A Luminescent Metal–Organic Framework Thermometer with Intrinsic Dual Emission from Organic Lumophores

A new mixed‐ligand metal–organic framework (MOF), ZnATZ‐BTB, has been constructed as a luminescent ratiometric thermometer by making use of the intrinsic dual emission at cryogenic temperatures. Its twofold interpenetrated network promotes the Dexter energy transfer (DET) between the mixed organic lumophores. The temperature‐dependent luminescent behavior arises from the thermal equilibrium between two separated excited states coupled by DET, which is confirmed by Boltzmann distribution fitting. The small excited‐state energy gap allows ZnATZ‐BTB to measure and visualize cryogenic temperatures (30–130 K) with significantly high relative sensitivity (up to 5.29 % K^?1 at 30 K). Moreover, it is the first example of a ratiometric MOF thermometer the dual emitting sources of which are widely applicable mixed organic ligands, opening up new opportunities for designing such devices.     

Free energy and states of fractional-order hereditariness

Complex materials, often encountered in recent engineering and material sciences applications, show no complete separations between solid and fluid phases. This aspect is reflected in the continuous relaxation time spectra recorded in cyclic load tests. As a consequence the material free energy cannot be defined in a unique manner yielding a significative lack of knowledge of the maximum recoverable work that can extracted from the material. The non-uniqueness of the free energy function is removed in the paper for power-laws relaxation/creep function by using a recently proposed mechanical analogue to fractional-order hereditariness.     

功率对氘代辉光放电聚合物结构和力学性能的影响

采用射频辉光放电聚合技术,在低压等离子体聚合装置上开展在5~20 W功率下氘代辉光放电聚合物薄膜的制备及性能研究。利用傅里叶变换红外吸收光谱仪表征薄膜的化学结构,讨论了功率变化对其官能团结构的影响规律。利用元素分析仪和纳米压痕仪表征薄膜中氘原子的相对含量和薄膜的力学性能。研究表明:随着功率的升高,薄膜中的氘含量先升高后降低,在10W时达到最大,薄膜中SP3 CD的相对含量增加,SP3 CD2的相对含量减小;聚合物薄膜的硬度和杨氏模量均随功率的增加而减小。     

Elastic behavior of composites containing multi-layer coated particles with imperfect interface bonding conditions and application to size effects and mismatch in these composites

This paper proposes a procedure to deal with n-layered inclusion based composites with imperfect interfaces (which conditions consist of displacement or stress vector jumps) respecting spherical symmetry. For that purpose, “discontinuity matrices” have been introduced. These matrices have been derived for several classical interface-models and an asymptotic method has been used to determine some of them. A self-consistent condition based on a strain-energy equivalence in the case of inclusion-matrix type composite materials is restated for n-layered inclusions with imperfect interfaces and applied to get estimates of such composites materials. The remarkable feature of the presently self consistent approach is that it does not need any tedious algebra providing the attached interface models respect the spherical symmetry. The present Generalized Self Consistent Model (GSCM) is then used to study size effects and mismatch in composites reinforced by coated inclusions.     

冶金法生产太阳能级硅的除硼方法、技术及工艺

太阳能作为一种绿色可再生能源受到了广泛关注,而杂质去除是从冶金级硅中获得太阳能级硅所需的纯化过程,对硅基太阳能电池的制备至关重要。冶金法制备太阳能级多晶硅新工艺技术由于其能耗低、成本低和污染少等优点,成为研究开发的热点,但如何有效地去除硼是我们面临的最严峻的挑战之一。本文综述了硼的热力学和动力学性质(溶解度、扩散率、扩散系数、传质系数和活度系数)以及近年来除硼的相关课题研究(吹气、炉渣处理、等离子体处理、酸浸和溶剂精炼)。研究发现,溶剂精炼是一种很有前途的获取高纯硅的方法,硅的富集率以及硼的去除率均可达到90%以上,而添加剂能够加强硼化物的形成和析出来改进除硼工艺,且后续几乎可被完全消除,不会对精炼硅造成污染,这将更加有效除硼并增加工艺实用性。最后本文对几种除硼工艺进行了比较分析,并对冶金法的应用前景进行了展望。     

Total Synthesis of the 7,10‐Epimer of the Proposed Structure of Amphidinolide N,Part II: Synthesis of C17–C29 Subunit and Completion of the Synthesis

The total synthesis of 7,10‐epimer of the proposed structure of amphidinolide N was accomplished. The requisite chiral C17–C29 subunit was assembled stereoselectively via Keck allylation, Shi epoxidation, diastereoselective 1,3‐reduction, and a later oxidative synthesis of the THF framework. The C1–C13 and C17–C29 subunits were successfully coupled using a Enders RAMP “linchpin” as the C14–C16 three carbon unit, thereby controlling the chirality at C14 and C16. The labile allyl epoxy moiety was successfully constructed by Grieco–Nishizawa olefination at a final stage of the synthesis.     

Dual Chemical Modification of a Polytheonamide Mimic: Rational Design and Synthesis of Ion‐Channel‐Forming 48‐mer Peptides with Potent Cytotoxicity

Polytheonamide B ( 1 ) is a natural peptide that displays potent cytotoxicity against P388 mouse leukemia cells (IC₅₀=0.098 nm ). Linear 48‐mer 1 is known to form monovalent cation channels on binding to lipid bilayers. We previously developed a fully synthetic route to 1 , and then achieved the design and synthesis of a structurally simplified analogue of 1 , namely, dansylated polytheonamide mimic 2 . Although the synthetically more accessible 2 was found to emulate the channel function of 1 , its cytotoxicity was decreased 120‐fold. Herein, the chemical preparation and biological evaluation of seven analogues 3 – 9 of 2 are reported. Compounds 3 – 9 were modified at their N terminus and/or the side chain of residue 44 of 2 to alter their physicochemical properties. The total synthesis of 3 – 9 was accomplished in a unified fashion by a combination of solid‐phase and solution‐phase chemistry. Systematic evaluation of the hydrophobicities, single‐channel currents, ion‐exchange activities, and cytotoxicities of 3 – 9 revealed that their hydrophobicities are correlated with the total magnitude of ion exchange and determine their cytotoxic potency. Consequently, the most hydrophobic analogue 9 exhibited the lowest IC₅₀ value, which is comparable to that of 1 . Therefore, these results clarified that the bioactivity of the polytheonamide‐based peptides can be rationally controlled by changing their hydrophobicity at the N and C termini of the 48‐amino‐acid sequence.     

THE GENERALIZED RIEMANN PROBLEM FOR A SCALAR NONCONVEX COMBUSTION MODEL-THE PERTURBATION ON INITIAL BINDING ENERGY

In this article,we study the generalized Riemann problem for a scalar nonconvex Chapman-Jouguet combustion model in a neighborhood of the origin (t ＞ 0) on the (x,t) plane.We focus our attention to the...     

A Light-Harvesting/Charge-Separation Model with Energy Gradient Made of Assemblies of meta-Pyridyl Zinc Porphyrins

Self-assembly of porphyrins is a fascinating topic, not only for mimicking chlorophyll assemblies in photosynthetic organisms, but also for the potential of creating molecular-level devices. Herein, zinc porphyrin derivatives bearing a meta-pyridyl group at the meso position were prepared and their assemblies studied in chloroform. Among the porphyrins studied, one with a carbamoylpyridyl moiety gave a distinct ¹H NMR spectrum in CDCl₃, which allowed the supramolecular structure in solution to be probed in detail. Ring-current-induced chemical-shift changes in the ¹H NMR spectrum, together with vapor-pressure osmometry and diffusion-ordered NMR spectroscopy, among other evidence, suggested that the porphyrin molecules form a trimer with a triangular cone structure. Incorporation of a directly linked porphyrin–ferrocene dyad with the same assembling properties in the assemblies led to a rare example of a light-harvesting/charge-separation system in which an energy gradient is incorporated and reductive quenching occurs.