The photovoltaic perovskite, methyl­ammonium lead triiodide [CH3NH3PbI3 (MAPbI3)], is one of the most efficient materials for solar energy conversion. Various kinds of chemical and physical modifications have been applied to MAPbI3 towards better understanding of the relation between composition, structure, electronic properties and energy conversion efficiency of this material. Pressure is a particularly useful tool, as it can substantially reduce the interatomic spacing in this relatively soft material and cause significant modifications to the electronic structure. Application of high pressure induces changes in the crystal symmetry up to a threshold level above which it leads to amorphization. Here, a detailed structural study of MAPbI3 at high hydro­static pressures using Ne and Ar as pressure transmitting media is reported. Single-crystal X-ray diffraction experiments with synchrotron radiation at room temperature in the 0–20 GPa pressure range show that atoms of both gaseous media, Ne and Ar, are gradually incorporated into MAPbI3, thus leading to marked structural changes of the material. Specifically, Ne stabilizes the high-pressure phase of NexMAPbI3 and prevents amorphization up to 20 GPa. After releasing the pressure, the crystal has the composition of Ne0.97MAPbI3, which remains stable under ambient conditions. In contrast, above 2.4 GPa, Ar accelerates an irreversible amorphization. The distinct impacts of Ne and Ar are attributed to differences in their chemical reactivity under pressure inside the restricted space between the PbI6 octahedra.

A device for compensating deviations from a coaxial arrangement of components of a regulating organ, said regulating arrangement being comprised of a regulating organ, a crown pipe, and an immersion cup which serve for controlling the gas pressure of a coke oven chamber, with the regulating arrangement being comprised of an immersion cup with a water immersion that seals the gas space of a coke oven chamber versus the gas collecting main and/or plant units downstream, and wherein the height of the water level of the water immersion represents a regulating means to control the gas pressure, and wherein said regulating arrangement is furthermore comprised of an immersion pipe that configures a specially shaped crown pipe at its end submerging into the water of the immersion cup, and that is comprised of a regulating organ to regulate the water level.

Exemplary embodiments of a gas pressure regulator comprise a regulator body, an adaptor sleeve, a retainer and an indexing ring. The regulator body includes a proximal portion, a distal portion, a ported intermediate portion therebetween, and a main bore. The adaptor sleeve axially receives the distal portion and includes an outer threading for engaging an air source adaptor of a paintball marker. The retainer threadably engages the main bore within the distal end, thereby axially securing the adaptor sleeve onto the distal end. The indexing ring receives the distal portion therethrough for resiliently biased axial movement of the indexing ring between a locking position and an unlocking position. When the indexing ring is in its unlocking position, the adaptor sleeve is rotatable with respect to the regulator body. When the indexing ring is in its locking position, the adaptor sleeve is rendered substantially non-rotatable with respect to the regulator body.

Systems, methods, and controllers for controlling gas-fired appliances such as warm air furnaces are disclosed. An illustrative furnace system can include a burner unit in communication with a combustion air flow conduit and heat exchanger, a variable speed inducer fan or blower adapted to provide a flow of combustion air to the burner unit, a furnace controller and motor speed control unit adapted to regulate the speed of the inducer fan or blower, and a pneumatically modulated gas valve adapted to variably output gas pressure to the burner unit based at least in part on the combustion air flow.

Disclosed is a heat exchanger including: a heat exchanger body; a gas inlet for introducing exhaust gas into the heat exchanger body; a coolant inlet for introducing a coolant into the heat exchanger body; a gas outlet for discharging the exhaust gas that is cooled by heat exchange with the coolant; and a coolant outlet for discharging the coolant that completes heat exchange with the exhaust gas. In this case, the heat exchanger body includes: a laminated tube core formed by laminating a plurality of gas channels side by side; a housing formed so as to enclose the laminated tube core except for opposite ends thereof; and a wave fin plate integrally provided with a plurality of wave fins and arranged within each of the gas channels, wherein each of the wave fins includes a fixed pitch section, and a variable pitch section.