简介：船舶锅炉用水的处理，各种教材均从不同侧面介绍了具体方法，但是对水处理的机理、处理的原因没有作具体分析,文章运用化学知识，对水处理的重要性、水处理的原理、投药的具体计算方法进行了详细的论述，以便为现实操作提供可参考的方法。

简介：Ananalyticalstudywaspresentedonactivecontrolofsoundtransmissionintoavibro-acousticenclosurecomprisingtwoflexibleplates.Twotypesofactuatorswereused,i.e.acousticactuatoranddistributedleadzirconatetitanatepiezoelectric(PZT)actuatorinsteadofpointforceactuator.Usingthemodalacoustictransferimpedance-mobilitymatrices,theexcitationandinteractioninthecoupledsoundtransmissionsystemcanbedescribedwithclearphysicalsignificance.Withthecontrolsystemdesignedtogloballyreducethesoundfield,differentcontrolsystemconfigurationswereconsidered,includingthestructuralactuatorontheincidentplate,actuatoronthereceivingplate,acousticactuatoronthecavity,andtheircombinations.Theeffectivenessandperformanceofthecontrolstrategycorrespondingtoeachsystemconfigurationwerecomparedanddiscussed.Theroleandcontrolmechanismofeachtypeofactuatorwereofparticularinterest.Itwasshownthattheincidentplateactuatoriseffectiveincontrollingthecavity-dominatedmodesandthestructuralmodesdominatedbytheincidentplateandreceivingplate.Twomaincontrolmechanismsareinvolvedinthiscontrolconfiguration,i.e.,modalsuppressingandmodalrearrangement.Forcontrolsystemconfigurationwithonlyacousticactuatorintheenclosure,themechanisminvolvedinthisarrangementispurelymodalsuppression.Desirableplacementsofstructuralactuatorsintermsoftotalpotentialenergyreductionwerealsodiscussed.

简介：文章分析了当前专科物理教材存在的问题,讨论了适应形势改革教材的几种思路.

简介：通过对航海类专业大学物理课程的教学实践,探讨航海院校航海类专业大学物理课程教学的改革,来更好地提高学生学习大学物理课程的效率,为航海类专业后续课程学习打下必要的理论基础.