Ground state of spin-1 Bose-Einstein condensates with spin-orbit coupling in a Zeeman field

We systematically investigate the weakly trapped spin-1 Bose-Einstein condensates with spin-orbit coupling in an external Zeeman field. We find that the mean-field ground state favors either a magnetized standing wave phase or plane wave phase when the strength of Zeeman field is below a critical value related to the strength of spin-orbit coupling. Zeeman field can induce the phase transition between standing wave and plane wave phases, and we determine the phase boundary analytically and numerically. The magnetization of these two phases responds to the external magnetic field in a very unique manner, the linear Zeeman effect magnetizes the standing wave phase along the direction of the magnetic field, but the quadratic one demagnetizes the plane wave phase. When the strength of Zeeman field surpasses the critical value, the system is completely polarized to a ferromagnetic state or polar state with zero momentum

A review of net zero energy buildings in hot and humid climates: Experience learned from 34 case study buildings

Sustainable development in the building sector requires the integration of energy efficiency and renewable energy utilization in buildings. In recent years, the concept of net zero energy buildings (NZEBs) has become a potential plausible solution to improve efficiency and reduce energy consumption in buildings. To achieve an NZEB goal, building systems and design strategies must be integrated and optimized based on local climatic conditions. This paper provides a comprehensive review of NZEBs and their current development in hot and humid regions. Through investigating 34 NZEB cases around the world, this study summarized NZEB key design strategies, technology choices and energy performance. The study found that passive design and technologies such as daylighting and natural ventilation are often adopted for NZEBs in hot and humid climates, together with other energy efficient and renewable energy technologies. Most NZEB cases demonstrated site annual energy consumption intensity less than 100 kW-hours (kWh) per square meter of floor space, and some buildings even achieved “net-positive energy” (that is, they generate more energy locally than they consume). However, the analysis also shows that not all NZEBs are energy efficient buildings, and buildings with ample renewable energy adoption can still achieve NZEB status even with high energy use intensity. This paper provides in-depth case-study-driven analysis to evaluate NZEB energy performance and summarize best practices for high performance NZEBs. This review provides critical technical information as well as policy recommendations for net zero energy building development in hot and humid climates

Convexity and log-concavity of the partition function weighted by the parity of the crank

Let $M_0(n)$ (resp. $M_1(n)$) denote the number of partitions of $n$ with even (reps. odd) crank. Choi, Kang and Lovejoy established an asymptotic formula for $M_0(n)-M_1(n)$. By utilizing this formula with the explicit bound, we show that $M_k(n-1)+M_k(n+1)>2M_k(n)$ for $k=0$ or $1$ and $n\geq 39$. This result can be seen as the refinement of the classical result regarding the convexity of the partition function $p(n)$, which counts the number of partitions of $n$. We also show that $M_0(n)$ (resp. $M_1(n)$) is log-concave for $n\geq 94$ and satisfies the higher order Tur\'an inequalities for $n\geq 207$ with the aid of the upper bound and the lower bound for $M_0(n)$ and $M_1(n)$.Comment: 29 page

Compression Process of Pore inside Explosive Charge in a Warhead under Launching Load

In this paper, the compression process of the pore inside explosive charge in a warhead under launching load is simulated and its influence on premature explosion is discussed. The relationship between the pore compression, distortion, and the form of 'igniting hot spot' has been established. The analysis of result indicates that the stress wave in the explosive charge developed due to launching load is a key factor in the pore compression process. The volume change of the pore, which is related to its original volume, is a major factor affecting the form of 'ignition hot spot'. It appears that a specific size of the pore may not lead to the premature explosion of explosive charge in a warhead under launching load. The quantitative relationship between the dangerous size range of the pore and the launching load is a core research subject of warhead safety during launching. With this objective, numerical computing was undertaken to assess the pore's distortion parameter inside the explosive charge of a warhead, and generate database for warhead safety under launching load.Defence Science Journal, 2010, 60(3), pp.244-250, DOI:http://dx.doi.org/10.14429/dsj.60.34

High temperature constitutive model of q345B steel

In order to accurately predict the flow stress of Q345B steel at high temperature, the Q345B steel was subjected to a hot compression test on the Gleeble-1500D thermal simulation test machine at a deformation temperature of 1 173,15~1 373,15 K and a strain rate of 0,01~10 s-1. Through the obtained true stress-strain curve, strain factors are introduced into the Arrhenius equation to establish a more accurate strain-coupled constitutive model. The results show that the correlation coefficient of the Arrhenius model considering strain compensation is 0,993, and the average absolute error is 4,59 %, which can accurately predict the flow stress. The experimental data and the calculated prediction curve fit well, which verifies the feasibility of the model

High temperature constitutive model of q345B steel

In order to accurately predict the flow stress of Q345B steel at high temperature, the Q345B steel was subjected to a hot compression test on the Gleeble-1500D thermal simulation test machine at a deformation temperature of 1 173,15~1 373,15 K and a strain rate of 0,01~10 s-1. Through the obtained true stress-strain curve, strain factors are introduced into the Arrhenius equation to establish a more accurate strain-coupled constitutive model. The results show that the correlation coefficient of the Arrhenius model considering strain compensation is 0,993, and the average absolute error is 4,59 %, which can accurately predict the flow stress. The experimental data and the calculated prediction curve fit well, which verifies the feasibility of the model