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51.
CaCl2对垃圾焚烧飞灰热处理特性的影响 总被引:11,自引:4,他引:7
以华东某城市生活垃圾焚烧厂飞灰为原料,对飞灰中重金属进行了高温热处理研究,主要考察了CaCl2对重金属蒸发的影响,并对蒸发物化学形态及成分进行了分析.结果表明:CaCl2能有效促进飞灰中Pb和Cd的蒸发,当温度为1 050℃,CaCl2的添加比例为15%时,Cd的蒸发率由原灰的43.8%剧增到88.3%,而重金属Cu的蒸发率则随着CaCl2添加比例的增加有所降低;当CaCl2的添加比例为10%时,各重金属的蒸发率均随温度的升高而有不同程度的增加;对所收集的蒸发物进行成分及物相分析显示,蒸发物主要以NaCl和KCl为主,重金属Pb以双金属氯化物(KPb2Cl5)形式蒸发. 相似文献
52.
选择性催化还原NOx的V2O5/TiO2催化剂特性研究 总被引:4,自引:0,他引:4
采用浸渍法制备了V2 O5/TiO2 催化剂 ,研究了浸渍液和催化剂的红外光谱。利用XRD研究了催化剂中V2 O5的含量和晶相情况 ,V2 O5在催化剂载体表面呈单层分布 ,单层分布实验阈值为 7% ;利用程序升温 (TPD)法研究了NH3在催化剂表面上的脱附 ,起峰温度为40 9K ,峰顶温度为 487K ,出现一个化学脱附峰 相似文献
53.
给水管网中管内壁腐蚀管垢特征分析 总被引:5,自引:3,他引:2
使用扫描电镜(SEM)、X荧光光谱分析(XRF)、X射线衍射分析(XRD)以及X光电子能谱(XPS)对给水管网中铸铁管和镀锌钢管上的管内壁腐蚀管垢进行微观形态、化学组成、晶体结构和化合物构成等物理化学特征分析.发现管垢外部平滑而致密,内部为多孔结构.铁是管垢最重要的化学组成,管垢基本上是含铁的化合物.外层管垢可能的化学组成是α-FeOOH、γ-FeOOH、α-Fe2O3、γFe2O3、FeCl3等三价铁化合物,而内层管垢则为Fe3O4、FeCl2、FeCO3等二价铁及二价铁与三价铁共同存在的化合物.管垢的特征取决于管网水力条件、水质条件和管材本身特性. 相似文献
54.
石英砂负载氧化铁吸附除锑、磷的XRD、FTIR以及XPS研究 总被引:3,自引:0,他引:3
通过XRD、FTIR以及XPS方法研究了石英砂负载氧化铁(IOCS)吸附锑、磷的机理.研究结果表明,IOCS表面氧化铁的晶型为α-Fe2O3;OH-及Fe-O键可以在FTIR谱图上检测到.XPS测定结果表明,IOCS吸附锑过程中氧原子及铁原子发生了电子转移,而IOCS吸附磷的过程几乎没有发生电子转移.XPS的价带谱研究表明,IOCS与锑的结合强度大于IOCS与磷的结合强度.由于锑、磷的吸附,导致IOCS表面铁原子的浓度有所降低;XPS溅射结果表明,锑较磷更能与深层的氧化铁发生反应. 相似文献
55.
碳黑改性TiO2薄膜光催化剂的结构性质 总被引:1,自引:0,他引:1
通过碳黑掺杂制备了改性的TiO2薄膜光催化剂(CB-TiO2),并采用液氮吸附、X射线衍射(XRD)和紫外-可见光漫反射光谱(DRS)对催化剂的比表面积、物相、晶粒度和最大激发波长等结构性质进行了表征.结果表明,CB-TiO2的吸附性能大大改善,不同热处理温度下,BET比表面积增加50%~80%;同时碳黑掺杂能够减小催化剂的晶粒尺度,使相变温度降低.相应的光催化降解试验也表明,碳黑改性TiO2的活性大大提高,其一级反应速率常数为普通TiO2的1.5倍. 相似文献
56.
Martín-Gil J Martín-Gil FJ del Carmen Ramos-Sánchez M Martín-Ramos P 《Environmental science and pollution research international》2005,12(5):285-289
Goal, Scope and Background In this paper, we attempt to elucidate the composition and origin of the orange patina on the surfaces of the West-Porch
of Salisbury Cathedral by comparison to other known patinas: (i) the orange-brown patina on the marble surfaces of the Acropolis
in Athens and the Arch of Titus in Rome whose analyses have shown very high amounts of phosphates, and generally amino acids
from animal-skin glue or other protein binders; (ii) the phosphated patinas which also contain oxalates, found in 1996 on
Catalonian calcareous sandstones and in the calcareous dolomites of the Monastery of Silos, Spain, whose origin is either
the application of calcium caseinate, or egg yolk and animal glue; and (iii) the patinas with only oxalates found in some
of Verona's monuments (St Zeno) and Spanish sites as in the Monastery of Guadalupe and Cuenca cathedral, formed either by
the mineralization of algal filaments or by biological reactions yielding oxalate from yolk egg (added to stone as part of
preservative empirical treatments).
Methods In the winter of 2003, the West-Porch of Salisbury Cathedral received conservation works, but the old patina was not entirely
removed. This fact has allowed us to collect the samples for its study. The IR spectra were registered with a Golden Gate
ATR Mk II system using attenuated total reflectance Fourier transform infrared (ATR/FTIR) spectrometry. Mineral composition
was determined by XRD (Philips PW 1710 spectrometer with Cu tube), whereas major and trace elements analyses were performed
by XRF (Philips PW1480 PW). Microscopy examination was performed on a Leica M655 microscope. Phosphate, oxalate, calcium and
sulphate contents were analysed by usual chemical methods.
Results ATD-FTIR spectra of the Salisbury's patina exhibit peaks at 2361, 2341 and 671 cm–1 (assigned to phosphates); 3410, 1680,
1620, 1122 and 602 cm–1 (assigned to sulphates); and 1447/1437 and 876 cm–1 (attributed to carbonates). The little peaks at
1620 and 798 cm–1 could be assigned to oxalates. XRD and XRF have led to identify the carbonates, phosphates and sulphates
as pertaining to the species dolomite, hydroxyapatite and gypsum, respectively. Oxalates are detected only in small amounts
by chemical analyses but wewellite and weddellite have not been well identified. The interface between the patina and the
calcareous dolomite is very uneven and full of cavities in certain cases, but well-defined and rather smooth in other cases.
In accord with the very small amounts of the oxalates found, remnants of micro-organisms are not detected in the patinas.
Discussion The Salisbury's patina is a composite material formed by particulates and matrix constituents. Regarding the patina particulate,
e.g. animal bones, it is necessary to refer to the apatite phase composition. The bone mineral contains 4–8 wt % of carbonate
in animal body and its presence in the apatite phase is advantageous as it increases the mechanical strength. We think that
FTIR bands at around 1440 and 876 cm–1 arise from vibration of CO32– ions, but not necessarily from the limestone. They could
be attributed to carbonated hydroxyapatite through the substitution of groups PO43– for CO32– in the lattice of hydroxyapatite.
Concerning the matrix and also from the FTIR spectra, the absence of specific bands of the following species: proteins (3350–3225,
1660, 1550–1535, 1270–1230 and 620 cm–1), oils (1778, 1738 and 1051 cm–1), bee waxes (3000, 1470, 720–730 and 1700 cm–1) and
aged egg-yolk (2954, 2920, 2850, 1650, 1549, 1465 and 1240 cm–1) had led us to exclude these usual binders. On the other hand,
the amount of sulphates in the paste that covers the walls of the Salisbury's Cathedral is excessively high (above 20% in
weight) to consider it as a biotransformation product of calcium oxalate from fungal biofilms. Consequently, we must think
that the gypsum found in the samples has a man-made origin (it was deliberately added as part of a protective paste) and that
it is the matrix searched for. Thus, we deduce that the patina of Salisbury's Cathedral is a special stucco made mixing plaster
with powdered bone (the colour of the bones is the same that it exhibits in the patina), low quantities of an uncharacterized
binder (collagen, possibly) and water.
Conclusion We believe that the patina of the Salisbury's Cathedral is a variant of the Greco-Latin empirical protective treatment that
included bone as a hardening material. Nevertheless, we also think that the presence of the bones in the paste could be related
to an aesthetical intention: gaining a warm tone for the original stone through the ochre colour of the bones.
Recommendation and Perspective Our results have been an excuse to contribute to the controversy started at the 80's on the origin of orange-brown patinas
observed on stone surfaces of Greco-Latin and medieval monuments. There are two major theories on provenance: biological vs.
man-made. In Salisbury Cathedral, neither of them has been proven through scientific evidence as yet. Our opinion is that
Salisbury patina can be classified into the man-made group. 相似文献
57.
58.
The present work is directed to characterize the phosphogypsum (PG) wastes associated with phosphoric acid produced by the wet process in industrial facility for the production of fertilizers and chemicals in Egypt. The PG waste samples were characterized in terms of spectroscopic analysis (X-ray diffraction, X-ray fluorescence, IR spectra) and radiometric analysis (γ- and α-measurements). The γ-ray measurements showed that the average activity concentrations are 140 ± 12.6, 459 ± 36.7, 323 ± 28.4, 8.3 ± 0.76 and 64.3 ± 4.1 Bq/kg for U-238, Ra-226, Pb-210, Th-232 and K-40, respectively. The α-particle measurements of uranium isotopes showed that the average activity concentrations of U-238, U-235 and U-234 were 153 ± 9.8, 7 ± 0.38, 152 ± 10.4 Bq/kg, respectively. The average radiochemical recovery (%) of the destructive α-particle measurements is ∼70% with a resolution (FWHM) of ∼30 keV. Activity ratios of U-238/Ra-226 and U-238/Pb-210 were less than unity (i.e., <1) and equal to 0.31 ± 0.02 and 0.47 ± 0.16, respectively. The isotopic ratios of U-238/U-235 and U-238/U-234 (in PG and PR samples) were close to the normal values of ∼21.7 and ∼1, respectively and are not affected by the wet processing of phosphate rock (PR). The obtained results of PG waste samples were compared with phosphate rock (PR) samples. The radiation hazard indices are namely, radium activity index (Ra-Eq > 370 Bq/kg), total absorbed gamma dose rate (Dγr > 5 nGy/h) and radon emanation fraction (Rn-EF > 20%). Uncertainty of the sample counting was 95% confidence level of σ. The results indicated the necessity to find suitable routes to decrease and/or redistribute the radionuclide of environmental interest (i.e., Ra-226) in PG wastes, consequently to reduce its radiation impacts in the surrounding environment. 相似文献
59.
Abdul-Wahab SA Worthing MA Al-Maamari S 《Environmental monitoring and assessment》2005,107(1-3):313-327
The aim of this work is to characterize the mineral phases present in the atmosphere at three locations in northern Oman. Samples of atmospheric particles were collected using a high volume sampler. Three indoor and one outdoor location were chosen in this investigation. Sampling locations included a residential house located nearby the cement plant, a residential house located nearby a refinery plant, and a residential house located at Al-Suwayq residential area. Indoor air was sampled from these three houses. Moreover, for the Al-Suwayq residential house, sampling was also taken outside the house for comparison. The dust samples were analysed for their microanalysis characterization and their mineral contents as well. The microanalysis enabled us to identify the metals present in the particles. Furthermore, the mineralogical analysis of the sample filters showed the presence of quartz as the principal phase inside the house of Al-Suwayq, whereas quartz, dolomite, and gypsum were common phases outside the house. In the residential house nearby the cement plant, it was found that calcite, quartz, dolomite and goethite were the principal phases whereas the particles collected from the house nearby the refinery composed primarily of dolomite and calcite. The airborne dust collected at the refinery and Al-Suwayq were probably sourced in the natural environment and mobilised by natural processes. However, at the cement factory the crushing and grinding of limestone during the industrial process has contributed significantly to the airborne dust load. Generally, the information obtained in this study will be invaluable as no data for the mineral content of atmospheric dust existed in the Oman. 相似文献
60.
近年来在地下水污染修复方面,纳米铁的应用十分广泛.纳米铁比表面积大,活性高,反应速率快,使其表面腐蚀产物多.因此,纳米铁在地下水中的腐蚀产物矿相的变化及其在污染物去除方面可能产生的影响受到越来越多的关注.本文模拟地下水厌氧环境,对纳米铁在水中的腐蚀产物通过激光拉曼、X射线衍射和X射线光电子能谱3种表征手段进行研究.结果表明:纳米铁在厌氧超纯水中的腐蚀产物为大量磁铁矿(Fe_3O_4)并夹杂少量磁赤铁矿(γ-Fe_2O_3)和纤铁矿(γ-FeOOH).在厌氧地下水中还观测到微量四方纤铁矿(β-FeOOH)和菱铁矿(FeCO_3)的存在. 相似文献