硬度（hardness of water）
硬度（hardness of water）
相关考题：
4．— Did you have anyone ______the trees?—Yes，l had the trees ______．A． to water ;waterB． to water; wateredC． water ; to be wateredD． water; watered
The boiler water alkalinity in a coil-type auxiliary boiler should be maintained at the pH recommended by the boiler manufacturer to______.A.precipitate(使沉淀) silica （硅石）from solutionB.reduce corrosion in the heating coilC.prevent clogging and erosion in the coilD.maintain zero water hardness
Conditions for crossing a rough bar are usually best at ______.A.low water slackB.high water slackC.high water ebbD.high water flood
The height of tide is the ______.A.depth of water at a specific time due to tidal effectB.difference between the depth of the water and the area's tidal datumC.difference between the depth of the water and the high water tidal levelD.difference between the depth of the water at high tide and the depth of the water at low tide
单选题Why the cooling water of the diesel engine should be treated? Because the（）ACooling water is alkalescenceBcooling water is acidityCcooling water has salinityDcooling water has impurity
单选题Supposing there is a water container. The taller the container, ______ at the bottom.Agreater will the water pressure beBthe water pressure will be greaterCthe greater the water pressure will beDgreater the water pressure will be
单选题Supposing there is a water container. The taller the container, _____at the bottom.Agreater will the water pressure beBthe water pressure will be greaterCthe greater will be the water pressureDgreater the water pressure will be
单选题When distilling salt water the cooling water discharging from the distiller is fed back to evaporator as feed water （）.Ato cut down the amount of cooling water neededBto prevent an excess amount of cooling water from being discharged to the bilgesCto supply hot water to the evaporator for more economical operationDNone of the above is tree
单选题Which of the following may hardness of the boiler water cause?（） (1) scale formation (2) tube failure (3) corrosionA（1）and（2）B（1）and（3）C（2）and（3）D（1），（2）and（3）
单选题The height of tide is the （）.Adepth of water at a specific time due to tidal effectBdifference between the depth of the water and the area's tidal datumCdifference between the depth of the water and the high water tidal levelDdifference between the depth of the water at high tide and the depth of the water at low tide
单选题淡水注入管（）Afresh water filling pipeBsea water filling pipeCballast water filling pipeDbilge water filling pipe
单选题In a diesel engine jacket water cooler, with seawater cooling the fresh water, the（）Asea water temperature must never be warmer than 40℃Bjacket water pressure should always be greater than the sea water pressureCjacket water temperature must always be less than 60℃Djacket water pressure must always be less than the sea water pressure
单选题The boiler water alkalinity in a coil-type auxiliary boiler should be maintained at the pH recommended by the boiler manufacturer to（）Aprecipitate silica from solutionBreduce corrosion in the heating coilCprevent clogging and erosion in the coilDmaintain zero water hardness
单选题眼镜片膜层有 ①dye ②Antireflection film ③Water-proof film ④Hardness film ⑤Impact resistantfilm，膜层由表及里的顺序是（）A②③④⑤B⑤②③①C⑤④②③D②④⑤①
单选题Conditions for crossing a rough bar are usually best at （）.Alow water slackBhigh water slackChigh water ebbDhigh water flood
单选题Measure （） by means of lead wire.Athe clearance of the main bearingBthe diameter of main bearingCthe hardness of main bearingDthe tolerance of main bearing
单选题Shims of different thicknesses are inserted between the shells to enable adjustment of （）.Athe bearing clearancesBthe bearing thicknessCthe bearing strengthDthe bridge hardness
名词解释题硬度（hardness）