X-ray Absorption Spectroscopic Investigation of Trace Vanadium Sites in Coal

X-ray absorption spectroscopy was used to probe the chemical and structural environment of vanadium in coal. It was found that vanadium exists in at least two environments, in both of which it was coordinated to oxygens. There was no evidence of vanadium in nitrogen (porphyrin) or sulfide environments. It was also found that the vanadium environments in the raw coal did not survive unchanged in a liquefaction process. These findings have implications for coal cleaning processes and for trace element release into the liquefaction process stream.     

Analytical Methods of the Organic Sulfur Compounds in Garlic

Garlic is a kind of widely planted agricultural product in China, which has plenty of nutritional and healthy functions, such as antibacterial, anti-inflammatory, and anti-oxidation. These functions are mainly attributed to the organic sulfur compounds, including the flavor precursors, thiosulfinates and thioether volatile compounds. The organic sulfur compounds either have its own biological activities, or multiple compounds work together to produce the same physiological effect. However, considering the poor stability and property diversity of the organic sulfur compounds, the analysis of organic sulfur compounds remains a big challenge. Existing reports are mainly on the determination of several compounds or one group of compounds, and there has been no comprehensive analysis of the organic sulfur compounds in garlic yet. Therefore, in the present review, the analysis methods of the main flavor precursors, thiosulfinates and thioether volatile compounds in garlic were separately discussed and summarized, including the sample pretreatment and detection methods.     

大蒜中有机硫化合物及其分析方法

大蒜是在我国广泛种植和食用的农产品,具有抗菌、抗炎、抗氧化等多种营养健康功能。这些主要得益于大蒜中的有机硫化合物,包括蒜氨酸等风味前体化合物、大蒜素等硫代亚磺酸酯和大蒜烯等硫醚类挥发性化合物等。这些有机硫化合物或各自具有其生物活性,或多种化合物相互协同,共同产生同一种生理功效。但有机硫化合物普遍具有易酶解或稳定性差等特点,且不同类别有机硫化合物的化学性质差异也较大,目前对大蒜中有机硫化合物的分析方法仍然存在局限性,现有报道多是对某类化合物进行总量测定,或是针对个别化合物进行测定,尚未有研究对大蒜中的有机硫化合物进行全面系统的分析。因此,本研究分别对大蒜中主要风味前体化合物、硫代亚磺酸酯和硫醚类挥发性化合物的分析方法进行了分类讨论和综述,包括其样品前处理方法和检测方法。     

连续光源原子吸收光谱法测定土壤中的有效硫含量

[目的]为了建立连续光源原子吸收光谱法测定土壤中有效硫的方法.[方法]采用连续光源原子吸收光谱法,在富燃乙炔-空气火焰条件下,通过测定CS双原子分子吸收,确定土壤提取液中有效硫的含量,研究优化试验条件.[结果]在CS 258.056 nm时测定硫元素的检出限为3.97 mg/L,定量限为14.8 mg/L,CS分子吸收具有较宽的线性范围,方法在试验浓度范围(0 ～500 mg/L)内获得良好的线性.对土壤标准物质中有效硫元素含量的测定结果均在其不确定度范围内.[结论]连续光源原子吸收光谱法是一种测定土壤中有效硫元素含量的简便、快速、准确的方法.     

燃煤固硫的热力学研究

从化学热力学的角度，分析了燃煤掺烧固硫时的吸放热情况和反应的SO2平衡体积分数规律，表明固硫反应的放热量较石灰石分解吸热量高，并且其热力学推动力很大。实验证实，往燃煤中掺入适当量的固硫剂，不仅对混合物的发热量无不良影响，而且一定条件下还可提高混合物的总发热量。     

矿物成分对超细化煤粉燃烧硫转化影响的实验研究

选用超细化鹤岗、铁法、准噶尔3种原煤、脱灰煤(HCl/HF脱灰),与分别添加MgO、CaO、Al₂O₃和Fe₃O₄矿物的脱灰煤制成试验样品.使用DTG(热重/差热分析仪)对不同样品进行燃烧实验,GC-MS(气相色谱质谱联用仪)分析烟气中SO₂,设定气体流量为50mL/min,氧气体积分数为20%,升温速率为20℃/min,考察矿物成分对煤粉燃烧时硫转化的影响.结果发现,超细化3种煤的原煤样品燃烧过     

不同供硫水平对水稻生长和养分吸收的影响

为探明硫素对水稻生长的影响和水稻吸硫特性,进行水培试验。结果表明,缺硫导致水稻生长明显受阻,生育推迟,抽穗结实不良,根量少,根细长。随着施硫量的增加,水稻产量随着增加,当硫肥浓度超过0.180mmol/L时,各处理的千粒重、结实率就不再增加,表明当培养液的硫浓度≥0.180mmol/L时可满足水稻金优82正常生长的需要。无硫处理的水稻最终没有结实。水稻地上部和根系的含硫量随着施硫量的增加而提高,它们之间的差异达到极显著水平。成熟收获后,植株和根系氮、磷、钾含量随着硫肥供应量的增加有下降的趋势;随着供硫水平提高,谷粒的硫含量增加,当供硫浓度达0.18mmol/L时谷粒硫含量不再增加;而谷粒氮、磷、钾含量也有上升的趋势。     

蔬菜中二氧化硫残留结果的调查与风险评估

采用蒸馏-滴定法对市场上抽检的六大类共计274件蔬菜样品进行了二氧化硫的检测,以了解样品中二氧化硫的残留量,并在此基础上评估了各类蔬菜对人体的健康风险。结果表明,检测样品中二氧化硫残留量最高的是银耳(801 mg/kg),其次是黄花菜(280mg/kg),最小的是马铃薯(5 mg/kg);二氧化硫残留对人体健康有一定的风险,风险较大的是银耳和黄花菜,其风险商值HQ均大于1,其余的品种HQ均小于1,没有食用风险。     

In Situ X-ray Absorption Study of Surface Complexes: Selenium Oxyanions on agr-FeOOH

A novel application of x-ray absorption spectroscopy has provided structural information for ions sorbed at oxide-water interfaces. As an example, in situ extended x-ray absorption fine structure (EXAFS) measurements of adsorbed selenate and selenite ions at ah alpha-FeOOH(goethite)-water interface have been performed; these measurements show that selenate forms a weakly bonded, outer-sphere complex and that selenite forms a strongly bonded, inner-sphere complex. The selenite ion is bonded directly to the goethite surface in a bidentate fashion with two iron atoms 3.38 angstroms from the selenium atom. Adsorbed selenate has no iron atom in the second coordination shell of selenium, which indicates retention of its hydration sphere upon sorption. This method provides direct structural information for adsorbed species at solid-liquid interfaces.     

硫对设施水培大蒜光合特性及NPK元素吸收的影响

为研究硫对大蒜光合特性和N、P、K元素吸收的影响,试验采取设施水培大蒜。结果表明,在0~2.25 mmol·L-1硫浓度范围内,光合色素含量、光合速率(Pn)、气孔导度(Gs)和胞间CO2浓度(Ci)随施硫浓度增加而升高,至硫浓度为2.25 mmol·L-1时最高;蒸腾速率(E)在1.50 mmol·L-1时最高;当硫处理浓度为3.75 mmol·L-1时,鳞茎和蒜薹中全氮含量最高;鳞茎和蒜薹中全P和全K含量均以2.25 mmol·L-1时最高,较不施硫处理分别高出235.98%,152.03%,41.11%和44.85%。     

X-ray Photoelectron Spectroscopic Studies of Interactions in Multicomponent Metal and Metal Oxide Thin Films

Changes in chemical oxidation states in alloys and at solid-solid interfaces were monitored by using x-ray photoelectron spectroscopy. For an oxidized Nichrome surface, the chromium component was selectively converted to chromic oxide while nickel remained in the metallic state. When this surface was overlaid with a 20-angstrom-thick aluminum film, the chromic oxide was reduced to chromium and the aluminum was oxidized to aluminum oxide in a reaction zone consisting of no more than 10 angstroms of the interface. This scheme appeared general for solid-solid contacts and was predicted, to a first approximation, by bulk thermodynamic free energies.     

江西省有机资源调查报告

通过调查湖口、南昌、上高、泰和、兴国、余江县有机资源及其利用状况,量化分析相应区域有机资源利用情况,以此为基础衡量江西省有机资源量及其利用现状,总结存在问题,并提出建议。结果显示2007～2008年江西省年均作物秸秆产量1764.6万t,作物秸秆直接还田31.8%,间接还田12.0%,燃烧还田52.5%,其它用途3.8%;绿肥种植面积53.33万hm2,占总耕地面积的25.1%,年产鲜草1237.2万t,其中直接还田85.6%,间接还田14.4%;人畜禽有机肥料年产9074万t,还田利用比例64.7%,流失35.3%;江西省直接还田、间接还田、燃烧还田和其它利用四种秸秆利用方式,养分回收占施肥量的比例分别为9.9%、10.1%、22.9%和4.6%。深入研究高效秸秆还田技术,扩大绿肥种植面积,开发新型有机肥综合利用模式,平衡利用有机肥资源,有效提升江西省整体农田质量是今后研究的重要发展方向。     

Time-Resolved X-ray Absorption Spectroscopy of Carbon Monoxide-Myoglobin Recombination After Laser Photolysis

Results are presented for the first time-resolved x-ray absorption measurements with a time resolution of 300 microseconds on a dynamically evolving chemical system. By synchronizing a neodymium: yttrium-aluminum-garnet pulsed laser with the bursts of x-rays emitted from the Cornell High Energy Synchrotron Source, it was possible to monitor at room temperature the recombination of carbon monoxide with myoglobin after laser photolysis. Changes in the pre-edge structure and in the position of the iron edge of this protein were detected as a function of time.     

施用有机肥对高粱苗期吸收汞的影响

[目的]探索施用有机肥对高粱吸收重金属汞的影响。[方法]以高粱(青选一号)为试材,采用盆栽试验研究不同汞水平下施用有机肥对土壤汞的形态转化及植物吸收汞的影响。[结果]同一汞水平、不同有机肥水平下,高粱苗期土样中的汞全量差异不显著;同一有机肥水平下,随着汞施用量的增加,土样中汞全量递增。施用有机肥可明显降低土壤中有效态汞的含量。高粱幼苗茎叶和根的汞含量随着汞施入量的增加而增加,茎叶的含量明显小于根。同一汞水平下,不施有机肥和施用有机肥的高粱幼苗茎叶和根的汞含量差异显著。[结论]施用有机肥明显降低了高粱幼苗茎叶和根中汞的含量。     

活性炭,活化煤,石油焦对LAS—Na吸附的研究

本文通过活性炭，活化煤和石油焦对阴离子表面活性剂的吸附，研究了其吸附能力以及吸附量与浓度之间的关系，初步探讨了其吸附理论和吸附机制。     

三江平原小叶章湿地土壤有机硫矿化特征研究

利用开放系统培养法,分别在不同温度和水分条件下,研究了三江平原小叶章典型草甸和小叶章沼泽化草甸两种湿地类型的不同层土壤有机硫的矿化特征。结果表明,在不同培养条件下,两种小叶章湿地土壤有机硫的矿化具有一致性:每层土壤有机硫累积矿化量随培养时间的延长而增加,二者之间符合一级动力学方程。上层土壤有机硫的矿化量高于下层土壤,好气培养条件下每层土壤有机硫的累积矿化量均高于淹水条件下矿化量;30℃培养条件下每层土壤有机硫的累积矿化量均高于20℃培养条件下矿化量。温度、水分条件和土壤类型对土壤有机硫的矿化影响显著,但它们之间的交互作用影响不明显。对比两种湿地类型不同层土壤有机硫的矿化,发现在不同培养条件下,小叶章沼泽化草甸土壤有机硫的矿化速率和潜力均高于小叶章典型草甸。     

硫硅配施对土壤铜形态和水稻吸收铜的影响

铜是江西省农田中主要重金属污染物之一,为减轻和控制铜对水稻生长的危害,提高水稻产量和品质,通过盆栽试验,研究不同硫肥（0、30、60、90 kg·hm-2,以S计）与硅肥（0、0.5、1.0、1.5 g·kg-1,以Si计）配施对水稻吸收铜及土壤铜形态的影响。结果表明：（1）在铜污染的农田中施用硫、硅肥都能降低土壤中酸可提取态Cu含量,提高残渣态Cu的含量,但土壤铁锰氧化物结合态Cu和有机物/硫化物结合态Cu含量因硫、硅用量不同而存在差异;（2）硫、硅各处理可通过促进铜在水稻根部累积或减少土壤有效态Cu的含量,减少铜在茎、叶、糙米中的吸收累积。从对糙米中铜含量及产量的影响可知,硫用量30 kg·hm-2和硅用量1.0 g·kg-1互作效果最佳,在生产上具有应用前景。     

聊城市耕地地力监测点土壤有机质含量变化研究

本研究采用聊城市耕地地力监测点数据,分析了全市土壤有机质含量变化特征。结果表明:全市0~20、20~40 cm土层有机质含量逐年增加;表层有机质含量高于下层,样点间变异大于下层。东阿县平均值最高,阳谷县平均值最低。东阿、临清含量降低,其他县(市、区)表现出含量增加趋势。表层有机质含量总体不高,全市历年平均值都不足15.00 g/kg。应大力推进土地流转,促进土地规模化经营,培肥基础地力。     

Laser-EXAFS: Fast Extended X-ray Absorption Fine Structure Spectroscopy with a Single Pulse of Laser-Produced X-rays

The extended x-ray absorption fine structure (EXAFS) spectrum of aluminum has been measured with a nanosecond pulse of soft x-rays generated by a laser-produced plasma. This technique provides a practical alternative to synchrotorn radiation for the acquisition of EXAFS data. It also provides a unique capability for the analysis of molecular structure in highly transient chemical species.