空气流经阀门,其焓变化 _____ ,压力变化 _____ ,熵变化 _____ ,温度变化 ______ 。( )
A.
小于 mso-font-kerning:0pt;mso-ansi-language:EN-US;mso-fareast-language:ZH-CN; mso-bidi-language:AR-SA" xml:lang="EN-US">0 ,等于 mso-font-kerning:0pt;mso-ansi-language:EN-US;mso-fareast-language:ZH-CN; mso-bidi-language:AR-SA" xml:lang="EN-US">0 ,等于 mso-font-kerning:0pt;mso-ansi-language:EN-US;mso-fareast-language:ZH-CN; mso-bidi-language:AR-SA" xml:lang="EN-US">0 ,大于 mso-font-kerning:0pt;mso-ansi-language:EN-US;mso-fareast-language:ZH-CN; mso-bidi-language:AR-SA" xml:lang="EN-US">0
B.
等于 mso-font-kerning:0pt;mso-ansi-language:EN-US;mso-fareast-language:ZH-CN; mso-bidi-language:AR-SA" xml:lang="EN-US">0 ,小于 mso-font-kerning:0pt;mso-ansi-language:EN-US;mso-fareast-language:ZH-CN; mso-bidi-language:AR-SA" xml:lang="EN-US">0 ,大于 mso-font-kerning:0pt;mso-ansi-language:EN-US;mso-fareast-language:ZH-CN; mso-bidi-language:AR-SA" xml:lang="EN-US">0 ,小于 mso-font-kerning:0pt;mso-ansi-language:EN-US;mso-fareast-language:ZH-CN; mso-bidi-language:AR-SA" xml:lang="EN-US">0
C.
等于 mso-font-kerning:0pt;mso-ansi-language:EN-US;mso-fareast-language:ZH-CN; mso-bidi-language:AR-SA" xml:lang="EN-US">0 ,小于 mso-font-kerning:0pt;mso-ansi-language:EN-US;mso-fareast-language:ZH-CN; mso-bidi-language:AR-SA" xml:lang="EN-US">0 ,大于 mso-font-kerning:0pt;mso-ansi-language:EN-US;mso-fareast-language:ZH-CN; mso-bidi-language:AR-SA" xml:lang="EN-US">0 ,等于 mso-font-kerning:0pt;mso-ansi-language:EN-US;mso-fareast-language:ZH-CN; mso-bidi-language:AR-SA" xml:lang="EN-US">0
D.
等于 mso-fareast-font-family:宋体;color:#666666;mso-font-kerning:0pt" xml:lang="EN-US">0 ,小于 mso-font-kerning:0pt" xml:lang="EN-US">0 ,小于 mso-fareast-font-family:宋体;color:#666666;mso-font-kerning:0pt" xml:lang="EN-US">0 ,大于 mso-font-kerning:0pt" xml:lang="EN-US">0 mso-font-kerning:0pt" xml:lang="EN-US">