A historical perspective of river basin management in the Pearl River Delta of China

Three innovations in water and soil conservancy technology in the Pearl River Delta of South China, i.e., dike building, land reclamation, and dike-pond systems, were examined from a historical perspective. They were found to best reflect local farmers' efforts to cope with the challenges of various water disasters and to build a harmonious relationship with the changed environment. These technologies were critical to the agricultural success and sustainability over the past 2000 years, and reflected local farmers' wisdom in balancing land use and environmental conservation. Imprudent use of a new agricultural technology could damage the environment, and could disturb the human-environment relationship, as evidenced by the more frequent flooding that followed inappropriate dike building and premature reclamation. It is suggested that as the urbanization and industrialization process in the delta region continues, the kind of thinking that made the water and soil conservancy sustainable needs to be incorporated into the design of similar technologies for water use and river basin management today.     

菌渣-发酵床废弃垫料堆肥中温室气体排放及与微生物的关系

堆肥是处理农业废弃物最适宜的技术之一,但堆肥产生的有害和温室气体排放导致环境污染问题.本研究以生猪养殖发酵床废弃垫料及菌渣为原料,利用强制通风静态堆肥技术研究垫料和菌渣不同配比及添加EM菌剂对堆肥过程温室气体排放和微生物区系的影响.结果表明,不同堆肥处理温室气体排放通量以堆肥前20 d较大,堆肥中后期降低;微生物总量和种类在不同堆肥处理间没有发生显著性变化;CO_2和N_2O排放速率与细菌、真菌和甲烷氧化菌间具有显著的正相关关系.整个堆肥期间,以菌渣为主料并添加EM菌剂的堆肥处理温室气体减排效果最佳,相对其他3个处理温室气体减排0.7%~10.2%.由此认为,以菌渣为主料和通过添加EM菌剂的堆肥方式可以作为降低菌渣-发酵床废弃垫料堆肥过程温室气体排放的策略.     

绿色壁垒的法律分析

面对我国国际贸易深受国外绿色壁垒影响的现状,我国应以国际规则坚决抵制贸易保护主义,制定绿色产品及其包装发展鼓励条例,并不断完善环境管理和绿色保障法律制度。     

The Investigation of the Toughening Mechanism of PHBV/PBAT with a Novel Hyperbranched Ethylenediamine Triazine Polymer Based Modifier: The Formation of the Transition Layer and the Microcrosslinking Structure

A new type of designed hyperbranched ethylenediamine trazine polymer (HBETP) is successfully synthesized and characterized based upon NMR and GPC. The prepared HBETP is used to modify the poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV)/poly(butylene adipate-co-terephthalate) (PBAT) blends. The effect of HBETP on the microstructure, mechanical properties and thermal properties of the blends is studied. The results indicate that upon addition of 1.0 wt% of HBETP, the impact strength of the PHBV/PBAT blends is increased by 47.1%; ?T_g of the blends decreases from 53.2 to 49.9 °C. These results, together with the morphology analysis of the fractured surface of the blends, conclude the formation of the transition layer between PHBV and PBAT. Also, the XRD result shows that the addition of HBETP can limit the growth of the PHBV crystals and causes the decrease of both the crystallinity and the grain crystalline size. The DSC result demonstrates that the addition of HBETP mainly affects the crystallization of the HB-HV binary eutectic region within PHBV. The mechanism of PHBV/PBAT toughening is due to the formation of the strong physical hydrogen bonding and the chemical micro-crosslinking between HBETP and PHBV/PBAT, which is proposed based on XPS characterization.     

生草栽培下果园土壤固碳潜力研究

果园是我国南方红壤丘陵区重要的土地利用类型之一,但目前丘陵区果园中存在一些不合理开发、传统粗放式的经营、水土保持技术缺乏等因素,导致水土流失严重,土壤退化严重。寻求合理的土壤管理措施,减少果园水土流失,增加红壤的碳汇功能一直是学术界和生产实践面临的重要问题。本研究以福建尤溪长期定位试验为研究平台,研究顺坡开垦＋清耕、梯台开垦＋清耕、梯台开垦＋套种平托花生Arachis pintoi这3种垦殖方式对红壤果园有机C含量的影响,并利用Jenny模型对不同处理的土壤有机碳动态进行模拟。结果表明,经过14年的垦殖,清耕模式导致土壤容重增大,而梯台生草处理土壤容重比开垦前降低了1.8%;生草栽培不但提高了果园土壤有机碳含量,且生草栽培处理的土壤有机碳储量比清耕处理提高了13.9%～34.7%,其与清耕处理间的差异达到显著性水平;本试验条件下果园土壤有机碳平衡值为16.607~25.608 g/kg,并以此估算得到生草栽培处理0~20 cm土层有机碳储量平衡值为54.801 t/hm2,其固碳潜力为24.6951 t/hm2,分别是顺坡清耕和梯台清耕处理的4.2倍和1.5倍。因此可以认为生草栽培有利于提高土壤的碳汇功能。     

Chemical deactivation of V2O5-WO3/TiO2 SCR catalyst by combined effect of potassium and chloride

V₂O₅-WO₃/TiO₂ catalyst was poisoned by impregnation with NH₄Cl, KOH and KCl solution, respectively. The catalysts were characterized by X-ray diffraction (XRD), inductively coupled plasma (ICP), N₂ physisorption, Raman, UV-vis, NH₃ adsorption, temperature-programmed reduction of hydrogen (H₂-TPR), temperature-programmed oxidation of ammonia (NH₃-TPO) and selective catalytic reduction of NO _x with ammonia (NH₃-SCR). The deactivation effects of poisoning agents follow the sequence of KCl>KOH?NH₄Cl. The addition of ammonia chloride enlarges the pore size of the titania support, and promotes the formation of highly dispersed V = O vanadyl which improves the oxidation of ammonia and the high-temperature SCR activity. K⁺ ions are suggested to interact with vanadium and tungsten species chemically, resulting in a poor redox property of catalyst. More importantly, potassium can reduce the Brønsted acidity of catalysts and decrease the stability of Brønsted acid sites significantly. The more severe deactivation of the KCl-treated catalyst can be mainly ascribed to the higher amount of potassium resided on catalyst.     

运用关联度分析硒镧复合作用下巴西蘑菇氨基酸含量与砷含量的关系

通过采用混合培养料试验、日立8810型氨基酸自动分析仪和原子吸收法测定氨基酸含量和砷含量以及灰色系统理论分析关联度,研究了硒镧复合作用下巴西蘑菇子实体氨基酸含量和砷含量的变化和关系,为栽培砷含量低的巴西蘑菇提供科学依据.各硒镧复合处理的关联度排序为:B4>B1>B2>B0>B3.其中B4处理关联度最大,为0.835 1,B2最小,为0.726 9,说明硒镧浓度对巴西蘑菇子实体各氨基酸含量与砷含量有一定影响.各氨基酸含量与重金属砷含量关联度顺序为:丙氨酸>酪氨酸>胱氨酸>苯丙氨酸>赖氨酸>组氨酸>天门冬氨酸>异亮氨酸>苏氨酸>缬草氨酸>亮氨酸>甘氨酸>脯氨酸>精氨酸>丝氨酸>谷氨酸>甲硫氨酸.其中丙氨酸含量与砷含量关联度最大,为0.856 6,说明硒镧复合作用下巴西蘑菇子实体中丙氨酸含量与重金属砷含量的关系最为密切;关联度最小的是甲硫氨酸.     

下垫面条件对流域极端事件影响及综合应对框架

在剖析下垫面条件变化对流域极端水文事件演变影响的基础上,构建了流域极端水文事件综合应对技术框架,并阐述其中的关键研究命题。结果表明,自然植被条件能够提高流域干旱之前土壤含水量并降低干旱过程中土壤蒸发速率,在一定程度上起到减缓干旱的强度和持续时间的作用;水利工程通过调节流域水资源的时空分布,增加可利用水资源量,能够缓解甚至规避流域干旱事件,但同时可能加剧坝址下游地区的干旱程度。自然植被条件将延长降水坡面产-汇流历时、降低洪峰流量,对极端降水洪涝事件具有一定的消减作用;此外,流域水土保持和修建水利工程等下垫面条件改变有利于河道行洪过程,能够起到缓解洪涝事件的作用。基于下垫面条件变化的流域极端水文事件综合应对技术框架包括旱涝事件监测、机理识别、影响评价和综合应对四个方面的内容,其中的关键研究命题主要为下垫面条件变化对流域极端水文事件影响的定量评估、面向流域极端水文事件合理的水土资源配置及其集成管理等。     

油田采出液乳化程度的影响因素试验研究

通过模拟油田采出液,考察了油水比、聚合物、表面活性剂及天然固体颗粒物对油田采出液乳化程度的影响。试验表明:随着油水比下降,模拟水样含油量降低,油珠Zeta电位升高,平均粒径变大,水样乳化稳定性减弱;HPAM会吸附于油珠表面从而增强其负电性,降低油珠间的有效碰撞,使油珠的平均粒径较小,导致油水分离较困难;表面活性剂会直接降低水样的表面张力,增强油水亲和性,导致水样含油量增大,同时增强了油珠的负电性,不利于油珠的集结聚并;天然固体颗粒物本身有一定的电负性,降低了油珠的Zeta电位,增加油珠的静电排斥,妨碍油珠的聚并,同时使水样的含油量升高,最终导致乳状液稳定。