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排序方式: 共有471条查询结果,搜索用时 15 毫秒
1.
云南磷肥工业副产氟资源综合利用途径初探 总被引:1,自引:0,他引:1
根据云南磷肥工业发展情况 ,提出对磷肥工业副产氟资源综合利用的设想 ,并介绍目前国内已有的一些氟资源综合利用的工艺技术 相似文献
2.
微波消解-ICP-AES法测定菜油中P、S 总被引:2,自引:0,他引:2
采用微波加热,在高温高压下酸消解样品,运用电感耦合等离子体原子发射光谱法(ICP-AES)同时测定菜油中P、S。本法选用紫外区谱线P178.221nm、S180.669nm,避免了基体中存在的Fe、Zn、Al、Cu、Mn、Ca等元素的光谱干扰。实验通过用纯氮吹扫光谱仪光路的方法消减空气中氧对紫外线的吸收,获得了足够的灵敏度。该方法简便、快速,稳定可靠,P、S检出限分别为0.067、0.078μg/ml,RSD为1.35%~5.05%,回收率为89.0%~100.9%。 相似文献
3.
D. Bojinova R. Velkova Iv. Grancharov St. Zhelev 《Nutrient Cycling in Agroecosystems》1996,47(3):227-232
It is well known that the production of phosphoric fertilizers by traditional methods is connected with certain environmental problems, particularly related to use of acids during the decomposition of natural phosphates. A basic problem is also the fact that only 15 – 20% of the phosphorus contained in superphosphates is assimilated by plants.The development of methods to process natural phosphates without acid precipitation has potential advantages and in this respect biotechnological processing of natural phosphates in order to obtain organo-mineral fertilizers is very promising. The possibility of bioconverting the phosphorus of natural phosphates by usingAspergillus niger fungi through their deep incubation has been investigated. The investigations aim to achieve a high degree of P2O5 extraction from the phosphates with conversion from a non-utilizable to a utilizable form. The influence of the fungal strain, the kind of nutritive medium and the time of incubation of the process of biological mobilization of the phosphate rock is examined.It was established that the time of incubation, the kind of micro-organisms of theAspergillus niger group, as well as the kind of nutritive medium, influence significantly the process of bioconversion and the conversion of phosphorus from non-utilizable to water-soluble and utilizable for plants form. A maximum degree 90% of phosphorus extraction in the form of water-soluble and citrate-soluble has been reached for 10-day incubation. Physicochemical examinations have been carried out and they have proved that, as a result of the produced organic acids, a process of decomposition of the initial Tunisian phosphorite takes place. 相似文献
4.
CAST的工作原理与设计计算 总被引:7,自引:0,他引:7
详细论述了循环式活性污泥法(CAST)的工作原理,对该工艺的设计计算作了探讨,提出了设计方法,并提供了有关计算公式和操作时间分配。 相似文献
5.
María Jos García Carlos Lucena Francisco Javier Romera 《International journal of molecular sciences》2021,22(9)
Iron (Fe) and phosphorus (P) are two essential elements for plant growth. Both elements are abundant in soils but with poor availability for plants, which favor their acquisition by developing morphological and physiological responses in their roots. Although the regulation of the genes related to these responses is not totally known, ethylene (ET) and nitric oxide (NO) have been involved in the activation of both Fe-related and P-related genes. The common involvement of ET and NO suggests that they must act in conjunction with other specific signals, more closely related to each deficiency. Among the specific signals involved in the regulation of Fe- or P-related genes have been proposed Fe-peptides (or Fe ion itself) and microRNAs, like miR399 (P), moving through the phloem. These Fe- or P-related phloem signals could interact with ET/NO and confer specificity to the responses to each deficiency, avoiding the induction of the specific responses when ET/NO increase due to other nutrient deficiencies or stresses. Besides the specificity conferred by these signals, ET itself could confer specificity to the responses to Fe- or P-deficiency by acting through different signaling pathways in each case. Given the above considerations, there are preliminary results suggesting that ET could regulate different nutrient responses by acting both in conjunction with other signals and through different signaling pathways. Because of the close relationship among these two elements, a better knowledge of the physiological and molecular basis of their interaction is necessary to improve their nutrition and to avoid the problems associated with their misuse. As examples of this interaction, it is known that Fe chlorosis can be induced, under certain circumstances, by a P over- fertilization. On the other hand, Fe oxides can have a role in the immobilization of P in soils. Qualitative and quantitative assessment of the dynamic of known Fe- and P-related genes expression, selected ad hoc and involved in each of these deficiencies, would allow us to get a profound knowledge of the processes that regulate the responses to both deficiencies. The better knowledge of the regulation by ET of the responses to these deficiencies is necessary to properly understand the interactions between Fe and P. This will allow the obtention of more efficient varieties in the absorption of P and Fe, and the use of more rational management techniques for P and Fe fertilization. This will contribute to minimize the environmental impacts caused by the use of P and Fe fertilizers (Fe chelates) in agriculture and to adjust the costs for farmers, due to the high prices and/or scarcity of Fe and P fertilizers. This review aims to summarize the latest advances in the knowledge about Fe and P deficiency responses, analyzing the similarities and differences among them and considering the interactions among their main regulators, including some hormones (ethylene) and signaling substances (NO and GSNO) as well as other P- and Fe-related signals. 相似文献
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9.
M. D. A. Bolland 《Nutrient Cycling in Agroecosystems》1993,35(1-2):83-91
The relationship between plant yield and values of soils tests for phosphorus (P) was studied in long-term field experiments
in south-western Australia for soil previously fertilized with rock phosphate and superphosphate. The rock phosphates studied
were: Queensland (Duchess) apatite rock phosphate; reactive apatite rock phosphate from North Carolina; and rock phosphate
from Christmas Island (as either C-grade ore or Calciphos). The P fertilizers were applied once only at the start of each
experiment, and in subsequent years, soil samples were collected in January-March to measure soil test values. These were
compared with plant yields measured later on in that year. The Colwell alkaline bicarbonate soil test was used in all years
in all experiments. Olsen, Bray, lactate and Troug tests were used in some years in some experiments.
For all soil tests the relationships between yield and soil test values was generally different for rock phosphate and superphosphate.
For a given source of P, none of the different soil test reagents was significantly superior for predicting plant yields.
The relationship between yield and soil test value was also generally different for different plant species. At one site cultivation
was included as a treatment and the relationship varied depending on the cultivation treatment of the topsoil before sowing
oats (Avena sativa). The relationship between yield and soil test also differed between years. 相似文献
10.
L. K. Rihko-Struckmann Y. Ye L. Chalakov Y. Suchorski H. Weiss K. Sundmacher 《Catalysis Letters》2006,109(1-2):89-96
In the first part of this work, the electrical conductivity of vanadium phosphorous oxide (VPO) catalyst was investigated
by means of the 2-probe EIS method. The VPO showed an extremely low conductivity at low oxygen partial pressure, which is
the prevailing condition in the anodic compartment in an electrochemical membrane reactor (EMR). In the second part of this
study, fresh as well as VPO catalyst already used in an EMR were characterised with XRD, XPS and temperature programmed oxidation
(TPO). The XRD measurements revealed an unchanged bulk phase structure after operation in the EMR. Significant differences
in the average oxidation states of vanadium in the catalyst layer in the EMR were determined via XPS, where the catalyst surface
facing the electrolyte membrane was more oxidised than the surface facing the anodic gas compartment. The lowered uptake and
release of oxygen was observed in TPO experiments for the catalyst used in the EMR. 相似文献