带热水供应的家用空调器运行特性研究

针对家用空调的特点,提出了对家用空调冷凝热进行回收利用的观点,利用热回收系统加热生活用水,并建立了一种新型的带热水供应的家用空调试验系统。通过该试验系统各测点的试验数据,对该设备在空冷运行模式和水冷热回收运行模式两种情况下的运行特性作了相应的分析,给出了一些重要参数的实验结果,并分析讨论了在热回收时水温变化对系统的影响。结果表明,制冷和制热同时协调运行时,不仅不影响机组原有的性能,并且在制冷和提供生活热水的同时,提高了系统的总能效比,达到节能环保的目的。     

爆炸压实工艺参数对钢管能量与变形的影响

为了指导研究爆炸压实工艺参数的选择,通过改变爆轰速度与装药厚度来改变爆炸冲击能,重点研究爆炸压实工艺参数对钢管能量与变形的影响.研究表明:当其他工艺因素相同、仅爆轰速度不同时,将导致爆轰压力、钢管壁速度、爆炸冲击能、粉末压实能等显著不同,但钢管的变形与能量却几乎不变;当采用爆轰速度极高的黑索今炸药时,由于爆轰压力与爆炸冲击能过高,导致钢管头部被切掉;对硝酸脲炸药而言,随着装药厚度与炸药/钢管质量比增加,钢管的能量与变形、爆炸冲击能与粉末压实能单调增加.     

Computational analysis methods to quantify a.c. impedance data

For the interpretation of a.c. impedance data, two data analysis techniques are described and evaluated. The first method is a least squares analysis of a nonlinear model. Modifications to a previously published algorithm, CIRFIT, include a least squares estimate of the double layer capacitance. Also, two convergence techniques for CIRFIT were explored and evaluated. The second method is a nonlinear least squares analysis of an equivalent circuit consisting of three RC parallel combinations, the final circuit containing a diffusion limiting impedance. The method satisfactorily estimated the component values of the proposed equivalent circuit, even when two time constants were closely spaced. Both methods could be valuable in analyzing, modeling, and interpreting experimental a.c. impedance data.     

Modelling net primary productivity of terrestrial ecosystems in East Asia based on an improved CASA ecosystem model

By using a land cover map, normalized difference vegetation index (NDVI) data sets, monthly meteorological data and observed net primary productivity (NPP) data, we have improved the method of estimating light use efficiency (LUE) for different biomes and soil moisture coefficients in the Carnegie–Ames–Stanford Approach (CASA) ecosystem model. Based on this improved model we produced an annual NPP map (in 1999) for the East Asia region located at 10–70° N, 70–170° E (about 19.66% of the terrestrial surface of the Earth). The results show that the mean NPP for the study area in 1999 was 374.12 g carbon (C) m^?2 year^?1 and the total NPP was 1.096 × 10¹⁴ kg C year^?1, making up 17.51–18.39% of the global NPP. Comparison between the estimated NPP obtained from this improved CASA ecosystem model and the observed NPP obtained from two NPP databases indicates that the estimated NPP is close to the observed NPP, with an average error of 5.15% for the study region. We used two different land cover maps of China to drive the improved CASA model by keeping other inputs unchanged to determine how the classification accuracy of the land cover map affects the estimated NPP, and the results indicate that an accurate land cover map is important for obtaining an accurate and reliable estimate of NPP for some regions, especially for a particular biome.     

利用TG-FTIR研究造纸黑液碱木质素的热解机理

采用热重-傅里叶红外光谱（TG-FTIR）联用的分析方法对造纸黑液碱木质素的热解失重特性和产物生成特性进行了研究。结果表明：碱木质素热解失重过程可分为3个阶段,其中200~500℃是碱木质素主要的热解挥发阶段,反应符合一级反应动力学模型,利用Coats-Redfern动力学模型计算得出不同升温速率下热解主反应的表观活化能为39.3~43.1 kJ/mol。FTIR的实时分析结果表明：碱木质素热解的气态产物主要有H₂O、CO₂、CO、CH₄、甲醇、酚类和N₂O;产物中的CH₄、甲醇、酚类和N₂O主要在300~500℃区间内释放,随着热解温度的升高,这些气态产物在420℃附近集中释放,且产量达到最大。     

基于紫外吸收光谱法的水中氨氮浓度测量方法研究

氨氮是水中常见的污染物,是各类水质检测重要 的指标。水中氨氮含量超标会影 响水生植物、动物的生长,导致水体环境恶化,水环境受到污染。因此,加强水中氨氮 的监测尤为重要。本文基于紫外光谱检测技术,搭建了水中氨氮浓度紫外光谱检测系统。 通过检测系统将液相氨氮转换为气相氨气,获得氨气在 190-235nm波长间的紫外吸 光度,并分别采用傅里叶滤波和傅里叶变换两种数据处理方式对吸光度信号进行分析。 结果表明,经傅里叶滤波后氨气的吸光度在190-235nm波长间存在明显的周期性的峰 值,周期约为4nm,随着氨气浓度的增加其吸光度峰值也增大。通过最小二乘法拟合 发现,氨气的吸光度和浓度之间存在着良好的线性关系,相关系数为0.99814。经傅里 叶变换后的吸光度信号在频域中存在特征频率,通过拟合发现,振幅强度与氨氮浓度之 间同样存在线性关系,相关系数为0.98686。实验证明可以根据氨气吸 光度获得氨氮的 浓度,为水中氨氮浓度的检测提供了新的检测手段。     

溴化锂吸收式热泵及其在电站冷却水余热回收中的应用

利用热泵技术回收利用电站凝汽器冷却水余热资源是节能减排的一项重要措施.调查和研究了溴化锂吸收式热泵在电站冷却水余热回收中的应用、存在的主要问题和解决措施.研究表明:热泵回收的余热可用于加热供暖用的热网水、进除氧器的补水和凝汽器凝结水等;污垢和腐蚀是影响电站溴化锂热泵安全经济运行的主要问题;添加阻垢缓蚀剂、杀菌剂和清洗可防治污垢;合理选材、添加缓蚀剂和保持换热管清洁可防治腐蚀.     

Applying of Switch Strong Tracking UKF in Spacecraft Autonomous Celestial Navigation

Star & Horizon sensor based autonomous navigation methods play an increasingly important role in spacecraft celestial navigation. However,the measurements of star sensors and horizon sensor are frequently affected by uncertain noises from space environment. To improve the estimation precision,a state estimation algorithm named Switch Strong Tracking Unscented Kalman Filter( SSTUKF) is presented. Firstly,the adaptive fading factor is deduced through the adoption of unknown instrumental diagonal matrixes to real time rectify the measurement covariance matrix. Secondly,according to the deduction of Chebyshev law of large numbers,innovation criterion is introduced during estimation to decrease the unnecessary calculation. Finally,SSTUKF is suggested through the adoption of adaptive fading factor and innovation criterion. The filter can switch between the normal filter mode and adaptive filter mode. As the calculation of innovation criterion is less than the adaptive fading factor,SSTUKF improves the estimation efficiency. To demonstrate the effectiveness,SSTUKF is applied to Star & Horizon sensor based autonomous navigation system with uncertain measurement noises. The simulation results verify the proposed algorithm.     

工艺参数对自蔓燃制备氮化硅粉体的影响

采用自蔓燃高温合成方法(self-propagating high-temperature synthesis,简称SHS)合成氮化硅粉体,分析了自蔓燃高温合成氮化硅过程中氮气、温度、稀释剂与孔隙率等方面的影响。采用XRD研究相的组成,用SEM观察粉末的显微结构。研究结果表明:只要控制反应中的工艺参数,就可以采用自蔓燃得到不同相含量的Si3N4粉体;考虑到燃烧温度(Tcom),在氮化硅粉体的合成过程中,涉及到3个反应机制:低温机制,中温机制,高温机制;氮气压力下硅粉的自蔓燃合成反应,必须要引入Si3N4稀释剂,来控制反应温度和反应速度,获得不同相含量的粉体;NH4Cl在反应中分解,为反应提供了NH3,并与硅粉反应;压坯气孔率控制在30%~70%,否则反应不能进行。SHS法可以制备纯度很高的氮化硅粉体。此法较传统方法合成的氮化硅设备简单,成本低廉,纯度高,填充性好,烧结活性好。     

基于AHP和模糊综合评价的高校校园规划评价研究

校园规划的方案对大学校园建设起着举足轻重的决定作用,研究如何更加科学地对规划方案进行评价具有非常重要的现实意义．首先通过调查分析,建立了较为简洁、全面的高校校园规划评价指标体系,并采用层次分析方法（AHP）对指标权重进行了分析;然后建立了基于模糊综合评价的高校校园规划评价方法,并结合具体案例进行了实证分析．通过建立的基于层次分析法和模糊综合评价的高校校园规划评价方法体系,可以帮助决策者更加准确和客观地选择校园规划方案．