Non-cyanide Copper Plating on Steel Substrate in Alkaline Tartrate Bath

以酒石酸盐为络合剂,胺化合物为辅助络合剂,研究钢铁基体上碱性无氰镀铜工艺,探讨了搅拌、镀液温度、PH、ρ(Cu2+)和添加剂对镀层外观的影响。考察了镀液的深镀能力和抗fE2+、fE3+、zn2+及Sn4+杂质能力以及镀层与铁基体的结合力。实验结果表明:可以在宽广的工艺条件下获得光亮的铜镀层;阴极电流效率随温度、PH和ρ(Cu2+)提高而增大,在实验确定的工艺条件下ηκ为82%左右;镀液深镀能力达91%;计时电位曲线试验结果表明,基体上的钝化膜在沉积初期被破坏而处于活化状态,使得铜镀层与钢铁基体有足够的结合力。The process of non-cyanide copper electroplating on steel substrate was developed using tartrate as complexing agent and amine compound as assistant complexing agent.The effects of agitation,bath temperature,pH,ρ(Cu2+) and additive on deposit appearance were studied.The bath covering power,the ability of anti-impurities to Fe2+,Fe3+,Zn2+,Sn4+ and adhesion of copper to steel substrate were tested.The results show that,in this bath the bright copper coating can be electrodeposited under wide condition ranges;the current efficiency is about 82% and is increased with the increasing of bath temperature,pH and ρ(Cu2+);the covering power of the bath is 91%.Chronopotentiometric curves prove that the passivation films on steel substrate could be spoiled at the early stage of electrodeposition and the substrate could be activated and therefore adhesion is strong enough between copper deposit and the substrate.广东省教育部产学研结合专项资金项目(2006D90404019);福建省科技计划重点项目(2008H0086);国家自然科学基金项目(20873114

Effects of changes in precipitation on soil respiration in coastal wetlands of the Yellow River Delta

Soil moisture fluctuation caused by changes in precipitation patterns associated with global change is an important driving force for the dynamic changes of soil respiration. However, it is unclear how coastal wetlands respond to changes in precipitation patterns, and thus cause changes in the ecosystem blue carbon function. To explore the response and mechanism of soil respiration and environmental and biological factors to precipitation changes, the soil carbon flux observation system was applied to monitor wetland soil respiration rates under different precipitation treatments relying on increased and decreased precipitation fields outside the control experiment platform of the Yellow River Delta coastal wetland in 2017. The results showed that: (1) with increased precipitation, the wetland soil temperature gradually decreased; simultaneously,both precipitation increase and decrease significantly increased wetland soil moisture (P &lt; 0.05); (2) changes in precipitation significantly affected vegetation species composition, aboveground and belowground biomass allocation, and root/shoot ratio (P &lt; 0.05). A 40% and 60% precipitation increase significantly increased the wetland plant species and vegetation root shoot ratio; however,it significantly reduced the aboveground biomass of wetland vegetation. In addition,a 40% increase and 60% decrease of precipitation significantly increased the aboveground biomass of wetland vegetation; (3) there was no significant effect of precipitation changes on annual soil respiration in wetlands. Nevertheless,a 60% and 40% precipitation increase both significantly increased the soil respiration rate in wetlands during the non-flooding season (P &lt; 0.05); (4) the wetland soil respiration and moisture showed a quadratic curve (P &lt; 0.05) with the correlation coefficient decreasing with precipitation increase. Furthermore, during the wetland non-flooding season, soil respiration and temperature were exponentially correlated (P &lt; 0.05) with soil temperature sensitivity (Q10) increasing with increasing precipitation. There was no significant correlation between soil respiration and temperature during flooding periods; (5) during the flooding period,the soil respiration rate was inversely correlated with the surface water level (P&lt; 0.001).</p

Enhancement of Coastal Blue Carbon: Concepts, Techniques, and Future Suggestions

The blue carbon function and carbon sequestration potential of coastal ecosystems, such as salt marshes, mangroves and seagrass beds, have emerged as one of the long-term solutions to mitigate global climate change. However, the blue carbon sequestration technology has been neglected in most ecological protection and restoration projects of coastal ecosystems. Besides, in the process of project implementation and management, the dynamic monitoring and systematic evaluation of carbon sink are imperfect. This study proposes the concept of enhancement of coastal blue carbon, focusing on four key technologies of soil carbon emission reduction technology, plant carbon sequestration technology, soil microbial carbon sequestration technology, and carbon deposition and burial technology, to explore the technology system and approach to enhance coastal blue carbon. This study suggests accelerating forward-looking layout and system research, mainly by developing technologies of coastal blue carbon sequestration, achieving synergies between ecological conservation and restoration and carbon sequestration, strengthening the monitoring and evaluation of carbon sequestration and sink enhancement, and establishing a longterm management mechanism for the development of coastal blue carbon sink, which would provide theoretical and technical support for the formulation of coastal blue carbon and the enhancement of carbon sink function, and play an active role in enhancing ecological carbon sink capacity and achieving the goal of carbon peak and carbon neutrality in the future

Response of soil CO_2 and CH_4 emissions to changes in moisture and salinity at a typical coastal salt marsh of Yellow River Delta

Aims Globally, coastal salt marshes have been considered as major blue carbon sinks and contributors for climate change mitigation. Understanding the effects of soil moisture and salinity on soil CO_2 and CH_4 emissions will advance better understand of long-term storage of soil carbon in coastal salt marshes. Methods We conducted a simulation experiment with a gradient of water treatments (25%, 50%, 75% and 100% soil saturated water content) and salt treatments (9 g·kg~(-1) and 18 g·kg~(-1)). And we investigated soil carbon mineralization rates, soil properties, microbial biomass and community structure of typical salt marsh soils in the Yellow River Delta. Important findings We found that: (1) There was no interaction between soil moisture and salinity content on soil CO_2, CH_4 emissions and CH_4:CO_2, and soil CO_2 emissions showed a unimodal curve along the soil moisture gradients and a significant decrease with increasing soil salinity content. The increased soil moisture significantly promoted soil CH_4 emissions, but the increased soil salinity content significantly inhibited soil CH_4 emissions. (2) There was a weak significant interaction between moisture and salinity content on dissolved organic carbon (DOC). Under low water treatment, DOC content decreased with increasing soil salinity content, but increased under high water treatment. There was a significant positive relationship between soil CO_2 emissions and DOC content. (3) Soil microbial biomass exhibited a trend of first increasing and then decreasing with the increasing soil moisture, while soil salinity content significantly decreased microbial biomass. There was a significant positive correlation of microbial biomass with CO_2 and CH_4 emissions. (4) Both soil moisture and salinity treatments modified soil microbial community structure. Soil moisture and salinity treatments significantly increased and decreased the number of bacteria and alpha diversity index, respectively. Both soil CO_2 and CH_4 emissions were positively correlated with the number of bacteria and alpha diversity index. The climate is gradually drying and warming in this region due to climate change. Therefore, we speculated that changes in microbial biomass and community structure, soil moisture and salinity content may have potentially profound effects on the carbon-sink function at coastal salt marsh

EFFECTS OF TIDAL CREEK MORPHOLOGY ON SPATIAL DISTRIBUTION OF SOIL ORGANIC CARBON IN SOIL IN TIDAL WETLAND

Soil organic carbon is a major carbon pool in tidal wetland ecosystems. By dividing the level of the tidal creek and calculating its morphological characteristic index, the spatial distribution characteristics of the typical tidal creek system were analyzed, taking a typical natural tidal channel as the research object. The spatial distribution characteristics of soil organic carbon were analyzed by geostatistical methods. In addition, the effects of morphological characteristics of the tidal creek on the spatial distribution of soil organic carbon were explored. The results showed that there was obvious spatial heterogeneity in the morphological characteristics of the tidal creek. In the middle tidal flats, the connectivity of the tidal creek network was higher, and the density, curvature and bifurcation ratio were also higher than that in other tidal zones. The tidal creek length gradually increased with the increase of tidal creek development grade, while the tidal creek curvature gradually decreased with the increase of tidal creek development grade. The spatial interpolation results showed that the lowest soil organic carbon in 0 to 10 cm soil layer occurred in the middle tidal flats where tidal creeks were more developed, and within the 10~ 20 cm soil layer, soil organic carbon showed a gradually increasing trend from sea to land, and showed a strip-shaped spatial distribution choracteristic. In the low tidal flats, the mean value of soil organic carbon in a third-order creek was significantly greater than that in a first-order creek. In the middle tidal flats, the mean value of soil organic carbon in a second-order creek was significantly greater than that in a third-order and a first-order creek. The soil organic carbon of the high tide flats was not significantly correlated with the tide creek development level. Within the 0 to 10 cm soil layer, the soil organic carbon gradually increased with increasing distance to the tidal creek in low and middle tidal flats. Within the 10 to 20 cm soil layer, the soil organic carbon gradually decreased with increasing distance to tidal creek in the middle tidal flats. However, there was no correlation between the soil organic carbon and the distance to the tidal creek in high tidal flats. The spatial heterogeneity in the morphological characteristics of the tidal creek was one of the important factors of spatial differences in soil organic carbon content in the tidal wetland. Therefore, morphology changes in tidal creeks should be considered in order to accurately estimate the soil carbon pools in tidal wetlands