PCB circuit board chemistry laboratory
1. Acid Number (Acid Value) The acid value refers to the amount of free acid contained in 1 g of grease, wax or flux. The method is to dissolve the sample in hot alcohol with phenol titanium as an indicator, and the number of milligrams of potassium hydroxide required for titration is its acid value.
2. Baume is a liquid specific gravity representation of an imperial system. It is a unit of gravity that commemorates the French chemist Antoine Baume' and takes its surname as a liquid substance. The conversion to the metric weight is as follows: ◠4°C pure The density of water is 1g/cm; the ratio of other "same water" to the "pure water" is taken as the specific gravity, which is the metric "Specific Gravity" (Sp.Gr.; Specific Gravity). ◠If the liquid is heavier than water, the Be value is: Be=145-(145÷SP.Gr.) ◠If the liquid is lighter than water, the Be value is: BE=140÷(SP.Gr.-130)
3. The Desiccator dryer is a thick glassware. The seal is dense and airtight. A desiccant (such as calcium chloride or silica gel) can be placed in the bottom to keep the placed items dry.
4, Mole Moore, gram, gram atom refers to the mass of a substance "unit". For example, the gram molecular weight of sulfuric acid is 98 grams, so that 196 grams of sulfuric acid can be referred to as 2 "mole" sulfuric acid. For example, if the gram atom of carbon is 12 grams, 36 grams of carbon may be referred to as 3" moles" of carbon. The "molar concentration" means the number of moles of the substance contained in 1 liter of the aqueous solution, for example, 1 mole of sulfuric acid, that is, 98 grams of pure sulfuric acid per liter of the acid solution.
5, Normal ConcentraTIon (Strength) standard concentration, equivalent concentration is a representation of the concentration of aqueous solution, with N as a symbol, commonly used in the chemical field. The gramm molecular weight or gram atom of the substance is divided by its valence to obtain the gram equivalent. For example, the molecular weight of sulfuric acid is 98 grams, and the root price is 2, so its gram equivalent is 49 grams. The gram atom of copper is 63.54 g, and the valence is 2, so its gram equivalent is 31.77 g. Where 1 liter of aqueous solution contains 49 grams of pure sulfuric acid, it is called 1N concentration of sulfuric acid (in the case of divalent sulfuric acid, the molar concentration is twice the equivalent concentration, ie 1M = 2N, so 1N sulfuric acid is equal to 0.5) M sulfuric acid). When another 1 liter aqueous solution contains 31.77 grams of copper ions, the equivalent concentration is also 1N. pH Value is the artificial representation of the acidity and alkalinity of aqueous solution. The correct way of writing is to write small p and large H. The correct definition of the word is: the reciprocal of the hydrogen ion concentration (indicated by [H]) in water (1/[H]), and then the logarithm (log 1/[H]), which becomes the pH value. For example, the hydrogen ion concentration of an aqueous solution is 1/10,000 (abbreviated as 10-5), the reciprocal should be 105, and the logarithm of log 105 is obtained, that is, pH=5. It is a simplified digital method of expressing abstract ideas. Those with a pH between 0 and 7 are acidic, and the lower the number, the stronger the acidity. The pH is 7 to 14 and the alkalinity is higher. If the pH is expressed in mathematical formula: pH=log1/[H], it is entirely an artificial formula, not a mathematical truth.
6. QualitaTIve Analysis Qualitative analysis refers to the chemical analysis of what kind of "component" is contained in the material. It can be determined by traditional hand-operated method or instrumental analysis method to find out the elements of its composition.
7. QuanTITIve Analysis quantitative analysis is based on the "content" of various components in the material. The chemical analysis is to find out the weight of each component.
8. Volumetric Analysis Volumetric analysis refers to a simple manual chemical analysis method using solution titration, which is the most commonly used method in chemical laboratories. Be' Baume' ; Baume degree (In English specific gravity representation) MW Molecule Weight ; molecular weight Ph Acidity or Alkalinity of Aqueous Solntion; pH value of aqueous solution (note that this symbol must be written as small p large H, but wrong) Gr. Specific Gravity ;
Y star picket/Star picket( Y fence post ) :
Material : carbon steel
Standard : Australia and New Zealand standard
Usuage : mainly to used for farm picket,garden and fence ,Y star Picket is popular used in Australian and New zealand markets .
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The detail specifications of the star Picket as follows:
1.Star picket black bitumen painted or hot dipped galvanized.
2.1.58 kgs/meter & 2.04kgs/meter
3.450mm to 2400mm
4.Material:low carbon steel, Q235
5.Surface finish:powder Coated/hot dip galvanized/bituminous painted.
paint and hot dipped galvanized Y fence post with different size:1.58kgs/m, 1.86kgs/m, 1.9kgs/m,2.04kgs/m
black/PVC-Coated/hot dip galvanized/bituminous painted.
size:
1.58kgs/m, 1.86kgs/m,1.9kgs/m,2.04kgs/m
material:
Billet steel or rail steel
length:
450mm,1350mm,1500mm,1650mm,2400mm or according to your requirement
paking:
10PCS/bundle ,400pcs/pallet ,200pcs/pallet
Varies length: 450mm,1350mm,1500mm,1650mm,2400mm
surface:
|
|
2.04kg/M |
1.90kg/M |
1.86kg/M |
1.58kg/M |
|
Size |
28*28*30mm |
28*28*30mm |
28*28*30mm |
28*28*30mm |
|
Thickness |
3mm |
2.6mm |
2.5mm |
2.3mm |
|
|
0.45M |
0.60M |
0.90M |
1.35M |
1.50M |
1.65M |
1.80M |
2.10M |
2.40M |
|
Holes (Australia) |
2 |
3 |
5 |
11 |
14 |
14 |
14 |
7 |
7 |
|
Holes (New Zealand) |
|
|
|
7 |
7 |
7 |
8 |
|
|
|
|
Star Picket (Australia&New Zealand) Length |
||||||||||
|
0.45M |
0.60M |
0.90M |
1.35M |
1.50M |
1.65M |
1.80M |
2.10M |
2.40M |
2.70M |
3.00M |
|
|
SPEC |
PCS/MT |
PCS/MT |
PCS/MT |
PCS/MT |
PCS/MT |
PCS/MT |
PCS/MT |
PCS/MT |
PCS/MT |
PCS/MT |
PCS/MT |
|
2.04kg/M |
1089 |
816 |
544 |
363 |
326 |
297 |
272 |
233 |
204 |
181 |
163 |
|
1.90kg/M |
1169 |
877 |
584 |
389 |
350 |
319 |
292 |
250 |
219 |
195 |
175 |
|
1.86kg/M |
1194 |
896 |
597 |
398 |
358 |
325 |
298 |
256 |
224 |
199 |
179 |
|
1.58kg/M |
1406 |
1054 |
703 |
468 |
422 |
383 |
351 |
301 |
263 |
234 |
211 |
Steel Picket,Fence post,Y star picket,Metal Star Pickets,Y fence post,Y post
BAODING JIMAOTONG IMPORT AND EXPORT CO., LTD , https://www.chinagroundscrew.com