1. Potato science cutting potato method:
(1) Small potatoes below 40g can be sown with whole potatoes.
(2) 51g-100g of potato tubers, can be two longitudinally.
(3) 100g-150g potato chips, all three open longitudinal oblique cutting method, that is, the potato chips are cut longitudinally three times.
(4) Potato chips of 150g or more, from the tail of the tuber, according to the number of bud eyes, according to the arrangement of the potato buds, several small potato husks of small triangles are formed, and each small triangle potato stalk preferably has more than two healthy bud eyes.
Pay attention to the top advantage when cutting the block, try to bring the top bud. The cut should be placed near the bud eye to facilitate rooting.
2, potato cut size: cut seed potatoes weighing 35 ~ 40g, each cut with 2 sound buds.
3, potato cutting time: generally 2 to 3 days before sowing, it is not appropriate to prematurely cut, to prevent the length of seedlings or water loss.
4, chemical dressing: use 2 kg of 70% methyl thiophanate plus 1 kg of 72% agricultural streptomycin and evenly mix 50 kg of talcum powder into a powder, requiring 30 minutes after the potato is cut. The seed dressing treatment is carried out, and the amount of the powder to be mixed is 50 kg of the cut potato pieces mixed with 2 kg of the mixture.
Be sure to pay attention to the removal of miscellaneous potatoes, diseased potatoes and slender buds when cutting, to prevent dead seedlings from growing in the ground or to get sick, affecting potato yield and potato price.
Niobium Metals, plate, bar, wire, tube, target
Purity 99.95% min.
Density 8.6 g/cc
SGS certificate
Niobium belongs to the group of refractory metals. Refractory metals are metals that have a higher melting point than platinum (1 772 °C). In refractory metals, the energy binding the individual atoms together is particularly high. Refractory metals have a high melting pointcoupled with a low vapor pressure, high modulus of elasticity and high thermal stability. Refractory metals are also characterized by a low coefficient of thermal expansion. Compared to other refractory metals, niobium has a relatively low density of only 8.6 g/cm3
Niobium is located in the same period as Molybdenum in the periodic table. Its density and melting point are therefore comparable to those of molybdenum. In the same way as Tantalum, niobium is prone to hydrogen embrittlement. The heat treatment of niobium therefore takes place in a high vacuum and not in a hydrogen atmosphere. Both niobium and tantalum also offer a high level of resistance against all acids and good formability.
At -263.95 °C, niobium has the highest transition temperature of all elements. Below this temperature, niobium is superconducting. And what is more, niobium boasts a very special range of properties:
Properties |
||
Atomic number |
41 |
|
Atomic mass |
92.91 |
|
Melting point |
2 468 °C / 2 741 K |
|
Boiling point |
4 900 °C / 5 173 K |
|
Atomic volume |
1.80 · 10-29 [m3] |
|
Vapor pressure |
at 1 800 °C |
5 · 10-6 [Pa] |
at 2 200 °C |
4 · 10-3 [Pa] |
|
Density at 20 °C |
8.55 [g/cm3] |
|
Crystal structure |
body-centered cubic |
|
Lattice constant |
329.4 · 10-12 [m] |
|
Hardness at 20 °C |
formed |
110 - 180 [HV10] |
recrystallized |
60 - 110 [HV10] |
|
Modulus of elasticity at 20 °C |
104 [GPa] |
|
Poisson number |
0.35 |
|
Coefficient of linear thermal expansion at 20 °C |
7.1 · 10-6 [m/(m·K)] |
|
Thermal conductivity at 20 °C |
52 [W/(m·K)] |
|
Specific heat at 20 °C |
0.27 [J/(g·K)] |
|
Electrical conductivity at 20 °C |
7 · 10-6 [1/(Ω·m)] |
|
Specific electrical resistance at 20 °C |
0.14 [(Ω·mm2)/m] |
|
Sound speed at 20 °C |
Longitudinal wave |
4 920 [m/s] |
Transverse wave |
2 100 [m/s] |
|
Electron work function |
4.36 [eV] |
|
Capture cross-section for thermal neutrons |
1.15 · 10-28 [m2] |
|
Recrystallization temperature (annealing time:1 hour) |
850 - 1 300 [ °C] |
|
Superconductivity (transition temperature) |
< -263.95 °C / < 9.2 K |
Niobium Bar,High Purity Niobium Bar,Pure Niobium Round Bars,Pure Niobium Bars 99.95%
Baoji Shengyuan Metal Material Co., Ltd. , https://www.baojisymetal.com