Abstract: A flame retardant treatment of a lignocellulosic material, which includes: optionally steam exploding the lignocellulosic material, impregnating the optionally steam-exploded lignocellulosic material, in or with an aqueous solution, from 0.5% to 10% of phytic acid and from 1% to 30% of urea, based on the total weight of the aqueous solution, optionally drying of the impregnated lignocellulosic material, until the impregnated lignocellulosic material has a moisture content from 5% to 20% by weight, cooking the impregnated and optionally dried lignocellulosic material, the resulting flame-retarded lignocellulosic material including a phosphorous content originating from the phytic acid from 0.1% to 10% by weight.

Abstract: A method and system for assigning power to sub-bands in a multiple access communications system, where users are assigned iteratively to sub-bands, and at each iteration a provisional partial power budget is determined for the subset of sub-bands comprising the sub-bands to which users have been assigned in the present time slot and the sub-band under consideration in the sequence, where the fraction of the total available power determined as the provisional partial power budget corresponds to the fraction of the number of sub-bands in the subset from the total number of sub-bands to be assigned, and the provisional power allocation for the sub-band under consideration is obtained by performing a waterfilling distribution of the provisional partial power budget amongst the subset of the sub-bands, based on the channel gain of the users already assigned to sub-bands in the present time slot.

Abstract: A flame retardant treatment of a lignocellulosic material, which includes: optionally steam exploding the lignocellulosic material, impregnating the optionally steam-exploded lignocellulosic material, in or with an aqueous solution, from 0.5% to 10% of phytic acid and from 1% to 30% of urea, based on the total weight of the aqueous solution, optionally drying of the impregnated lignocellulosic material, until the impregnated lignocellulosic material has a moisture content from 5% to 20% by weight, cooking the impregnated and optionally dried lignocellulosic material, the resulting flame-retarded lignocellulosic material including a phosphorous content originating from the phytic acid from 0.1% to 10% by weight.

Abstract: A mechanism is presented for attributing users to one or more of a plurality of sub-bands in a multiple access communications system, wherein in an initial assignment phase, a first user is selected for a sub band, for example on the basis of a user priority. Users having complementary channel gains to that of the first user are identified, and then a second sub-band user maximizing a performance metric reflecting the achieved throughput, and/or fairness across users, is selected to accompany the first user on that sub-band. The initial assignment phase may terminate once all users have been assigned to a sub-band once. After the first phase is complete, the first user for each sub-band may be the user whose achieved total throughput is furthest from a target throughput defined for that user, wherein each user is assigned to the remaining sub-band to which no first user is currently attributed offering the highest channel gain for that user.

Abstract: A system and method for assigning users to a particular sub band in a given time slot in a NOMA system, where whichever pair of users corresponds to the smallest “candidate pair user throughput deviation value”, reflecting the aggregate of the respective difference between the average throughput across all users (K) and the known throughput of each of the two users under consideration (k1k2), and each user attributed to a sub-band other than the selected sub-band. User pairs for consideration may consider all possible pairs, or may be limited to candidate pairs satisfying together, or comprising one or both users who satisfy a criterion such as channel gain, distance to a target, throughput or a combination of some or all of these factors. The power allocated to each sub-band may be attributed by a waterfilling algorithm.

Abstract: A method of determining a performance metric for a selection of a first user and a second user among a set of candidate users for attribution to a sub-band in a multiple access communications system based on Non-Orthogonal Multiple Access (NOMA), is provided wherein the first user (k1) and the second user (k2) are selected as the pair of candidate users corresponding to an extremum of the ratio between a first term reflecting the total throughput achievable by any pair of the candidate users assigned to the sub-band (s) under consideration, and a second term reflecting the known throughput achieved by that same pair of candidate users over a predetermined preceding period.

Abstract: A mechanism for attributing users to a plurality of sub bands in a time slot t in a multiple access communications system, said method comprising assigning a combination of users to a sub band on a Proportional Fairness basis, that is to say whichever combination of users maximizes a Proportional Fairness performance metric for that channel, where the performance metric is weighted by a weighting factor reflecting the difference for that user between a target throughput and a projected throughput.

Abstract: Power allocation in NOMA systems for example on the basis Proportional Fairness calculations depends on knowledge of user throughput on a specified sub-band, which implies that users have already been allocated to particular sub-bands. Meanwhile, maximum throughput can generally be achieved where there is the greatest possible difference in transmission power for the users on a given sub-band, so that optimal allocation of users to sub-bands requires knowledge of the power available for each user.

Abstract: Heterojunction structure, also referred to as a heterostructure, of semiconductor material, in particular for a high electron mobility transistor (HEMT), includes a substrate, a stack of at least three buffer layers of a same semiconductor material with a wide bandgap EG1 based on a column-III nitride, namely an unintentionally doped first buffer layer, a second buffer layer, an unintentionally doped third buffer layer, an unintentionally doped intermediate layer, and a barrier layer arranged on the intermediate layer, said barrier layer being of a semiconductor material with a wide bandgap EG2 based on a column-III nitride; the second buffer layer has constant P+ doping throughout some or all of its thickness; and the third buffer layer includes a first region which is unintentionally doped throughout its entire thickness and at least one second region adjacent to said first region with N+ doping surrounding the first region.

Abstract: A mechanism for attributing users to a plurality of sub bands in a time slot t in a multiple access communications system, said method comprising assigning a combination of users to a sub band on a Proportional Fairness basis, that is to say whichever combination of users maximizes a Proportional Fairness performance metric for that channel, where the performance metric is weighted by a weighting factor reflecting the difference for that user between a target throughput and a projected throughput.

Abstract: Heterojunction structure, also referred to as a heterostructure, of semiconductor material, in particular for a high electron mobility transistor (HEMT), includes a substrate, a stack of at least three buffer layers of a same semiconductor material with a wide bandgap EG1 based on a column-III nitride, namely an unintentionally doped first buffer layer, a second buffer layer, an unintentionally doped third buffer layer, an unintentionally doped intermediate layer, and a barrier layer arranged on the intermediate layer, said barrier layer being of a semiconductor material with a wide bandgap EG2 based on a column-III nitride; the second buffer layer has constant P+ doping throughout some or all of its thickness; and the third buffer layer includes a first region which is unintentionally doped throughout its entire thickness and at least one second region adjacent to said first region with N+ doping surrounding the first region.

Abstract: Power allocation in NOMA systems for example on the basis Proportional Fairness calculations depends on knowledge of user throughput on a specified sub-band, which implies that users have already been allocated to particular sub-bands. Meanwhile, maximum throughput can generally be achieved where there is the greatest possible difference in transmission power for the users on a given sub-band, so that optimal allocation of users to sub-bands requires knowledge of the power available for each user.

Abstract: A heterojunction structure of semiconductor material, for a high electron mobility transistor includes a substrate, a buffer layer, arranged on the substrate, of a large bandgap semiconductor material, based on a nitride from column III, where the buffer layer is not intentionally doped with n-type carriers, a barrier layer arranged above the buffer layer, of a large bandgap semiconductor material based on a nitride from column III, where the width of the bandgap of the barrier layer is less than the width of the bandgap of the buffer layer. The heterojunction structure additionally comprises an intentionally doped area, of a material based on a nitride from column III identical to the material of the buffer layer, in a plane parallel to the plane of the substrate and a predefined thickness along a direction orthogonal to the plane of the substrate, where the area is comprised in the buffer layer.