共查询到20条相似文献,搜索用时 31 毫秒
1.
Francine Pratlong Pierre Boulot Eric Issert Martine Msika Frédéric Dupont Bruno Bachelard Pierre Sarda Jean-Louis Viala Daniel Jarry 《黑龙江环境通报》1994,14(3):191-198
One hundred and ninety women who contracted toxoplasmosis after the seventh week of pregnancy underwent antenatal diagnosis, including ultrasound examination and biological tests. Tests included Toxoplasma isolation in fetal blood and amniotic fluid by mouse inoculation, specific IgM and IgA in fetal blood, and non-specific tests. Twenty fetuses had positive specific as well as non-specific tests for Toxoplasma infection. At birth, four of these presented with clinical congenital toxoplasmosis and 12 with subclinical forms. Antenatal diagnosis enabled the detection of 83 per cent of the infected fetuses. Under specific conditions, cordocentesis permits early diagnosis and considerably reduces the number of terminations of pregnancy. 相似文献
2.
Alexander Lerchl 《Die Naturwissenschaften》1999,86(7):340-342
The relationship between average monthly air temperature and sex ratios at birth (SRB) was analyzed for children born in
Germany during the period 1946–1995. Both the absolute temperature and – more markedly – the monthly temperature deviations
from the overall mean were significantly positively correlated with the SRB (P<0.01) when temperatures were time-lagged against the SRB data by –10 or –11 months. It is concluded that the sex of the offspring
is partially determined by environmental temperatures prior to conception.
Received: 26 August 1998 / Accepted in revised form: 18 February 1999 相似文献
3.
Reversed sex change by widowed males in polygynous and protogynous fishes: female removal experiments in the field 总被引:1,自引:0,他引:1
Sex change, either protogyny (female to male) or protandry (male to female), is well known among fishes, but evidence of bidirectional
sex change or reversed sex change in natural populations is still very limited. This is the first report on female removal
experiments for polygnous and protogynous fish species to induce reversed sex change in the widowed males in the field. We
removed all of the females and juveniles from the territories of dominant males in the cleaner wrasse Labroides dimidiatus (Labridae) and the rusty angelfish Centropyge ferrugata (Pomacanthidae) on the coral reefs of Okinawa. In both species, if new females or juveniles did not immigrate into the territories
of the widowed males, some of them emigrated to form male–male pairs. When a male–male pair formed, the smaller, subordinate
partner began to perform female sexual behaviours (n = 4 in L. dimidiatus; n = 2 in C. ferrugata) and, finally, released eggs (n = 1, respectively). Thus, the reversed sex change occurred in the widowed males according to the change of their social status.
These results suggest that such female removal experiments will contribute to the discovery of reversed sex change in the
field also in other polygnous and protogynous species. 相似文献
4.
Madhukar Shivajirao Dama 《Die Naturwissenschaften》2013,100(6):559-569
Human populations show remarkable variation in the sex ratio at birth which is believed to be related to the parental condition. In the present study, the global variation of sex ratio at birth (SRB, proportion of male offspring born) was analyzed with respect to indirect measure of condition, the intelligence quotient (IQ). IQ correlates strongly with lifespan across nations, which makes it a good indicator of health of the large populations. Relation between three standard measures of average national IQ and SRB was studied using multiple linear regression models. Average national IQ was positively correlated with SRB (r?=?0.54 to 0.57, p?<?0.001). Further, IQ emerged as a powerful predictor of SRB after controlling for the effects of all the known covariates like fertility, maternal age, polygyny prevalence, wealth, son preference, latitude, low birth weight, and neonatal mortality in the regression models. These results suggest that the striking variation of offspring sex ratio across nations could be caused in part by the difference in general condition of populations. 相似文献
5.
Although turbidite deposits are classically considered to be good reservoir rocks for oil and gas, there are no reports concerning
their source rock potential in the literature. The sediments from the Vallfogona Formation in the South-Eastern Pyrenees present
numerous organic matter-rich levels interbedded in sandstones and coarse turbidite deposits. Two types of organic matter deposits
were differentiated on the basis of organic geochemistry and petrography: type A and type B. Type A was deposited in a carbonate
marine environment under hypersaline conditions as indicated mainly by even/odd n-alkane predominance, pristane and phytane ratio (Pr/Ph) < 1, presence of gammacerane, and trisnorneohopane over trisnorhopane
ratio (Ts/Tm) > 1. Type B was deposited in a more mud-rich marine environment evidenced by the predominance of odd n-alkane, Pr/Ph ≥ 1, Ts/Tm < 1, the absence of gammacerane, similar concentrations of the C27 and C29 regular steranes, and the greater abundance of C27 diasteranes. Turbidite facies can be regarded as an environment where organic matter sedimentation is heterogeneous in type
and amount. This study suggests that turbidite deposits with interbedded organic matter-rich levels may act as a combined
source–reservoir system. 相似文献
6.
Tejedor MT Cenarro A Tejedor D Stef M Palacios L de Castro I García-Otín AL Monteagudo LV Civeira F Pocovi M 《Die Naturwissenschaften》2011,98(11):943-949
Variations in the gene encoding the low-density lipoprotein receptor (LDLR) can cause familial hypercholesterolemia (FH), one of the most common inherited metabolic disorders in humans. The functional
effects of the p.Gln92Glu and p.Asn564His alterations are predicted as benign, but the c.313 + 1G>C and p.Lys799_Phe801del
changes are believed to cause disease. Although p.Gln92Glu and c.313 + 1G>C have been observed only in Spain, p.Asn564His
and p.Lys799_Phe801del are widespread in Western Europe. In order to estimate the ages (t generations) of these four variants of the gene, to determine their possible origin and to consider the influence of age
and selective pressure on their spread, we analyzed 86 healthy individuals and 126 FH patients in Spain. Most of the FH patients
investigated carried two of these four LDLR variants simultaneously, while only one patient carried three of them simultaneously. Haplotype analyses were based on five
LDLR SNPs: c.81T>C, c.1413G>A, c.1725C>T, c.1959T>C and c.2232G>A. The results suggest that p.Gln92Glu and c.313 + 1G>C arose
at about the same time (99 and 103 generations ago, respectively) in the CACTG haplotype and that p.Asn564His and p.Lys799_Phe801del
appeared in the CGCCG haplotype and might be slightly more recent variations (92 and 95 generations ago, respectively). Low
selective pressures could explain the maintenance of these variants in spite of their ages. The origin of p.Gln92Glu and c.313 + 1G>C
appears to be in Spain whereas p.Asn564His and p.Lys799_Phe801del could have been introduced in Spain by Celtic migrations
in the seventh to fifth centuries BC. 相似文献
7.
Huang V Sakata JT Rhen T Coomber P Simmonds S Crews D 《Die Naturwissenschaften》2008,95(12):1137-1142
Kratochvil et al. (Naturwissenschaften 95:209–215, 2008) reported recently that in the leopard gecko (Eublepharis macularius) of the family Eublepharidae with temperature-dependent sex determination (TSD), clutches in which eggs were incubated at
the same temperature produce only same-sex siblings. Interpreting this result in light of studies of sex steroid hormone involvement
in sex determination, they suggested that maternally derived yolk steroid hormones could constrain sex-determining mechanisms
in TSD reptiles. We have worked extensively with this species and have routinely incubated clutches at constant temperatures.
To test the consistency of high frequency same-sex clutches across different incubation temperatures, we examined our records
of clutches at the University of Texas at Austin from 1992 to 2001. We observed that clutches in which eggs were incubated
at the same incubation temperature produced mixed-sex clutches as well as same-sex clutches. Furthermore, cases in which eggs
within a clutch were separated and incubated at different temperatures produced the expected number of mixed-sex clutches.
These results suggest that maternal influences on sex determination are secondary relative to incubation temperature effects. 相似文献
8.
W. Nentwig 《Die Naturwissenschaften》1999,86(9):411-421
Ecology is defined as the set of complex interactions between the biotic and abiotic environments. Human ecology concerns
principally the population ecology "only" of Homo sapiens, but it also includes all aspects of global ecology because humans are the most important species. Human demography is characterized
by a recent decline in mortality and fertility rates. These demographic transitions have largely been completed in industrialized
countries, but not in the 140 developing countries. Approximately 100 countries are following the same demographic pattern
as industrialized countries, however with a time delay of several generations. China has effectively reduced its population
increase by means that would be unacceptable in Western democracies. Some 44 developing countries still show increasing population
growth and no detectable demographic transition in birth rate. Thus one part of the world shows limited (and, in the long
run, shrinking) population growth, and another continues with a strong increase. All populations are limited in their development
by their sustainability by their environment, for example, food and energy resources, and the extent of pollution which the
use of these resources produces. It is argued that in the case of human population the limits of sustainability have already
been reached with the 6 billion humans alive today, since at least 20% of these suffer from hunger, natural resources are
overexploited, and biodiversity is threatened. In the coming 200 years it is more likely that the total population will substantially
oscillate rather than approach the predicted 12 billion. The most important goal of human ecology should therefore be to slow
population growth as far as possible. 相似文献
9.
10.
The bathymetric distribution of marine benthic invertebrates is likely governed by a combination of ecological and physiological
factors. The present study investigates oxygen consumption and heartbeat rate in response to attempted feeding at 1, 100 and
150 atm in the shallow-water spider crab, Maja brachydactyla, from temperate European waters. No significant difference was evident between the resting heartbeat rate of specimens at
1 or 100 atm, which were 56 and 65 bpm, respectively (Mann–Whitney, U = 5382.0; n = 95, 98; p = 0.079). However, at 150 atm the resting heartbeat rate was significantly higher than that observed for 100 atm at 108 bpm
(Mann–Whitney, U = 149.0; n = 45, 98; p < 0.001). At 150 atm, feeding was never observed and coupled with the elevated resting heartbeat rate; it is suggested by
150 atm continued survival is unfeasible. At 1 and 100 atm, feeding instigated a distinct increase in heartbeat rate, which
remained elevated for over 30 h. This increase peaked within 1 h at 1 atm. At 100 atm, this required 4 h and postprandial
oxygen consumption was significantly higher than at 1 atm (Kruskal–Wallis, H = 85.036; df = 2; p < 0.001). Elevated hydrostatic pressure is hypothesized to extend the duration and the total metabolic energy devoted to
specific dynamic action. The metabolic requirements of feeding under hyperbaric conditions may even reach such a critical
demand that feeding is entirely inhibited. 相似文献
11.
We have found that giant hornets (Vespa mandarinia japonica) are killed in less than 10 min when they are trapped in a bee ball created by the Japanese honeybees Apis cerana japonica, but their death cannot be solely accounted for by the elevated temperature in the bee ball. In controlled experiments, hornets
can survive for 10 min at the temperature up to 47°C, whereas the temperature inside the bee balls does not rise higher than
45.9°C. We have found here that the CO2 concentration inside the bee ball also reaches a maximum (3.6 ± 0.2%) in the initial 0–5 min phase after bee ball formation.
The lethal temperature of the hornet (45–46°C) under conditions of CO2 concentration (3.7 ± 0.44%) produced using human expiratory air is almost the same as that in the bee ball. The lethal temperature
of the honeybee is 50–51°C under the same air conditions. We concluded that CO2 produced inside the bee ball by honeybees is a major factor together with the temperature involved in defense against giant
hornets. 相似文献
12.
为了对挺水植物在水环境与水生态修复中的应用提供参考依据,选取黄菖蒲(Iris pseudacorus L.)为对象,通过模拟水培实验,对比研究了6种水体硝态氮质量浓度(10.68、23.88、42.22、63.33、82.92、97.13 mg·L~(-1))下,黄菖蒲地上和地下生物量、根冠比、叶绿素含量、氮累计吸收量以及对硝态氮去除效果的差异,以期明确模拟水体硝态氮质量浓度对黄菖蒲生长及其氮吸收能力的影响.结果显示,首先,不同硝态氮质量浓度对黄菖蒲地上部分(茎叶)生长的影响大于地下部分(根);当硝态氮质量浓度为10.68 mg·L~(-1)时,黄菖蒲的根冠比增加;当硝态氮质量浓度为42.22~97.13 mg·L~(-1)时,黄菖蒲的根冠比减少.其次,黄菖蒲适宜生长的硝态氮质量浓度为23.88~63.33 mg·L~(-1);硝态氮质量浓度低于10.68 mg·L-1或高于82.92mg·L-1时,均会对黄菖蒲的叶绿素合成产生抑制作用.再次,黄菖蒲对氮的累积量随硝态氮质量浓度增加而增加,且地下部分对氮的累积能力优于地上部分;6种浓度下,单株黄菖蒲的氮累计吸收量为10.56~75.43 mg,其地下部分依次为地上部分的7.2、2.3、2.5、2.1、1.6以及1.5倍.此外,黄菖蒲对氮的利用效率与硝态氮质量浓度之间成显著的幂函数关系,且地上部分的氮利用效率高于地下部分.最后,黄菖蒲对硝态氮的去除率随硝态氮质量浓度增加而增加,6种浓度下黄菖蒲对硝态氮的去除率介于94.9%和99.3%之间,且水体中硝态氮质量浓度随时间延续呈指数函数降低.结果表明,黄菖蒲对硝态氮有很好的去除效果,但黄菖蒲的生长及其对氮的吸收与去除效率受水体硝态氮质量浓度影响显著,且地上部分较地下部分更为敏感. 相似文献
13.
Cerumen, or propolis, is a mixture of plant resins enriched with bee secretions. In Australia, stingless bees are important
pollinators that use cerumen for nest construction and possibly for colony’s health. While extensive research attests to the
therapeutic properties of honeybee (Apis mellifera) propolis, the biological and medicinal properties of Australian stingless bee cerumen are largely unknown. In this study,
the chemical and biological properties of polar extracts of cerumen from Tetragonula carbonaria in South East Queensland, Australia were investigated using gas chromatography-mass spectrometry (GC-MS) analyses and in
vitro 5-lipoxygenase (5-LOX) cell-free assays. Extracts were tested against comparative (commercial tincture of A. mellifera propolis) and positive controls (Trolox and gallic acid). Distinct GC-MS fingerprints of a mixed diterpenic profile typical
of native bee cerumen were obtained with pimaric acid (6.31 ± 0.97%, w/w), isopimaric acid (12.23 ± 3.03%, w/w), and gallic
acid (5.79 ± 0.81%, w/w) tentatively identified as useful chemical markers. Characteristic flavonoids and prenylated phenolics
found in honeybee propolis were absent. Cerumen extracts from T. carbonaria inhibited activity of 5-LOX, an enzyme known to catalyse production of proinflammatory mediators (IC50 19.97 ± 2.67 μg/ml, mean ± SEM, n = 4). Extracts had similar potency to Trolox (IC50 12.78 ± 1.82 μg/ml), but were less potent than honeybee propolis (IC50 5.90 ± 0.62 μg/ml) or gallic acid (IC50 5.62 ± 0.35 μg/ml, P < 0.001). These findings warrant further investigation of the ecological and medicinal properties of this stingless bee cerumen,
which may herald a commercial potential for the Australian beekeeping industry. 相似文献
14.
Humin, the most recalcitrant and abundant organic fraction of soils and of sediments, is a significant contributor to the
stable carbon pool in soils and is important for the global carbon budget. It has significant resistance to transformations
by microorganisms. Based on the classical operational definition, humin can include any humic-type substance that is not soluble
in water at any pH. We demonstrate in this study how sequential exhaustive extractions with 0.1 M sodium hydroxide (NaOH) + 6 M
urea, followed by dimethylsulphoxide (DMSO) + 6% (v/v) sulphuric acid (H2SO4) solvent systems, can extract 70–80% of the residual materials remaining after prior exhaustive extractions in neutral and
aqueous basic media. Solid-state 13C NMR spectra have shown that the components isolated in the base + urea system were compositionally similar to the humic
and fulvic acid fractions isolated at pH 12.6 in the aqueous media. The NMR spectra indicated that the major components isolated
in the DMSO + H2SO4 medium had aliphatic hydrocarbon associated with carboxyl functionalities and with lesser amounts of carbohydrate and peptide
and minor amounts of lignin-derived components. The major components will have significant contributions from long-chain fatty
acids, waxes, to cuticular materials. The isolates in the DMSO + H2SO4 medium were compositionally similar to the organic components that resisted solvation and remained associated with the soil
clays. It is concluded that the base + urea system released humic and fulvic acids held by hydrogen bonding or by entrapment
within the humin matrix. The recalcitrant humin materials extracted in DMSO + H2SO4 are largely biological molecules (from plants and the soil microbial population) that are likely to be protected from degradation
by their hydrophobic moieties and by sorption on the soil clays. Thus, the major components of humin do not satisfy the classical
definitions for humic substances which emphasise that these arise from microbial or chemical transformations in soils of the
components of organic debris. 相似文献
15.
Ji Shulan Liu Zhipei Liu Zhipeng Ren Haiyan 《Frontiers of Environmental Science & Engineering in China》2007,1(3):325-328
A bacterial strain, ZY3, growing on sex steroid hormones as the sole source of carbon and energy was isolated from the sewage
treatment plant of a prophylactic steroids factory. ZY3 degrades the 3-methoxy-17β-hydroxy-1,3,5(10),8(9)-δ-4-estren (MHE).
This strain was preliminarily identified as Raoultella sp. ZY3 according to its morphology and its 16S rRNA gene sequence. During the experimental period (72 h), the optimum temperature,
pH and 3-MHE concentration for the degradation of hydride by the strain ZY3 were 35°C, 10 and 10 mg/L, respectively. The degradation
rate of the sex steroid hormones increased to 87% and 85% after the addition of maltose and peptone, respectively.
Translated from China Environmental Science, 2005, 25(5): 585–588 [译自: 中国环境科学] 相似文献
16.
Marcelo Perantoni Darci M. S. Esquivel Eliane Wajnberg Daniel Acosta-Avalos Geraldo Cernicchiaro Henrique Lins de Barros 《Die Naturwissenschaften》2009,96(6):685-690
Magnetotactic microorganisms use the interaction of internal biomineralized nanoparticles with the geomagnetic field to orientate.
The movement of the magnetotactic multicellular prokaryote Candidatus Magnetoglobus multicellularis under an applied magnetic field was observed. A method using digital image processing techniques
was used to track the organism trajectory to simultaneously obtain its body radius, velocity, U-turn diameter, and the reorientation
time. The magnetic moment was calculated using a self-consistent method. The distribution of magnetic moments and radii present
two well-characterized peaks at (9 ± 2) × 10−15 and (20 ± 3) × 10−15 A m2 and (3.6 ± 0.1) and (4.3 ± 0.1) μm, respectively. For the first time, simultaneous determination of the distribution of the
organism radii and magnetic moment was obtained from the U-turn method by a new digital imaging processing. The bimodal distributions
support an organism reproduction process model based on electron microscopy observations. These results corroborate the prokaryote
multicellular hypothesis for Candidatus M. multicellularis. 相似文献
17.
Stephan Baumgartner Martin Wolf Peter Skrabal Felix Bangerter Peter Heusser André Thurneysen Ursula Wolf 《Die Naturwissenschaften》2009,96(9):1079-1089
Quantitative meta-analyses of randomized clinical trials investigating the specific therapeutic efficacy of homeopathic remedies
yielded statistically significant differences compared to placebo. Since the remedies used contained mostly only very low
concentrations of pharmacologically active compounds, these effects cannot be accounted for within the framework of current
pharmacology. Theories to explain clinical effects of homeopathic remedies are partially based upon changes in diluent structure.
To investigate the latter, we measured for the first time high-field (600/500 MHz) 1H T1 and T2 nuclear magnetic resonance relaxation times of H2O in homeopathic preparations with concurrent contamination control by inductively coupled plasma mass spectrometry (ICP-MS).
Homeopathic preparations of quartz (10c–30c, n = 21, corresponding to iterative dilutions of 100−10–100−30), sulfur (13x–30x, n = 18, 10−13–10−30), and copper sulfate (11c–30c, n = 20, 100−11–100−30) were compared to n = 10 independent controls each (analogously agitated dilution medium) in randomized and blinded experiments. In none of the
samples, the concentration of any element analyzed by ICP-MS exceeded 10 ppb. In the first measurement series (600 MHz), there
was a significant increase in T1 for all samples as a function of time, and there were no significant differences between homeopathic potencies and controls.
In the second measurement series (500 MHz) 1 year after preparation, we observed statistically significant increased T1 relaxation times for homeopathic sulfur preparations compared to controls. Fifteen out of 18 correlations between sample
triplicates were higher for controls than for homeopathic preparations. No conclusive explanation for these phenomena can
be given at present. Possible hypotheses involve differential leaching from the measurement vessel walls or a change in water
molecule dynamics, i.e., in rotational correlation time and/or diffusion. Homeopathic preparations thus may exhibit specific
physicochemical properties that need to be determined in detail in future investigations.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
18.
Laura Rodríguez-Loeches Alejandro Barro Martha Pérez Frank Coro 《Die Naturwissenschaften》2009,96(4):531-536
Both sexes of Phoenicoprocta capistrata have functional tymbals. The scanning electron microscopy revealed differences in the morphology of these organs in males
and females. Male tymbals have a well-developed striated band, constituted by 21 ± 2 regularly arranged striae whereas female
tymbals lack a striated band. This type of sexual dimorphism is rare in Arctiidae. The recording of the sound produced by
moths held by the wings revealed that while males produced trains of pulses organized in modulation cycles, females produced
clicks at low repetition rate following very irregular patterns. Statistically, there are differences between sexes in terms
of the duration of pulses, which were 355 ± 24 μs in the case of males and 289 ± 29 μs for females. The spectral characteristics
of the pulses also show sexual dimorphism. Male pulses are more tuned (Q
10 = 5.2 ± 0.5) than female pulses (Q
10 = 2.7 ± 0.5) and have a higher best frequency (42 ± 1 kHz vs. 29 ± 2 kHz). To our knowledge, this is the first report on
an arctiid moth showing sexual dimorphism in tymbal’s anatomy that leads to a best frequency dimorphism. Males produce sound
at mating attempts. The sounds recorded during mating are modulation cycles with the same spectral characteristics as those
recorded when males are held by the wings. The morphological and acoustic features of female tymbals could indicate a process
of degeneration and adaptation to conditions under which the emission of complex patterns is not necessary.
Frank Coro no longer works at Universidad de La Habana. 相似文献
19.
Where clocks are redundant: weak circadian mechanisms in reindeer living under polar photic conditions 总被引:1,自引:0,他引:1
Biological rhythms are a result of interplay between endogenous clocks and the ambient light–dark (LD) cycle. Biological timing
in resident polar organisms presents a conundrum because these experience distinct daily LD cycles for only a few weeks each
year. We measured locomotor activity in reindeer, Rangifer tarandus platyrhynchus (SR, n = 5 and 6) and R. tarandus tarandus (NR, n = 6), ranging freely at 78 and 70°N, respectively, continuously throughout 1 year using data loggers. NR, but not SR, are
gregarious which enabled us to examine the integrated effects of differences in social organisation and the photic environment
at two different latitudes on the organisation of activity. In both sub-species, ultradian bouts of activity and inactivity
alternated across the 24-h day throughout the year. This pattern was modified by the LD cycle in NR but barely at all in SR.
Periodogram analysis revealed significant ultradian rhythmicity in both sub-species; the frequency of daily cycles of activity
increased from three per day in winter to nearly five in summer. We conclude that this increase, and a concomitant increase
in the level of daily activity, reflected the seasonal increase in the animals’ appetite and the quality of their forage.
Secondly, the combination, most evident in SR, of a weak photic response, weak circadian mechanisms and a weak social synchronization
reduces the constraints of biological timing in an environment which is effectively non-rhythmic most of the year and permits
expression of the basic ultradian pattern of ruminant activity. Third, the weaker 24-h rhythmicity in SR compared to NR indicates
a latitudinal decrease in circadian organization and photic responsiveness in Rangifer. 相似文献
20.
酸性矿山废水(AMD)具有酸度高并含有大量可溶性Fe、硫酸根及重(类)金属的特点,采用生物矿化法促使AMD中Fe向羟基硫酸铁次生矿物转变,对AMD后期石灰中和减少氢氧化铁和废石膏的产生,提高中和效率具有实际意义.本研究模拟AMD,考察了初始pH、Fe~(2+)浓度、Fe/Na摩尔比对嗜酸性氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans)体系中Fe~(2+)氧化率、总Fe沉淀率、次生铁矿物矿相的影响.结果表明,高浓度Na~+会抑制A.ferrooxidans的氧化能力,当Na~+浓度在A.ferrooxidans耐受范围内时,其不影响Fe~(2+)氧化及总Fe沉淀去除效果,表现在160、80、20 mmol·L~(-1)的Fe~(2+)分别在72、48、48 h内被完全氧化,培养至终点时平均总Fe沉淀率分别为20.04%、16.43%、0.99%.此外,在Fe~(2+)浓度为160mmol·L~(-1)体系中,当Fe/Na摩尔比为1.0、2.0时,pH为2.0~2.6时获得次生铁矿物均为纯净施氏矿物.而当Fe/Na摩尔比降至0.5时,次生铁矿物的合成途径开始向黄钠铁矾转移,且其特征衍射峰随着Na~+浓度提高而愈加显著.本研究结果可为生物合成次生铁矿物工艺的优化及其在AMD治理领域的有效应用提供必要的参数支撑. 相似文献