ABSTRACT Plants and insects have co-existed for millions of years. Although research has been conducted on various insect species that induce galls on various plant tissues, information is particularly scarce when it comes to insects that form galls on the tough trunk of their host plants. This contribution describes the gall-inducing aphid Nipponaphis hubeiensis sp. nov. from the Zhushan County, Shiyan City, Hubei Province of China. This aphid induces enclosed galls with woody external layer on the trunk of Sycopsis sinensis (Saxifragales: Hamamelidaceae), an uncommon ecological niche in the aphid-plant interaction system. Morphological features for the identification of new species are provided. In addition, a partial sequence of the nuclear gene EF1α was amplified and sequenced to construct a cluster graph. Based on the clustering graph combined with morphology traits, the gall-forming aphid was classified into Nipponaphis. The unique ecological habits of this new aphid will bring innovative perspectives to the study of the evolution and diversity in aphid-host interaction.

The influence of the Nb5+-doped content and the doping CaCO3 on the electrical properties and the microdefects of BSTN ceramics by Positron Annihilation Techniques were studied, which were fired at 1350 ºC for 2 hours in air. The PTCR characteristics in the BSTN samples were also investigated. Moreover, the information on microdefects in BSTN ceramics was demonstrated by coincidence Doppler broadening spectrum measurements and positron annihilation lifetime spectra. Meanwhile, the influence of the defects on the electrical properties of the ceramics was also revealed. Furthermore, the critical donor-dopant content was 0.4 mol%, which corresponding room-temperature resistivity and the resistivity jumping ratio was 714.3 Ω·cm and 2.77 × 102, respectively. In addition, the average positrons annihilate lifetime t of the BSTN ceramics was investigated as well.

The effects of the sintering time on the electrical properties and the positive temperature coefficient of resistance (PTCR) effect of Ba1.006(Ti1-xNbx)O3 (BTN) ceramics were investigated, which were sintered at 1190 ºC for 0.5-6 hours in a reducing atmosphere and then re-oxidized at 800 ºC for 1 hour. The results indicated that the sintering time affected the electrical properties and the PTCR effect of the multilayer BTN samples, whose room-temperature resistance decreased with an increase of the sintering time at same sintering temperature of 1190 ºC. However, the resistance jump first increased and then reduced as a function of the sintering time. Furthermore, The BTN ceramics exhibited a pronounced PTCR effect, with a resistance jump greater by 3.6 orders of magnitude, along with a low RT resistance of 0.14 Ω at a reoxidated temperature of 800 ºC after sintering at 1190 ºC for 2 h in a reducing atmosphere. In addition, the activation energy of samples obtained at different sintering times had also been investigated.