Greenhouse gas emissions from croplands of China

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. The impacts of agroecosystems on global climate attribute to emissions of three greenhouse gases, namely carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O)

An improved moving particle semi-implicit method for dam break simulation

Dam break is quite a common and hazard phenomenon in shipbuilding and ocean engineering. The objective of this study is to investigate dam break hydrodynamics with improved Moving Particle Semi-implicit method (MPS). Compared to traditional mesh methods, MPS is feasible to simulate surface flows with large deformation, however, during the simulation, the pressure oscillates violently, due to misjudgment of surface particles as well as particles gathering together. To modify these problems, a new arc method is applied to judge free surface particles, and a collision model is introduced to avoid particles from gathering together. Hydrostatic pressure is simulated by original and improved MPS. The results verify that improved MPS method is more effective. Based on these, dam break model is investigated with improved MPS

Analysis and reflection on the musical simulation in erhu performances

自古以来二胡演奏家为了运用更好的方式去诠释作品，采用模拟不同的音响效果配合二胡的演奏技巧，加之投入自身真挚的情感进行二度创作，将观众带入到音乐的情感和形象当中，从而表达出作品的音乐魅力。本文将立足于对二胡作品演奏中所产生的各类模拟音效的现象进行分析，对二胡模拟音效的演奏进行再认识，并进一步理解模拟音效对二胡作品演奏的意义。 本文共四个章节，以模拟音效为主旨，探讨二胡作品中模拟音效的现象，对二胡作品及模拟的表演奏手法进行梳理和归纳，从对作品的分类中了解各类风格的模拟音响效果，并联系音乐文本作进一步理解，同时从美学认识角度解释模拟音效中对欣赏者形成一定的同构联觉和审美认同感以及对二胡演奏中如何更...Since long ago, erhu players have been reproducing music by simulating natural sounds and putting into their emotions to guide the audience into their emotion and better express the charm of music. This article introduces erhu’s playing technique of simulating different natural sounds to further explore the deeper aesthetics of this musical instrument. This article consists of four chapters. The ...学位：艺术学硕士院系专业：艺术学院_音乐与舞蹈学学号：1872014115365