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This study compares the mechanical properties of the retard-bonded and conventionally bonded prestressed concrete (RBPC and BPC, respectively) under uniform loads. Results show that the prestressed strands and concrete of the RBPC T-beams are firmly bonded with harden of retard-bonded materials, thereby exhibiting the same mechanical properties as that of the BPC beams. The growth rate of the long-term deflections of the RBPC T-beam is slightly lower than that of the BPC T-beam. Given the effect of concrete shrinkage, creep and time variation of prestress loss, the regular patterns of deflection growth of the RBPC T-beam mid-spans are analysed based on the age-adjusted effective modulus method, method of equivalent prestress load and calculation model of prestress loss. Accordingly, the long-term deflection development curves of the RBPC T-beam mid-spans under self-weight, prestressing force and external loads are obtained. Calculation results are in good agreement with the test results. This method has immense applicability for the computation of the RBPC T-beams, and can be used to estimate the long-term deflection growth of regular patterns of the RBPC components.

More space truss construction has been planned to develop and utilize space resources. These trusses are designed in the way of large-scale, complex, modular, and on-orbit assembly. To meet the upcoming challenge of large-scale space infrastructure construction, it is necessary to study space truss automation design and robotic construction. This paper proposes an ordinal finite screw adjacency matrix model (OFSAMM), focusing on the relationship between assembly motions, to express and compute a space truss structure. In this model, a space truss is abstracted as a set of ordered assembly motions, each of which is recorded as a finite screw as the basic element of the truss and its assembly. The operation of truss transformation is also derived under this model. Therefore, the truss configuration, the assembly sequence, the truss sub-assembly, the truss components, and the on-orbit assembly task can be expressed and calculated in a unified model, which is calculated and stores the truss topology and assembly with the minimum storage cost. At the end of this paper, we introduce how to synthesize and optimize space truss design through two cases. The study will help to improve design efficiency. Furthermore, it provides a theoretical basis for the automatic construction of space truss structures, especially in the next stage.

It is an important way to improve carrier mobility by reducing the contact resistance in organic transistors. In this paper, two kinds of transistors were fabricated with copper phthalocyanine semiconductor. Then by experimental methods, we tested the devices with different structure and different channel length, and analyzed the effect of structure on contact resistance as well as output characteristic. The results demonstrate that gate voltage can effectively reduce the contact resistance in the top contact device.

Osteomyelitis is commonly developed viahematogenous spreading or direct inoculation of bacteria from orthopedics trauma. Pathogens-induced bone destruction impedes the penetration of antibiotics to the infection site, and the severe inflammation further compromises the traditional treatment outcome. In this work, vancomycin-loaded oligochitosan nanoparticles (Van-NPs) with antibacterial, antibiofilm, antioxidant as well as bone regenerative properties are prepared using sodium tripolyphosphate (TPP) as a crosslinker, and employed for the treatment of osteomyelitis. Van-NPs exhibit strong interactions with dissociative S. aureusand biofilms due to the positive zeta potential, the additional effect between vancomycin (Van) and oligochitosan (OCS) further contributes to an enhanced antibacterial and antibiofilm outcome. The in vitroosteogenic differentiation of rBMSCs is facilitated by the antioxidant ability of Van-NPs and the TPP-induced activation of ERK1/2 and p38 signaling pathways. Moreover, the combination of Van-NPs with PLGA-PEG-PLGA gel (Gel/Van-NPs) achieves successful localized treatment of osteomyelitis in terms of enhanced bacteria elimination, inflammatory modulation, and accelerated bone regeneration. Therefore, Gel/Van-NPs may serve as a promising biomaterial for the optimal treatment of osteomyelitis.

3-Chloro-3,6-dinitro-2,2-dimethyl-4-chromanone is the first 3-chloro-3-nitro-4-chromanone to be synthesized by nitrating its corresponding 4-chromanone at the 3 position and then chlorinating the nitration product. Its structure was determined by IR, NMR, MS and x-ray crystallography. It crystallizes as a pair of enantiomers with 2 molecules in the primitive triclinic space group P $$\overline 1$$ (#2) with a = 9.476(2), b = 10.906(3), c = 6.578(5) Å, and α = 101.08(3), β = 90.13(3), γ = 73.23(1)°, V = 637.7500 Å3, and Z = 2. The nitro group at the 6 position conjugates with the benzene ring. The pyranone ring has a half-chair conformation; the chloro group occupies the pseudoequatorial position, and the nitro group occupies the pseudoaxial position. The 2 and 3 positions are essentially antiperiplanar, minimizing steric interaction.

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