共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
The basic trypsin inhibitor of bovine pancreas 总被引:6,自引:0,他引:6
3.
4.
Polyaspartic acid (PASP) has been extensively studied in recent years as a green scale inhibitor. PASP was synthesized by thermal polycondensation of maleic anhydride and ammonium carbonate in this study. The optimal polycondensation reaction conditions were the raw material (maleic anhydride and ammonium carbonate) molar ratio of 1.0:1.2, the polymerization temperature of 180°C and reaction time of 2.0 hr. The results showed that PASP exhibits very good scale inhibiting performance. The inhibition rate was 95% for calcium carbonate and 90% for calcium sulfate by the application of 5 mg/L PASP. 相似文献
5.
An inhibitor of urease activity effectively reduces ammonia emissions from soil treated with urea under Mediterranean conditions 总被引:4,自引:0,他引:4
Alberto Sanz-Cobena Thomas H.Misselbrook Augusto Arce Juan I. Mingot Jose Antonio Diez Antonio Vallejo 《Agriculture, ecosystems & environment》2008,126(3-4):243-249
Urea is an important source of ammonia (NH3) emissions to the atmosphere from agricultural soils. Abatement strategies are necessary in order to achieve NH3 emission targets by reducing those emissions. In this context, a field experiment was carried out on a sunflower crop in spring 2006 with the aim of evaluating the effect of the N-(n-butyl) thiophosphoric triamide (NBPT) in the mitigation of volatilized NH3 from a urea-fertilised soil. Ammonia emission was quantified, using the integrated horizontal flux (IHF) method, following application of urea with and without the urease inhibitor NBPT. Urea and a mixture of urea and NBPT (0.14%, w/w) were surface-applied at a rate of 170 kg N ha−1 to circular plots (diameter 40 m). The soil was irrigated with 10 mm of water just after the application of urea to dissolve and incorporate it into the upper layer of soil. Over the duration of the measurement period (36 days) three peaks of NH3 were observed. The first peak was associated with hydrolysis of urea after irrigation and the others with the increase of ammonia in soil solution after changes in atmospheric variables such as wind speed and rainfall. The total NH3 emission during the whole experiment was 17.3 ± 0.5 kg NH3–N ha−1 in the case of urea treated soils and 10.0 ± 2.2 kg NH3–N ha−1 where NBPT was included with the urea (10.1 and 5.9%, respectively, of the applied urea–N). The lower NH3 emissions from plots fertilised with urea + NBPT, compared with urea alone, were associated with a reduction in urease activity during the first 9 days after inhibitor application. This reduction in enzymatic activity promoted a decrease in the exchangeable NH4+ pool. 相似文献
6.
7.
8.
The inhibition and dispersion of polyepoxysuccinate (PESA, self-manufactured) to inorganic scale was evaluated by scale static beaker test to CaC03 and Ca3(P04)2, stability test to zinc salt, and dispersion test to ferric oxide. The experimental results demonstrated that PESA functioned excellent scale inhibition to CaC03 and Ca3(P04)2, good stability to zinc salt and special dispersion to ferric oxide. Under the water with hardness 500-1200 mg/L, alkalinity 1000 mg/L, and dosage of PESA 31.2 mg/L, PESA scale inhibition ratio reached more than 85.0%. At dosage of PESA 20.8 mg/L inhibition ratio on calcium phosphate reached 38.9%, at optimum dosage of PESA 9.1 mg/L, the stability ratio was up to 96.1%; while at dosage of PESA 3.6 mg/L, transmittance ratio reached 64.4%. Therefore, PESA can be considered a soluble, high effective and versatile inhibitor. 相似文献
9.
10.
11.
Red mud was investigated in triglyceride transesterification with a view to determine its viability as a basic catalyst for use in biodiesel synthesis.The effect of calcination temperature on the structure and activity of red mud catalysts was investigated.It was found that highly active catalyst was obtained by simply drying red mud at 200°C.Utilization of red mud as a catalyst for biodiesel production not only provides a cost-effective and environmentally friendly way of recycling this solid red mud waste,significantly reducing its environmental effects,but also reduces the price of biodiesel to make biodiesel competitive with petroleum diesel. 相似文献
12.
13.
14.
P. Kirkinen M.D. M. Ryynänen P. Haring H. Torkkeli L. Pääkkönen A. Martikainen 《黑龙江环境通报》1994,14(11):1074-1076
A case of early-onset, severe spinal muscular atrophy is reported. Normal fetal breathing movement patterns and heart rate accelerations were observed in spite of the severe hypotonia evident at birth. 相似文献
15.
SU Jian-qiang YU Zhi-ming SONG Xiu-xian TIAN Yun HONG Hua-sheng ZHENG Tian-ling 《环境科学学报(英文版)》2005,17(6):1047-1050
The relationship between Alexandrium tamarense (Lebour) Balech, one of red-tide alga, and two strains of marine bacteria, Bacillius megaterium(S7 ) and B. halmapulus( S10 ) isolated from Xiamen Western Sea, was investigated by evaluating the growth state of A. tamarense and the variation of β-glucosidase activity in co-culture system. The results showed the growth and multiplication of the alga were related with the concentration, genus speciality of the bacteria, and growth stage of the alga itself. The growth of A. tamarense was obviously inhibited by S7 and S10 at high concentration. Either inhibition or promotion contributed much more clearly in earlier than in later stageof the growth of the alga. Furthermore, there was a roughly similar variation trend of the activity of extra-cellular enzyme, β- glucosidase, in the water of the separately co-cultured bacteria S7 and S10 with the alga. The β-glucosidase activity(β-GlcA) rapidly increased during the later algal growth accompanying the increase of the lysis of the alga cells. The obvious inhibition of A. tamarense by marine bacteria at high concentration and evident increase of β-GlcA in co-colture system would help us in better understanding the relationship between red-tide alga and bacteria, and also enlightened us the possible use of bacteria in the bio-control of red-tide. 相似文献
16.
17.
Fatemeh Ghanbary Nasser Modirshahl Morteza Khosravi Mohammad Ali Behnajady 《环境科学学报(英文版)》2012,24(4):750-756
Titanium dioxide (TiO2) nanoparticles were prepared by sol gel route. The preparation parameters were optimized in the removal of 4-nitrophenol (4-NP). All catalysts were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). An artificial neural network model (ANN) was developed to predict the photocatalytic removal of 4-NP in the presence of TiO2 nanoparticles prepared under desired conditions. The comparison between the predicted results by designed ANN model and the experimental data proved that modeling of the removal process of 4-NP using artificial neural network was a precise method to predict the extent of 4-NP removal under different conditions. 相似文献
18.
Okuyama T 《Die Naturwissenschaften》2011,98(1):15-22
Individual variation is a ubiquitous and important factor that affects ecological dynamics. This study examined individual
variation in the nest-use pattern of the jumping spider Phidippus audax. Although the jumping spider is a diurnal species, field observations in this study revealed that the majority of individuals
remained in their nests during the day. An accompanying examination of the hunger level of the spiders revealed that spiders
that remained in nests were more starved than those observed outside nests. If spiders actively forage when they are starved,
as has been suggested by previous studies, one would expect to see the opposite trend (i.e., spiders that remained in nests
are more satiated). Thus, the pattern observed in the field contradicts the known behavioral pattern of the spiders. An individual-based
model was used to investigate the behavioral mechanism of the spider and the discrepancy found in the observations. A basic
assumption of the model is that spiders possess distinct inactive and active phases (biphasic activity pattern), and transitions
between the two phases are regulated by the hunger level of the spider. Data from a laboratory experiment were used to examine
the assumptions of the model partially. The model was able to capture patterns observed in the data, suggesting that the pattern
of transitions in biphasic activity is an important trait of the foraging behavior of the jumping spider. 相似文献
19.
Polyaluminum chloride was synthesized with a membrane reactor, and the process characteristics, membrane fouling and cleaning were investigated. 相似文献
20.
1999年,位于重庆开县最边缘山区的麻柳乡发生了一场激烈的群体访事件,当地百姓把乡政府围攻起来讨说法,并用砖头把政府的门窗砸烂.这一事件促使麻柳乡政府深刻反思,多方查找原因,从而在实践中展开了对有效工作方式方法的探索,形成了具有基层民主特色的“八步工作法”.根据“八步工作法”的实践经验,基层环保工作是否也可以进行一场革命,创新思维,打开基层环保工作的瓶颈. 相似文献