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1.
The film thickness plays an important role in the performance of materials applicable to different technologies including chemical sensors, catalysis and/or energy materials. The relationship between the surface and volume of the functional layers is key to high performance evaluations. Here we demonstrate the thermophoretic deposition of different thicknesses of the functional layers designed using flame combustion of tin 2-ethylhexanoate dissolved in xylene, and measurement of thickness by scanning electron microscopy and focused ion beam. The parameters such as spray fluid concentration (differing Sn2+ content), substrate-nozzle distance and time of the spray were considered to investigate the layer growth. The results showed ≈ 23, 124 and 161 μm thickness of the SnO2 layer after flame spray of 0.1, 0.5 M and 1.0 M tin 2-EHA-Xylene solutions for 1200 s. While Sn2+ concentration was 0.5 M for all the flame sprays, the substrates placed at 250, 220 and 200 mm from the flame nozzle had layer thicknesses of 113, 116 and 132 µm, respectively. Spray time dependent thickness growth showed a linear increase from 8.5 to 152.1 µm when the substrates were flame sprayed for 30 s to 1200 s using 0.5 M tin 2-EHA-Xylene solutions. Changing the dispersion oxygen flow (3–7 L/min) had almost no effect on layer thickness. Layers fabricated were compared to a model found in literature, which seems to describe the thickness well in the domain of varied parameters. It turned out that primary particle size deposited on the substrate can be tuned without altering the layer thickness and with little effect on porosity. Applications depending on porosity, such as catalysis or gas sensing, can benefit from tuning the layer thickness and primary particle size.  相似文献   
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Tris(2‐butoxyethyl) phosphate (TBOEP), triphenyl phosphate (TPHP) and tris(1‐chloro‐2‐propyl) phosphate (TCIPP) are current high‐volume organophosphate flame retardants/plasticizers (PFRs) and are abundant in the indoor environment. While recent in vitro research has indicated potential toxic effects in the endocrine system, biotransformation of these compounds is still underexplored. In this study, we aimed to characterize the metabolite formation for three PFRs in primary human hepatocytes, an in vitro system that mimics in vivo liver metabolism more closely than hepatic subcellular fractions or cell lines. Cryopreserved human hepatocytes were thawed and suspended in media with 50 μm TBOEP or TCIPP, or 20 μm TPHP up to 2 h. Extracts were analyzed by liquid chromatography–quadrupole‐time‐of‐flight‐mass spectrometry. Quantification of biotransformation products in hepatocytes exposed for 2 h revealed that bis(1‐chloro‐2‐propyl) phosphate and diphenyl phosphate corresponded to less than half of the depletion of TCIPP and TPHP, respectively, while bis(2‐butoxyethyl) 2‐hydroxyethyl phosphate compared to 40–66% of the depletion of TBOEP. Other metabolite structures of these PFRs were produced at 4‐ to 10‐fold lower rates. These findings help interpret biological levels of the major metabolites and relate it to levels of their parent PFR. Percentage of substrate depletion was largest for TBOEP followed by comparable values for TPHP and TCIPP, indicating that hepatic clearance of TPHP and TCIPP would be slower than that of TBOEP. The resulting higher levels and longer presence of TPHP in the circulation after exposure, would allow TPHP a larger time window to exert its suspected adverse effects compared to TBOEP. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
4.
Many chemical substances are detectable in house dust, and they are consequently taken into our bodies via the mouth and nose. Triphenyl phosphate (TPhP), a flame retardant that has an estrogen-like effect in vitro, is present in house dust at high concentrations. Estrogen exposure during development has significant influences on reproductive behavior in rodents, and its effects persist until maturity. In the present study, we investigated the effect of early life exposure to TPhP on the reproductive behavior of female rats. Oral treatment with TPhP (25 or 250 mg/kg), ethinyl estradiol (EE; 15 μg/kg) as a positive control, or sesame oil as a negative control, were given to female rats (from birth to 28 days of age). The 8-week-old rats were bilaterally ovariectomized. At 12–15 weeks of age, the rats were subjected to odor preference and sexual behavior tests. In the odor preference test, the oil group showed significantly higher preference for male odor than female odor, but the low-dose TPhP treatment group lost the preference for male odor, indicating a possible outcome of early life TPhP exposure on sexual recognition. In the sexual behavior test, both the EE and TPhP treatment groups displayed significantly less proceptive behavior. These results suggest that early life exposure to TPhP disturbs the normal sexual behavior of female rats.  相似文献   
5.
We investigated the effect of the type and amount of expandable graphite (EG) and blackcurrant pomace (BCP) on the flammability, thermal stability, mechanical properties, physical, and chemical structure of viscoelastic polyurethane foams (VEF). For this purpose, the polyurethane foams containing EG, BCP, and EG with BCP were obtained. The content of EG varied in the range of 3–15 per hundred polyols (php), while the BCP content was 30 php. Based on the obtained results, it was found that the additional introduction of BCPs into EG-containing composites allows for an additive effect in improving the functional properties of viscoelastic polyurethane foams. As a result, the composite containing 30 php of BCP and 15 php of EG with the largest particle size and expanded volume shows the largest change in the studied parameters (hardness (H) = 2.65 kPa (+16.2%), limiting oxygen index (LOI) = 26% (+44.4%), and peak heat release rate (pHRR) = 15.5 kW/m2 (−87.4%)). In addition, this composite was characterized by the highest char yield (m600 = 17.9% (+44.1%)). In turn, the change in mechanical properties is related to a change in the physical and chemical structure of the foams as indicated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis.  相似文献   
6.
A novel liquid phosphorous-containing flame retardant anhydride (LPFA) with low viscosity was synthesized from 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and methyl tetrahydrophthalic anhydride (MeTHPA) and further cured with bisphenol-A epoxy resin E-51 for the preparation of the flame retardant epoxy resins. Both Fourier transform infrared spectroscopy (FT-IR), mass spectrometry (MS) and nuclear magnetic resonance (NMR) measurements revealed the successful incorporation of DOPO on the molecular chains of MeTHPA through chemical reaction. The oxygen index analysis showed that the LPFA-cured epoxy resin exhibited excellent flame retardant performance, and the corresponding limiting oxygen index (LOI) value could reach 31.2%. The UL-94V-0 rating was achieved for the flame retardant epoxy resin with the phosphorus content of 2.7%. With the addition of LPFA, the impact strength of the cured epoxy resins remained almost unchanged, but the flexural strength gradually increased. Meanwhile, all the epoxy resins showed good thermal stability. The glass transition temperature (Tg) and thermal decomposition temperature (Td) of epoxy resin cured by LPFA decreased slightly compared with that of MeTHPA-cured epoxy resin. Based on such excellent flame retardancy, low viscosity at room temperature and ease of use, LPFA showed potential as an appropriate curing agent in the field of electrical insulation materials.  相似文献   
7.
采用标准的kε湍流模型、EDC(涡耗散)燃烧模型和DO(离散坐标)辐射换热模型对多重射流燃烧反应器内的流动及燃烧状况进行了三维全尺寸数值模拟。研究了不同工艺条件下燃烧反应器内温度、速度以及各反应组分的分布状况,考察了燃烧反应器径向温度分布等参数对最终颗粒尺寸、形貌特征的影响规律,并与同工艺条件下实验结果进行了验证,数值模拟与实验结果吻合良好。所建立的数学模型为燃烧反应器结构设计和工艺条件优化提供了依据,同时模拟结果也为纳米颗粒成核生长过程的研究提供理论依据。  相似文献   
8.
狗皮膏大鼠长期毒性试验的体内血液铅变化研究   总被引:1,自引:0,他引:1  
目的:建立火焰原子吸收光谱法测定血铅方法,测定狗皮膏长期毒性试验的大鼠血铅浓度动态变化规律,为狗皮膏的安全性用药提供参考。方法:连续外用给予大鼠高、中、低剂量(7,3.5,1.75 g.kg-1)狗皮膏90 d,于给药前、给药后10,30,45,52,60,90 d及停药后16,28 d取血,采用微波消解仪消解血液样品,用石墨炉原子吸收光谱法测量血铅含量。结果:经方法学考察本次试验的标准曲线回归方程A=0.004 9X+0.017,r=0.999 5,检测限为0.380μg.L-1,精密度检查RSD 1.4%,混合血样中血铅值175.77μg.L-1,RSD 6.0%。大鼠给予狗皮膏后,血铅浓度逐渐升高,给药中、低剂量30 d后及高剂量10 d后血铅浓度达到稳定,给药量与血铅浓度具有剂量依赖性,停药后血铅浓度降低。结论:本方法测定准确可靠,适合于血铅的测定,狗皮膏长期大剂量外用可引起血铅升高。  相似文献   
9.
目的:了解牡荆叶、茎中Zn、Fe、Cu、Mn 4种微量元素的分布情况。方法:采用硝酸和高氯酸(体积比为4+1)分解样品,火焰原子吸收光谱法测定牡荆叶、茎中微量元素Zn、Fe、Cu、Mn的含量。对各元素进行了加标回收试验,回收率在95.00%~103.70%之间,RSD<4.9%。结果:相关微量元素在牡荆叶、茎中均含量丰富。结论:牡荆茎、叶中Zn、Fe含量差异较大,Cu、Mn含量差异相对较小。  相似文献   
10.
目的探讨微波消解-火焰原子吸收法测定儿童头发中Cu、Zn、Ca、Fe的含量。方法采用微波消解技术,硝酸和过氧化氢彻底分解头发样品,消解后的样品用火焰原子吸收分光光度法测定Cu、Zn、Ca、Fe的含量。结果用微波消解技术-火焰原子吸收法测定儿童头发中Cu、Zn、Ca、Fe,铜浓度在(0~1.0)μg/mL、锌浓度在(0~2.0)μg/mL,钙浓度在(0~20.0)μg/mL,铁浓度在(0~1.0)μg/mL,范围内呈良好的线性关系,相关系数r均大于0.999,0.15≤RSD≤5.66,回收率均在90.0%~105%之间。结论该方法能够满足儿童头发中Cu、Zn、Ca、Fe的分析要求。  相似文献   
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