ABSTRACT
We demonstrated a deep-red laser source by intracavity frequency-doubled crystalline Raman laser for the first time, to the best of our knowledge. The actively Q-switched 1314 nm Nd:LiYF4 laser was first converted to the eye-safe Raman laser using a KGd(WO4)2 (KGW) crystal, which was subsequently frequency-doubled in a bismuth borate crystal. Benefiting from the KGW bi-axial properties, the deep-red laser source was able to lase separately at two different spectral lines at 730 and 745 nm. Under an optimal repetition rate of 4 kHz, the maximum average powers of 1.7 and 2.0 W were attained with good beam quality of M2≈1.7. The corresponding pulse durations were determined to be 3.0 and 2.8 ns with the peak powers up to approximately 140 and 180 kW, respectively.
ABSTRACT
Based on the 1981-2006 observation data from agricultural meteorological stations at Minle (high altitude) and Zhangye (low altitude) in northwest arid area, the effects of air temperature change at the two altitudes on the growth and yield of spring wheat were studied. It was shown that during study period, the air temperature at the two altitudes had an increasing trend, and the increment was greater at high altitude than at low altitude. At high altitude, the growth duration of spring wheat shortened but the grain yield increased; while at low altitude, the growth duration shortened and the yield decreased. When the mean daily air temperature during spring wheat growth period increased by 1 degrees C, the growth duration shortened by 8.3 days at high altitude and by 3.8 days at low altitude. The growth duration and grain yield of spring wheat at high altitude had a slight increase when the maximum air temperature during growth period was below 30.4 degrees C, but decreased when the maximum air temperature was above 30.4 degrees C.
Subject(s)
Altitude , Biomass , Temperature , Triticum/growth & development , ChinaABSTRACT
OBJECTIVE: In the interest of establish planting base of Angelica sinensis on a large scale, enhance economic benefit, and improve decision-making reasons, the eco-climatic applicability of A. sinensis was studied. METHOD: Using integral regression, eco-climatic applicability and the effect of meteorological conditions for the yield of A. sinensis' were analysed by field experimental data. RESULT: Selected > or =0 degrees C accumulated temperature and annual precipitation as leading index, altitude as assistant index, yield and rate of finished products as reference index, the integrated eco-climatic division index and the planting division applicability of A. sinensis was confirmed. CONCLUSION: Accordancing to theory of climate similitude and leading index summarisation, combining with assistant index and reference index, the integrated division index of eco-climate was confirmed. The planting division of co-climate applicability was divided into 5 grades as best suitable, suitable hypo-suitable, just suitable and no suitable regions. At the same time,the way to enhanced utilizing efficiency of eco-climate resources was brought forward.
