释疑鼓劲渡难关 化危克艰谱新篇——会员畅谈年会讲座收获

年年岁岁花相似,今年花开别样红。中国网印及制像协会4月21日在江西婺源召开的五届三次理事会议暨2009年会,却开出了新意。协会结合当前国际国内经济形势和会员单位经营状况,特邀北京大学经济学院、清华大学CIMS中心客座教授、中国职业经理人开发中心主任张耀升先生以“金融危机下的中小企业经营之道”为题,举行了专题培训讲座。培训师语言风趣幽默、通俗易懂,     

贝类蛋白改性技术研究进展

贝类在水产品中占有重要的地位,贝类蛋白营养丰富,具有独特的风味和功能特性,但由于贝类产品受地域的限制且易腐败,其在食品工业中的实际应用较少。已有研究证明,通过改性能进一步优化贝类蛋白的功能特性,使其更好的应用于食品加工领域,从而解决蛋白质资源短缺的问题。本文论述了物理改性法、化学改性法和酶解改性法三大类贝类蛋白改性技术的机制及优缺点,不仅为改进贝类蛋白改性技术和开发新兴的贝类产品提供了理论支持,还为拓宽贝类产品在食品工业中的应用范围提供了依据。     

新型冠状病毒肺炎疫情期间城镇再生水厂污泥处理处置运行实践

新冠肺炎疫情期间,污泥处理处置过程的安全性问题更加凸显.与此同时,由于污水水质及水量变化,北京市中心城区的污泥高级厌氧消化处理系统处于低负荷运行状态,对运行稳定性提出较大挑战.通过对污泥处理过程及出泥泥质特性分析,明确了污泥高级厌氧消化工艺在污泥稳定化及病原体灭活方面的优势.通过梳理新冠肺炎防控期间的经验做法,提出了污泥高级厌氧消化系统应对低负荷运行的具体举措.此外,针对污泥运输及后续利用环节,介绍了人员防护及区域消杀的建议.以期为疫情常态化防控期间,城镇污水处理厂污泥处理处置环节的安全稳定运行提供借鉴.     

求解材料非线性系统动力响应的新方法

本文有两方面的内容:(1)结合解析方法和数值方法优点,本文提出求解材料非线性系统动力分析的新方法,并推导了相关公式。新方法利用了分段Lagrange插值多项式和Duhamel积分来求解非线性系统动力响应。当动力荷载表示为分段多项式时,在本构关系的每一个直线段上,可以求出Duhamel积分的精确解。再考虑到刚度转换点上位移和速度的连续性,我们就可以在整个时域上给出非线性系统动力响应的精确解。由于有精确解作为基础,因而和逐步积分法相比,本文方法不但具有较高的计算精度,大大减少了计算工作量,而且彻底地避免了许多数值方法所常遇到的收敛性和稳定性问题。(2)本文提出在原有单层工业厂房结构的侧面加设斜拉杆的抗震加固改造方案,并将此计算方法应用于它的抗震加固计算中。     

Calculated dosimetric parameters of the IoGold 125I source model 3631-A

Basic dosimetric parameters as recommended by the AAPM Task Group No. 43 (TG-43) have been determined for recently available IoGold 125I brachytherapy seeds. Monte Carlo methods (MCNP) were used in the calculation of these parameters in water, and results compared with soon to be published experimental parameters also for 125I IoGold seeds as well with parameters for model 6702 and 6711 125I seeds. These parameters were the radial dose function, anisotropy factor and constant, and the dose rate constant. Using MCNP, values for the radial dose function at 0.5, 2.0, and 5.0 cm were 1.053, 0.877, and 0.443, respectively. The anisotropy factor was 0.975, 0.946, 0.945, and 0.952 at 0.5, 1.0, 2.0, and 5.0 cm, respectively, with an anisotropy constant of 0.95. The IoGold dose rate constant was determined by excluding the low energy titanium characteristic x rays produced in the IoGold titanium capsule. Using this post TG-43 revised NIST air kerma methodology, the IoGold dose rate constant was 0.96 cGy h-1 U-1. These calculatively determined parameters for IoGold seeds were compared with those determined experimentally for IoGold seeds, and also compared with parameters determined for model 6702 and 6711 seeds as presented in TG-43.     

Leaf area index measurements in a tropical moist forest: A case study from Costa Rica

The role of tropical forests in sustainable development mechanisms and payments for environmental services is becoming increasingly important. Therefore, there is a greater need for accurate and detailed information about their biophysical characteristics (e.g., Leaf area index-LAI) along different stages of ecological succession. Remote sensing offers the possibility of providing relatively accurate estimations of such biophysical characteristics at a reasonable cost for most regional projects. The objectives of this study are to (1) document the variability of LAI in different stages of secondary growth in a tropical moist forest, (2) estimate LAI from spectral vegetation indices (SVIs), and (3) link LAI to the estimation of other canopy physiognomic characteristics. We found that segregation of LAI measurements by successional stage (early, intermediate, late) contributed to a better definition of the relationship between LAI and the SVIs. In addition, we conclude that the propagation of errors of precision through the SVI formulas must be taken into consideration along with intra-site and radiometric variability when uncertainty terms are calculated. From a linear regression analysis, we found that there is only a minimal difference between the nonparametric Theil-Sen and classical least-squares regressions. We also found that not only does the Lorentzian cumulative transition function describe the relationship between LAI and the SVIs, it also provides an estimate of the range of LAI values to which each index is sensitive.     

Comparison of environmental impacts of two residential heating systems

This paper presents a comparison of environmental impacts of two residential heating systems, a hot water heating (HWH) system with mechanical ventilation and a forced air heating (FAH) system. These two systems are designed for a house recently built near Montreal, Canada. The comparison is made with respect to the life-cycle energy use, the life-cycle greenhouse gas (GHG) emissions, the expanded cumulative exergy consumption (ECExC), the energy and exergy efficiencies, and the life-cycle cost. The results indicate that the heating systems cause marginal impacts compared with the entire house in the pre-operating phase. In the operating phase, on the other hand, they cause significant environmental impacts. The HWH systems with a heat recovery ventilator (HRV) using either electricity or natural gas have the lowest life-cycle energy use and lowest ECExC. The HWH and FAH systems using electricity as energy source have the lowest GHG emissions. Finally, the FAH systems have, on the average, a lower life-cycle cost than the HWH systems.     

绿色节能建筑技术在亚热带地区超高层建筑中的应用

以"珠江城"和"发展中心大厦"为例探讨幕墙、空调、电梯等方面的节能设计,以及可再生能源与建筑一体化没计的方式、方法.