Effects of woody elements on simulated canopy reflectance: Implications for forest chlorophyll content retrieval

An important bio-indicator of actual plant health status, the foliar content of chlorophyll a and b (Cab), can be estimated using imaging spectroscopy. For forest canopies, however, the relationship between the spectral response and leaf chemistry is confounded by factors such as background (e.g. understory), canopy structure, and the presence of non-photosynthetic vegetation (NPV, e.g. woody elements)—particularly the appreciable amounts of standing and fallen dead wood found in older forests. We present a sensitivity analysis for the estimation of chlorophyll content in woody coniferous canopies using radiative transfer modeling, and use the modeled top-of-canopy reflectance data to analyze the contribution of woody elements, leaf area index (LAI), and crown cover (CC) to the retrieval of foliar Cab content. The radiative transfer model used comprises two linked submodels: one at leaf level (PROSPECT) and one at canopy level (FLIGHT). This generated bidirectional reflectance data according to the band settings of the Compact High Resolution Imaging Spectrometer (CHRIS) from which chlorophyll indices were calculated. Most of the chlorophyll indices outperformed single wavelengths in predicting Cab content at canopy level, with best results obtained by the Maccioni index ([R₇₈₀ − R₇₁₀] / [R₇₈₀ − R₆₈₀]). We demonstrate the performance of this index with respect to structural information on three distinct coniferous forest types (young, early mature and old-growth stands). The modeling results suggest that the spectral variation due to variation in canopy chlorophyll content is best captured for stands with medium dense canopies. However, the strength of the up-scaled Cab signal weakens with increasing crown NPV scattering elements, especially when crown cover exceeds 30%. LAI exerts the least perturbations. We conclude that the spectral influence of woody elements is an important variable that should be considered in radiative transfer approaches when retrieving foliar pigment estimates in heterogeneous stands, particularly if the stands are partly defoliated or long-lived.     

有速度脉冲的近场地震下中心支撑钢框架抗震性能评估

近场地震具有的长周期速度脉冲会显著改变结构的响应,使结构在瞬间产生较大的侧移。用屈服点谱(YPS)法对两个中心支撑钢框架算例进行了抗震性态评估,并将得出的结构峰值位移和层间位移角与非线性时程分析的结果进行了比较,评价了YPS法结构抗震评估的精度。     

Attrition resistance of cobalt F–T catalysts for slurry bubble column reactor use

There exists much current interest in the use of supported Co catalysts and slurry bubble column reactors (SBCR) for the conversion of natural gas to higher hydrocarbons via the Fischer–Tropsch (F–T) synthesis. Catalyst attrition resistance is extremely important in the operation of slurry-phase reactor systems because of potential problems with plugging of system filters and/or contamination of the liquid products. This paper addresses the effects of different supports, promoters, and preparation methods on the attrition resistance of Co F–T catalysts for SBCR use.

The calcined supports had attrition resistances (inversely related to % fines <11 μm generated during attrition testing) as follows:

−Al₂O₃>TiO₂(rutile)SiO₂

Loading of Co onto the supports improved the attrition resistances of both alumina and silica significantly. It has essentially no effect on titania. The resulting catalysts had attrition resistances in the order

Co/Al₂O₃>Co/SiO₂>Co/TiO₂(rutile)>Co/TiO₂(anatase)

The addition of small amounts of metal (Ru, Cu) and oxide (La, Zr, K, Cr) promoters had mainly small effects on the attrition resistance of the supported Co catalysts. However, it would appear that the addition of Zr to Co/alumina had a negative impact on its attrition resistance. The different preparation methods used in this study (aqueous impregnation, non-aqueous impregnation, and kneading) did not appear to have a significant effect on catalyst attrition resistance.     

贵州糍粑辣椒的制作工艺

本研究以贵州花溪辣椒、遵义朝天椒、贵州灯笼椒3种干辣椒为主要原料;盐、姜、蒜、料酒、辣椒籽为辅料在传统糍粑辣椒制作基础上进行工艺优化。在单因素试验的基础上,采用Box-Behnken响应面法对糍粑辣椒进行工艺优化,确定最佳配比。研究表明:贵州花溪干辣椒、遵义干朝天椒、贵州干灯笼椒配比为3:2:3(2.60 g:1.70 g:2.60 g),姜蒜比为1:1(2.14 g:2.14 g),辣椒籽炒制时间为30 s(0.83 g),盐含量为1.50 g,料酒含量0.50 mL,煮制时间为6 min,此条件下制作的糍粑辣椒感官评分为93.87±1.60,制作出来的糍粑辣椒不仅色泽鲜艳、香味浓郁、辣感适中、质地均匀,风味独特,各项理化指标、微生物指标均符合贵州糍粑辣椒的地方安全标准,具有良好的产品质量特色,为糍粑辣椒的工业化开发和推广提供了一定的理论基础。     

Production of Biogenic Amines and Their Potential Use as Quality Control Indices for Hake (Merluccius merluccius, L.) Stored in Ice

ABSTRACT: The production of tyramine, histamine, putrescine, cadaverine, agmatine, and spermidine was studied for use as quality indices in muscle of gutted hake stored in ice for 25 d. The changes in biogenic amine concentrations were correlated with trimethylamine nitrogen levels. All concentrations except for spermidine, increased progressively throughout storage. During storage, cadaverine reached 72.14 mg/kg while there were no significant increases in histamine and tyramine. The levels of free amino acids, which may be metabolized into biogenic amines, were not correlated to respective biogenic amines levels. The production of cadaverine and agmatine occurred prior to spoilage and these biogenic amines may indicate freshness of hake stored in ice.     

辽宁省种植冬麦的农业气候指标研究

本文通过对可能影响冬麦生育过程的若干因子的分析，筛选出４个主要气候因子，作为辽宁省种植冬麦的农业气候指标。这４个农业气候指标是：越冬前活动积温为４２０～５４０℃，越冬前降水１２０～１７０ｍｍ，抽穗到成熟期降水 １１０～ １５０ｍｍ，越冬期可耐一 ８００ ℃负积温及一２４～一２６℃的极端最低气温。由此，以农业气候相似论为依据，可以实现以沈阳为中心的辽宁省部分地区冬麦北移种植的构想。     

绿色印染助剂的开发与原料选用

指出了印染助剂中被禁用的非环保助剂的致癌、天才畸、生物降解性差等危害性，同时详细介绍了无毒性、生物降解性好的替代产品及原材料的选用，以予科技人员进一步开发符合环保要求和生态指标的绿色印染助剂。     

Process capability indices—an overview of theory and practice

A range of process capability indices is widely used to measure process performance. The simplicity of the formulae for these capability indices is both a strength and a weakness. The underlying assumptions behind capability indices are frequently overlooked. Capability studies usually result in single point estimates which may result in misleading assessments of process performance. Point estimates ignore sampling error, and safer estimates can be obtained by constructing confidence intervals. The construction of confidence intervals is considered in some detail. Testing or measurement variability give rise to additional uncertainty in process capability assessments. Inaccurate assessments of process performance can result if the basic assumptions and sources of uncertainty are overlooked.     

利用国产设备生产保鲜乳──10吨/班保鲜乳生产线的设计

利用国产设备生产保鲜乳对我国乳品工业的发展具有深远的实际意义。本文着重就生产工艺技术参数的确定进行了设计计算。     

A critical review of methods used to estimate linoleic acid Δ6‐desaturation ex vivo and in vivo

Δ6‐desaturase is located in a pivotal position in the metabolism of essential fatty acids (EFA). Various methods have been used to estimate Δ6‐desaturase activity, including the assessment of: (i) tissue fatty acid compositions (and associated product/precursor ratios), (ii) Δ6‐desaturase activities ex vivo, and (iii) isotopically labelled linoleic acid metabolism in vivo. This review critically examines these methods and considers their appropriateness and reliability in assessing linoleic acid metabolism in diabetes and cardiovascular disease. In general, there was a good agreement between the three methods and the effect of experimental diabetes on linoleic acid metabolism. In humans, however, the effect of diabetes on tissue fatty acid composition was inconsistent, and there was a paucity of data on linoleic acid metabolism ex vivo and in vivo. The inconsistency in human fatty acid compositional data may relate to variable and uncontrolled intakes of linoleic acid and its n‐6 metabolites, but also to a less extreme insulin deficiency as studied in animals. Risk markers for cardiovascular disease generally reduced rat liver Δ6‐desaturase activity ex vivo. This was not, however, reflected in tissue fatty acid compositions in these controlled studies. Linoleic acid metabolism, as determined by tissue fatty acid composition in humans, is reduced in cardiovascular disease; however, the omnivorous dietary patterns and decreased linoleic acid intakes make this conclusion potentially unreliable. Few stable‐isotope studies have been conducted on the effect of cardiovascular risk markers on linoleic acid metabolism, and there is a requirement for this type of work to be standardised to facilitate inter‐study comparisons. These studies may eventually help optimise EFA intake in health and disease conditions.