影像纹理窗口大小对山地阔叶林不同群落有效叶面积指数估测的影响

森林叶面积指数是陆地表面过程和地球系统气候模型的基本参数,更是森林结构的关键参数之一,已广泛应用于辐射、植物光合作用和降雨截流估测等方面。论文以川西南山地阔叶林5种不同群落类型为研究对象,基于地面调查的112个20 m×20 m样地和SPOT 5数据,运用5种图像处理技术,包括光谱反射率、植被指数、影像单波段纹理、简单波段比纹理和主成分纹理,提取相应影像信息,建立多元回归模型估算有效叶面积指数（LAIe）。结果表明：光谱反射率、单波段纹理参数和植被指数对LAIe估测能力相对较低,利用植被指数仅获得实测LAIe约65%的精度（R²=0.65,RMSE=0.28 m²/m²）;更为有效的是运用所有比值处理的纹理特征参数值来估测LAIe,可获得实测LAIe约74%的变异（R² =0.74,RMSE=0.20 m²/m²）;改进最理想的是利用主成分处理建立的回归模型（R²=0.85,RMSE=0.10 m²/m²）。不同群落的LAIe估测,整体上相应地优于研究区结果,其中栲群落决定系数R²更是高达0.89（RMSE=0.07 m²/m²）。对于研究区阔叶林以窗口7×7、9×9比较成功,而各群落以窗口9×9较好。因此比值处理、主成分处理的纹理特征参数引入及高空间分辨率数据的使用,能显著提高LAIe估测精度。     

石化企业VOCs无组织排放源强的反演模拟

针对石化行业面源无组织排放VOCs难以准确定量的问题,建立了基于开路式傅里叶变换红外光谱技术(OP-FTIR)的面源污染源源强反演模型,并进行了现场模拟试验。试验结果表明,风向、风速、大气稳定度、监测距离、数据处理周期等都是影响反演模型准确性的重要灵敏度参数。以反演源强Q_P与实际排放量Q的比值(Q_P/Q)为量化指标,对各影响因素进行优化处理,确定了构建反演模型适用的边界条件。当各灵敏度参数稳定于适用边界条件之内时,Q_P/Q为0.85~0.90。     

Handling Techniques: The Influence of Weight and Height for Experts and Novices

The purpose of this study was to evaluate the influence of the weight of the load (12 kg, 22 kg) and of the height of the grasp (high: 126 cm; middle: 64 cm and 95 cm; low: 33 cm) on the handling techniques adopted by six experienced handlers and six novices having only limited handling experience during a free box-handling task. Each subject had to transfer two sets of 16 boxes from a platform to a four-wheel cart. The observations dealt with the position of the subject at the beginning of transfer and at deposit (position of the back, knees and feet, pelvic orientation, position of the hands), his way of moving during the transfer (position of the feet), and his way of positioning and moving the box during handling (tilt of the box, impulse given to the box, grip change). The results show that the weight and the height of grasp/deposit had an influence on the techniques adopted by expert handlers and novices. Some of these variations are common to both groups but many of them are not, such as the position of the knees, the grips and the position of the box. This study suggests that there is not one method that is suitable for all situations, and that expert handlers may have learned how to adjust their methods to the working environment. A better understanding of the experts’ techniques could help in redesigning efficient training programs.     

联用技术在砷形态分析中的研究进展

摘要：目前用于元素砷的形态分析技术主要是色谱与原子光谱、质谱等的联用,最常用的是HPLC与ICP—OES、ICP—MS的联用,方法准确可靠,灵敏度高,但是不能提供砷化合物的分子结构信息。因此以色谱一电喷雾质谱（ESI—MS）的联用作为定性分析的主要手段,但是ESI—MS灵敏度低,易受基体干扰,因此需要复杂的前处理技术。     

Bolted flange joints equipped with FBG sensors in industrial piping systems subjected to seismic loads

The vulnerability of major-hazard industrial plants to natural hazards has been recognized as an emergent issue whose importance is underlined by the Sendai Framework, established immediately after the Tohoku earthquake of 2011, in Japan. Hence, seismic risk analysis is of paramount importance as testified by the intense research activity that characterized the last years. In this respect, structural health monitoring can represent a valuable tool able to strongly help the decision-making phase. Along this main vein, optical fibers (OFs) represent a class of sensors able to both monitor critical conditions, as leakage of hazardous material, and activate safety barriers, if any. More precisely, optical fibers represent an economic solution, whose characteristics appear particularly suitable for dangerous environments like major-hazard plants. However, investigations relevant to their use for seismic monitoring of chemical/petrochemical plants are rather limited, especially when subject to strong dynamic excitations. As a result, this paper deals with the analysis of optical fiber Bragg gratings (FBGs) applied to bolted flange joints (BFJ) under cyclic loadings. More precisely, two experimental programs, i.e., a cyclic test on a single BFJ and a series of shaking table tests on BFJs of a multicomponent system, demonstrated the effectiveness of the proposed monitoring systems in detecting hazardous conditions and, thus, their potential use in conjunction with safety barriers.     

Characterization of humic acids extracted from the sediments of the various rivers and lakes in China

The humic acids (HAs) isolated from the sediments of the various rivers,lakes,and reservoirs in China were studied using elemental analyzer,fourier transform infrared (FT-IR),and CP/MAS 13C nuclear magnetic resonance (NMR) spectroscopy.The results showed that the HAs were characterized by some common chemical and physicochemical properties,but they also pose some differences in the C-containing functional groups.The C/N,C/H,O/C,and O/H ratios differ widely for the various HAs,showing that the elemental comp...     

不同面源强度影响下城市河流溶解性有机质光谱特征变化

采用紫外-可见吸收光谱（UV-vis）和三维荧光光谱结合平行因子法（EEMs-PARAFAC）研究两条面源输入强度不同的城市河流春夏两季水体中溶解性有机质（DOM）含量和组成变化.结果表明,两条河流夏季水体DOM腐殖化程度和相对分子质量均显著高于春季（P<0.01）. PARAFAC模型共解析出C1（UVC类富里酸）、 C2（类色氨酸）、 C3（类胡敏酸）和C4（UVA类富里酸）这4个化学组分,C1[（31±6）%]和C2[（31±4）%]为水体DOM中主要荧光组分.高面源输入水平的河流春季各组分荧光强度均低于夏季,而低面源输入水平的河流与之相反.随机森林回归模型表明,C3%对河流水质变化敏感度最高（R²=0.75,P<0.001）,具有很好的指示作用;水面覆盖率（Cover）对C4%有显著预测重要性（P<0.001）, C4%易受光化学氧化作用影响.主成分分析（PCA）和Adonis检验表明,氮和磷为水体自生源过程的重要推动力,面源输入强度和季节变化对城市河流水体状况有显著影响（R²=0.775,P<0.001）.城...     

多晶硅切割液废液的回收与利用

结合工程实际,介绍了太阳能产业用多晶硅片切割过程中产生的割液废液的处理工艺及回收工艺,并分析了它的投资成本和经济效益。     

色谱及联用技术在药物污染检测中的应用

医药品是一类新型环境污染物,由于其具有长期输入、环境中降解/去除缓慢、生物效应显著等特性被界定为"准持久性"污染物,受到社会各界的广泛关注.为更好了解该类污染物在环境中的迁移转化规律和生物效应,分析检测是必不可少的环节,本文就近年来我国运用色谱及联用技术检测药物污染的方法进行综述.     

环境样品中汞形态分析技术的进展

汞的毒性、环境行为、生物有效性不仅跟其浓度有关,还决定于其化学形态,因此汞的形态分析在环境科学中具有重要意义。样品前处理几乎是汞形态分析研究中不可或缺的步骤,而色谱和光谱/质谱联用技术是目前普遍采用的分离检测方法。文章对近十年来这些方面的研究进展进行了综述,主要包括样品的前处理方法如酸/碱溶剂萃取、微波辅助萃取、固相萃取、固相微萃取、单滴微萃取、分散液液微萃取等,以及色谱(液相色谱、气相色谱)和毛细管电泳与光谱/质谱(紫外可见光谱、原子吸收光谱、原子荧光光谱、等离子体质谱等)的联用技术在汞化合物形态分析中的应用情况。最后提出今后应重点研究建立高效、简便的前处理方法,发展高分离度、高灵敏度、高速度的分离检测联用技术,以便更好地对汞的形态进行分析监测。