中国森林公园旅游业发展的就业效应分析

发展旅游业是扩大就业的重要渠道。森林公园旅游业是中国森林旅游业的主体。本文首先概述了中国森林公园建设与发展状况,并基于林业统计年鉴数据,分析中国森林公园旅游业发展及直接就业效应,进而采用投入产出法对森林公园旅游业的间接就业效应进行了测算,最后总结全文并提出相关政策建议。研究结果表明:森林公园旅游业持续发展的就业效应可观。测算数据显示,2011-2020年森林公园旅游业的总体就业量为512.1万人,其中直接和间接就业量分别为238.5万人和273.6万人。     

Interactions between biological and abiotic pathways in the reduction of chlorinated solvents

While biologically mediated reductive dechlorination continues to be a significant focus of chlorinated solvent remediation, there has been an increased interest in abiotic reductive processes for the remediation of chlorinated solvents. In situ chemical reduction (ISCR) uses zero‐valent iron (ZVI)–based technologies, such as nanoscale iron and bimetallic ZVI, as well as naturally occurring reduced minerals incorporating dual‐valent iron (DVI), such as magnetite, green rust, and iron sulfides that are capable of dechlorinating solvents. A more recent area of development in ISCR has been in combining biological and abiotic processes. There are several ways in which biological and abiotic processes can be combined. First, the interaction between the two may be “causative.” For example, the Air Force Center for Engineering and the Environment's biogeochemical reductive dechlorination (BiRD) technology combines a mulch barrier with hematite and gypsum to create an iron‐sulfide‐based reducing zone. Biodegradation under sulfate‐reducing conditions produces sulfide that combines with the hematite to form iron sulfides. As such, the BiRD technology is “causative”; the biological processes create reducing minerals. The biological generation of other reducing minerals such as magnetite, siderite, and green rust is feasible and is, with magnetite, observed in nature at some petroleum sites. A second type of interaction between abiotic and biotic processes is “synergistic.” For example, biological processes can enhance the activity of reduced metals/minerals. This is the basis of the EHC® ISCR technologies, which combine ZVI with a (slowly) degradable carbon substrate. This combination rapidly creates buffered, strongly reducing conditions, which result in more complete solvent degradation (i.e., direct mineralization). The extent and level of reducing activity commonly observed are much greater when both the carbon substrate and the ZVI are present. When the carbon substrate is expended, the reducing activity due to ZVI alone is much less. The understanding of biogeochemical processes and their impact on abiotic processes is still developing. As that understanding develops, new and improved methods will be created to enhance volatile organic compound destruction. © 2009 Wiley Periodicals, Inc.     

A fiber-optic redox sensor for the iron(III)–iron(II) transition

A phenosafranine-containing Nafion film attached to the distal end of a fiber-optic probe forms a functional redox-sensitive optical sensor. The synthetic cationic photoactive dye phenosafranine, 3,7-diamino-5-phenylphenazinium chloride, responds with changes in light absorbance between its oxidized and reduced forms. This optical property persists when phenosafranine is sorbed into Nafion, a perfluorosulfonate anionic film. Optical properties of the sensor are similar to those seen by others in solution. At high redox conditions, such as an open nitrogen-purged aqueous pH 6.5 solution, optical absorbance of phenosafranine is high, while at low redox conditions, such as an aqueous pH 6.5 iron(II) solution, optical absorbance of phenosafranine is low. Titration of a closed pH 6.5 aqueous solution with a standard iron(II) solution lowers redox potential in a predictable manner and can be followed by the optical redox sensor in parallel with a commercial redox potential electrode.     

骆马湖泥-水界面磷铁硫原位同步变化特征

利用薄膜梯度扩散（DGT）原位采样装置获取了骆马湖全湖8个典型湖区泥-水界面（SWI）活性磷（P）、铁（Fe）、硫（S）垂向分布信息，据此定量估算三者交换通量.结果表明，骆马湖沉积物剖面P、Fe、S浓度范围分别为0~2.05，0~11.10和0.01~0.63mg/L，并在微小尺度呈高度空间异质性.在水平方向上活性P、Fe主要表现为西北湖区高于东南湖区，而活性S则未表现出明显的分布规律；就垂直剖面而言，活性P、Fe、S自界面向下呈升高趋势，并在60mm深度内出现峰值，且活性P和Fe剖面呈明显的同步变化特征；活性P、Fe在多数点位具有显著的正相关性（r>0.65，P<0.01），且各采样点沉积物中的总铁与总磷比值[w（∑Fe）/w（∑P）]均高于15，这表明Fe的地球化学循环过程对于骆马湖内源磷释放起重要控制作用；8个采样点样品中活性P、Fe、S交换通量分别为0.066~0.698，1.671~5.592和0.007~0.071mg/（m²·d），表明P、Fe、S由沉积物向水体释放.西北湖区表现出较高的P通量和活性P浓度，这可能会增加南水北调过程中水质污染的风险，应予以重视.以上结果支持了P、Fe耦合释放机制，明确了骆马湖SWI的活性P、Fe、S迁移特征.     

MASS BALANCE MODEL ESTIMATION OF PHOSPHORUS CONCENTRATIONS IN RESERVOIRS1

ABSTRACT: Mass balance models have been common tools in lake quality management for some years. However, verification for use on reservoirs, especially in the Western United States, has been seriously lacking, In this study, such a verification is attempted using data from the U.S EPA National Eutrophication Survey. Several models from the literature are compared for accuracy in application to the western reservoir data. Model standard error and correlation between estimated and observed reservoir phosphorus concentrations are the Criteria used for comparison. Standard errors am further used to calculate uncertainty of trophic state classification based on estimated phosphorus concentration. The model proposed by Dillon and Rigler (1974) proved most accurate, with a correlation coefficient of 0.86 and standard error of 0.2, based on logarithmic transformed values. Deficiencies in the other models appear to & from coefficients fit to lake data and from inappropriate model formulation.     

基于卫星测高数据的2002～2018年太湖水位变化监测

针对传统水位监测方法的弊端以及太湖水位变化监测的现实需求,基于Envisat和Cryosat-2测高数据,采用Morlet小波分析、Mann-Kendall检验法研究2002年6月～2018年12月近20a的水位以及周期变化,并应用实测数据进行精度验证,从气象因素和人为影响两方面分析其不同时间尺度的变化趋势以及原因.结...     

Degradation of phenol in an upflow anaerobic sludge blanket(UASB) reactor at ambient temperatureKE

A synthetic wastewater containing phenol as sole substrate was treated in a 2.8 L upflow anaerobic sludge blanket(UASB) reactor at ambient temperature. The operation conditions and phenol removal efficiency were discussed, microbial population in the UASB sludge was identified based on DNA cloning, and pathway of anaerobic phenol degradation was proposed. Phenol in wastewater was degraded in an UASB reactor at loading rate up to 18 gCOD/(L·d), With a 1:1 recycle ratio, at 26(1℃, pH 7.0-7.5. An UASB reactor was able to remove 99% of phenol up to 1226 mg/L in wastewater with 24 h of hydraulic retention time(HRT). For HRT below 24 h, phenol degradation efficiency decreased with HRT, from 95.4% at 16 h to 93.8% at 12 h. It further deteriorated to 88.5% when HRT reached 8 h. When the concentration of influent phenol of the reactor was 1260 mg/L(corresponding COD 3000 mg/L), with the HRT decreasing(from 40 h to 4 h, corresponding COD loading increasing), the biomass yields tended to increase from 0.265 to 3.08 g/(L·d). While at 12 h of HRT, the biomass yield was lower. When HRT was 12 h, the methane yield was 0.308 L/(gCOD removed), which was the highest. Throughout the study, phenol was the sole organic substrate. The effluent contained only residual phenol without any detectable intermediates, such as benzoate, 4-hydrobenzoate or volatile fatty acids(VFAs). Based on DNA cloning analysis, the sludge was composed of five groups of microorganisms. Desulfotomaculum and Clostridium were likely responsible for the conversion of phenol to benzoate, which was further degraded by Syntrophus to acetate and H2/CO2. Methanogens lastly converted acetate and H2/CO2 to methane. The role of epsilon-Proteobacteria was, however, unsure.