太阳能电池生产线中新型等离子体刻蚀机刻蚀工艺探讨

介绍了一种新型等离子体刻蚀机的使用条件,通过对各种参数变化的组合实验,得到了最佳工艺数据.利用该刻蚀机生产的电池片刻蚀效果好,刻蚀后经检测,电池片漏电流小,并联电阻大,提高了电池片的综合性能指标.     

Synthesis,characterization of β-CD based novel hydrogels with dual objectives of drug release and dye removal

Iranian Polymer Journal - In our recent work, we have reported on hydrogels devoid of cross-linkers. After observing the successful swelling and water retention properties, we have introduced...     

Difference expansion based reversible data embedding and edge detection

Multimedia Tools and Applications - Difference Expansion (DE) based techniques are evolving in the last decade. The DE based techniques aims at reversibly embedding the data into cover content....     

Heavy metal accumulation in vegetables irrigated with water from different sources

The present study was carried out to assess levels of different heavy metals like iron, manganese, copper and zinc, in vegetables irrigated with water from different sources. The results indicated a substantial build-up of heavy metals in vegetables irrigated with wastewater. The range of various metals in wastewater-irrigated plants was 116–378, 12–69, 5.2–16.8 and 22–46 mg/kg for iron (Fe), manganese (Mn), copper (Cu) and zinc (Zn), respectively. The highest mean levels of Fe and Mn were detected in mint and spinach, whereas the levels of Cu and Zn were highest in carrot. The present study highlights that both adults and children consuming vegetables grown in wastewater-irrigated soils ingest significant amount of these metals. However, the values of these metals were below the recommended maximum tolerable levels proposed by the [Joint FAO/WHO Expert Committee on Food Additives (1999). Summary and conclusions. In 53rd Meeting, Rome, June 1–10, 1999]. However, the regular monitoring of levels of these metals from effluents and sewage, in vegetables and in other food materials is essential to prevent excessive build-up of these metals in the food chain.     

A new characteristic of liquid-liquid systems—inversion holdup of intensely agitated dispersions

As the holdup of dispersed phase in an agitated liquid-liquid dispersion is increased at fixed agitation, a point is reached (called inversion holdup) when the dispersion inverts—the dispersed phase becomes continuous and vice versa. In this work, we present experimental data which suggest that the inversion holdup for sufficiently intense turbulence is independent of all the operational parameters associated with a stirred tank, e.g., stirrer speed, vessel volume, impeller size, and impeller type; it depends only on the properties of the liquid-liquid system. The inversion holdup was verified to remain unchanged even for inversion in turbulent flow field in the annular space between two coaxial cylinders. A hypothesis involving drops in near contact with each other at high holdups is used to explain the experimental data. The new finding may also provide a qualitative basis for selecting a liquid-liquid system with desired extent of mixing in the dispersed phase for carrying out transport and reactions in multiphase systems.     

Phase behavior,density, and crystallization of polyethylene in n‐pentane and in n‐pentane/CO2 at high pressures

The phase behavior and volumetric properties of polyethylene (PE) in solutions of n‐pentane and n‐pentane/CO₂ were studied in a temperature (T) range of 370–440 K at pressures up to 60 MPa. Measurements were conducted with a variable‐volume view‐cell system equipped with optical sensors to monitor the changes in the transmitted light intensity as the P or the T of the system was changed. Lower‐critical‐solution‐temperature‐type behavior was observed for all of the liquid–liquid (L–L) phase boundaries, which shifted to higher pressures in solutions containing CO₂. The solid–fluid (S–F) phase boundaries were investigated over a P range of 8–54 MPa and took place in a narrow T range, from 374 to 378 K in this P interval. The S–F phase boundary showed a unique feature in that the demixing temperatures showed both increasing and decreasing trends with P depending on the P range. This was observed in both the PE/n‐pentane and PE/n‐pentane/CO₂ mixtures. The density of these solutions were measured as a function of P at selected temperatures or as a function of T at selected pressures that corresponded to the paths followed in approaching the phase boundaries (S–F or L–L) starting from a homogeneous one‐phase condition. The data showed a smooth variation of the overall mixture density along these paths. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2201–2209, 2003     

Investigation of the effect of functionalized carbon nanotube and graphene oxide in guar gum-based mixed matrix membrane for gas separation application

The present study deals with preparing mixed matrix membranes (MMMs), a new polysaccharide-based natural polymer used as a matrix with functionalized carbon nanotubes (FCNTs) and graphene oxide (GO) used as an inorganic filler. This work identified the effect of the inorganic fillers (FCNTs or GO) with naturally occurring polymer for gas separation. The incorporation of fillers improves the gas separation performance of MMMs. In GG/FCNTs MMMs, the selectivities of CO₂/N₂ and CO₂/H₂ were enhanced by 55.24% and 57.89%, respectively. Moreover, in GG/GO MMMs, the selectivities of CO₂/N₂ and CO₂/H₂ were improved by 99.50% and 50%, respectively. The membrane was characterized by scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). The SEM analysis of GG/GO MMMs reveals layered structure, and GG/FCNTs MMMs create passages to transport gases. The Universal testing machine (UTM) is used to analyze the mechanical properties of pristine and modified membranes.     

Investigations on physical,mechanical, morphological and water absorption properties of ramie/hemp/kevlar reinforced vinyl ester hybrid composites

Structural uses in the vehicle, aerospace, and sporting goods industries are being supplanted by hybrid composites that utilized natural fibers as reinforcements. The main focus of this work is to fabricate and characterize the ramie, hemp, and kevlar fabric reinforced hybrid vinyl ester composites. The composite laminates were fabricated via economically feasible and flexible hand lay-up technique. Overall six composites were prepared by varying the stacking sequence, including both hybrid and non-hybrid composites. The prepared composites were subjected to physical analysis (density, void fraction), mechanical tests (tensile, flexural, interlaminar shear, and impact test), morphological analysis (scanning electron microscopy), and water absorption test. The hybrid composites exhibited lesser void percentage than the non-hybrid composites. The mechanical properties were maximum for kevlar fabric skinned with core natural fabric reinforced composites (L-5, L-6) due to hybridization of highly strengthened kevlar fabrics. Moreover, the number fabric layers reinforced to achieve the standard thickness also affected the mechanical properties. All composite morphologies exhibited the same failure characteristics, including transverse interlaminar shear cracking, microbuckling, and fiber rip. The texture of the Kevlar yarns is uniform, but the texture of the natural fabric yarns is relatively less uniform. In comparison to the salt water medium, the percentage of water absorbed by composites in normal and distilled water was greater. This is due to the presence and accumulation of salt particles on the surface of the materials, which inhibits the action of water molecules, resulting in a drop in the proportion.     

Performance of clay masonry prisms with light weight plaster exposed to standard fire exposure

Clay bricks are one of the most widely used materials in building construction due to their advantages, including local availability, ease of fabrication and cost-effectiveness. Fire is one of the dangerous hazards that can cause damage the life and property. Lightweight plasters play a vital role in insulating the masonry construction during fire accident. There is only limited data and information available on the fire performance of Clay Brick Masonry (CBM) insulated with lightweight plaster. An extensive investigation was undertaken to evaluate the residual strength properties and physical characteristics of CBM prisms exposed to elevated temperatures. CBM prisms plastered with M-sand mortar, vermiculite mortar, and perlite mortar were used for the investigation. Protected prisms were exposed to elevated temperatures following the ISO 834 standard fire curve for durations of 30 min (821°C), 60 min (925°C), 90 min (986°C), and 120 min (1029°C). Mechanical properties such as axial load carrying capacity, stress–strain behaviour, elastic modulus, and crack pattern were examined. The mechanical properties of CBM prisms were found to be highly influenced by the type of plastering, intensity, and the duration of heating. The microstructure and image analysis confirmed the effects of temperature exposure on protective plasters. Equations are proposed to determine the residual axial compressive strength and the elastic modulus of CBM. It was found that the specimens plastered with perlite mortar had better fire resistance.