Mixture Of Sulfuric Acid Research Articles

A chamber study of the influence of boreal BVOC emissions and sulfuric acid on nanoparticle formation rates at ambient concentrations

Abstract. Aerosol formation from biogenic and anthropogenic precursor trace gases in continental background areas affects climate via altering the amount of available cloud condensation nuclei. Significant uncertainty still exists regarding the agents controlling the formation of aerosol nanoparticles. We have performed experiments in the Jülich plant–atmosphere simulation chamber with instrumentation for the detection of sulfuric acid and nanoparticles, and present the first simultaneous chamber observations of nanoparticles, sulfuric acid, and realistic levels and mixtures of biogenic volatile compounds (BVOCs). We present direct laboratory observations of nanoparticle formation from sulfuric acid and realistic BVOC precursor vapour mixtures performed at atmospherically relevant concentration levels. We directly measured particle formation rates separately from particle growth rates. From this, we established that in our experiments, the formation rate was proportional to the product of sulfuric acid and biogenic VOC emission strength. The formation rates were consistent with a mechanism in which nucleating BVOC oxidation products are rapidly formed and activate with sulfuric acid. The growth rate of nanoparticles immediately after birth was best correlated with estimated products resulting from BVOC ozonolysis.

Plasma Corrosion in Oxalic Acid Anodized Coatings Depending on Tartaric Acid Content

Study investigated the optimal anodizing conditions for fabricating an oxide film that produces less contamination in a corrosive plasma environment, using oxalic acid and tartaric acid. Oxide films were produced using sulfuric acid, oxalic acid, and tartaric acid electrolyte mixtures with various mole ratios. The oxide film made by adding 0.05M tartaric acid to 0.3M oxalic acid showed higher breakdown voltage and lower leakage current. Additionally, contamination particles were reduced during plasma etching, thus demonstrates that this mixture presented optimal conditions. However, higher tartaric acid content (0.1 M, 0.15 M) led to lower breakdown voltages and higher leakage currents. Also, it resulted in more cracking during thermal shock tests as well as the generation of more contamination particles during plasma processing.

Decapsulation of Plastic Encapsulated Microelectronics with Copper Wire Bonds

Abstract A novel method for copper wire bond decapsulation was developed, which involves conducting a sequential process to ensure minimal corrosion or, in some cases, no corrosion/degradation of the copper wire. It requires a pre-treatment which involves mechanical milling or acid etching; the main decapsulation process, utilizing a mixture of nitric and sulfuric acid under electrically biased conditions; and a post decapsulation procedure of encapsulant debris removal using a solvent. Previous studies use decapsulation methods that reveal either the ball bond or the wedge bond, separately, and thus cannot be used to perform wire pull tests. Exposing both the ball and wedge bond is not trivial, as the wire tends to break at the loop due to the long exposure time. The three-step process, when properly executed, ensures that the entire wire along with both ball and wedge bonds are exposed with minimal damage. Five parameters were found to affect the decapsulation process. These are as follows: acid ratio, biasing voltage, time of exposure, temperature and mold compound type. Careful control of these parameters can result in little to no copper wire degradation.

モジホコリを利用した細胞内ATP濃度を指標とする環境汚染度分析手法の開発

This paper was to consider methods to sensitively detect the effects of environmental pollution. A variety of environmental pollution exists in Japan and abroad, and biomonitoring with organisms is the main way levels of pollution in environmental specimens are determined. This paper considered changes in pH due to industrial effluent, sodium sulfite, and NaCl as factors for pollution. Physarum polycephalum is a protist that is sensitive to environmental pollution. This paper examined the effects of pollution on ATP levels in P. polycephalum and this paper explored the potential for these effects to serve as an index of environmental pollution. Results indicated that ATP levels were lowered by (1) a rise in the pH of a mixture of sulfuric acid and nitric acid, (2) increased levels of sodium sulfite, and (3) increased levels of sodium chloride. In addition, ATP levels and factors for environmental pollution were also examined. Results revealed the tolerance limits of P. polycephalum to pollutants. Thus, results revealed that ATP levels decrease as a result of environmental pollution. Results also suggested that ATP levels cannot be used as a pollution index since ATP levels cannot sensitively detect the effects of environmental pollution.

Micro fabrication of aluminum oxide patterns using local anodization

In this study, a novel process for fabricating micro Al2O3 patterns using local anodization is proposed. On the basis of double layer theory, the anodizing region was localized on an aluminum surface near a micro tool electrode with a small inter-electrode gap. The localized oxide formation process was observed by field emission scanning electron microscope (FE-SEM) including energy dispersive spectroscopy (EDS). It was confirmed that micro-scale localized aluminum oxide was fabricated on the aluminum surface. Features of the anodized oxide line were investigated using different ratios of sulfuric and oxalic acid mixtures at various pulse durations and voltage conditions. The experimental results show that an insulating aluminum oxide line pattern was fabricated on 10 µm aluminum foil. Subsequently, a coplanar waveguide (CPW) micro patch antenna was fabricated and characterized by a PNA network analyzer. The local anodization can be used for fabricating micro-electric circuits without masks and substrate; which will promise the next generation of micro electronic devices.

Comparison of effectiveness of citric acid and other acids in leaching of low-grade Indonesian saprolitic ores

Comparison effect of chemical citric acid and other leaching reagents including inorganic acid and other organic acid on nickel extraction from low-grade Indonesian saprolitic ores was evaluated. Two saprolitic ores from two different mining areas (Sulawesi Island and Halmahera Island) in Indonesia were used to investigate the leaching performance and mineral dissolution behaviors of different ore samples using different leaching reagents. Leaching was performed using citric, sulfuric, nitric, hydrochloric, lactic, and oxalic acids. The saprolitic ore from Sulawesi Island (SS) has higher serpentine and lower goethite contents than the saprolitic ore from Halmahera Island (SH). These differences significantly affect the leaching performances and metal dissolution behaviors. Citric acid and sulfuric acid were more effective than other acid solutions for nickel extraction from both samples. Citric acid was very effective for dissolving nickel from serpentine, but did not recover nickel from goethite. In contrast, inorganic acids, namely sulfuric, nitric, and hydrochloric acids, can extract nickel from lateritic ores by dissolving goethite as well as serpentine, but the nickel recoveries achieved with sulfuric acid were higher than those achieved with other inorganic acids. A comparison of the leaching performances of the two samples shows that nickel recovery from SS was higher than that from SH when citric acid leaching was used, but the samples gave similar nickel recoveries in all inorganic acid and lactic acid leaching processes. Moreover, oxalic acid is the least effective reagent for nickel extraction from both samples, because of nickel oxalate precipitation after nickel dissolution. In addition, the effect of a sulfuric acid–citric acid mixture on the nickel dissolution rate was investigated to confirm the individual influences of citric acid and sulfuric acid on the leaching behavior of each sample. The results show that an increase in the amount of sulfuric acid affected the dissolution rate of nickel in leaching of SH much more than that in leaching of SS. In general, the effect of citric acid in the mixture of sulfuric acid and citric acid is attractive. Moreover, citric acid offers not only high nickel recovery and high selectivity of leaching but also an environmentally safe process and low acid consumption.

Fully Converting Graphite into Graphene Oxide Hydrogels by Preoxidation with Impure Manganese Dioxide.

Potassium permanganate (KMnO4) has been proved to be an efficient oxidant for converting graphite into graphite oxide, but its slow diffusion in the interlayer of graphite seriously restricts the production of graphene oxide (GO). Here, we demonstrate that the preoxidation of graphite by impure manganese dioxide (MnO2) in a mixture of concentrated sulfuric acid (H2SO4) and phosphorus pentoxide (P2O5) can efficiently improve the synthesis of GO when KMnO4 is employed as the oxidant. The prepared honey-like GO hydrogels possess a high yield of single-layer sheets, large sizes (average lateral size up to 20 μm), wide ranges of stable dispersion concentrations (from dilute solutions, viscous hydrogels, to dry films), and good conductivity after reduction (~2.9 × 10(4) S/m). The mechanism for the improved synthesis of GO by impure MnO2 was explored. The enhanced exfoliation and oxidation of graphite by oxidative Mn ions (mainly Mn(3+)), which are synergistically produced by the reaction of impure MnO2 with H2SO4 and P2O5, are found to be responsible for the improved synthesis of such GO hydrogels. Particularly, preoxidized graphite (POG) can be partially dispersed in water with sonication, which allows the facile construction of flexible and highly conductive graphene nanosheet film electrodes with excellent electrochemical sensing properties.

Strong Acid-Nonionic Surfactant Lyotropic Liquid-Crystalline Mesophases as Media for the Synthesis of Carbon Quantum Dots and Highly Proton Conducting Mesostructured Silica Thin Films and Monoliths.

Lyotropic liquid-crystalline (LLC) materials are important in designing porous materials, and acids are as important in chemical synthesis. Combining these two important concepts will be highly beneficial to chemistry and material science. In this work, we show that a strong acid can be used as a solvent for the assembly of nonionic surfactants into various mesophases. Sulfuric acid (SA), 10-lauryl ether (C12E10), and a small amount of water form bicontinuous cubic (V1), 2D-hexagonal (H1), and micelle cubic (I1) mesophases with increasing SA/C12E10 mole ratio. A mixture of SA and C12E10 is fluidic but transforms to a highly ordered LLC mesophase by absorbing ambient water. The LLC mesophase displays high proton conductivity (1.5 to 19.0 mS/cm at room temperature) that increases with an increasing SA content up to 11 SA/C12E10 mole ratio, where the absorbed water is constant with respect to the SA amount but gradually increases from a 2.3 to 4.3 H2O/C12E10 mole ratio with increasing SA/C12E10 from 2 to 11, respectively. The mixture of SA and C12E10 slowly undergoes carbonization to produce carbon quantum dots (c-dots). The carbonization process can be controlled by simply controlling the water content of the media, and it can be almost halted by leaving the samples under ambient conditions, where the mixture slowly absorbs water to form photoluminescent c-dot-embedded mesophases. Over time the c-dots grow in size and increase in number, and the photoluminescence frequency gradually shifts to a lower frequency. The SA/C12E10 mesophase can also be used as a template to produce highly proton conducting mesostructured silica films and monoliths, as high as 19.3 mS/cm under ambient conditions. Aging the silica samples enhances the conductivity that can be even larger than for the LLC mesophase with the same amount of SA. The presence of silica has a positive effect on the proton conductivity of SA/C12E10 systems.

Liquid – liquid equilibria of quaternary system phosphoric acid/sulfuric acid/water/tri-n-butyl phosphate and the formation of extraction complex at 303.2 K

Nowadays, with the increasing scarcity of phosphate ore, many researchers are focused on the purification of wet – process phosphoric acid, which is leaching with strong acids. It produces mixtures of phosphoric acid and sulfuric acid (or nitric acid, or hydrochloric acid), which requires a separation process of mixed acids. This paper conducts an experiment about liquid – liquid equilibrium data of quaternary system H3PO4 – H2SO4 – H2O – TBP (tri – n – butyl phosphate). It determines mass percents of phosphoric acid in the two equilibria phases, and analyzes density, viscosity of two equilibrium phases. Equilibria data obtained are correlated by the Hand equation, Othmer – Tobias equation and Bachman equation, which all show good linear fitting. In addition, the formations of extraction complexes are analyzed with Pitzer's model and Sergievskii-Dannus's model, which calculates the thermodynamic equilibrium constant of extraction process.

Effect of the p-tert-butylcalix[6]arene modifier on the electrochemical properties of the modified carbon paste electrode

The electrochemical properties of partially blocked electrodes obtained by mixing p-tert-butylcalix[6]arene with the paste of carbon-paste electrodes were studied. The differential capacitance, surface charge, and background current on the modified electrodes decreased relative to the same characteristics on the unmodified electrode for all supporting electrolytes under study (sodium chloride, sodium sulfate, hydrochloric acid, sulfuric acid, phosphoric acid, and phosphate buffer mixtures). The effect of p-tert-butylcalix[6]arene on Faraday currents was studied in the case of the anodic oxidation of vinpocetine and sodium ethylenediaminetetraacetate (EDTA). The signal to background ratio increased on the modified electrodes. At 3 wt % modifier, the signal-to-background ratio for the modified electrode was 2.8- and 3.3-fold higher for vinpocetine and sodium EDTA, respectively.

Dissolution of Germanium in Sulfuric Acid Based Solutions

Introduction The usage of germanium has recently been considered for the MOSFET channel in order to improve the performance of the integrated semiconductor devices. Since Ge is oxidized easily and dissolves in to the wet solution, much attention is required for wet cleaning process with minimal dissolution of Ge. The present study covers the mechanism of Ge dissolution in sulfuric acid based solution in view of different application as the selective NiPt-etch during germanidation and the IIPR strip from Ge. Experiments 80nm Ge layers were epitaxially grown on 300mm Si wafers. These wafers were cut into coupons for following tests to determine the Ge loss in sulfuric acid based solutions. All tests were performed in a beaker at 30 degrees C and the amount of each solution was 50ml. (1) Dissolution phenomenon Coupons were immersed in the sulfuric acid based solutions, 30 to 98 wt% sulfuric acid with and without 5g/L of an oxidizer. The oxidizer used in the study is peroxosulfuric acid generated by Electrolyzing Sulfuric Acid, and is referred hereinafter to ESA. The dissolution of the Ge in the sulfuric acid solution was assessed by ICP-MS (Inductively Coupled Plasma-Mass Spectrometry), and it allowed us to calculate the dissolved volume and dissolution rate. (2) Dissolution mechanism In order to study the dissolution mechanism in the sulfuric acid based solutions, the surface of the coupon was examined with XPS (X-ray Photoelectron Spectroscopy) before and after immersion to 30wt% sulfuric acid solution and 2wt% hydrogen peroxide solution. The solutions were subjected to ICP-MS after immersion and the results were compared with the XPS data. Results and discussion (1) Dissolution phenomenon Figure 1 shows the dissolution rate of Ge after immersing the different coupons in the sulfuric acid based solutions, 30 to 98 wt% sulfuric acid with and without 5g/L of an oxidizer. When no oxidizer is added, the Ge dissolution rate is less than 1nm/min regardless of sulfuric acid concentration. However, it can be observed that Ge dissolved in an inverse proportion to the sulfuric acid concentration when the oxidizer is existed in the solution. (2) Dissolution mechanism Results of XPS analysis conducted on the original surface before immersion as shown in Figure 2. Peaks for Ge, GeO and GeO2 are apparent. When the coupons were immersed in the sulfuric acid, the XPS determinate that no GeO2 is present and only Ge and GeO are remained. When immersed in the hydrogen peroxide solution, both Ge and GeO peaks are detected but GeO peak is much weaker than that with sulfuric acid. No GeO2 is present in either condition. Additionally, a significant increase in dissolution is observed when the Ge coupon was immersed in hydrogen peroxide solution. These results indicate that GeO2dissolves readily in all solutions tested, and that GeO does not serve as a strong passive film during dissolution, and that active dissolution of Ge requires both water and oxidizer. Proposed dissolution reaction is: GeO2 + H2O → HGeO3 -+ H+ GeO + 2H2O → HGeO3 -+ 3H+ + 2e- Ge + H2O → GeO + 2H++ 2e- Considering the peaks of the original surface and the effect of UPW and sulfuric acid above mentioned, the foremost surface is GeO2as shown in Figure 3. Conclusion Conclusions drawn from the present study are as follows; 1) Dissolution of Ge is inversely proportional to sulfuric acid concentration only when an oxidizer is present in its solution. 2) The surface of Ge consists of three layers, i.e. GeO2, GeO and and Ge with the foremost layer being GeO2. 3) Only GeO2 dissolves in solutions without oxidizer, but Ge readily dissolves only when it is present in the solution. The ultimate goal of the present study is to enable either the selective etch of the both NiPt-etch during germanidation or strip IIPR from Ge without germanide or Ge dissolution. When Ge is treated with sulfuric acid including an oxidizer, as shown Figure 1, the higher sulfuric acid concentration is, the less Ge dissolution rate is. This result indicates that it is important to keep sulfuric acid concentration as high as possible when sulfuric acid with oxidizer is applied for Ge wet cleaning process. SPM is difficult to apply for Ge wet cleaning process because it is a mixture of sulfuric acid and 30wt.% hydrogen peroxide in order to generate oxidizer. Since the water from 30wt.% hydrogen peroxide results the sulfuric acid concentration of SPM lower, SPM dissolves Ge easily. Figure 1

Analysis of pre-ignited improvised incendiary devices using portable Raman

In this work, the use of a portable Raman spectrometer is evaluated for the non-invasive analysis of two types of pre-ignited improvised incendiary devices (IIDs), the classic Molotov cocktails and the chemical ignition Molotov cocktails (CIMCs). The most common ignitable liquids (ILs) used to make classic Molotov cocktails (gasoline, diesel fuel, kerosene and ethanol) were measured in seven different clear and colored glass bottles to evaluate if the container features could hamper the Raman measurements. The results showed that the portable Raman spectrometer can be employed to detect ILs in glass bottles without disturbances. Chemical changes on the ILs are produced when they are mixed with acid; therefore, to evaluate the use of the portable Raman spectrometer for the analysis of CIMCs required an investigation of how time and movement influence the measurements. Thus, two different IL–sulfuric acid mixtures commonly used to make CIMCs (gasoline–sulfuric acid and diesel fuel–sulfuric acid) were measured over time under static and motion conditions. In spite of the intense fluorescence encountered in both CIMCs, it was possible to identify the acid and the gasoline for the first hours of the reaction both in the static and motion experiments. Concerning the diesel fuel present in the CIMC, it underwent instantaneous chemical changes under both measurement conditions, showing high fluorescence that impeded its identification. In view of the results achieved, the portable Raman spectrometer can be a useful instrument for the rapid, non-invasive and safe analysis of pre-ignited IIDs.

Surface Treatment And Modification Of Graphene Using Organosilane And Its Thermal Stability

Abstract In this study, graphene was functionalized via acid oxidation in the presence of a mixture of concentrated sulfuric acid and nitric acid. The oxidized graphene was silanized using the coupling agent, 3-aminopropyltriethoxsilane, resulting in functionalized graphene. The oxidized graphene and functionalized graphene were characterized by X-Ray diffraction, Fourier transform infrared spectroscopy, High-resolution micro Raman spectroscopy, thermogravimetric analysis, and atomic force microscopy to confirm the presence of functional moieties on the graphene surface. Thermal studies also demonstrate that the functionalized material is thermally stable up to higher temperatures.

Environmentally Benign Electrofinishing Process for Selective Material Removal and Reduced Surface Roughness of Materials (like Nb, Ti, Ta, SS and Mo) in Low Viscosity Water Based Electrolytes

Post finishing processes are used to within every material manufacturing process. Various techniques are used to remove burrs, radius edges, and polish to a desired surface finish. These techniques improve the overall performance of the material for its application and generally improve the overall appearance of the material. This paper will discuss a range of applications and materials in which a pulse reverse electrochemical approach, in water based HF-free electrolytes, has been used to obtain these desired finish properties. A specific application of interest that requires a high quality surface finish to obtain the desired performance is the Niobium superconducting radio frequency cavities (SRF) required for the International Linear Collider and other high energy physics projects. In order for these cavities to achieve the required particle acceleration gradients, electropolishing is conducted as a final surface finishing operation. Conventional electropolishing of SRF cavities is based on the well-established viscous salt film theory[1] and utilizes a viscous electrolyte consisting of a mixture of sulfuric acid (95-98%) and hydrofluoric acid (49%), in a 9:1 volume ratio.[2] The HF is included to depassivate the niobium oxide film during electropolishing.[3]Based on prior surface finishing activities using pulse reverse waveforms in low viscosity aqueous electrolytes,[4] we speculated that a new paradigm was evolving and could be applied to electropolishing of SRF cavities. Within this activity Faraday used guidelines and observations from 1”x1” (6.4 cm2) and 3”x3” (58.1 cm2) coupons to scale the bipolar EP process to single cell SRF cavities of ~1,800 cm2 surface area. We recently reported these results at the 16th International Conference on RF Superconductivity in collaboration with Fermi National Accelerator Laboratory (FNAL) who declared that this cavity demonstrated the highest performance of any cavity previously processed at FNAL. This presentation will focus pulse/pulse reverse electrofinishing processes being developed by Faraday Technology. It will explore various strongly passive materials and their applications specific surface finishing requirements. These materials include but are not limited to titanium alloys, tantalum alloys, nickel alloys, stainless steels, niobium, and molybdenum alloys.

Water Activities and Osmotic Coefficients of Aqueous Solutions of Five Alkylaminium Sulfates and Their Mixtures with H2SO4at 25oC

Alkylaminium sulfates are frequently detected in ambient aerosols, and are believed to be important in the nucleation of new particles in the atmosphere, despite the comparatively low gas phase concentrations of amines. In this study, water activities and osmotic coefficients have been measured, using a chilled mirror dew point technique, of aqueous mixtures of sulfuric acid and the following alkylaminium sulfates: methylaminium, ethylaminium, dimethylaminium, diethylaminium, and trimethylaminium sulf-ate. The samples were prepared by mixing solutions of the five corresponding amines and aqueous sulfuric acid and determining the exact aminium to sulfate molar ratios by ion chromatography. The results were correlated using an extended Zdanovskii–Stokes–Robinson equation to enable concentration/water activity rela-tionships to be calculated over the entire composition range from pure aqueous sulfuric acid to pure aqueous aminium sulfate. Water activities and osmotic coefficients for aminium:sulfate ratios o...

Green preparation of reduced graphene oxide using a natural reducing agent

A simple and efficient method was introduced for the high-conversion preparation of graphene oxide (GO) from large graphite flakes (average flake size=100μm) using a simplified Hummer׳s method. Natural reducing agents such as lemon juice and vinegar were compared with hydrazine (N2H4) as potential reducing agents. Graphene was prepared by chemical reduction of GO because this method was low cost and could be used for large-scale graphene production. This one-pot graphene preparation was performed at room temperature. Different degrees of oxidation of graphite flakes were obtained by stirring graphite in a mixture of sulfuric acid and potassium permanganate at different oxidation times, and highly exfoliated GO sheets were produced. GO was subsequently reduced effectively by lemon juice, a new, green, and potential reducing agent with pH 2.3. This reduced GO exhibited a high electrical conductance of 24.6μS attributed to its higher C/O ratio (≈8:2) compared with other samples.

Atmospheric oxidation of isoprene and 1,3-butadiene: influence of aerosol acidity and relative humidity on secondary organic aerosol

Abstract. The effects of acidic seed aerosols on the formation of secondary organic aerosol (SOA) have been examined in a number of previous studies, several of which have observed strong linear correlations between the aerosol acidity (measured as nmol H+ m−3 air sample volume) and the percent change in secondary organic carbon (SOC). The measurements have used several precursor compounds representative of different classes of biogenic hydrocarbons including isoprene, monoterpenes, and sesquiterpenes. To date, isoprene has displayed the most pronounced increase in SOC, although few measurements have been conducted with anthropogenic hydrocarbons. In the present study, we examine several aspects of the effect of aerosol acidity on the secondary organic carbon formation from the photooxidation of 1,3-butadiene, and extend the previous analysis of isoprene. The photooxidation products measured in the absence and presence of acidic sulfate aerosols were generated either through photochemical oxidation of SO2 or by nebulizing mixtures of ammonium sulfate and sulfuric acid into a 14.5 m3 smog chamber system. The results showed that, like isoprene and β-caryophyllene, 1,3-butadiene SOC yields linearly correlate with increasing acidic sulfate aerosol. The observed acid sensitivity of 0.11% SOC increase per nmol m−3 increase in H+ was approximately a factor of 3 less than that measured for isoprene. The results also showed that the aerosol yield decreased with increasing humidity for both isoprene and 1,3-butadiene, although to different degrees. Increasing the absolute humidity from 2 to 12 g m−3 reduced the 1,3-butadiene yield by 45% and the isoprene yield by 85%.

실란화 반응으로 표면 개질된 다중벽 탄소나노튜브(MWCNTs)와 Methyl Methacrylate의 유화중합을 통한 MWCNTs/Poly(methyl methacrylate) 복합 입자 제조 및 그 형태학적 특성

본 연구에서는 다중벽 탄소나노튜브(MWCNTs)를 질산과 황산의 혼산으로 산화시켜 표면에 카르복시기를 도입 후, <TEX>$SOCl_2$</TEX>와 1,4-butanediol을 사용하여 MWCNT-OH를 제조하였다. 제조된 MWCNT-OH는 3-methacryloxypropyltrimethoxylsilane(MPTMS)와 실란화 반응으로 methacrylate기가 도입된 MWCNT-MPTMS를 제조하였다. MWCNT-MPTMS와 methyl methacrylate(MMA)를 사용하여 유화중합법으로 MWCNT-MPTMS/PMMA 복합 입자를 제조하였다. 음이온 계면 활성제인 sodium dodecylbenzene sulfonate(SDBS)를 사용하여 유화중합한 MWCNT-MPTMS/PMMA는 균일한 입도, 좁은 입도분포 및 계면에서의 화학결합으로 인하여 <TEX>$T_g$</TEX>가 순수 MWCNT를 사용하여 중합한 시료보다 <TEX>$3.4^{\circ}C$</TEX> 높아짐을 확인하였다. In this study, multi-walled carbon nanotubes (MWCNTs) were oxidized with a mixture of nitric acid and sulfuric acid. After oxidation, oxidized MWCNTs were treated with thionyl chloride (<TEX>$SOCl_2$</TEX>) and 1,4-butanediol (BD) in sequence at room temperature to introduce hydroxyl groups on the surface of MWCNTs. The prepared MWCNT-OH was silanized with 3-methacryloxypropyltrimethoxylsilane (MPTMS) to make MWCNT-MPTMS. The MWCNT-MPTMS was used as fillers in emulsion polymerization to make MWCNT-MPTMS/PMMA composite particles with 3 kinds of emulsifiers, hexadecyltrimethylammoniumbromide (CTAB) as a cationic, sodium dodecylbenzene sulfonate (SDBS) as an anionic and polyethylene glycol tert-octylphenyl ether (Triton X-114) as a nonionic emulsifier. Morphologies of composite emulsions were confirmed by a particle size analyzer (PSA) and a scanning electron microscope (SEM). Morphologies of emulsion polymerized MWCNT-MPTMS/PMMA with SDBS showed more uniform particle size distribution compared to those of other two emulsifiers used emulsions. MWCNT-MPTMS/PMMA showed <TEX>$3.4^{\circ}C$</TEX> higher <TEX>$T_g$</TEX> compared to pristine MWCNT/PMMA due to covalent bond formation at interface of MWCNT-MPTMS and PMMA.

Microscopic residues of bone from dissolving human remains in acids.

Dissolving bodies is a current method of disposing of human remains and has been practiced throughout the years. During the last decade in the Netherlands, two cases have emerged in which human remains were treated with acid. In the first case, the remains of a cremated body were treated with hydrofluoric acid. In the second case, two complete bodies were dissolved in a mixture of hydrochloric and sulfuric acid. In both cases, a great variety of evidence was collected at the scene of crime, part of which was embedded in resin, polished, and investigated using SEM/EDX. Apart from macroscopic findings like residual bone and artificial teeth, in both cases, distinct microscopic residues of bone were found as follows: (partly) digested bone, thin-walled structures, and recrystallized calcium phosphate. Although some may believe it is possible to dissolve a body in acid completely, at least some of these microscopic residues will always be found.

Sol-gel synthesis and leaching of potassium hollandites

The results of a physicochemical study of hollandite-type minerals synthesized by the citrate-nitrate sol-gel method in the K2O-M2O3-TiO2 systems (M = Ga, Fe, Cr) and subjected to leaching in a mixture of hydrogen peroxide and sulfuric acid are reported. The materials thus prepared are stable up to 400°C and decompose above this temperature. The experiments performed confirm a decrease in the potassium content of these triple oxides upon such chemical treatment by 26–36% of the initial level, which makes these oxides promising for use as electrode materials for lithium-ion batteries.