Strong public concern and increasingly strict legislations [1] have made it highly imperative to devise versatile materials that can efficiently eliminate a wide range of organic pollutants from indoor and outdoor emissions. These pollutants contribute to photochemical smog and ground-level ozone and have raised severe concern owing to probable short-and long-term adverse health effects.[2] Most airpurification systems are based on photocatalysts, adsorbents such as activated carbon, or ozone-promoted oxidation. [3] However, all the currently used materials have limited efficiency in removing several volatile organic compounds (VOCs) under ambient conditions. Herein, we report a novel mesoporous manganese oxide/nanogold catalyst for efficient elimination of VOCs. To the best of our knowledge, g-MnO 2 materials reported to date have surface areas of no higher than 130 m 2 g À1 . [4] In the present study, mesoporous g-MnO 2 with a very high surface area (> 300 m 2 g À1 ) was obtained for the first time through a surfactant-assisted wet-chemistry route. Au nanoparticles were deposited on this oxide by a vacuum ultraviolet radiation (VUV)-assisted laser ablation (VALA) method to induce lattice defects [5,6] and strong metal-support interactions.[7] The material reveals an exceptionally good ability to remove VOCs (as well as NO x and SO 2 ) at ambient temperature, and this efficiency increases with increasing temperature. The high activity of these materials could be correlated to their redox properties and to the facile formation of radical species on their surface.We recently reported that high-surface-area mesoporous metal oxide materials are capable of eliminating VOCs at ambient temperature. [8][9][10][11][12] With these promising results in hand, we investigated a range of metal oxides and noblemetal catalysts and found that mesoporous g-MnO 2 with a very high surface area and modified with gold nanoparticles can efficiently eliminate a wide range of VOCs under ambient dark conditions. We chose three different classes of VOCs, namely acetaldehyde, toluene, and n-hexane, which are major components of indoor as well as outdoor organic pollutants, to demonstrate the efficacy of our mesoporous g-MnO 2 /nanogold catalysts.The mesoporous g-MnO 2 material rapidly eliminated acetaldehyde, with complete removal achieved within 1 h at room temperature ( Figure 1 b; see also Figure S1 in the Supporting Information) and with 18 % CO 2 formation after 24 h reaction (Figure 1 a). The formation of CO 2 increased rapidly with a slight increase in the temperature and reached 94 % at 60 8C (Figure 1 a). This result indicates that the acetaldehyde is rapidly adsorbed onto the mesoporous gMnO 2 and gradually decomposes on its surface. The efficiency of acetaldehyde removal is about 2-3-times better than those of conventional materials used to remove VOCs (Figure 1 b).We studied acetaldehyde removal at different concentrations to evaluate the efficacy of these materials in comparison with traditional amelioration methods, such as u...

Mesoporous manganese oxide was prepared by using a straightforward, template-assisted method. The resulting material was crystalline and of uniform pore diameter. The material was characterized by HR-TEM, HR-SEM, XRD, XPS, and EXAF-XANES, and pore size distributions were calculated from nitrogen sorption studies. These materials with very high surface area of 316 m 2 /g have a novel hierarchical structure with spherical particles (<1 µm size), which are composed of γ-manganese oxide nanofibrous aggregates with intraparticle mesoporosity. The materials show an exceptionally high ability to eliminate volatile organic compounds (VOCs) at room temperature and the ability increases with increasing temperature. The results indicate that these materials are very promising for applications to emission control and to indoor air purification, as sorbents and catalysts. The materials show very high performance in room temperature removal of NO x and SO 2 even at low concentrations. The VOCs removal ability was further enhanced after Au deposition by a vacuum-assisted laser ablation (VALA) method. Detailed characterization reveals the role of lattice defects, strong metal-support and adsorbate-adsorbent interactions, along with readily available lattice oxygen for the elimination of VOCs.

Strong public concern and increasingly strict legislations [1] have made it highly imperative to devise versatile materials that can efficiently eliminate a wide range of organic pollutants from indoor and outdoor emissions. These pollutants contribute to photochemical smog and ground-level ozone and have raised severe concern owing to probable short-and long-term adverse health effects.[2] Most airpurification systems are based on photocatalysts, adsorbents such as activated carbon, or ozone-promoted oxidation. [3] However, all the currently used materials have limited efficiency in removing several volatile organic compounds (VOCs) under ambient conditions. Herein, we report a novel mesoporous manganese oxide/nanogold catalyst for efficient elimination of VOCs. To the best of our knowledge, g-MnO 2 materials reported to date have surface areas of no higher than 130 m 2 g À1 . [4] In the present study, mesoporous g-MnO 2 with a very high surface area (> 300 m 2 g À1 ) was obtained for the first time through a surfactant-assisted wet-chemistry route. Au nanoparticles were deposited on this oxide by a vacuum ultraviolet radiation (VUV)-assisted laser ablation (VALA) method to induce lattice defects [5,6] and strong metal-support interactions.[7] The material reveals an exceptionally good ability to remove VOCs (as well as NO x and SO 2 ) at ambient temperature, and this efficiency increases with increasing temperature. The high activity of these materials could be correlated to their redox properties and to the facile formation of radical species on their surface.We recently reported that high-surface-area mesoporous metal oxide materials are capable of eliminating VOCs at ambient temperature. [8][9][10][11][12] With these promising results in hand, we investigated a range of metal oxides and noblemetal catalysts and found that mesoporous g-MnO 2 with a very high surface area and modified with gold nanoparticles can efficiently eliminate a wide range of VOCs under ambient dark conditions. We chose three different classes of VOCs, namely acetaldehyde, toluene, and n-hexane, which are major components of indoor as well as outdoor organic pollutants, to demonstrate the efficacy of our mesoporous g-MnO 2 /nanogold catalysts.The mesoporous g-MnO 2 material rapidly eliminated acetaldehyde, with complete removal achieved within 1 h at room temperature ( Figure 1 b; see also Figure S1 in the Supporting Information) and with 18 % CO 2 formation after 24 h reaction (Figure 1 a). The formation of CO 2 increased rapidly with a slight increase in the temperature and reached 94 % at 60 8C (Figure 1 a). This result indicates that the acetaldehyde is rapidly adsorbed onto the mesoporous gMnO 2 and gradually decomposes on its surface. The efficiency of acetaldehyde removal is about 2-3-times better than those of conventional materials used to remove VOCs (Figure 1 b).We studied acetaldehyde removal at different concentrations to evaluate the efficacy of these materials in comparison with traditional amelioration methods, such as u...

SynopsisDual-in-line packages (DIPS) were formed from epoxy molding compounds with various physical properties using a transfer molding machine. The compounds were prepared by changing kinds and amounts of additives and addition methods. The thermal shock test was carried out by the following procedures. The plastic package was soaked alternately in liquid nitrogen (-196°C f and in liquid solder (250°C) in the cycle of 140 s. The packages were intermittently subjected to optical microscopic inspection for crack initiation. The median life to crack initiation is defined to be the number of the cycles when half of the specimens exhibited crack initiation. Glass transition temperature, coefficient of linear expansion, and flexural modulus were measured to calculate thermal stress in plastic packages. According to the linear fracture mechanics, the following expression was obtained among the median life N , thermal stress u t , and strength ub: N = C/o: * ( U , / U , )~. We found the linear relation between logarithm of Nu; and logarithm of u 6 / u , for various packages, and obtained that the value of C and rn are estimated as 3 X lo' MPa2 and 5.5, respectively. Therefore, the median life can be predicted from the glass transition temperature! coefficient of linear expansion, flexural modulus, and strength of plastic materials for packages.

ABSTRACT:Melting behavior under high pressure of nylon 6, nylon 6-clay hybrid (NCH) and poly(butylene terephthalate) was investigated by high-pressure differential thermal analysis (DTA). It was found that the melting temperature and the pressure dependency of the melting temperature of NCH were low compared with those of nylon 6. Using the melting temperature, the pressure dependency of the melting temperature, and the heat of fusion (the enthalpy of fusion), the Clausius-Clapeyron equation was used to determine the volume changes on melting of the polymers at atmospheric pressure ⌬V m0 (DTA). ⌬V m0 (DTA) of NCH was lower than that of the nylon 6 ␣-form. The smaller ⌬V m0 (DTA) of NCH was attributed to the presence of nylon 6 ␥-form in NCH. The values of ⌬V m0 (DTA) for nylon 6 and poly(butylene terephthalate) were similar to those obtained from pressure-volume-temperature relationships ⌬V m0 (PVT) of those polymers. The entropies of fusion were constant and independent of pressures up to 100 MPa. The volume changes on melting (⌬V m in cm 3 /g) under high pressure can be approximately described by the following equation: ⌬V m ϭ 0.165T m V w (dT m /dP)/ (dT m0 /dP)/298, where T m and T m0 are the melting temperatures (in K) under high pressure and atmospheric pressure, respectively and V w is the van der Waals volume of the polymer (cm 3 /g).

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