CHECK-IT (China Holland Educational Competence and Knowledge Center on IT) is a unique international internship center set up by a consortium of the Software School of Xiamen University and five Universities of Applied Sciences of the Netherlands in Aug. 2009. In this paper, we discuss the implementation of CHECK-IT. First, we introduce the background and history of CHECK-IT, and then focus on the establishment of the center, the selection of the internship projects, and the effective management of the progress. Based on the long experience of supervising, this paper proposes an enhanced internship project that is funded by the State Administration of Foreign Experts and reports preliminary results of this programme. In addition, suggestions based on experience are made for future development and monitoring to achieve beneficial outcomes for all participants involved.
Structure directing agents (SDAs) are widely used in the synthesis of ubiquitous porous materials, such as zeolites, but their application and role in the synthesis of metal-organic frameworks (MOFs) has been comparatively understudied. Here we report a diverse family of anionic MOFs with all frameworks constructed exclusively from the same metal cation and plant-based organic linker—Zr(IV) cations and ellagate anions. Applying the same synthesis conditions but only changing the species of the SDA resulted in 10 novel zirconium ellagate MOFs (denoted SU-103 – SU-112) with varying dimensionality, topologies, Zr(IV) coordination geometries, intermolecular framework interactions, and framework interpenetration. Modern electron diffraction and electron microscopy techniques revealed the location of the SDA molecules in the pores of all MOFs, enabling a detailed study of their interactions. Despite having similar framework compositions, the properties of these MOFs noticeably differ due to the different ammonium SDAs and the unique framework structures obtained. The MOFs demonstrate chemical stability in aqueous media, basic conditions, and concentrated salt solutions, which is attributed to the strong Zr-catecholate chelating interactions consolidating the frameworks. We anticipate these 10 MOFs are only a small portion of a potential plethora of MOFs that could be discovered within this system. This lays the groundwork for the discovery of many other chemically robust structure-directed MOFs made with different cationic SDAs, framework metal cations, as well as other organic linkers with polyanionic functional groups.
Male infertility has become an important issue of global concern. Semen analysis is the cornerstone of male fertility assessment. External quality assessment (EQA) of sperm concentration, motility, and morphology is widely recognized in the world. However, over the past 34 years, the implementation of EQA for semen analysis has varied across different countries, and there is no global consensus. The goal of this paper is to first explore the overall development of EQA during this period. Secondly, it aims to discuss the extent of difference of participating laboratories in different countries. Finally, the paper examines the differences in EQA programs developed by various EQA providers in order to seek a global standard. In total, 29 papers met the inclusion criteria and were included in this review. There is inconsistent in the implementation of EQA across different countries, and there is no global consensus. Policies for EQA of semen analysis vary from country to country. Some countries mandate laboratory participation, while others permit voluntary involvement. Different EQA organizers choose different ways to calculate assigned value and acceptance limits. The coefficient of variation (CV) for each EQA item was large. The CVs of concentration, motility, morphology, and viability were 12.7-138.0 %, 17.0-127.0 %, 7-375 %, and 6-41.1 %, respectively. The results of the semen analysis varied considerably among the participating laboratories. The collaborative efforts of national policymakers, EQA organizers, and all participating laboratories are essential to improving the current situation.
Quantum loop and dimer models are archetypal examples of correlated systems with local constraints. Obtaining generic solutions for these models is difficult due to the lack of controlled methods to solve them in the thermodynamic limit. Nevertheless, these solutions are of immediate relevance to both statistical and quantum field theories, as well as the rapidly growing experiments in Rydberg atom arrays and quantum moir\'e materials, where the interplay between correlation and local constraints gives rise to a plethora of novel phenomena. In a recent work [X. Ran, Z. Yan, Y.-C. Wang, et al, arXiv:2205.04472 (2022)], it was found through sweeping cluster quantum Monte Carlo (QMC) simulations and field theory analysis that the triangular lattice quantum loop model (QLM) hosts a rich ground state phase diagram with lattice nematic, vison plaquette (VP) crystals, and the $\mathbb{Z}_2$ quantum spin liquid (QSL) close to the Rokhsar-Kivelson point. Here, we focus on the continuous quantum critical point separating the VP and QSL phases and demonstrate via both static and dynamic probes in QMC simulations that this transition is of the (2+1)D cubic* universality. In this transition, the fractionalized visons in QSL condense to give rise to the crystalline VP phase, while leaving their trace in the anomalously large anomalous dimension exponent and pronounced continua in the dimer and vison spectra compared with those at the conventional cubic or O(3) quantum critical points.
Based on the investigation above background of stem cell research, this paper obtains the research topics of different time-window series with LDA topic segment model, and then the emerging topics are identified and judged according to the assumption of emerging topic definition. This paper proposes a new method to detect and identify the emerging topic in the topic evolution model. In this method, first, the time of the whole dataset is divided into several time-window series, and then the topics in total time-windows are segmented by LDA model. The composite relationships between topics are calculated by integrating the relationships of consistency, co-occurrence and semantics between topics. Those composite relationships are used to indicate and visualize the evolutionary relationships among topics. The emerging topics are detected by analyzing the characters of different evolutionary types including topics' differentiation, integration, emerging and decrease. And then the model's effectiveness is verified by case study in the stem cell field and expert judgment. Finally, the model's disadvantages and the next jobs are introduced in the paper.
By developing a cluster sampling of stochastic series expansion quantum Monte Carlo method, we investigate a spin-$1/2$ model on a bilayer square lattice with intra-layer ferromagnetic (FM) Ising coupling and inter-layer antiferromagnetic Heisenberg interaction. The continuous quantum phase transition which occurs at $g_c=3.045(2)$ between the FM Ising phase and the dimerized phase is studied via large scale simulations. From the analyzes of critical exponents we show that this phase transition belongs to the (2+1)-dimensional Ising universality class. Besides, the quantum entanglement is strong between the two layers, especially in dimerized phase. The effective Hamiltonian of single layer seems like a transverse field Ising model. However, we found the quantum entanglement Hamiltonian is a pure classical Ising model without any quantum fluctuations. Furthermore, we give a more general explanation about how a classical entanglement Hamiltonian emerges.
Abstract Pure organic room‐temperature phosphorescence (RTP) materials have been widely utilized in security signs, anti‐counterfeiting, data encrypting, and other fields, which have attracted great attention. In the past few years, smart materials with color‐tunable organic RTP materials are reported by many researchers, while the work focused on the color‐tunable polymeric RTP materials is still rare, especially for molecular weight‐dependent polymeric RTP systems. Here, we designed and prepared three molecular weight polymers P1, P2, and P3 by different polymerization reaction times, and found that the fluorescence emissions of these polymer powders are various. Unexpectedly, the molecular weight‐dependent polymeric RTP materials are achieved through doping these polymers into polyacrylonitrile (PAN) matrix, and the International de l'Eclairage was redshift from (0.205,0.257) to (0.503,0.435). This phenomenon is ascribed to the different aggregation states formed by assembly of different molecular weight polymeric chains. Meanwhile, the electrostatic interaction between phosphor and PAN is hardly affected by water. Therefore, advanced information encryption can be achieved by using these polymeric phosphors as anti‐counterfeiting ink.
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