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关键词： Biofilm   Oxygen mass transfer   Aeration rates   Microbial community  

摘要： A laboratory-scale aerobic fluidized bed biofilm reactor (AFBBR) was established to evaluate the oxygen mass transfer (OMT) process and its impact on municipal wastewater treatment performance. Aeration rates had different effects on the OMT of the wastewater and biofilm. In the wastewater, oxygenation performance, oxygen uptake rate (OUR), and volumetric OMT coefficient (k(L)a) improved under high aeration rates. However, within the biofilm, the OMT process under the aeration rate of 0.096 L/(min.L) were higher than under other conditions [0.064 L/(min.L) and 0.128 L/(min.L)]. The denitrifying bacteria (DNB) abundance under the aeration rate of 0.096 L/(min.L) were improved so that total nitrogen (TN, 66.98 +/- 4.23%) and ammonia nitrogen (NH4+-N, 74.70 +/- 2.30%) removal were higher than those under other aeration conditions. These results showed that suitable aeration could improve wastewater treatment efficiency through changing the OMT process and microbial community structure.

关键词： Calcium looping   CO2 capture   Carbonator modelling   Fluidized bed hydrodynamics   CaO/Al2O3 composite  

摘要： This manuscript presents a general model for the fluidized bed carbonator reactor of the Calcium Looping (CaL) process based on bed hydrodynamics, kinetics and sorbent properties. The model proposed relies on the Kunii-Levenspiel theory for circulating fluidized beds in the fast fluidization regime and considers recent findings on the CO2 capture properties of CaO, including the effects of the diffusion-controlled carbonation stage and CaO modification by means of additives. By performing a sensitivity analysis, it is found that the solids inventory in the carbonator and superficial gas velocity are the main operational and hydrodynamic factors affecting the CO2 capture efficiency. Decay constant of the fraction of solids in the lean region and fraction of solids in the dense region are also identified as two important model parameters. Model predictions are shown to agree with experimental results retrieved from pilot-scale tests. The main novelty of the model is the consideration of a CaO/Al2O3 composite either as main CO2 sorbent used in the carbonator or as a make-up flow fed into the calciner. Using CaO/Al2O3 as the main CO2 sorbent leads to a 14.17% loss of capture efficiency after 100 cycles compared to 72.81% when using limestone derived CaO. It is demonstrated that feeding a very low ratio (similar to 0.1) of the CaO/Al2O3 composite or a rather high ratio (similar to 5) of limestone as makeup flow, leads to a significant improvement of the capture efficiency. The results obtained may be relevant for optimizing CaL operation conditions to be used in power plants.

关键词： 热流体   水化学   环境同位素   形成年龄   地热系统  

摘要： 利用大量的地热流体化学成分及环境同位素（δD、δ18O、14C）测试数据，深入分析了隆起山地 构造对流型、沉降盆地传导型地热流体的化学特征及分布规律，进而对地热流体的环境同位素分 布特征及形成年龄进行了梳理总结，得出了明确的结论。结果表明：隆起山地构造对流型地热田 地热流体主要以断裂上升泉的形式出露，分布于西秦岭-祁连造山带，补给来源为当地及周边大气 降水入渗，地热流体形成年龄一般小于 5 000 ~ 30 000 a，水质较好，属“开启型”的地热系统；热储层 岩性、断裂规模及水热循环方式和深度等明显控制着地热流体化学类型、环境同位素特征和形成 年龄。沉降盆地传导型地热田地热流体主要以管井开采的方式出露；热储埋藏深度小于 1 600 m 的 地热井，地热流体补给来源为当地及周边大气降水入渗，形成年龄一般小于 5 000 ~ 30 000 a，水质相对较好，属“半开启-半封闭型”的地热系统；热储埋藏深度介于 1 600 ~ 2 600 m 之间的地热开采 井，主要为地质历史时期逐步形成的“古水”，水化学类型复杂且水质较差，地热流体形成年龄介于30 000 ~ 50 000 a,属“封闭型”的地热系统；热储层岩性、埋藏深度、地下水在岩层中的滞留时间与循 环深度等明显控制着地热流体化学类型、环境同位素富集程度和形成年龄。

关键词： IFRS   Cash flow   Board independence   Auditor industry specialization  

摘要： Purpose This study aims to explore the relationship between audit partner and firm industry specialization and board of director independence on the decision by Taiwanese firms to use International Financial Reporting Standards (IFRS) flexibility concerning reporting interest income and expense and dividends received in different sections of the statement of cash flows. This flexibility existed in Taiwan for the first time in 2013, the year that Taiwan switched from its own generally accepted accounting principle to IFRS. Design/methodology/approach Using 2013 data for a sample of 1,227 firms, 354 of whom changed their reporting classification, this study examined the interaction effect of board independence and partner-level and firm-level auditor industry specialization on the cash flow reporting decision using logistic regression. Findings The results show there is a substitute relationship between board independence and partner-level industry specialization on the change in cash flow reporting classification, but a complementary relationship between board independence and firm-level auditor specialization. Further, both partner-level and firm-level auditor industry specializations have a complementary (but negative) relationship with board independence as to whether the firm is likely to report interest expense paid in the operating or financing activities sections. Practical implications An important implication is that knowing the levels of audit firm and partner specialization and how independent the board is, is useful for researchers and regulators in investigating auditor-client relationships and understanding the influences of variables investigated here on the outcome(s) of accounting policy and regulatory changes. Originality/value This study improved the field's understanding of the impacts of audit partner and firm specialization, board independence and relevant interactions on cash flow reporting choices.

关键词： Redox reactions   Reaction products   Coal   Mercury   Pyrolysis  

摘要： The migration of mercury pollutants is an inevitable problem in the coal pyrolysis/circulating fluidized bed (CFB) combustion-staged conversion process. To explore the influence of circulating ash on the occurrence and migration of mercury in a staged process, two-stage mercury removal experiments were conducted in a fixed-bed reactor with high-mercury coal. The effects of ash-to-coal ratio, ash particle size, metal oxides in ash, and ash-coal placement types on mercury in coal pyrolysis gas, liquid, and solid products were investigated. The results showed that mercury in coal pyrolysis volatiles mainly escapes in the form of Hg-0 and Hg2+, and Hg-0 is the main form of mercury in the volatiles. Fe2O3, CaO, and MgO in circulating ash reacted with Hg-0 in coal pyrolysis volatiles at a high temperature to oxidize Hg-0 to Hg2+. Larger ash-to-coal ratio and smaller ash particle size could significantly increase the conversion efficiency of Hg-0 to Hg2+. When ash and coal were mixed, the oxidation rate of Hg-0 during coal pyrolysis was significantly better than that in the layered pyrolysis of ash and coal. Temperature was the most important factor affecting Hg-0 escape during coal pyrolysis. The combustion experiments of pyrolysis semicoke showed that the mercury in semicoke and tar completely escaped in the form of Hg-0. This study provides a reference for the purification of mercury-containing pollutants in the pyrolysis and combustion-staged conversion process.

关键词： 卡门涡街   Fluent仿真   气固两相流   静电感应  

摘要： 针对现有静电感应式煤尘测量装置在低浓度、粒子运动速度较低情况下测量不精确且功能单一的问题,依据卡门涡街的原理,提出在测量管道中安装带狭缝圆柱发生体,从而提高煤尘粒子的运动速度,增大静电传感器的感应电荷量,提高煤尘浓度测量精度;同时,对测量管道内由于颗粒速度的周期性变化所感应出的静电信号周期性变化,进行快速傅里叶变换(FFT),求解颗粒的速度流量信息,实现对煤尘的多参数测量。仿真试验结果表明:依据感应电荷的周期性变化可以获得煤尘的流速(流量)和浓度参数。此装置结构简单,既可提高煤尘浓度测量精度,又能满足煤尘速度、流量测量的要求。

关键词： 抛物线   以退为进   深度反思   二次函数最值   活水   源与流   坐标  

摘要： 问题如图1,已知抛物线y=ax^(2)+ba+3与x轴交于A、B两点,过点4的直线l与抛物线交于点C,其中4的坐标是(1,0),C点坐标是(4,3).

关键词： 乙醇-水溶液   泡沫   表面张力   界面弹性  

摘要： 对有机硅表面活性剂FC-7160和几种典型的碳氢表面活性剂在50%(体积分数,下同)乙醇-水溶液中的泡沫结构、含液量和液膜的表面弹性进行了研究。结果表明,和水溶液相比,FC-7160在50%乙醇-水溶液中的气泡较小且为近圆形,且含液量较高;碳氢表面活性剂在50%乙醇-水溶液中形成的液膜扩张模量为0 mN/m,没有表面弹性,所以其泡沫产生之后立即消失;而FC-7160在50%乙醇-水溶液中的表面弹性较高,在液膜处的分子排列更为紧密,一方面增大了表面黏度,另一方面提高了液膜强度,所以其在50%乙醇-水溶液中的泡沫具有一定的稳定性。

关键词： 分子运动   活化水   渗透力   小分子团水   团簇结构   活水   外部环境   表面张力  

摘要： 1认识活水与活水养殖1.1活水定义说起活水,大多数人都以为是指流动的水,实际上活水包含两层意思:传统意义上的活水直观意思是指流动的水,是相对外部环境而言。现代意义上的活水也称活化水,是指具有高活性的水,是相对水分子间的内部团簇结构而言,具有水分子运动能力强,表面张力小,渗透力、扩散力、溶解力、代谢力强,溶氧高等特点,因此有人为便于理解称之为"小分子团水",具体评价指标为水的半幅宽度。

关键词： Internally   Circulating   Fluidized bed   Particle tracing   Solid circulation rate  

摘要： Internally circulating fluidized beds(ICFBs)enable effective control of the reactions and heat distribution in *** ICFB contains two or more connected fluidized regions with different gas velocities to promote controlled solid *** control of solid circulation rate(G_(0))is a critical *** recorded single particle trajectories by tracing a fluorescent particle,based on which particle flow behaviors were analyzed in different regions.G_(0)was obtained for a wide range of operating *** increase in gas velocity in the down-and upflow beds shortened the particle circulation time in both beds and G_(0)increased *** the static bed height increased,the differential pressure on both sides of the circulation port increased,which resulted in an increase in the solid circulation *** the orifice area increased,the flow resistance through the orifice decreased and thus the solid circulation rate increased.G_(0)increased with the decrease in particle *** gas velocity in the upflowing bed and orifice area was the most important parameter to control the solid circulation rate.G_(0)was compared with the experimental measurements in literature and predictions using the correlation based on Bernoulli’s equation,and they agreed well.