Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-28 Cooperative journals: 《中国科学院院刊》
Abstract： Compared with soil degradation of black soil of other areas in the world, which caused by conventional tillage regarding as ploughed with residue return, soil degradation in Northeast China caused by rotary-till and residue remove or burning is more serious. Conservation tillage with residue cover and no or reduced tillage is one of the most important techniques for the protection and utilization of black soil. This paper briefly presents the derivation and definition of conservation tillage, and its main techniques in the world, as well as the issue of application and extension in China. Over the past 15 years, the expert team from Chinese Academy of Sciences (CAS), together with Jilin Province’s agricultural sector, universities, local academies of science, and other related units, overcame the barrier of demonstration and extension of conservation tillage in black soil region in Northeast China. They developed high performance no-till planter and strip-tiller, and proposed the techniques of wide-narrow row no-till, strip-till, ridge-till in Northeast China. This innovative application of conservation tillage in Northeast China is called Lishu model, and the effects of its wide extension in Northeast China is prospected.
Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-19 Cooperative journals: 《中国科学院院刊》
Abstract： Liaohe Plain is an important region of the temperate agro-ecosystem in China. To develop efficient agriculture in Liaohe Plain is the key to the stability of food production in Northeast China. However, the sustainable development of agro-ecosystem in Liaohe Plain has been severely constrained by decreasing cultivated land and worsening environment caused by long-term excessive use of resources. Focusing on the development of local agriculture and the management on agricultural resources, Shenyang Agro-ecosystem Experimental Station has conducted a series of long-term experiments since 1990s to explore the change of soil fertility under different management modes of soil nutrients. The retention, transformation and control mechanisms of fertilizer nitrogen in local agro-ecosystem have been clarified by isotope tracing techniques. A series of conservation tillage techniques have been established in rainfed arable soils based on the management mode of “nitrogen control with carbon to achieve a balance”. Fertilizer efficiency has grown and the risk of non-point source pollution in agro-ecosystems decreased with the development of environmental-friendly and stabilized fertilizers. Through the combination between research, trial and extension, efficient management on soil and fertilizer provides scientific and technological support for regional modern agricultural development and ecological environment construction.
Subjects: Mechanics >> Applied Mechanics submitted time 2022-12-21 Cooperative journals: 《应用力学学报》
Abstract：
In order to explore the influence of the circumferential groove of the non-load bearing lobe of the dynamic pressure elliptical bearing and the oil supply pressure on the nonlinear dynamics of the bearing-rotor system,this paper uses the separation variable method to quickly solve the approximate analytical solution of the oil film pressure distribution on the elliptical bearing,and then obtains the law of the oil film pressure with the eccentricity under different aspect ratios.The influence of slot width and oil pressure on dynamic characteristics of bearing rotor is analyzed.In the non-loaded area of the elliptical bearing,only slotting and not supplying pressure oil has little effect on the stability of the system.Increasing the slotted width and the oil pressure in the slot can effectively suppress the half frequency vibration of the rotor in the bearing.When the slot width is 0.3 times of the lower pad width,and the oil pressure increases to 0.8 MPa,the half-frequency eddy amplitude of rotor vibration is greatly reduced,the amplitude of rotor vibration is significantly reduced,and the stable operation speed can be increased from 5 300 r/min to 8 400 r/min.
Subjects: Dynamic and Electric Engineering >> Electrical Engineering submitted time 2019-03-05 Cooperative journals: 《电气工程学报》
Abstract：架空导线载流温升模型是线路动态增容决策、安全运行状态监测和载流量 评估等领域的理论基础。但由于碳纤维复合芯导线（ACCC 导线）与传统架空导线 在材料、结构及运行温度上的差异，使得当前的载流温升计算模型无法直接应用于 ACCC 导线，限制了 ACCC 导线动态增容的发展和输电潜力的挖掘。为此，本文根据 热平衡原理和热电类比理论建立了 ACCC 导线的载流量温升模型，并利用粒子群优化 算法对模型参数进行了辨识求解。设计了 ACCC 导线载流温升实验平台，在自然对流 条件下对其热动态过程进行了实测和模拟。结果表明，粒子群辨识方法可有效辨识出 模型参数，该模型在计算导线温升过程上具有较高的精度。
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-04-12 Cooperative journals: 《计算机应用研究》
Abstract： The spatial and angular resolution are comparatively low owing to the limitation of the resolution of its pixel sensor which is due to design reasons. To address the above problem, this paper presented a new super-resolution method based on global and local views to simultaneously enhance both the spatial and angular resolutions of a light field image. First of all, it adaptively chose local views according to the position of the novel view, and then used spatial super-resolution convolution neural network to get high resolution sub-images such as global-view and local-view images, subsequently it extracted and fused the depth and color features from the image obtained by backward warping the input views. Then put the results into the angular super-resolution network which produced a novel view image as the final result. The experimental results demonstrate that the reconstruction effect of this method is superior to the state-of-the-art’s. And in peak signal to noise ratio get 3dB promotion and structural similarity image measure upgrade about 0.02. In addition, it is not only able to improve spatial and angular resolution of multi-view images, but also to maintain edge information of the novel view, thus effectively avoiding the loss of objects and yielding a better reconstruction effect.
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