Corrosiveness of Copper-based Preservatives to 4 Types of Metals

The corrosive rates of 4 types of metals as well as epoxy-coated metal in a variety of preservatives derived from different copper sources and ingredients were measured in this paper.The main results show that:CCA is less corrosive to red brass and Q235A steel than other copper formulations;Copper-based preservatives such as ACQ and CuAz derived from basic cupric carbonate or cupric hydroxide are much less corrosive to Q235A steel than those from cupric sulfate;Ethanolamine is less corrosive to Q235A steel than ammonia in ACQ derived from cupric hydroxide,while other ingredients are the same;Epoxy resin coating could be used for protecting red brass,Q235A steel and zinc hot-dipped galvanized mild steel from corrosion.

Simplified quantitative analysis method and its application in the insitu synthesized copper-based azide chips

Copper-based azide(Cu(N_(3))2 or CuN_(3),CA)chips synthesized by in-situ azide reaction and utilized in miniaturized explosive systems has become a hot research topic in recent years.However,the advantages of in-situ synthesis method,including small size and low dosage,bring about difficulties in quantitative analysis and differences in ignition capabilities of CA chips.The aim of present work is to develop a simplified quantitative analysis method for accurate and safe analysis of components in CA chips to evaluate and investigate the corresponding ignition ability.In this work,Cu(N_(3))2 and CuN_(3)components in CA chips were separated through dissolution and distillation by utilizing the difference in solubility and corresponding content was obtained by measuring N_(3)-concentration through spectrophotometry.The spectrophotometry method was optimized by studying influencing factors and the recovery rate of different separation methods was studied,ensuring the accuracy and reproducibility of test results.The optimized method is linear in range from 1.0-25.0 mg/L,with a correlation coefficient R^(2)=0.9998,which meets the requirements of CA chips with a milligram-level content test.Compared with the existing ICP method,component analysis results of CA chips obtained by spectrophotometry are closer to real component content in samples and have satisfactory accuracy.Moreover,as its application in miniaturized explosive systems,the ignition ability of CA chips with different component contents for direct ink writing CL-20 and the corresponding mechanism was studied.This study provided a basis and idea for the design and performance evaluation of CA chips in miniaturized explosive systems.

Metal-organic-framework-derived copper-based catalyst for multicomponent C-S coupling reaction

Copper-based metal-organic frameworks(Cu-MOFs)are a promising multiphase catalyst for catalyzing C-S coupling reactions by virtue of their diverse structures and functions.However,the unpleasant odor and instability of the organosulfur,as well as the mass-transfer resistance that exists in multiphase catalysis,have often limited the catalytic application of Cu-MOFs in C-S coupling reactions.In this paper,a Cu-MOFs catalyst modified by cetyltrimethylammonium bromide(CTAB)was designed to enhance mass transfer by increasing the adsorption of organic substrates using the long alkanes of CTAB.Concurrently,elemental sulfur was used to replace organosulfur to achieve a highly efficient and atom-economical multicomponent C-S coupling reaction.

Effects of Preservatives on the Quality of Ranunculus Cut Flowers

The preservation effects of 9 kinds of preservatives were discussed in this paper. And their effects on ornamental quality of cut Ranunculus asiaticus were in-vestigated. The results showed arranging cut Ranunculus asiaticus in a vase fil ed with 200 mg/L 8-HQC＋1% sucrose＋75 mg/L AgNO3 would effectively slow down the weight loss, promote the rise of flower diameter, prolong life and maintain the chlorophyl and anthocyanin content of cut flower. The preservative had a good fresh-keeping effect and was suitable for promotion in actual production.

Catalytic combustion of methane over nano ZrO_2-supported copper-based catalysts

The nano ZrO2-supported copper-based catalysts for methane combustion were investigated by means of N2 adsorption, TEM, XRD, H2-TPR techniques and the test of methane oxidation. Two kinds of ZrO2 were used as support, one （ZrO2-1） was obtained from the commercial ZrO2 and the other （ZrO2-2） was issued from the thermal decomposition of zirconium nitrate. It was found that the CuO/ZrO2-2 catalyst was more active than CuO/ZrO2-1. N2 adsorption, H2-TPR and XRD measurements showed that larger surface area, better reduction property, presence of tetragonal ZrO2 and higher dispersion of active component for CuO/ZrO2-2 than that of CuO/ZrO2-1. These factors could be the dominating reasons for its higher activity for methane combustion.

Comparative clinical study of conjunctival toxicities of newer generation fluoroquinolones without the influence of preservatives

AIMTo compare the conjunctival epithelial toxicities of three newer-generation fluoroquinolones without preservatives.METHODSIn a prospective, randomized, double blind comparative study, 47 eyes of 47 patients with a primary pterygium were enrolled, and divided randomly into three groups (levofloxacin 0.5%, gatifloxacin 0.3%, and moxifloxacin 0.5%). After pterygium surgery with the same conjunctival autograft technique, each patient maintained a regimen with a randomly assigned fluoroquinolone eye drop. Patients were examined every other day after surgery until the epithelium had completely healed. Photos were taken and used to measure the area of residual epithelial defects. Conjunctival healing time and speed (initial defect area/healing time (mm2/d) compared in each group using Kruskal-Wallis tests.RESULTSThere were no significant differences in mean age, gender, and conjunctival defect size of the donor site between these groups. However, the mean of conjunctival healing time and speed were statistically different in each group. The mean of conjunctival epithelial healing time was 8.93±2.69d (levofloxacin group), 10.31±2.96d (gatifloxacin group), and 13.50±4.10d (moxifloxacin group), P=0.006. The mean conjuctival epithelial healing speed was 6.18±1.39 mm2/d (levofloxacin group), 5.52±1.68 mm2/d (gatifloxacin group), and 4.40±1.30 mm2/d (moxifloxacin group), P=0. 003.CONCLUSIONWithout the influence of preservatives, levofloxacin and gatifloxacin might be less toxic to the regeneration of conjunctival epithelial cells and cause a faster conjunctival wound healing relative to moxifloxacin.

Simultaneous spectrophotometric determination of four preservatives in foodstuffs by multivariate calibration and artificial neural networks

Benzoic acid （BA）, methylparaben （MP）, propylparaben （PP） and sorbic acid （SA） are food preservatives, and they have well defined UV spectra. However, their spectra overlap seriously, and it is difficult to determine them individually from their mixtures without preseparation. In this paper, seven different chemometric approaches were applied to resolve the overlapping spectra and to determine these compounds simultaneously. With respect to the criteria of % relative prediction error （RPE） and % recovery, principal component regression （PCR） and radial basis function-artificial neural network （RBF-ANN） were the preferred methods. These two methods were successfully applied to the analysis of some commercial samples.

Relative efficacy of heartwood extracts and proprietory wood preservatives as wood protectants

The relative potentials of either heartwood extracts (air dry extracts in 60 percent methanol) of very durable woods (Afzelia africana J.E. Smith; Erythrophleum suaveolens (Guill & Perr.) Brenam. Syn. E guinensis G.Don. or Milicia excelsa (Welw) C.C. Berg. Syn. Chlorophora excelsa (Welw) Benth.) or any of two proprietary wood preservatives (AWPA type 揅? Chromated Copper Arsenate (CCA) or 5 percent solution of AWPA Standard Designation P ??type 揅? Pentanchlorophenol (Penta) in light oil solvent) to suppress attack on pressure treated Antiaris toxicaria Lesch Sapwood by either any of three species of decaying fungi (Coridopsis Polyzona Klotzch; Lenzites trabea; or Trametes cingulata Fr.) under soil block exposure conditions were investigated and threshold values determined. Extract/preservative dosages were either 8.009; 24.778; 48.056; 96.111 or 144.167 kg穖-3 (0.5; 1.5; 3.0; 6.0 or 9.0 1b/ft3). Exposure was for either 14 or 28 weeks and in accordance with ASTM D1413 72 Provisions. Conclusions reached were that at threshold values the ability of either any of the heartwood extracts or proprietary wood preservatives to suppress attack under conditions in this study was significant at 0.01. Relative efficacy of those biocides was dependent on fungal species. Neither any of the heartwood extracts nor any of the proprietary wood preservatives (except in the case of Trametes cingulata attack on CCA treated wood at highest retention level) was able to confer 搗ery durable?rating on treated wood. Possible reasons for the reduced relative durability of extracts visa vis native heartwood were advanced. At the highest retention level (144.167 kg穖-3) there was no significant difference (at 0.05 level) between efficacy of each of the heartwood extracts and any of the proprietary wood preservatives (CCA or Penta).

Effect of preparation methods of aluminum emulsions on catalytic performance of copper-based catalysts for methanol synthesis from syngas

Various Cu/ZnO/Al2O3 catalysts have been synthesized by different aluminum emulsions as aluminum sources and their pertormances tor methanol synthesis from syngas have been investigated. The influences of preparation methods of aluminum emulsions on physicochemical and catalytic properties of catalysts were studied by XRD, SEM, XPS,N2 adsorption-desorption techniques and methanol synthesis from syngas. The preparation methods of aluminum emulsions were found to influence the catalytic activity, CuO crystallite size, surface area and Cu0 surface area and reduction process. The results show that the catalyst CN using the aluminum source prepared by addition the ammonia into the aluminum nitrate （NP） exhibited the best catalytic performance for methanol synthesis from syngas.

A highly hydrothermal stable copper-based catalyst for catalytic wet air oxidation of m-cresol in coal chemical wastewater

Catalytic wet air oxidation(CWAO) can degrade some refractory pollutants at a low cost to improve the biodegradability of wastewater. However, in the presence of high temperature and high pressure and strong oxidizing free radicals, the stability of catalysts is often insufficient, which has become a bottleneck in the application of CWAO. In this paper, a copper-based catalyst with excellent hydrothermal stability was designed and prepared. TiO_(2) with excellent stability was used as the carrier to ensure the longterm anchoring of copper and reduce the leaching of the catalyst. The one pot sol–gel method was used to ensure the super dispersion and uniform distribution of copper nanoparticles on the carrier, so as to ensure that more active centers could be retained in a longer period. Experiments show that the catalyst prepared by this method has good stability and catalytic activity, and the catalytic effect is not significantly reduced after 10 cycles of use. The oxidation degradation experiment of m-cresol with the strongest biological toxicity and the most difficult to degrade in coal chemical wastewater was carried out with this catalyst. The results showed that under the conditions of 140℃, 2 MPa and 2 h, m-cresol with a concentration of up to 1000 mg·L^(-1) could be completely degraded, and the COD removal rate could reach 79.15%. The biological toxicity of wastewater was significantly reduced. The development of the catalyst system has greatly improved the feasibility of CWAO in the treatment of refractory wastewater such as coal chemical wastewater.

Comprehensive first-principles studies on phase stability of copper-based halide perovskite derivatives A_lCu_mX_n(A = Rb and Cs;X = Cl, Br, and I)

Recently,inorganic copper-based halide perovskites and their derivatives(CHPs)with chemical formulas AlCumXn(A=Rb and Cs;X=Cl,Br and I;l,m,and n are integers.),have received increasing attention in the photoluminescence field,due to their lead-free,cost-effective,earth-abundant and low electronic dimensionality.Ascribed to flexible valence charge of Cu(Cu1+and Cu2+)and complex competing phases,the crystal structures and phase stabilities of CHPs are complicated and ambiguous,which limits their experimental applications.Via comprehensive first-principles calculations,we have investigated thermodynamic stabilities of possible crystal phases for AlCumXn by considering all the possible secondary phases existing in inorganic crystal structure database(ICSD).Our results are in agreement with existing experiments and further predicted the existence of 10 stable CHPs,i.e.Rb3 Cu2 Br5,Rb3 Cu2 I5,Rb Cu2 Cl3,Rb2 Cu I3,Rb2 Cu Br4,Rb Cu Br3,Rb3 Cu2 Br7,Cs3 Cu2 Br7,Cs3 Cu2 Cl7 and Cs4 Cu5 Cl9,which have not yet been reported in experiments.This work provides a phase and compositional map that may guide experiments to synthesize more novel inorganic CHPs with diverse properties for potential functional applications.

Study of Weak Acid Preservatives and Modified Atmosphere Packaging (MAP) on Mold Growth in Modal Agar System

Inhibition of spoilage mold of common contaminant of bakery goods in modal agar system by potassium sorbate and calcium propionate in wide range of concentration (0 - 2000 ppm) at different pH (5.5 - 7) was investigated. All Samples were examined daily for mold growth. Results showed that both potassium sorbate and calcium propionate can be used effectively to inhibit mold growth and the effectiveness of these preservatives is enhanced by increasing the concentration and decreasing the pH. The effect of modified atmosphere packaging (MAP) comprised of 60% or 80% CO2 (balance N2) and oxygen absorbents on the growth of mold was also studied on the agar system. The results indicated that mold growth was prevented up to 42 days in packs flushed with 60% or 80% CO2 (balance N2). It was also evident that all samples did not show mold growth for >40 days when packaged in the presence of oxygen scavenger sachet.

Migration of sulfur in in-situ gasification chemical looping combustion of Beisu coal with iron-and copper-based oxygen carriers

Chemical looping combustion(CLC)is an energy conversion technology with high efficiency and inherent separation of CO_(2).The existence of sulfur in coal may affect the CO_(2) purity and the performance of oxygen carrier due to the interactions between sulfur contaminants and oxygen carrier.The migration of sulfur in Beisu coal during the in-situ gasification chemical looping combustion(i G-CLC)process using two oxygen carriers(iron ore and Cu O/Si O_(2))was investigated respectively.The thermodynamic analysis results showed the formation of metal sulfides was thermodynamically favored at low temperatures and low oxygen excess coefficients,while they were obviously inhibited and the production of SO_(2) was significantly promoted with an increase in temperature and oxygen excess coefficient.Moreover,part of sulfur was captured and fixed in the forms of alkali/alkaline earth metal sulfate due to the high amount of alkali/alkaline earth metal oxides in the coal ash or/and oxygen carrier.The experimental results showed that the sulfur in coal mainly released in the form of SO_(2),and the sulfur conversion efficiency(XS)in the reduction stage were 51.04%and 48.24%when using iron ore and Cu O/Si O_(2) respectively.The existence of metal sulfides was observed in the reduced oxygen carriers.The values of XSin the reoxidation process reached 3.80%and 7.64%when using iron ore and Cu O/Si O_(2) respectively.The residue and accumulation of sulfur were also found on the surfaces of two oxygen carriers.

Effects of Copper-based Nutritional Foliar Fertilizers on Photosynthetic Characteristics,Yield and Disease Control Efficiency of Cotton

[Objectives] The effects of copper-based nutrient foliar fertilizer on photosynthetic characteristics,yield,accumulation and distribution of trace elements in various organs,disease prevention effect and soil enzyme activity were studied,so as to provide a theoretical basis for the application of foliar fertilizers in cotton production. [Methods]Through two years of field experiments,six treatments were set in total,namely spraying water( CK),traditional Bordeaux mixture( BDM),Kocide 2000( KCD),copper-based nutrient foliar fertilizer( CF),iron-copper-based nutrient foliar fertilizer( CFFe),and zinc-boron-copper-based nutrient foliar fertilizer( CFZnB). Randomized block arrangement was adopted. Chlorophyll content in leaves was measured at each growth stage of the cotton. Photosynthetic characteristics of leaves were measured at the peak bolling stage. Plants were sampled at initial boll opening stage. The whole plant was divided into root,stem,leaf and cotton boll parts,in which the total copper,total zinc,total iron contents and accumulations were determined. Soil samples were collected from each plot,followed by the determination of soil enzyme activity. Disease index was investigated at bud,flowering and boll-forming and boll opening stage. [Results]( 1) Spraying CFFe,CFZnB,CF and KCD could significantly improve chlorophyll content of cotton leaves,and the CFFe treatment had the highest increase up to13. 30%,followed by the CFZnB treatment,which was 11. 40% higher than the CK; and photosynthetic rate,stomata conductance and transpiration rate could be improved significantly,and the CFFe treatment showed the highest photosynthetic rate,which increased by 26. 35% compared with the CK,followed by the CFZnB treatment,which increased by 17. 96% compared with CK; and intercellular CO2 concentration was significantly reduced.( 2) Spraying BDM,KCD,CF,CFFe and CFZnB can significantly increase total copper content and accumulation in various cotton organs( except the total copper content in the stem part of the CFZnB treatment; the CFZnB and CFFe treatments can significantly increase total zinc content and accumulation in various cotton organs; and spraying CFFe,CFZnB and CF can significantly increase total iron content and accumulation in various cotton organs( except the total iron content in the stem part of the CF treatment).( 3)Spraying CFFe,CFZnB,CF,KCD and BDM greatly reduced the disease index at flowering and boll-forming and boll opening stages.( 4) The CFZnB and CFFe treatments had the highest soil urease activity,which was 7. 14% higher than that of the CK,but the difference from the CK was not significant; the catalase activity of each treatment was significantly higher than that of the BDM treatment; and the sucrase activity of each treatment was significantly higher than that of the CK.( 5) Spraying CFFe,CFZnB,CF and KCD significantly improved lint yield of cotton,and the CFZnB treatment showed the highest yield increase up to 12. 34%,followed by the CFFe treatment,with an increase in the range of 8. 77%-10. 20%. [Conclusions]Copper-based nutrient foliar fertilizers have dual functions of disease control and prevention and plant nutrition and health care,and not only can significantly increase cotton yield,but also has certain disease prevention effect.It is recommended to use copper-based nutrient foliar fertilizers.

EFFECT OF TIMBER DENSITY ON RETENTION OF WOOD PRESERVATIVES

The amount of CCA fixed in the southern pine treated with CCA have been eval-uated.The conclusions from these experiments are:with the timber density increases,the reten-tion based on weight/weight will decrease,but the retention based on weight/volume will bealmost constant.Retention by weight would be more influential than by volume.

Inhibition Effect of Herbal Preservatives on Listeria monocytogenes on Chilled Pork

This study investigated the growth situation of Listeria monocytogenes on chilled pork and the effect of herbal preservatives on this pathogen. The inhibitions of herbal preservatives were identified. The minimum inhibitory concentrations （MIC） of cinnamon and clove were all 0.79 mg.mL^-1, while the rosemary was 1.58 mg.mL^-1. And the composite herbal preservatives were got through orthogonal experiment. The optimum proportion was as following on agar medium： 1.16 mg.mL^-1 cinnamon＋2.38 mg. mL^-1 rosemary＋3.17 mg. mLl clove （herb combination number 5）, while on chilled pork, the strong inhibition of L. monocytogenes was showed, which demonstrated that the surface application of herb combination resulted in an effective delay of L. monocytogenes growth.

Tarnish Testing of Copper-Based Alloys Coated with SiO_2-Like Films by PECVD

The tarnishing test in the presence of hydrogen sulfide（H2S） vapors has been used to investigate the tarnish resistance capability of copper-based alloys coated with Si02-like films by means of plasma-enhanced chemical vapor deposition（PECVD） fed with a tetraethoxysilane/oxygen mixture.The chemical and morphological properties of the films have been characterized by using infrared absorption spectroscopy（IR） and scanning electron microscopy（SEM）with energy disperse spectroscopy（EDS）.The corrosion products of the samples after the tarnishing test have been identified by X-ray diffraction analysis（XRD）.It has been found that SiO2-like films formed via PECVD with a high O2 flow rate could protect copper-based alloys from H2S vapor tarnishing.The alloys coated at the O2 flow rate of 20 sccm remain uncorroded after 54days of H2S vapor tarnish testing.The corrosion products for the alloys deposited at a low O2flow rate after 54 days of tarnish testing are mainly composed of brochantite.

Tannin Resins for Wood Preservatives:A Review

Tannins and wood preservatives,in this article,are briefly introduced at beginning.The research and application progress on tannin resins for wood preservatives at home and abroad are reviewed.The significance and development prospects of research on tannins for wood preservatives are prospected.

Dynamic Kinetics of Methanol Synthesis over a Commercial Copper-Based Catalyst

Adsorption, surface reaction and process dynamics on the surface of a commercial copper-based catalyst for methanol synthesis from CO/CO2/H2 were systematically studied by means of temperature programmed desorption (TPD), temperature programmed surface reaction (TPSR), in-situ Fourier transform-inferred spec-troscopy(FTIR) and stimulus-response techniques. As a part of results, an elementary step sequence was suggested and a group of ordinary differential equations (ODEs) for describing transient conversations relevant to all species on the catalyst surface and in the gas phase in a micro-fixed-bed reactor was derived. The values of the parameters referred to dynamic kinetics were estimated by fitting the solution of the ODEs with the transient response data obtained by the stimulus-response technique with a FTIR analyzer as an on-line detector.

Effect of Sodium Chloride on Subsequent Survival of Staphylococcus aureus in Various Preservatives

Chemical preservatives in foods are nowadays added at lower concentrations. However, this may allow survival of bacterial cells and induce increased resistance to various preservatives. In this study, the effects of growth in NaCl (10% or 15%) on survival of Staphylococcus aureus strains in various chemical and physical preservatives were investigated. Growth of the strains for 20 h at 37°C in nutrient broth containing 10% NaCl enhanced survival in chemical preservatives (e.g. nutrient broth containing 20% NaCl, or 0.3% thyme extract, or 0.1% ascorbic acid). Growth at 37°C for 20 h in nutrient broth containing 15% NaCl or for 5 d in nutrient broth containing 10% NaCl greatly enhanced survival of the strains in the tested preservatives. For survival at low temperature (5°C) (physical preservative), cells grown at 37°C for 20 h in nutrient broth containing 10% NaCl were not more tolerant to low temperature. Growth of the strains at 37°C for 20 h in nutrient broth containing 15% NaCl or for 5 d in nutrient broth containing 10% NaCl only slightly increased the survival of cells at low temperature.