Results 21 to 30 of about 2,743 (170)

云南刀耕火种农业的变迁 [PDF]

open access: yes, 1998
departmental bulletin ...
4689   +3 more
core   +1 more source

Effects of Continuous Straw Returning Combined with Reduced Fertilizer Application on Rice Yield and Loss of Nitrogen and Phosphorus [PDF]

open access: yes, 2022
[Objective] The effects of straw returning combined with reduced chemical fertilizer application on rice yield and nitrogen and phosphorus losses with runoff were studied in order to provide a scientific basis for the recycling and reuse of local ...
Liang Fan   +8 more
core   +1 more source

Greenhouse gas emissions from croplands of China [PDF]

open access: yes, 2003
China possesses cropland of 1.33 million km 2. Cultivation of the cropland not only altered the biogeochemical cycles of carbon (C) and nitrogen (N) in the agroecosystems but also affected global climate.
Bohan, Liao   +13 more
core   +1 more source

Overreliance on Orthographic Similarity in L2‐Japanese Conceptual Processing by L1‐Chinese Learners

open access: yesInternational Journal of Applied Linguistics, EarlyView.
ABSTRACT Orthographic and phonological similarities between first (L1) and second (L2) languages can facilitate L2 processing. Particularly, L1‐Chinese learners of L2‐Japanese can benefit from the shared morphosyllabic Chinese characters (Japanese kanji/Chinese hanzi) because of their similar orthographies.
Xuehan Zhao, Kexin Xiong, Sachiko Kiyama
wiley   +1 more source

Compliance in Regulatory Gray Areas: The Case of the Organic Seed Standard

open access: yesPolicy Studies Journal, EarlyView.
ABSTRACT Adaptive regulations, designed to balance flexibility with accountability, can embed provisions that unintentionally leave room for firms to shirk on their responsibilities by exploiting flexibility. We call these provisions “regulatory gray areas,” and ask: how should we understand (non‐)compliance in adaptive regulatory settings?
Liza Wood   +3 more
wiley   +1 more source

Gradient distributions of nitrogen and organic carbon in the soils from inland to tidal flat in the Yellow River Delta [PDF]

open access: yes, 2014
黄河三角洲是我国典型的通过黄河冲积泥沙填海造陆形成的近代沉积区。区域受到黄河冲积、沉积等自然过程和农业耕种熟化等人类活动的双重影响。本研究通过在黄河三角洲地区内陆到河口海湾不同距离采集典型土壤类型剖面发生层样品,探讨土壤有机碳、总氮等生源要素的空间分布规律,为阐明我国典型海岸带地区陆源碳、氮的输送及循环特征提供基础依据。研究结果表明,黄河三角洲内陆与河口地区呈现出完全不同的土壤碳、氮分布规律。表层土壤碳、氮含量在黄河沿岸及三角洲南部均表现出由陆向海逐级递减的空间分布特征 ...
李远   +4 more
core   +1 more source

Regulating TGO Nucleation and Growth of MCrAlX Coatings via Femtosecond Laser Remelting: The Role of Reactive Elements in the Oxidation Resistance

open access: yesRare Metals, Volume 45, Issue 3, March 2026.
ABSTRACT MCrAlX coatings are widely used as bond coats in thermal barrier coating systems to protect turbine blades from high‐temperature oxidation. However, their oxidation resistance is often restricted by uncontrolled microstructures, surface roughness, and aggregation of reactive elements (REs). In this study, high‐repetition‐rate femtosecond laser
Wei Qian   +7 more
wiley   +1 more source

Design and Simulation of Contact Fatigue Testing System of Flexspline and Circular Spline in Harmonic Drive [PDF]

open access: yes, 2016
谐波齿轮传动是随着空间技术的发展而诞生的一种新型传动方式,其工作原理是利用柔轮的弹性变形波来实现运动或者动力传递,因其具有结构简单、传动精度高、传动比大等诸多优点,在航空、航天、机器人等领域得到了广泛应用。在谐波齿轮传动过程中,柔轮的运动情况比较复杂,作为弹性薄壁构件需承载交变应力,容易造成齿面磨损和疲劳断裂。因此,建立合适的模型对谐波齿轮传动过程中柔轮的错齿运动进行模拟分析具有重要意义。 本文首先针对谐波齿轮传动过程中柔轮的错齿运动设计了一种新的接触疲劳试验装置 ...
吴泽林
core  

Development of a Four‐Language Questionnaire to Investigate Environmental Risk Factors for the Development of Canine Atopic Dermatitis and to Monitor Disease Course and Progression

open access: yesVeterinary Dermatology, Volume 37, Issue 1, Page 34-44, February 2026.
Background: The chronic and multifactorial character of canine atopic dermatitis (cAD) often leads to poor disease control and treatment dissatisfaction. Environmental factors are likely to contribute to the disease development and may play a more important role than assumed previously.
Patricia Clara‐Maria Rhodius   +11 more
wiley   +1 more source

Behavior of a Flexspline in Harmonic Drive [PDF]

open access: yes, 1900
谐波齿轮传动是利用柔性工作构件的弹性变形波进行运动或者动力传递的一种新型传动方式,因其具有体积小、重量轻、精度高、单级传动比大、承载能力高等诸多优点,在航空航天、机器人、数控机床等领域得到了广泛的应用。柔轮作为谐波齿轮传动的关键构件很大程度上影响了谐波齿轮传动的承载能力、使用寿命等。柔轮为弹性薄壁件,在交变载荷作用下易导致齿面磨损和疲劳断裂。柔轮强度、变形与应力分析对谐波齿轮传动过程中的疲劳断裂评估及传动性能研究具有重要的意义。 本文首先根据已知参数、实际工况和谐波齿轮传动啮合参数选取原则 ...
刘淳剑
core  

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