红外光声光谱测定钨硅酸表面积碳物

钨硅酸是乙苯氧化脱氢反应的催化剂。其表面酸仅起促进表面积碳物形成的作用,并不影响催化剂的活性,活性中心是表面积碳物。因此,研究积碳物的结构对弄清反应机理进而改进催化剂十分重要。

结焦、积碳类污垢化学清洗剂配方的探讨

通过对结焦、积碳类垢物不同处理方法的比较研究,介绍了对此类垢物有良好处理效果的采用水基碱性多元复配配方。

Corrosion behavior of B10 copper-nickel alloy beneath a deposit caused by sulfate-reducing bacteria with carbon source starvation in marine environments

Copper-nickel alloys can suffer severe localized corrosion in marine environments containing sulfate-reducing bacteria(SRB),but the effect of SRB on the under-deposit corrosion of copper-nickel alloys is unknown.In this work,the corrosion behavior of B10 copper-nickel alloy beneath a deposit caused by SRB with carbon source starvation in artificial seawater was studied based on electrochemical measurements and surface analysis.Results demonstrate that SRB with an organic carbon starvation can survive in artificial water but most SRB cells have died.The survived SRB cells can attach to the bare and deposit-covered B10 copper-nickel alloy,leading to the corrosion acceleration.Due to the limitation of organic carbon source,the pitting corrosion of B10 copper-nickel alloy caused by SRB is not serious.However,serious pitting corrosion of the deposit-covered B10 copper-nickel alloy can be found both in abiotic and biotic conditions,and the pitting corrosion and uniform corrosion are further accelerated by SRB.There is a galvanic effect between the bare and deposit-covered specimens in the presence of SRB in the early stage but the galvanic effect after 5 d of testing can be neglected due to the low OCP difference values.

Spatial Distribution of Carbon and Nitrogen in Sediments of Xiangxi River

[Objective] This study was conducted to explore the spatial distribution of carbon and nitrogen in the sediments of Xiangxi River, which was the biggest tribu- tary near the Three Gorges Dam. [Method] Sediment samples were collected using customized cylindrical samplers at three sites along Xiangxi River estuary in May, 2015 to measure the contents of total carbon, total nitrogen and an isotope of car- bon δ^13C. [Result] The total carbon content in the sediments varied from 1.74% to 3.52%, and the total nitrogen content varied from 0.1% to 0.3%. The average total carbon content in the sediments near the estuary was lower than in the upstream. The total carbon content in the sediments near the estuary gradually decreased with depth increasing. However, the variations in total nitrogen content in both horizontal direction （along the river from the estuary to the upstream） and vertical direction were not so obvious as in total carbon content. The isotopic analysis showed the δ^13C value increased with depth increasing. The overall δ^13C near the estuary was lower than that in the upstream. [Conclusioal The results will provide scientific refer- ences for the distribution of biogenic elements in sediments of Xiangxi River and the evolution process of aquatic ecosystem.

Genetic Relationships Among Soluble Carbohydrates, Anthocyanins and Growth Characteristics in Leymus (Gramineae) Detected with Molecular Markers

Low-temperature soluble carbohydrate accumulations are commonly associated with anthocyanin coloration, attenuated growth and cold adaptation of cool-season grasses. The vrn-1 gene has potent effects on vernalization requirement, growth, and soluble carbohydrate accumulations of the winter-annual Triticeae species. Two hundred and four unmapped AFLP markers and genome-specific DNA markers genetically linked to the vrn-1 gene were used to detect QTL controlling soluble carbohydrate accumulations, anthocyanin coloration and growth characteristics in a segregating population derived from open pollinated Leymus cinereus x L. triticoides hybrids. These perennial Triticeae grasses are distinguished by adaptation and growth habit. As expected, positive trait correlations and pleiotropic gene effects were detected for soluble carbohydrate accumulations and anthocyanin coloration. Likewise, positive trait correlations and pleiotropic gene effects were detected for tillering, leaf development, leaf growth, regrowth and rhizome spread. However, soluble carbohydrate accumulations were not associated with attenuated growth. In fact, several DNA marker alleles, including one near vrn-Ns1, had positive effects on soluble leaf carbohydrate concentrations and low temperature growth. The corresponding DNA marker near vrn-Ns1 had more specific effects on tillering. We speculate that vrn-1 exerts quantitative effects on low-temperature soluble leaf carbohydrate accumulations and growth habit of the perennial Leymus. However, a number of other DNA markers displayed highly significant effects on soluble carbohydrate accumulations and various growth characteristics. Findings indicate that anthocyanin coloration may be a useful phenotypic marker for soluble carbohydrate accumulation. Although variation for soluble carbohydrates was not associated with attenuated growth in this population, this trait was under genetic control.

On the Unusual Holocene Carbonate Sediment in Lake Nam Co,Central Tibet

In lacustrine sediments,aragonite is a widespread mineral,whereas monohydrocalcite is a rare carbonate mineral. In the cold and high-attitude Xizang (Tibetan) Plateau,where aragonite has been commonly found in lacustrine sediments,there is no aragonite,but low-Mg calcite,monohydrocalcite and trace dolomite. The lake receives solutes primarily from surface runoffs and remains fairly constant water chemistry for a long time. The total CaCO3 percentage in sediments could be controlled by evaporation and inflow of detrital materials. The absence of aragonite is unusual when compared to other lacustrine sediments from the Tibetan Plateau. This could be due to low Ca/Mg ratio,low salinity,low Mg and Ca concentration. Monohydrocalcite might precipitate from the lake water mediated by biological activities. Low-Mg calcite originated from minor ostracoda shell and the precipitation of lake water with biological activities.

Research advance of biomass and carbon storage of poplar in China

This paper summarized the studies on biomass production, biomass growth models, biomass measurement, biomass and forest density, as well as carbon storage of poplars in China in recent 20 years. The existing problems on research of poplar biomass are discussed and some suggestions for enhancing biomass of poplars are put forward.

Age-related Changes of Carbon Accumulation and Allocation in Plants and Soil of Black Locust Forest on Loess Plateau in Ansai County, Shaanxi Province of China

The effects of reforestation on carbon （C） sequestration in China＇s Loess Plateau ecosystem have attracted much research attention in recent years. Black locust trees （Robinia pseudoacacia L.） are valued for their important use in reforestation and water and soil conservation efforts. This forest type is widespread across the Loess Plateau, and must he an essential component of any planning for C sequestration efforts in this fragile ecological region. The long-term effects of stand age on C accumulation and allocation after reforestation remains uncertain. We examined an age-sequence of black locust forest （5, 9, 20, 30, 38, and 56 yr since planting） on the Loess Plateau to evaluate C accumulation and allocation in plants （trees, shrubs, herbages, and leaf litter） and soil （0-100 cm）. Allometric equations were developed for estimating the biomass of tree components （leaf, branch, stem without bark, bark and root） with a de- structive sampling method. Our results demonstrated that black locust forest ecosystem accumulated C constantly, from 31.42 Mg C/ha （1 Mg = 106 g） at 5 yr to 79.44 Mg C/haat 38 yr. At the ＇old forest＇ stage （38 to 56 yr）, the amount of C in plant biomass significantly decreased （from 45.32 to 34.52 Mg C/ha） due to the high mortality of trees. However, old forest was able to accumulate C continuously in soil （from 33.66 to 41.00 Mg C/ha）. The C in shrub biomass increased with stand age, while the C stock in the herbage layer and leaf litter was age-independent. Reforestation resulted in C re-allocation in the forest soil. The topsoil （0-20 cm） C stock increased constantly with stand age. However, C storage in sub-top soil, in the 20-30, 30-50, 50-100, and 20-100 cm layers, was age-independent. These results suggest that succession, as a temporal factor, plays a key role in C accumulation and re-allocation in black locust forests and also in regional C dynamics in vegetation.

The Burial of Biogenic Silica, Organic Carbon and Organic Nitrogen in the Sediments of the East China Sea

We sampled the sediments of the East China Sea during 2005 and 2006, and analysed the contents of the biogenic matters: biogenic silica, organic carbon, and organic nitrogen. From the surface distribution we found the contents of these substances to be in the ranges of 0.72%-1.64%, 0.043%-0.82%, and 0.006%-0.11%, respectively. Their distributions were similar to each other, being high inside the Hangzhou Bay and low outside the bay. The vertical variations of the contents were also similar. In order to discuss the relation between them we analysed the variations of content with depth. They increased in the first 7 cm and then decreased with depth. The peaks were found at depths between 20 to 25 cm. The distribution of carbonate showed an opposite trend to that of biogenic matters. The content of total carbon was relatively stable with respect to depth, and the ratio of high organic carbon to carbonate showed a low burial efficiency of carbonate, which means that the main burial of carbon is organic carbon. In order to discuss the source of organic matters, the ratio of organic carbon to organic nitrogen was calculated, which was 8.01 to 9.65, indicating that the organic matter in the sediments was derived mainly from phytoplankton in the seawater.

Field trial on use of soybean crude extract for carbonate precipitation and wind erosion control of sandy soil

Wind erosion is a major cause of land desertification and sandstorm formation in arid and semi-arid areas.The objective of this study was to evaluate the potential of soybeans crude extract induced calcium carbonate precipitation(SICP)on reducing wind erosion risk of sandy soil.Field tests were carried out in Ulan Buh Desert,Ningxia Hui Autonomous Region,China.Results showed that the SICP method could significantly enhance the surface strength and wind erosion resistance of the topsoil.The optimal cementation solution(urea-CaCl2)concentration and spraying volume,according to experiments conducted on sandy land,were 0.2 mol/L and 4 L/m^2,respectively.Under this condition,the CaCO3 content was approximately 0.45%,the surface strength of sandy soil could reach 306.2 kPa,and the depth of wind erosion was approximately zero,after 30 d completion of SICP treatment.Soil surface strength declined with the increase of time,and long-term sand fixation effects of SICP treatment varied depending on topography.Whereas wind erosion in the top area of the windward slope was remarkable,sandy soils on the bottom area of the windward slope still maintained a relatively high level of surface strength and a low degree of wind erosion 12 month after SICP treatment.Scanning electron microscopy(SEM)tests with energy dispersive X-ray(EDX)confirmed the precipitation of CaCO3 and its bridge effect.These findings suggested that the SICP method is a promising candidate to protect sandy soil from wind erosion in desert areas.

Petroleum geological framework and hydrocarbon potential in the Yellow Sea

Sedimentary basins in the Yellow Sea can be grouped tectonically into the North Yellow Sea Basin (NYSB), the northern basin of the South Yellow Sea (SYSNB) and the southern basin of the South Yellow Sea (SYSSB). The NYSB is connected to Anju Basin to the east. The SYSSB extends to Subei Basin to the west. The acoustic basement of basins in the North Yellow Sea and South Yellow Sea is disparate, having different stratigraphic evolution and oil accumulation features, even though they have been under the same stress regime since the Late Triassic. The acoustic basement of the NYSB features China-Korea Platform crystalline rocks, whereas those in the SYSNB and SYSSB are of the Paleozoic Yangtze Platform sedimentary layers or metamorphic rocks. Since the Late Mesozoic terrestrial strata in the eastern of the NYSB (West Korea Bay Basin) were discovered having industrial hydrocarbon accumulation, the oil potential in the Mesozoic strata in the west depression of the basin could be promising, although the petroleum exploration in the South Yellow Sea has made no break-through yet. New deep reflection data and several drilling wells have indicated the source rock of the Mesozoic in the basins of South Yellow Sea, and the Paleozoic platform marine facies in the SYSSB and Central Rise could be the other hosts of oil or natural gas. The Mesozoic hydrocarbon could be found in the Mesozoic of the foredeep basin in the SYSNB that bears potential hydrocarbon in thick Cretaceous strata, and so does the SYSSB where the same petroleum system exists to that of oil-bearing Subei Basin.

Multi-Physics Modeling of Solid Oxide Fuel Cell Fueled by Methane and Analysis of Carbon Deposition

Internal reformation of low steam methane fuel is important for the high efficiency and low cost operation of solid oxide fuel cell. Understanding and overcoming carbon deposition is crucial for the technology development. Here a multi-physics model is established for the relevant experimental cells. Balance of electrochemical potentials for the electrochemical reactions, generic rate expression for the methane steam reforming, dusty gas model in a form of Fick＇s model for anode gas transport are used in the model. Excellent agreement between the theoretical and experimental current-voltage relations is obtained, demonstrating the validity of the proposed theoretical model. The steam reaction order in low steam methane reforming reaction is found to be 1. Detailed information about the distributions of physical quantities is obtained by the numerical simulation. Carbon deposition is analyzed in detail and the mechanism for the coking inhibition by operating current is illustrated clearly. Two expressions of carbon activity are analyzed and found to be correct qualitatively, but not quantitatively. The role of anode diffusion layer on reducing the current threshold for carbon removal is also explained. It is noted that the current threshold reduction may be explained quantitatively with the carbon activity models that are only qualitatively correct.

THE RESUSPENSION RATE OF SEDIMENTS IN 32°N SECTION ON THE EAST CHINA SEA

This research on the influence of sediment resuspension on the flux of materials in the margin of the East China Sea showed that the sediment resuspension rates, was 47.40%-79.18% in the surface layers, and 72.75%-96.96% in the bottom layers.The research confirmed that the Changjiang River runoff and the eddy area upwelling flow near 125°E were two important factors affecting the sediment resuspension in summer; the transformation of DOC to POC through the flocculation in the transitional region (123°-124°E) was also confirmed by comparison of the resuspension rate. The sediment resuspension was shown to be influenced by the seasonal factor, especially in the surface layer.

Overcoming coke formation in high-temperature CO_(2)electrolysis

High-temperature CO_(2)reduction reaction(HT-CO_(2)RR)in solid oxide electrochemical cells(SOECs)features near-unity selectivity,high energy efficiency,and industrial relevant current density for the production of CO,a widely-utilized“building block”in today’s chemical industry.Thus,it offers an intriguing and promising means to radically change the way of chemical manufacturing and achieve carbon neutrality using renewable energy sources,CO_(2),and water.Albeit with the great potential of HT-CO_(2)RR,this carbon utilization approach,unfortunately,has been suffering coke formation that is seriously detrimental to its energy efficiency and operating lifetime.In recent years,much effort has been added to understanding the mechanism of coke formation,managing reaction conditions to mitigate coke formation,and devising coke-formation-free electrode materials.These investigations have substantially advanced the HT-CO_(2)RR toward a practical industrial technology,but the resulting coke formation prevention strategies compromise activity and energy efficiency.Future research may target exploiting the control over both catalyst design and system design to gain selectivity,energy efficiency,and stability synchronously.Therefore,this perspective overviews the progress of research on coke formation in HT-CO_(2)RR,and elaborates on possible future directions that may accelerate its practical implementation at a large scale.

MONITORING POLYNUCLEAR AROMATIC HYDROCARBONS IN SEDIMENT POREWATER BY SPMD

A new mimic biological Semi permeable Membrane Device (SPMD) introduced for sampling organic pollutants yielded satisfactory results when it was first used as a passive sampler to concentrate and determine 16 kinds of polynuclear aromatic hydrocarbons (PAHs) by means of capillary GC on an HP 5890 GC FID in coastal sediment porewater. The concentration of PAHs in sediment porewater for naphthalene(N), acenaphthlene(AL), acenaphthene(AE), fluorene(F), phenaphthene(P), anthracene(A), fluoranthene(FA), pyrene(Py), benzoanthracene(BA), chrysene(Chr), benzofluor anthene(BF), benzofluoranthene(BF), benzopyrene(BP),indeno[1,2,3, cd] Pyrene(IP), dibenzanthracene(DA) and benzo perylene(BP) were: 50.36, under detection limits(UD), 18.19, 8.41, 8.40, 1.44, UD, 8.01, 524.15, 168.47, 50.13, 123.66, 63.48, 27.40, 82.04 and 58,81 ng/L, respectively.

Reconstructing Environmental Changes of a Coastal Lagoon with Coral Reefs in Southeastern Hainan Island

Coastal lagoons with small catchment basins are highly sensitive to natural processes and anthropogenic activities. To figure out the environmental changes of a coastal lagoon and its contribution to carbon burial, two sediment cores were collected in Xincun Lagoon, southeastern Hainan Island and (210) ~Pb activities, grain size parameters, total organic carbon(TOC), total nitrogen(TN), total inorganic carbon(TIC) and stable carbon isotopes(δ^(13)C) were measured. The results show that in 1770–1815, the decreasing water exchange capacity with outer open water, probably caused by the shifting and narrowing of the tidal inlet, not only diminished the currents and fined the sediments in the lagoon, but also reduced the organic matter of marine sources. From 1815 to 1950, the sedimentary environment of Xincun Lagoon was frequently influenced by storm events. These extreme events resulted in the high fluctuation of sediment grain size and sorting, as well as the great variation in contributions of terrestrial(higher plants, soils) and marine sources(phytoplankton, algae, seagrass). The extremely high content of TIC, compared to TOC before 1950 could be attributed to the large-scale coverage of coral reefs. However, with the boost of seawater aquaculture activities after 1970, the health growth of coral species was severely threatened, and corresponding production and inorganic carbon burial flux reduced. The apparent enhanced inorganic carbon burial rate after 1990 might result from the concomitant carbonate debris produced by seawater aquaculture. This result is important for local government long-term coastal management and environmental planning.

Combined influence of sedimentation and vegetation on the soil carbon stocks of a coastal wetland in the Changjiang estuary

Coastal wetlands play an important role in the global carbon cycle. Large quantities of sediment deposited in the Changjiang （Yangtze） estuary by the Changjiang River promote the propagation of coastal wetlands, the expansion of saltmarsh vegetation, and carbon sequestration. In this study, using the Chongming Dongtan Wetland in the Changjiang estuary as the study area, the spatial and temporal distribution of soil organic carbon （SOC） stocks and the influences of sedimentation and vegetation on the SOC stocks of the coastal wetland were examined in 2013. There was sediment accretion in the northern and middle areas of the wetland and in the Phragmites australis marsh in the southern area, and sediment erosion in the Scirpus mariqueter marsh and the bare mudflat in the southem area. More SOC accumulated in sediments of the vegetated marsh than in the bare mudflat. The total organic carbon （TOC） stocks increased in the above-ground biomass from spring to autumn and decreased in winter; in the below-ground biomass, they gradually increased from spring to winter. The TOC stocks were higher in the below-ground biomass than in the above-ground biomass in the P. australis and Spartina alterniflora marshes, but were lower in the below-ground biomass in S. mariqueter marsh. Stocks of SOC showed temporal variation and increased gradually in all transects from spring to winter. The SOC stocks tended to decrease from the high marsh down to the bare mudflat along the three transects in the order： P. australis marsh 〉 S. alterniflora marsh 〉 S. mariqueter marsh 〉 bare mudflat. The SOC stocks of the same vegetation type were higher in the northern and middle transects than in the southern transect. These results suggest that interactions between sedimentation and vegetation regulate the SOC stocks in the coastal wetland in the Changjiang estuary.

Variation in δ^(15)N of a lacustrine sedimentary sequence in the Nanling Mountains and its potential implication for climatic conditions over the past ~16000 years

Although extensive studies have been performed on nitrogen isotopes in lake sediments, understanding the complexity of the δ15N variation related to past environmental and climatic conditions still remains unclear. Supported by multi-proxy records including litho-units, organic carbon isotopes, ration of total organic carbon and total nitrogen, organic matter content, bulk dry density, the accumulation rate of organic matter, median grain size, magnetic susceptibility, and Rb/Sr and Ca/Mg ratios obtained from a sedimentary sequence in a small lake （i.e., Dahu Swamp） in the eastern Nanling Mountains in South China, we deduce that variation in the δ15N values results primarily from the sources of organic matter, which are significantly influenced by climatic conditions over the past -16 000 years. A low （or high） lake level resulting from dry （or wet） conditions would lead to more （or fewer） vascular plant remains in the sediments and stronger （or weaker） denitrification associated with hypolimnetic anoxia, resulting in lower （or higher） 615N values. In addition, dry （or wet） conditions would favor weakened （or strengthened） biogeochemical activity in the catchment, which could result in less （or more） external input of δ15N-enriched OM, thus leading to decreased （or increased） δ15N values. Our results indicate that the lake sediment δ15N record in the Nanling Mountains has the potential to provide valuable insight into past East Asian monsoon climate- driven environmental changes.

Application of a Step-by-Step Fingerprinting Identification Method on a Spilled Oil Accident in the Bohai Sea Area

In recent years,oil spill accidents occur frequently in the marine area of China.Finding out the spilled oil source is a key step in the relevant investigation.In this paper,a step-by-step fingerprinting identification method was used in a spilled oil accident in the Bohai Sea in 2002.Advanced chemical fingerprinting and data interpretation techniques were used to characterize the chemical composition and determine the possible sources of two spilled oil samples.The original gas chromatography -flame ionization detec-tion (GC-FID) chromatogram of saturated hydrocarbons was compared.The gas chromatography-mass spectrometry (GC/MS) chromatograms of aromatic hydrocarbons terpane and sterane,n-alkane and poly-aromatic hydrocarbons (PAHs) were analyzed.The correlation analysis on diagnostic ratios was performed with Student’s t-test.It is found that the oil fingerprinting of the spilled oil (designated as sz1) from the polluted sand beach was identical with the suspected oil (designated as ky1) from a nearby crude oil refinery factory.They both showed the fingerprinting character of mixed oil.The oil fingerprinting of the spilled oil (designated as ms1) collected from the port was significantly different from oil ky1 and oil sz1 and was with a lubricating oil fingerprint character.The identification result not only gave support for the spilled oil investigation,but also served as an example for studying spilled oil accidents.

Development and application of a system for the analysis of atmospheric, water and sediment nitrogen and carbon

Eutrophication and climate change, key environmental concerns, are both linked to the carbon and nitrogen cycles hence the improved understanding of these cycles is essential. Currently, there is no system that simultaneously measures the fluxes of the three key gas phase products of nitrogen and carbon cycling （CO2, CH4 and N2O） in submerged ecosystems with hourly time resolution. A ＂Lake-in-a-box＂ （mesocosm） was developed in the laboratory which allowed the monitoring of key components of the carbon and nitrogen cycles within the air, water and sediments. The approach is automated, simple and time efficient and novel in its ability to examine many different carbon and nitrogen compounds in all three physical component of the ＂lake＂. Dramatic fluctuations in gaseous flux and the concentrations of overlying water and sedimentary carbon and nitrogen compounds were noted over a three week period. These were split into five distinct phases which were linked to changes in sedimentary N and C cycling. The results highlighted the important of links between the two cycles and supported recent studies showing that estuarine sediments can act as both a source and a sink of nitrogen.