Source-independent quantum secret sharing with entangled photon pair networks.

The large-scale deployment of quantum secret sharing (QSS) in quantum networks is currently challenging due to the requirements for the generation and distribution of multipartite entanglement states. Here we present an efficient source-independent QSS protocol utilizing entangled photon pairs in quantum networks. Through the post-matching method, which means the measurement events in the same basis are matched, the key rate is almost independent of the number of participants. In addition, the unconditional security of our QSS against internal and external eavesdroppers can be proved by introducing an equivalent virtual protocol. Our protocol has great performance and technical advantages in future quantum networks.

Form-Stable Phase Change Material with Wood-Based Materials as Support.

Building shape-stable phase change materials (PCMs) are crucial for their practical applications. Particularly, it is vital to utilize renewable/recyclable biomass media as the support material of form-stable PCMs. In this review article, we summarized the recent developments for building form-stable PCMs consisting of wood as a supporting material, either carbonized wood or wood composites. Moreover, the electrothermal conversion and photothermal conversion of form-stable PCMs based on carbonized wood are also demonstrated. In addition, the current technical problems and future research developments of wood-based PCMs are discussed, especially the leakage problem of PCMs during the phase change transition process. All of this information will be helpful for the in-depth understanding and development of new PCMs suitable for wide application perspectives.

Eutectic Fatty Acids Phase Change Materials Improved with Expanded Graphite.

Low- and ultra-low-grade thermal energy have significant recycling value for energy saving and carbon footprint reduction. Efficient thermal energy storage technology based on phase change materials (PCMs) will help improve heat recovery. This study aimed to develop a composite eutectic fatty acid of lauric acid (LA) and stearic acid (SA) binary system with expanded graphite (EG). The experimental measured eutectic temperature was 31.2 °C with an LA-to-SA mass ratio of 7:3. Afterwards, 1~15 wt.% EG was composited to the eutectic acid, and the thermophysical properties of the composite PCMs were measured by differential scanning calorimetry (DSC) and transient plane source (TPS) methods. The results demonstrated that the phase transition temperature and latent heat of the composite PCMs were stable when the content of EG was more than 5%, and the thermal conductivity and thermal diffusion coefficient of the composite PCMs (10-15 wt.%) increased by 2.4-2.6 and 3.2-3.7 times compared with the pure eutectic acid, respectively. On this basis, a finned-coil-type reservoir was prepared, and an experimental study of heat storage and heat release performance was carried out. The results showed that the heat storage and heat release effects of the heat reservoir were the best when the EG ratio was 10 wt.%. The heat storage time was reduced by 20.4%, 8.1%, and 6.2% compared with the other three EG ratios, respectively; meanwhile, the heat release time was reduced by 19.3%, 6.7%, and 5.3%, respectively.

Analysis and Experimental Study on Water Vapor Partial Pressure in the Membrane Distillation Process.

In membrane distillation, the vapor pressure difference is the driving force of mass transfer. The vapor pressure is generally assumed by the saturation pressure and calculated by the Antoine equation. However, in the actual operation process, the feed solutions usually flow in a non-equilibrium state, which does not meet the theoretical and measurement conditions of the vapor-liquid equilibrium (VLE) state. This study tested the actual water vapor pressure of the pure water, lithium bromide (LiBr) solution, lithium chloride (LiCl) solution, and calcium chloride (CaCl2) solution under different flow conditions. The results showed that the actual water vapor pressure was lower than the saturation pressure overall, and the difference increased with temperature but decreased with the mass concentration. Therefore, in vacuum membrane distillation (VMD), air gap membrane distillation (AGMD), and sweeping gas membrane distillation (SGMD), the membrane flux calculated by water vapor saturation pressure was higher than the actual membrane flux, and the relative difference decreased and was less than 10% after 60 °C. In direct contact membrane distillation (DCMD), the water vapor pressure difference on both membrane sides was almost the same by using the saturation vapor pressure or the tested data since the pressure errors were partially offset in parallel flow or counter-flow modes.

Experimental Quantum Advantage with Quantum Coupon Collector.

An increasing number of communication and computational schemes with quantum advantages have recently been proposed, which implies that quantum technology has fertile application prospects. However, demonstrating these schemes experimentally continues to be a central challenge because of the difficulty in preparing high-dimensional states or highly entangled states. In this study, we introduce and analyze a quantum coupon collector protocol by employing coherent states and simple linear optical elements, which was successfully demonstrated using realistic experimental equipment. We showed that our protocol can significantly reduce the number of samples needed to learn a specific set compared with the classical limit of the coupon collector problem. We also discuss the potential values and expansions of the quantum coupon collector by constructing a quantum blind box game. The information transmitted by the proposed game also broke the classical limit. These results strongly prove the advantages of quantum mechanics in machine learning and communication complexity.

Research on Health and Thermal Comfort of Unit-Type Student Apartments in the Western China Science and Technology Innovation Harbor.

Background: In China, the collective living mode of "multiple people living in one room" is widely used in college students' dormitories; the space environment has high personnel density and poor thermal comfort and healthy environment. The unit-type apartments were completed in the western China science and technology innovation harbor that considers personal independence and public activity spaces. Aim: The purpose of this study is to explore the applicability, thermal comfort, healthy environment, and the correlation of influencing variables of the new unit-type apartment. Especially the influence of physical parameters on personal space under heating in winter and air conditioning in summer. Method: The field investigations and questionnaires to conduct a personal study of architectural space, healthy environment, and thermal comfort were carried out, and the measurement tests of the building's physical environment were carried out in winter and summer semesters. Results: The questionnaires survey shows that the privacy of the unit apartment is satisfactory, and the independent learning and communication is increased. The field measurement results show that due to the narrow space of the private room, the floor radiant heating mode still forms a hot and dry thermal environment in winter, and the temperature fluctuates significantly after the air conditioner is turned on in summer. Conclusions: The unit-type apartments align with young students' physiological and psychological characteristics and the behavioral aspects of postgraduates, with high comprehensive satisfaction up to 80%. However, the indoor thermal environment quickly fluctuates due to the narrow independent space. Moreover, 90% of the window ventilation ratio shows that it has become the main measure to actively regulate the indoor climate, which is beneficial to students' health but increases energy waste and further aggravates the fluctuation of the thermal environment. More refined regulations should be executed for heating in winter and air conditioning in summer.

Differential Phase Shift Quantum Secret Sharing Using a Twin Field with Asymmetric Source Intensities.

As an essential application of quantum mechanics in classical cryptography, quantum secret sharing has become an indispensable component of quantum internet. Recently, a differential phase shift quantum secret sharing protocol using a twin field has been proposed to break the linear rate-distance boundary. However, this original protocol has a poor performance over channels with asymmetric transmittances. To make it more practical, we present a differential phase shift quantum secret sharing protocol with asymmetric source intensities and give the security proof of our protocol against individual attacks. Taking finite-key effects into account, our asymmetric protocol can theoretically obtain the key rate two orders of magnitude higher than that of the original protocol when the difference in length between Alice's channel and Bob's is fixed at 14 km. Moreover, our protocol can provide a high key rate even when the difference is quite large and has great robustness against finite-key effects. Therefore, our work is meaningful for the real-life applications of quantum secret sharing.