperature was 700 ℃, obvious precipitates occurred at the phase boundaries, which were a mixture of carbon or nitride and secondary austenite; while the microhardness reached a maximum and the compactness of passivation film was worst, thereby, the corrosion resistance became worst; correspondingly corrosion occurred on nearly entire the ferrite phase in the steel, which indicated that the corrosion mechanism was a selective dissolution of ferrite phase. As the aging temperature raised up to 900 ℃ , the number of precipitates reduced, the microhardness decreased, the passivation film would become dense and the corrosion resistance was enhanced.
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