Dithiolodithiole as a Building Block for Conjugated Materials

The development of new conjugated organic materials for dyes, sensors, imaging, and flexible light emitting diodes, field‐effect transistors, and photovoltaics has largely relied upon assembling π‐conjugated molecules and polymers from a limited number of building blocks. The use of the dithiolodithiole heterocycle as a conjugated building block for organic materials is described. The resulting materials exhibit complimentary properties to widely used thiophene analogues, such as stronger donor characteristics, high crystallinity, and a decreased HOMO–LUMO gap. The dithiolodithiole (C₄S₄) motif is readily synthetically accessible using catalytic processes, and both the molecular and bulk properties of materials based on this building block can be tuned by judicious choice of substituents.     

Multiple optical line traps using a single phase-only rectangular ridge

An optical line trap has the ability to simultaneously trap and align microparticles in line formation due to its intensity profile. In this paper, we demonstrate a straightforward means to generate multiple optical line traps by simply placing a phase-only rectangular ridge in the path of a laser beam. By carefully positioning the rectangular ridge, we were able to control the separation between the optical trapping lines, which were then used to create multiple line formations of trapped particles. The simplicity of the proposed technique lends itself to the realization of a highly efficient optical line trap converter for easy modification of existing optical microscopes.     

Effect of substrate temperature on electrical and magnetic properties of epitaxial La1−x Pb x MnO3 films

Epitaxial La_1−x Pb _x MnO₃ (LPMO) thin films, grown on (100) SrTiO₃ substrates by laser ablation technique at different temperatures between 600 and 850°C, have been characterized for electrical and magnetic properties. The temperature dependence of resistivity showed that the metal-insulator transition temperature (T _MI) decreases with increasing substrate temperature, which has been attributed to decrease in Pb content in the filsm. The YBa₂Cu₃O _x /La_1−x MnO₃ heterostructures, exhibiting both superconductivity and ferromagnetism, have been fabricated.     

Facile, fast, and inexpensive synthesis of monodisperse amorphous nickel-phosphide nanoparticles of predefined size

Monodisperse, size-controlled Ni-P nanoparticles were synthesised in a single step process using triphenyl-phosphane (TPP), oleylamine (OA), and Ni(II)acetyl-acetonate. The nanoparticles were amorphous, contained ~30 at% P and their size was controlled between 7-21 nm simply by varying the amount of TPP. They are catalytically active for tailored carbon nanotube growth.     

The Use of Porous Fins for Heat Transfer Augmentation in Parallel-Plate Channels

In this study, a steady, fully developed laminar forced convection heat augmentation via porous fins in isothermal parallel-plate duct is numerically investigated. High-thermal conductivity porous fins are attached to the inner walls of two parallel-plate channels to enhance the heat transfer characteristics of the flow under consideration. The Darcy–Brinkman–Forchheimer model is used to model the flow inside the porous fins. This study reports the effect of several operating parameters on the flow hydrodynamics and thermal characteristics. This study demonstrates, mainly, the effects of porous fin thickness, Darcy number, thermal conductivity ratio, Reynolds number, and microscopic inertial coefficient on the thermal performance of the present flow. It is found that the highest Nusselt number is achieved at fully filled porous duct which requires the highest pumping pressure. The results show that using porous fins requires less pumping pressure with comparable high heat augmentation weight against fully filled porous duct. It is found that higher Nusselt numbers are achieved by increasing the microscopic inertial coefficient (A), the Reynolds number (Re), and the thermal conductivity of the porous substrate k ₂. The results show that heat transfer can be enhanced (1) with the use of high thermal conductivity fins, (2) by decreasing the Darcy number, and (3) by increasing microscopic inertial coefficient.     

Continuous determination of carbon monoxide evolved during thermal decomposition reactions

A device suitable for the continuous detection of carbon monoxide evolved during themal decomposition processes is described. The detector can be connected directly to thermoanalytical equipment of controlled gas atmosphere. Carbon monoxide collected by the carrier gas is passed through the device containing hopcalite catalyst. In the presence of oxygen carbon monoxide is converted to carbon dioxide in the cell and the temperature change caused by the heat of reaction is measured. According to experience, the change of temperature is linearly proportional to the amount of carbon monoxide released.The signal curve of the detector can be compared to the simultaneously recorded thermoanalytical curves and used to determine the step in which carbon monoxide was released.The detector is not completely selective to carbon monoxide, but in most cases the interferring gases can be removed from the carrier gas by various packings placed between the detector and the thermoanalytical equipment.

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Zusammenfassung Es wird ein geeignetes GerÄt zur kontinuierlichen Detektierung von in thermischen Zersetzungsprozessen freigesetztem Kohlenmonoxid beschrieben. Der Detektor kann direkt an eine thermoanalytische Apparatur mit überwachter GasatmosphÄre angeschlossen werden. Das vom Carriergas aufgenommene Kohlenmonoxid wird durch das GerÄt geleitet, das einen Hopcalit-Katalysator enthÄlt. In Gegenwart von Sauerstoff wird das Kohlenmonoxid in Kohlendioxid überführt und die durch die ReaktionswÄrme verursachte TemperaturÄnderung gemessen. ErfahrungsgemÄ\ ist die TemperaturÄnderung proportional der entwickelten Menge Kohlenmonoxid.Das Detektorsignal kann mit den gleichzeitig aufgezeichneten thermoanalytischen Kurven verglichen und zur Bestimmung dessen benutzt werden, in welchem Teilschritt Kohlenmonoxid freigesetzt wird.Der Detektor zeigt keine vollstÄndige SelektivitÄt, jedoch können Störgase durch verschiedene Füllungen zwischen Thermoanalysator und Detektor vom Carriergas getrennt werden.

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The authors thank Dr. A. Felinger for his kind help in the computer processing of the recordings.