Aimin Shi

Photosynthetic Responses of Four Hosta Cultivars to Shade Treatments

The effects of shade on the gas exchange of four Hosta cultivars were determined under differing irradiances (5, 30, 50, and 100 % of full irradiance) within pots. Irradiance saturation ranged between 400–800 μmol m−2 s−1 among the four cultivars, of which H. sieboldiana cv. Elegans and H. plantagenea cv. Aphrodite exerted the lowest saturation and compensation irradiances. The maximal photosynthetic rate (Pmax) was significantly higher in shade than in full irradiance in Elegans and Aphrodite, and was at maximum in seedlings grown in 30 % of full irradiance. The best shade treatment for cvs. Antioch and Golden Edger was 50 % of full irradiance. The diurnal gas exchange patterns in four cultivars were greatly influenced by the irradiance. Single-peak patterns of net photosynthetic rate (PN) and stomatal conductance (gs) were observed under 5 and 30 % full irradiance for all the cultivars while Elegans and Aphrodite suffered from midday depression in 50 % of full irradiance. Under open sky, all four cultivars showed two-peak patters in their diurnal gas exchange, but the midday depression was less in Antioch and Golden Edger than in Elegans and Aphrodite. According to their photosynthetic responses to shade, the shade tolerance of the four cultivars was in the order: Elegans>Aphrodite>Antioch>Golden Edger.

Development and test of ADS injector II RFQ accelerator

The injector II RFQ accelerator of ADS is used to accelerate protons of 10 mA from 35 keV to 2.1 MeV. The cavity structure of the RFQ is the same as that of the SNS RFQ which has a square cross section, and it adopts π-mode rods to enhance the RF (radio frequency) stability of the cavity. Low power tests show that the flatness of the cavity is better than ±0.01 and the unloaded Q value is 13000. CW (continuous wave) working condition was realized after a long time conditioning of the cavity. Beam tests were conducted with a current of 10 mA in pulse mode and CW mode, respectively, and it indicates that the transmission efficiency is 95.3%, output energy is 2.165 MeV, energy spread is 1.9%, and the transverse and longitudinal emittances are all 0.33 πmm·mrad. ©, 2015, Atomic Energy Press. All right reserved.

Design study of the SSC-LINAC re-buncher

A re-buncher with spiral arms for a heavy ion linear accelerator named as SSC-LINAC at HIRFL (the heavy ion research facility of Lanzhou) has been constructed. The re-buncher, which is used for beam longitudinal modulation and matching between the RFQ and DTL, is designed to be operated in continuous wave (CW) mode at the Medium-Energy Beam-Transport (MEBT) line to maintain the beam intensity and quality. Because of the longitudinal space limitation, the re-buncher has to be very compact and will be built with four gaps. We determined the key parameters of the re-buncher cavity from the simulations using Microwave Studio software, such as the resonant frequency, the quality factor Q and the shunt impedance. The detailed design of a 53.667 MHz spiral cavity and measurement results of its prototype will be presented.