联用紫外线辐射改性的羊毛织物茶色素同浴媒染工艺

以茶色素/金属媒染剂同浴媒染法为基础,对分别应用不同金属媒染剂的羊毛织物茶色素同浴媒染工艺进行筛选,对比经紫外线辐射改性前后的羊毛织物染色性能。结果表明,茶色素/铜媒同浴媒染的改性前后羊毛织物K/S值与固色率均较其余工艺高,并通过对比实验数据证实紫外线辐射有利于提升羊毛织物染色性能,故将其与茶色素/铜媒同浴媒染工艺联用进而增强茶色素染色效果。通过单因素分析对联用紫外线辐射改性的羊毛织物茶色素/铜媒同浴媒染工艺进行讨论并选择紫外线辐射改性时间、铜媒用量及染色时间等因子的优化范围,进而利用3因子二次通用旋转组合设计进行优化,从而确定优化工艺为(用量/对织物重(o.w.f)):紫外线辐射改性9 min,茶色素5.0%,铜媒1.7%,HCOOH 2.0%,pH=3.5~4.0,浴比1:50,95℃条件下染色60 min。与常规茶色素后铬媒染工艺相比,该优化工艺具有更好的染色效果和较低的金属媒染剂用量。     

表面处理对三元乙丙橡胶室温粘接性能影响

主要研究了紫外线、臭氧和紫外线 臭氧三种表面处理方法对三元乙丙橡胶室温粘接性能的影响.实验结果表明,当处理时间适当时,粘接试样的拉伸剪切强度均有所提高,其中紫外线处理提高幅度最大,约35%.经扫描电镜,表面光电子能谱分析表明,3种表面处理方法均可在三元乙丙橡胶的表面引入活性基团,改善表面的低活性.     

Oxidative and photochemical processes for the removal of galaxolide and tonalide from wastewater

Synthetic musks have been reported in wastewaters at concentrations as high as tens of micrograms per litre. The two most significant polycyclic musk fragrance compounds are 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta(g)-2-benzopyran (HHCB, trade name galaxolide^®) and 7-acetyl-1,1,3,4,4,6-hexamethyltetrahydronaphthalene (AHTN, trade name tonalide^®). We report the result of several irradiation and advanced oxidation processes carried out on samples of the effluent of a wastewater treatment plant located in Alcalá de Henares, Madrid. Wastewater samples were pre-ozonated and spiked with 500 ng/L of tonalide or galaxolide in order to obtain final concentrations in the same order as the raw effluent. The treatments assayed were ozonation with and without the addition of hydrogen peroxide (O₃, O₃/H₂O₂), ultraviolet (254 nm low pressure mercury lamp) and xenon-arc visible light irradiation alone and in combination with ozone (UV, O₃/UV, Xe, O₃/Xe) and visible light photocatalytic oxidation using a Ce-doped titanium dioxide photocatalyst performed under continuous oxygen or ozone gas bubbling (O₂/Xe/Ce-TiO₂, O₃/Xe/Ce-TiO₂). In all cases, samples taken at different contact times up to 15 min were analyzed. An analytical method based on stir bar sorptive extraction (SBSE), followed by comprehensive two-dimensional gas chromatography (SBSE-GC × GC-TOF-MS), was used for the automatic searching and evaluation of the synthetic musks and other nonpolar or semipolar contaminants in the wastewater samples. In all cases tonalide was more easily removed than galaxolide. The best results for the latter (more than 75% removal after 5 min on stream) were obtained from ozonation (O₃) and visible light photocatalytic ozonation (O₃/Xe/Ce-TiO₂). A significant removal of both pollutants (∼60% after 15 min) was also obtained during visible light photocatalysis (O₂/Xe/Ce-TiO₂). UV radiation was able to deplete tonalide (+90%) after 15 min but only reduced the concentration of galaxolide to about half of its initial concentration. The toxicity of treated samples decreased for O₃/UV and O₃/Ce-TiO₂, but increased during irradiation processes UV, Xe and Xe/Ce-TiO₂. Ozone treatments tend to decrease toxicity up to a certain dosage, from which point the presence of toxic transformation products has adverse effects on aquatic microorganisms.     

Immediate and long-term impacts of UV-C irradiation on photosynthetic capacity, survival and microcystin-LR release risk of Microcystis aeruginosa

In this study, the immediate and long-term impacts of shortwave ultraviolet (UV-C) irradiation on photosynthetic capacity, survival, and recovery of Microcystis aeruginosa were investigated. The risk of microcystin-LR (MC-LR) release during irradiation was also estimated. The cell density was determined by a flow cytometry, and typical chlorophyll fluorescence parameters, including the effective quantum yield, photosynthetic efficiency and maximal electron transport rate, were measured by a pulse amplitude modulated (PAM) fluorometer. Under various UV-C dosages (140-4200 mJ cm⁻²), photosynthetic capacities were reduced, to different degrees, accompanied by slight cytoclasis and complete degradation of extracellular MC-LR immediately after irradiation. In a 6-d cultivation following UV-C irradiation, cell density and extracellular MC-LR in the samples treated by 140 mJ cm⁻² UV-C irradiation increased from 4.0 × 10⁶ cells mL⁻¹ and 8 μg L⁻¹ to 5.1 × 10⁶ cells mL⁻¹ and 20 μg L⁻¹, respectively. Significant M. aeruginosa cytoclasis (cell density from 4.0 × 10⁶ to 1.0 × 10⁶ cells mL⁻¹) and MC-LR release (2-25 μg L⁻¹) occurred when the UV-C dosage reached 350 mJ cm⁻². Cell cytoclasis and MC-LR release were enhanced in the cultivated samples under higher UV-C dosages. Results revealed that photosynthetic parameters were useful tools to predict the recovery profiles of M. aeruginosa cells, and the MC-LR release risk should be considered after UV-C inactivation.     

Pasteurization of grapefruit juice using a centrifugal ultraviolet light irradiator

Studies are lacking on the nonthermal pasteurization of liquid foods using UV irradiators that centrifugally form very thin films to overcome the problem of limited penetration depth of UV. Grapefruit juice inoculated with Escherichia coli or Saccharomyces cerevisiae was processed at the following conditions: UV dose 4.8–24 mJ/cm²; treatment time 3.2 s, cylinder rotational speed 450–750 rpm, cylinder inclination angle 15–45°, outlet temperature 11 °C, and flow rate 300 ml/min, and was stored for 35 days. Appropriate dilutions of the samples were pour plated with TSA and TSA + 3% NaCl for E. coli and Sabouraud dextrose agar (SDA) and SDA + 5% NaCl for S. cerevisiae. Nonthermal UV processing at 19 mJ/cm², 450 rpm and 15° reduced E. coli in grapefruit juice by 5.1 log₁₀. A dose of 14 mJ/cm² reduced S. cerevisiae by 6.0 log₁₀. Inactivation increased linearly with increasing UV dose. The inactivations at 600 and 750 rpm were similar, and were better than at 450 rpm. The results at 30° and 45° were similar, and were better than at 15°. The occurrence of sublethal injury in either microorganism was not detected. Storing UV processed grapefruit juice at 4 and 10 °C reduced the surviving E. coli to below 1 log₁₀ cfu/ml in 14 days. Processing UV juice reduced the population of S. cerevisiae to less than 1 log₁₀ cfu/ml where it remained for 35 days during refrigerated storage. These results suggest that grapefruit juice may be pasteurized using a nonthermal UV irradiator that centrifugally forms a thin film.     

紫外吸收光谱法测定猪肉中蛋白质的含量

用紫外吸收光谱测定法测定了猪肉中蛋白质的含量，与凯氏定氨法对照，二者无显著性差异，前者准确度较高，重现性好，简单方便。     

Combined effect of selected non-thermal technologies on Escherichia coli and Pichia fermentans inactivation in an apple and cranberry juice blend and on product shelf life

The combination of novel, non-thermal technologies for preservation purposes is a recent trend in food processing research. In the present study, non-thermal hurdles such as ultraviolet light (UV) (5.3 J/cm²), high intensity light pulses (HILP) (3.3 J/cm²), pulsed electric fields (PEF) (34 kV/cm, 18 Hz, 93 μs) or manothermosonication (MTS) (4 bar, 43 °C, 750 W, 20 kHz) were examined. The objective was to establish the potential of these technologies, applied individually or in paired sequences, to inactivate Escherichia coli and Pichia fermentans inoculated in a fresh blend of apple and cranberry juice. The shelf-life evaluation of selected non-thermally treated samples was conducted over 35 days and compared to pasteurised samples and untreated juices. All treatments applied individually significantly reduced (1.8-6.0 log cfu/ml) microbial counts compared to the untreated sample (p < 0.01). Furthermore, UV treatment produced significantly greater inactivation (p < 0.05) for E. coli compared to P. fermentans. Combinations of non-thermal hurdles consisting of UV or HILP followed by either PEF or MTS resulted in comparable reductions for both microorganisms (p ≥ 0.05) to those observed in thermally pasteurised samples (approx. 6 log cfu/ml). Thermally pasteurised samples had a shelf life exceeding 35 days, while that of UV + PEF and HILP + PEF-treated samples was 14 and 21 days, respectively. These results indicate that combinations of these non-thermal technologies could successfully reduce levels of E. coli and P. fermentans in apple and cranberry juice, although optimisation is required in order to further extend shelf life.     

Effects of Ozone-Gas Bubble Size and pH on Ozone/UV Treatment

A series of ozone/UV treatment under injection of ozone with different ozone-gas bubble sizes was performed at pH 1.7 and 7.4. The increase in the bubble size and the decrease in pH enhanced the ozone utilization efficiency. The enhancement of ozone utilization efficiency was caused by the shift of the production pathway of hydroxyl radical (OH) from the OH production via O₃ ^– to the UV photolysis of H₂O₂. The lower pH caused this shift through the chemical equilibrium of H₂O₂ and HO₂ ^–, and the large bubbles caused this shift through the augmentation of H₂O₂ transport from the bubble surface to the bulk solution.     

Ultraviolet and violet upconversion luminescence in Ho-doped Y2O3 ceramic induced by 532-nm CW laser

Ultraviolet and violet upconversion luminescence spectra of holmium-doped Y₂O₃ were produced under the excitation of a compact continues-wave 532 nm solid-state laser. Emissions around 306, 362, 412, 390 and 428 nm can be assigned to the transitions of ³D₃ → ⁵I_J (J = 8, 7, 6), ⁵G₄ → ⁵I₈ and ⁵G₅ → ⁵I₈, respectively. Power dependence and upconversion dynamics analysis demonstrated that both the energy transfer upconversion (ETU) and the excited state absorption (ESA) processes were involved in the population of ³D₃ state via the coupled intermediate states ⁵S₂/⁵F₄. Fluorescence spectra in the visible and infrared ranges showed that ⁵G₄ and ⁵G₅ states were populated by the ESA process from ⁵I₆ and ⁵I₇ states, respectively, while the ⁵I₆ and ⁵I₇ states were radiatively populated from the excited ⁵S₂/⁵F₄ states. Upconversion mechanisms have been evaluated based on a rate equation model.     

Bicarbonate Effect in the Ozone-UV Process in the Presence of Nitrate

Ozonation and advanced oxidation processes (AOP) are very efficient methods for the destruction of refractory organic matters. These virtues have always been related to the production of hydroxyl radicals HO^?, which are extremely powerful and non-selective oxidants. In this study, the O₃-UV process is used as an AOP, where hydroxyl radicals are generated from the photodecomposition of ozone by short wavelength ultraviolet radiation. The obtained results indicated a weak scavenging effect of tert-butanol proving that hydroxyl radicals and ozone are not the only oxidants existing in the medium. Moreover, bicarbonate, known for a long time as effective HO^? radical scavengers, does not slow down the oxidation of benzoic acid, but surprisingly increases it. Chlorides significantly decrease the degradation of organic compounds through their reaction with HO^? radicals to produce chlorine. Carbonate radicals, nitrate and nitrogenated species as peroxynitrite/?peroxynitrous acid are involved in the oxidative mechanisms.