A new species of Gesneriaceae, Hemiboea crystallina Y.M.Shui & W.H.Chen from China and Vietnam, is described and illustrated. The new species is diagnostic by the combination of its inflated nodes, glabrous stem, glabrous and lanceolate leaves, 4-winged involucre, margin-reflected calyx segments and the glabrous surface inside corolla. Among the species without hairy ring inside corolla, its morphological distinctiveness from the most similar species, Hemiboea flaccida Chun ex Z.Y.Li, is discussed.

The new species Raphiocarpus axillaris D.J.Middleton from Tam Đảo National Park in northern Vietnam is described and illustrated.

Three-phase grid-connected inverters using solar energy are applied very popular with large capacity. These inverters usually have input power sources in the direct current (DC) that varies according to the weather conditions. The DC voltage often needs to boost up the higher voltage level to be in accordance with the output voltage of inverters. Then, the output voltage of the DC/DC boost converter is in the form of DC voltage. In order to measure this DC value in the two-stage inverters, the existing methods usually use isolated voltage sensors. This paper presents a strategy for estimating the DC voltage value of inverters without using sensors in order to reduce cost and volume for inverters. The proposed method contributes to decreasing the price of inverters while ensuring the power quality of inverter outputs. The simulated results on MATLAB/Simulink have validated the performance of the presented solution.