列管换热器内外侧对流传热系数分别是αi和α0且αi〉〉α0,要提高总传热系数,关键是()A、减小αiB、增大αiC、减小α0D、增大α0
列管换热器内外侧对流传热系数分别是αi和α0且αi〉〉α0,要提高总传热系数,关键是()
- A、减小αi
- B、增大αi
- C、减小α0
- D、增大α0
相关考题:
有一过程如下:Sub Sub1(m As Integer,total As Long)Dim i As Integertotal=1For i=1 To mtotal=total*iNextEnd Sub调用它的事件过程如下:Private Sub Command1_Click()Dim tot As Long,a As Integera=Val(InputBox("请输入数据"))Call Sub1(a,tot)Print totEnd Sub则输入数据5,运行结果为【 】。
阅读程序: Sub p( b () As Integer)For i =1To 4 b(i) = 2(iNext i End Sub Private Sub Command1_Click()Dim a (1 To 4) As Integer a(1)=5 a(2)=6 a(3)=7 a(4)=8 call p (a) For i=1 To 4 Print a(i) Next iEnd Sub运行上面的程序,单击命令按钮,输出结果为。
在列管换热器中,用饱和蒸汽加热空气,则下列判断正确的是()。A、空气的对流传热系数大于饱和蒸汽的对流传热系数B、换热器总传热系数K将接近饱和蒸汽的对流传热系数。C、空气一侧的对流热阻很小,可以忽略D、传热管的壁温将接近饱和蒸汽的温度
以下程序的运行结果是( ) #define MAX 10 int a[MAX],i; main() { printf("\n");sub1();sub3(A) ,sub2(),sub3(A) ; } sub2() { int a[MAX],i,max; max=5; for(i=0;i<max;i++)a[i]=i; } sub1() {for(i=0;i<MAX;i++)a[i]=i+i; } sub3(int a[]) { int i; for(i=0;i<MAX,i++)printf("%d",a[i]); printf("\n"); }A.0 2 4 6 8 10 12 14 16 18 0 1 2 3 4B.0 1 2 3 4 0 2 4 6 8 10 12 14 16 18C.0 1 2 3 4 5 6 7 8 9 0 1 2 3 4D.0 2 4 6 8 10 12 14 16 18 0 2 4 6 8 10 12 14 16 18
设有如下程序: Private Sub search(a()As Variant,ByVal key As Variant,index%) Dim I% For I = Lbound(a)To Ubound(A)If key=a(I)Then index=I Exit Sub End If Next I index=-1 End Sub Private Sub Form_Load() Show Dim b()As Variant Dim n As Integer b=Array(21,64,92,15,72,38,45,72) Call search(b, 45, n) Print n End Sub 程序运行后,输出的结果是A.2B.6C.10D.12
编写如下事件过程: Private sub sub1 (ByVal x1 As String, y1 As String) Dim xt As String Dim i As Integer i = Len(x1) Do While i>= 1 xt = xt + Mid(x1, i, 1) i=i-1 Loop y1 = xt End Sub Private Sub Form. Click() Dim s1 As String, s2 As String s1= "teacher" sub1 s1, s2 Print s2 End Sub 程序运行后,单击窗体,则窗体上显示的内容是A.rehcaetB.tahreeeC.themeeD.eerthea
编写如下事件过程: Option Base 1 Private Sub Form Click() Dim x1()As Integer Dim i As Integer Dim s As Integer ReDim x1(3) For i = 1 To UBound(x1) x1(i)=i + 1 Next i Call sub1(x1) For i = 1 To UBound(x1) s = s + x1(i) Next i Print s End Sub Private Sub sub1(n()As Integer) Dim i As Integer ReDim Preserve n(5) For i = 3 To 5 n(i)=n(i-1)*2 Next i End Sub 程序运行后,单击窗体,则窗体上显示的内容是A.6B.12C.24D.47
以下能够正确计算n!的程序是( )。A.Private Sub Commandl_C1ick()B.hiVate Sub Commandl_C1ick() n=5:x=1 n=5:x=1:i=1 DO DO X=x*1 X=X*1 i=i+1 i=i+1 Loop while i<n Loop While<n Print x Ptinte x End Sub End SubC.Private Sub Commandl_Click ()D.Pdvate Sub Commandl C1ick() n=5:X=1:i=1 n=5=:x=1:i=1 DO DO X=X*1 X=X*1 i=i+1 i=i+1 Loop While i>n Print x Print x End Sub End Sub
阅读程序 SUB P(B( ) AS INTEGER) FOR I=1 TO 4 B(I) =2*I NEXT I END SUB PRIVATE SUB COMMAND1_CLICK( ) DIM A( 1 TO 4) AS INTEGER A(1)=5 A(2) =6 A(3) =7 A(4) =8 P A( ) FOR I = 1 TO 4 MSGBOX A(I) NEXT I END SUB 运行上面的程序,单击命令按钮COMMAND1后,消息框4次输出的内容分别是( )。A.出错B.10, 12, 14, 16C.5, 6, 7, 8D.2, 4, 6, 8
class Super { public int i = 0; public Super(String text) { i = 1; } } public class Sub extends Super { public Sub(String text) { i = 2; } public static void main(String args[]) { Sub sub = new Sub(“Hello”); System.out.println(sub.i); } } What is the result?() A、 0B、 1C、 2D、 Compilation fails.
单选题class Super { public int i = 0; public Super(String text) { i = 1; } } public class Sub extends Super { public Sub(String text) { i = 2; } public static void main(String args[]) { Sub sub = new Sub(“Hello”); System.out.println(sub.i); } } What is the result?()A 0B 1C 2D Compilation fails.
单选题class super ( public int I = 0; public super (string text) ( I = 1 ) ) public class sub extends super ( public sub (string text) ( i= 2 ) public static void main (straing args) ( sub sub = new sub (“Hello”); system.out. PrintIn(sub.i); ) ) What is the result?()A Compilation will fail.B Compilation will succeed and the program will print “0”C Compilation will succeed and the program will print “1”D Compilation will succeed and the program will print “2”