碳钢的等温动态相图及其应用

建立并扼要讨论了,碳钢在任意等温温度下的时间一成分状态图及其应用,将这种由平衡或不平衡组织构成的状态图定义为;碳钢的等温动态相图     

A hierarchical analysis of terrestrial ecosystem model Biome-BGC: Equilibrium analysis and model calibration

The increasing complexity of ecosystem models represents a major difficulty in tuning model parameters and analyzing simulated results. To address this problem, this study develops a hierarchical scheme that simplifies the Biome-BGC model into three functionally cascaded tiers and analyzes them sequentially. The first-tier model focuses on leaf-level ecophysiological processes; it simulates evapotranspiration and photosynthesis with prescribed leaf area index (LAI). The restriction on LAI is then lifted in the following two model tiers, which analyze how carbon and nitrogen is cycled at the whole-plant level (the second tier) and in all litter/soil pools (the third tier) to dynamically support the prescribed canopy. In particular, this study analyzes the steady state of these two model tiers by a set of equilibrium equations that are derived from Biome-BGC algorithms and are based on the principle of mass balance. Instead of spinning-up the model for thousands of climate years, these equations are able to estimate carbon/nitrogen stocks and fluxes of the target (steady-state) ecosystem directly from the results obtained by the first-tier model. The model hierarchy is examined with model experiments at four AmeriFlux sites. The results indicate that the proposed scheme can effectively calibrate Biome-BGC to simulate observed fluxes of evapotranspiration and photosynthesis; and the carbon/nitrogen stocks estimated by the equilibrium analysis approach are highly consistent with the results of model simulations. Therefore, the scheme developed in this study may serve as a practical guide to calibrate/analyze Biome-BGC; it also provides an efficient way to solve the problem of model spin-up, especially for applications over large regions. The same methodology may help analyze other similar ecosystem models as well.     

Understanding the role of chronic environmental disturbance in the context of island biogeographic theory

Island biogeographic theory offers a powerful conceptual framework for understanding and managing insular diversity. The human impact on insular environments is constantly growing, especially because of tourism. We performed a simulation study aimed at improving the understanding of the role of disturbance in islands. We also built an individual-oriented computer model of an archipelago subjected to chronic disturbance of varying degree. Results are discussed in the light of island biogeographic theory. Relevant results show the importance of autoecological characteristics of the species considered, regarding the attainment of equilibrium and the species-area relationship in both disturbed and undisturbed cases. The possibility of bias in the predictions of the equilibrium model is pointed out. Fundamental criticisms concerning the ecological relevance of the equilibrium theory are discussed.     

非离子氨浓度换算方法的改进

根据氨溶于水时平衡常数与温度的关系,求出非离子氨摩尔百分比的表达式,接用公式在计算器上编程换算非离子氨浓度,可提高数据的准确性和批量数据处理效率。     

层次性通风网络平衡图的自动生成

风网平衡图是矿井通风管理的一种重要手段。笔者首次创造性的提出层次性的风网平衡图 ,把风网平衡图做成一个具有层次图形显示、连续双向查询、自动优化网络、数据管理的图形数据库。利用VLISP语言在AutoCAD平台上开发一套矿井通风平衡图的层次性生成及优化软件 ,可以扩展AutoCAD的数据接口、充分发挥它的图形功能、数据管理功能 ,使通风网络平衡图成为一个具有自动优化功能的数据库系统。软件具有可视化、自动风网优化、数据管理、效率高的特点     

外立面作用下水平湍流浮力射流火焰的附壁研究

用防火板模拟建筑外立面,设计了可控流速和开口尺寸的气体燃烧器产生水平湍流浮力射流火焰,系统研究了外立面抑制火焰卷吸所导致的水平湍流浮力射流火焰附壁规律。将火焰流场演变分为两个阶段:(1)出口到流场水平动量衰减为零(等价点)的阶段;(2)火焰附壁或不附壁的阶段。其中,火焰附壁与否很大程度上取决于等价点到出口的水平距离LE。通过分析,我们发现雷诺应力是导致流场水平动量衰减和火焰附壁的主要原因。由此,我们基于普朗特混合长度理论推导了雷诺应力的近似表达式并结合动量控制方程,获得了LE与修正弗洛德数Fr*的线性关系,从理论上解释了出口宽高比n(n=B/H,B是开口宽度;H是开口高度)越大,火焰越容易附壁的现象,并确定了不同开口及流速条件下,火焰附壁的临界条件。     

Equilibrium partitioning theory to predict the sediment toxicity of the anionic surfactant C(12)-2-LAS to Corophium volutator

The study of the effect of the sorption of linear alkylbenzene sulfonates (LAS) on the bioavailability to marine benthic organisms is essential to refine the environmental risk assessment of these compounds. According to the equilibrium partitioning theory (EqP), the effect concentration in water-only exposure will be similar to the effect concentration in the sediment pore water. In this work, sorption and desorption experiments with two marine sediments were carried out using the compound C₁₂-2-LAS. The effect of the sediment sorption on the toxicity of benthic organisms was studied in water-only and in sediment bioassays with the marine mud shrimp Corophium volutator. In addition, three common spiking methods were tested for its application in the toxicity tests, as well as the stability of the surfactant during the water-only and sediment-water test duration. LC50 values obtained from water-only exposure showed a good correspondence with the pore water concentrations calculated from the sorption and desorption isotherms in the spiked sediments.     

The effect of calcium and pH on nickel accumulation in and rhizotoxicity to pea (Pisum sativum L.) root-empirical relationships and modeling

The accumulation and rhizotoxicity of Ni to pea were investigated. Calcium, H, and Ni competed for root-binding sites with high pH and low Ca favoring more Ni accumulation. At low pH, Ca accumulation is the key factor determining root growth, while at medium to high pH, root elongation is more sensitive to Ni concentration. The tissue concentration of Ni and Ca ([Ni]t or [Ca]t, μmol g⁻¹ dry root) can be predicted from total dissolved Ni ([Ni]_T, μM), pH, and total dissolved Ca ([Ca]_T, mM) by two approaches. Approach 1 is the empirical equations [Ni]t = (0.361 pH-0.695[Ca]_T)*[Ni]_T and [Ca]t = 8.29 pH + 10.8 [Ca]_T. The second approach involves a two-step model. The surface-bound Ni and Ca are estimated from a surface adsorption model with binding constants derived from independent ion adsorption experiments. Then transfer functions are used to predict internal root Ni and Ca accumulation.     

Biosorption of Cu(II), Zn(II), Ni(II) and Pb(II) ions by cross-linked metal-imprinted chitosans with epichlorohydrin

Cross-linked metal-imprinted chitosan microparticles were prepared from chitosan, using four metals (Cu(II), Zn(II), Ni(II), and Pb(II)) as templates, and epichlorohydrin as the cross-linker. The microparticles were characterized by Fourier transform infrared spectroscopy, solid state (13)C nuclear magnetic resonance spectroscopy, and energy-dispersive X-ray spectroscopy. They were used for comparative biosorption of Cu(II), Zn(II), Ni(II) and Pb(II) ions in an aqueous solution. The results showed that the sorption capacities of Cu(II), Zn(II), Ni(II), and Pb(II) on the templated microparticles increased from 25 to 74%, 13 to 46%, 41 to 57%, and 12 to 43%, respectively, as compared to the microparticles without metal ion templates. The dynamic study showed that the sorption process followed the second-order kinetic equation. Three sorption models, Langmuir, Freundlich, and Dubinin-Radushkevich, were applied to the equilibrium isotherm data. The result showed that the Langmuir isotherm equation best fitted for monolayer sorption processes. Furthermore, the microparticles can be regenerated and reused for the metal removal.     

CO_2在哌嗪水溶液中的吸收和再生特性研究

利用压力釜在100⁵00 kPa 压力和303500 kPa 压力和303³23K温度下,研究了 2.0323K温度下,研究了 2.0 4.9的哌嗪水溶液对二氧化碳的平衡吸收量,测试了温度和浓度对平衡吸收量的影响。co2的平衡吸收量随着浓度的增加而增加。313 K的操作温度既能保证较高的吸收量,又能保证较快的吸收速率,因此是合适的操作温度。对3.5M的PZ水溶液,在温度为368 4.9的哌嗪水溶液对二氧化碳的平衡吸收量,测试了温度和浓度对平衡吸收量的影响。co2的平衡吸收量随着浓度的增加而增加。313 K的操作温度既能保证较高的吸收量,又能保证较快的吸收速率,因此是合适的操作温度。对3.5M的PZ水溶液,在温度为368³83K的条件下进行再生。温度为368 K时,再生效率为82.13%,再生过程需 55 min,而升温至383 K后再生效率大幅提升至 95.98%,再生时间迅速降为41 min。考虑到再生的时间、效率及能耗等因素,在 378 K下进行再生相对适宜。在373K 的操作温度下进行多次再生实验,PZ 水溶液经过10个周期的实验后9.76%,吸收容量与新鲜溶液相比只损失了并且只降低了1.0个pH,这也说明,PZ水溶液再生效率及连续再生能力较为突出。