2D-TCAD Simulation on Retention Time of Z2FET for DRAM Application

Traditional memory devices are facing more challenges due to continuous down-scaling. 6T-SRAM suffers from variability [1-2] and reliability [3-4] issues, which introduce cell stability problems. DRAM cells with one transistor, one capacitor (1T1C) struggle to maintain refresh time [5-6]. Efforts have been made to find new memory solutions, such as one transistor (1T) solutions [7-9]. Floating body based memory structures are among the potential candidates, but impact ionization or band-to-band tunnelling (B2BT) limits their refresh time [10]. A recently proposed zero impact ionization and zero subthreshold swing device named Z2FET [9, 11-12] has been demonstrated and is a promising candidate for 1T DRAM memory cell due to technology advantages such as CMOS technology compatibility, novel capacitor-less structure and sharp switching characteristics. In the Z2FET memory operation, refresh frequency is determined by data retention time. Previous research [11-12] is lacking systematic simulation analysis and understanding on the underlying mechanisms. In this paper, we propose a new simulation methodology to accurately extract retention time in Z2FET devices and understand its dependency on applied biases, temperatures and relevant physical mechanisms. Since the stored ‘1’ state in Z2FET is an equilibrium state [9, 11-12] and there is no need to refresh, we will concentrate on state ‘0’ retention. Two types of ‘0’ retention time: HOLD ‘0’ and READ ‘0’ retention time will be discussed separately

Influence of the Thermal Energy Storage Strategy on the Performance of a Booster Heat Pump for Domestic Hot Water Production System Based on the Use of Low Temperature Heat Source

[EN] Energy recovery from a low temperature heat source using heat pump technology is becoming a popular application. The domestic hot water demand has the characteristic of being very irregular along the day, with periods in which the demand is very intensive and long periods in which it is quite small. In order to use heat pumps for this kind of applications efficiently, the proper sizing and design of the water storage tank is critical. In this work, the optimal sizing of the two possible tank alternatives, closed stratified tank and variable-water-volume tank, is presented, and their respective performance compared, for domestic hot water production based on low temperature energy recovery in two potential applications (grey water and ultra-low temperature district heating). The results show that the efficiency of these kind of systems is very high and that variable-water-volume tanks allow a better use of the energy source, with an 8% higher exergy efficiency and around 3% better seasonal performance factor (SPF), being able to provide similar comfort levels with a smaller system size"Vicerectorado de Investigacion, Innovacion y Transferencia of the Universitat Politecnica de Valencia (Spain)" throught the project "REDUCCION DE LAS EMISIONES DE CO2 A ALTA TEMPERATURE A PARTIR DE LA RECUPERACION DE CALOR RESIDUAL MEDIANTE EL USO DE UNA BOMBA DE CALOR"with the reference SP20180039 from the program "Primeros proyectos de investigacion (PAID-06-18)".Masip, X.; Navarro-Peris, E.; Corberán, JM. (2020). Influence of the Thermal Energy Storage Strategy on the Performance of a Booster Heat Pump for Domestic Hot Water Production System Based on the Use of Low Temperature Heat Source. Energies. 13(24):1-24. https://doi.org/10.3390/en13246576S12413242050 Long-Term Strategy https://ec.europa.eu/clima/policies/strategies/2050_enEnergy Consumption Buildings https://ec.europa.eu/energy/en/topics/energy-efficiency/buildingsEnergy Consumption in Households http://ec.europa.eu/eurostat/statistics-explained/index.php/Energy_consumption_in_householdshttps://www.google.com.hk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwip0ubH48ztAhUEMN4KHRmLA0kQFjABegQIAxAC&url=https%3A%2F%2Feur-lex.europa.eu%2FLexUriServ%2FLexUriServ.do%3Furi%3DOJ%3AL%3A2009%3A140%3A0016%3A0062%3Aen%3APDF&usg=AOvVaw10tSQ3SpiUkxpXKuCB6R0nCecchinato, L., Corradi, M., Fornasieri, E., & Zamboni, L. (2005). Carbon dioxide as refrigerant for tap water heat pumps: A comparison with the traditional solution. International Journal of Refrigeration, 28(8), 1250-1258. doi:10.1016/j.ijrefrig.2005.05.019Pitarch, M., Navarro-Peris, E., Gonzálvez-Maciá, J., & Corberán, J. M. (2017). Experimental study of a subcritical heat pump booster for sanitary hot water production using a subcooler in order to enhance the efficiency of the system with a natural refrigerant (R290). International Journal of Refrigeration, 73, 226-234. doi:10.1016/j.ijrefrig.2016.08.017Pitarch, M., Hervas-Blasco, E., Navarro-Peris, E., Gonzálvez-Maciá, J., & Corberán, J. M. (2017). Evaluation of optimal subcooling in subcritical heat pump systems. International Journal of Refrigeration, 78, 18-31. doi:10.1016/j.ijrefrig.2017.03.015Hervas-Blasco, E., Pitarch, M., Navarro-Peris, E., & Corberán, J. M. (2018). Study of different subcooling control strategies in order to enhance the performance of a heat pump. International Journal of Refrigeration, 88, 324-336. doi:10.1016/j.ijrefrig.2018.02.003Meggers, F., & Leibundgut, H. (2011). The potential of wastewater heat and exergy: Decentralized high-temperature recovery with a heat pump. Energy and Buildings, 43(4), 879-886. doi:10.1016/j.enbuild.2010.12.008Liu, L., Fu, L., & Jiang, Y. (2010). Application of an exhaust heat recovery system for domestic hot water. Energy, 35(3), 1476-1481. doi:10.1016/j.energy.2009.12.004Baek, N. C., Shin, U. C., & Yoon, J. H. (2005). A study on the design and analysis of a heat pump heating system using wastewater as a heat source. Solar Energy, 78(3), 427-440. doi:10.1016/j.solener.2004.07.009Bertrand, A., Aggoune, R., & Maréchal, F. (2017). In-building waste water heat recovery: An urban-scale method for the characterisation of water streams and the assessment of energy savings and costs. Applied Energy, 192, 110-125. doi:10.1016/j.apenergy.2017.01.096High Efficiency Heat Pump for Domestic Hot Water Generation http://docs.lib.purdue.edu/iracc%0Ahttp://docs.lib.purdue.edu/iracc/953Østergaard, P. A., & Andersen, A. N. (2018). Economic feasibility of booster heat pumps in heat pump-based district heating systems. Energy, 155, 921-929. doi:10.1016/j.energy.2018.05.076Fischer, D., Toral, T. R., Lindberg, K. B., Wille-Haussmann, B., & Madani, H. (2014). Investigation of Thermal Storage Operation Strategies with Heat Pumps in German Multi Family Houses. Energy Procedia, 58, 137-144. doi:10.1016/j.egypro.2014.10.420Han, Y. M., Wang, R. Z., & Dai, Y. J. (2009). Thermal stratification within the water tank. Renewable and Sustainable Energy Reviews, 13(5), 1014-1026. doi:10.1016/j.rser.2008.03.001Haller, M. Y., Haberl, R., Mojic, I., & Frank, E. (2014). Hydraulic Integration and Control of Heat Pump and Combi-storage: Same Components, Big Differences. Energy Procedia, 48, 571-580. doi:10.1016/j.egypro.2014.02.067Liu, F., Zhu, W., Cai, Y., Groll, E. A., Ren, J., & Lei, Y. (2017). Experimental performance study on a dual-mode CO2 heat pump system with thermal storage. Applied Thermal Engineering, 115, 393-405. doi:10.1016/j.applthermaleng.2016.12.095Castell, A., Medrano, M., Solé, C., & Cabeza, L. F. (2010). Dimensionless numbers used to characterize stratification in water tanks for discharging at low flow rates. Renewable Energy, 35(10), 2192-2199. doi:10.1016/j.renene.2010.03.020Armstrong, P., Ager, D., Thompson, I., & McCulloch, M. (2014). Domestic hot water storage: Balancing thermal and sanitary performance. Energy Policy, 68, 334-339. doi:10.1016/j.enpol.2014.01.012Hervás-Blasco, E., Navarro-Peris, E., & Corberán, J. M. (2019). Optimal design and operation of a central domestic hot water heat pump system for a group of dwellings employing low temperature waste heat as a source. Energy, 188, 115979. doi:10.1016/j.energy.2019.115979Next Generation of Heat Pumps Working with Natural Fluids (NxtHPG) http://www.nxthpg.eu/Transient Systems Simulation Homepage http://www.trnsys.comMasip, X., Cazorla-Marín, A., Montagud-Montalvá, C., Marchante, J., Barceló, F., & Corberán, J. M. (2019). Energy and techno-economic assessment of the effect of the coupling between an air source heat pump and the storage tank for sanitary hot water production. Applied Thermal Engineering, 159, 113853. doi:10.1016/j.applthermaleng.2019.11385

Effects of Sigma-1 Receptor Ligands on Peripheral Nerve Regeneration

Peripheral nerve injuries lead to the loss of motor, sensory and autonomic functions in the territories supplied by the injured nerve. Currently, nerve injuries are managed by surgical repair procedures, and there are no effective drugs in the clinic for improving the capacity of axonal regeneration. Sigma-1 receptor (Sig-1R) is an endoplasmic reticulum chaperon protein involved in many functions, including neuroprotection and neuroplasticity. A few previous studies using Sig-1R ligands reported results that suggest this receptor as a putative target to enhance regeneration. The aim of this study was to evaluate the possible effects of Sig-1R ligands on axonal regeneration in a sciatic nerve section and repair model in mice. To this end, mice were treated either with the Sig-1R agonist PRE-084 or the antagonist BD1063, and a Sig-1R knock-out (KO) mice group was also studied. The electrophysiological and histological data showed that treatment with Sig-1R ligands, or the lack of this protein, did not markedly modify the process of axonal regeneration and target reinnervation after sciatic nerve injury. Nevertheless, the nociceptive tests provided results indicating a role of Sig-1R in sensory perception after nerve injury, and immunohistochemical labeling indicated a regulatory role in inflammatory cell infiltration in the injured nerve

Sensory Involvement in Amyotrophic Lateral Sclerosis

Although amyotrophic lateral sclerosis (ALS) is pre-eminently a motor disease, the existence of non-motor manifestations, including sensory involvement, has been described in the last few years. Although from a clinical perspective, sensory symptoms are overshadowed by their motor manifestations, this does not mean that their pathological significance is not relevant. In this review, we have made an extensive description of the involvement of sensory and autonomic systems described to date in ALS, from clinical, neurophysiological, neuroimaging, neuropathological, functional, and molecular perspectives

Estimate of dark halo ellipticity by lensing flexion

Aims. The predictions of the ellipticity of the dark matter halos from models of structure formation are notoriously difficult to test with observations. A direct measurement would give important constraints on the formation of galaxies, and its effect on the dark matter distribution in their halos. Here we show that galaxy-galaxy flexion provides a direct and potentially powerful method for determining the ellipticity of (an ensemble of) elliptical lenses. Methods. We decompose the spin-1 flexion into a radial and a tangential component. Using the ratio of tangential-to- radial flexion, which is independent of the radial mass profile, the mass ellipticity can be estimated. Results. An estimator for the ellipticity of the mass distribution is derived and tested with simulations. We show that the estimator is slightly biased. We quantify this bias, and provide a method to reduce it. Furthermore, a parametric fitting of the flexion ratio and orientation provides another estimate for the dark halo ellipticity, which is more accurate for individual lenses Overall, galaxy-galaxy flexion appears as a powerful tool for constraining the ellipticity of mass distributions.Comment: 6 pages,5 figures, submitted to AA, comments welcom

Codimension Two Branes in Einstein-Gauss-Bonnet Gravity

Codimension two branes play an interesting role in attacking the cosmological constant problem. Recently, in order to handle some problems in codimension two branes in Einstein gravity, Bostock {\it et al.} have proposed using six-dimensional Einstein-Gauss-Bonnet (EGB) gravity instead of six-dimensional Einstein gravity. In this paper, we present the solutions of codimension two branes in six-dimensional EGB gravity. We show that Einstein's equations take a "factorizable" form for a factorized metric tensor ansatz even in the presence of the higher-derivative Gauss-Bonnet term. Especially, a new feature of the solution is that the deficit angle depends on the brane geometry. We discuss the implication of the solution to the cosmological constant problem. We also comment on a possible problem of inflation model building on codimension two branes.Comment: 16 pages, no figures. v2: References added; v3: Reference added, Sec.4 and 5 combined into one; v4: References added, minor corrections, to appear in Physical Review

Sea quark polarization and semi-inclusive DIS data

We investigate the potential impact of forthcoming Jefferson Lab semi-inclusive polarized deep inelastic scattering proton measurements in the determination of the sea quark polarization in the nucleon by means of a next to leading order global QCD analysis. Specifically, we estimate the resulting improvement in the constraints on polarized parton densities for the different flavors, which is found to be significant for up and strange quarks, and the correlation between remaining uncertainty ranges for each of the parton species.Comment: 7 pages, 4 figures. Version to be published in the European Physical Journal