SEMI P23-1993
时间: 2024-08-15 21:02:59 浏览: 35
SEMI P23-1993是由Semiconductor Industry Association (半导体行业协会)发布的一项标准,它全称为"Standard for Thermal Management Practices – Electronic Equipment". 这个标准专门针对电子设备的热管理实践进行了规范,目的是为了优化电子元件、模块和系统的散热设计,确保其能够在高功率密度运行下保持稳定性能和延长使用寿命。P23-1993涵盖了热设计的各个阶段,包括热分析、冷却系统选择、材料属性考虑等,并对测试方法和评估流程也提出了指导。
相关问题
{matrix_p23,1'b0}
这看起来像是一个Verilog HDL中的代码片段。`{matrix_p23, 1'b0}` 表示一个拼接操作,将 `matrix_p23` 和 `1'b0` 进行拼接。
在Verilog HDL中,`matrix_p23` 和 `1'b0` 都是信号或变量的表示方式。这里的 `matrix_p23` 可能是一个信号或变量,而 `1'b0` 表示一个单个的位(bit)值,其中 `1` 是表示位的值,`'b0` 是表示二进制形式的表示方式。
拼接操作 `{}` 在Verilog HDL中用于将多个信号或变量按照顺序拼接成一个更大的信号或变量。
所以,`{matrix_p23, 1'b0}` 表示将 `matrix_p23` 和 `1'b0` 按顺序拼接在一起,形成一个新的信号或变量。具体的含义和用途需要根据代码上下文来确定。
在上一题Point2D和Point3D类的基础上,新建一个TestPointV2类,在TestPointV2类的main()方法中添加如下语句。 Scanner sc = new Scanner(System.in); System.out.println("Please enter the coordinates of p23:"); double p23x = sc.nextDouble(); double p23y = sc.nextDouble(); Point2D p23 = new Point2D(p23x, p23y); System.out.println("Please enter the coordinates of p31:"); double p31x = sc.nextDouble(); double p31y = sc.nextDouble(); double p31z = sc.nextDouble(); Point3D p33 = new Point3D(p31x, p31y, p31z); System.out.println("Please enter the coordinates of p24:"); double p24x = sc.nextDouble(); double p24y = sc.nextDouble(); double p24z = sc.nextDouble(); sc.close(); // The reference of the parent class refers to the object of the subclass. Point2D p24 = new Point3D(p24x, p24y, p24z); System.out.println("Does " + p23 + " coincide with " + p33 + "? -- "+ p23.equals(p33)); System.out.println("Does " + p33 + " coincide with " + p23 + "? -- "+ p33.equals(p23)); System.out.println("Does " + p33 + " coincide with " + p24 + "? -- "+ p33.equals(p24)); System.out.println("Does " + p24 + " coincide with " + p33 + "? -- "+ p24.equals(p33)); System.out.println("Does " + p23 + " coincide with " + p24 + "? -- "+ p23.equals(p24)); System.out.println("Does " + p24 + " coincide with " + p23 + "? -- "+ p24.equals(p23)); 假设引用变量p23、p33和p24所指点对象的坐标依次为(0, 0),(0, 0, 5),(0, 0, 5)。从键盘输入这三个点的坐标值,上述语句的运行结果如下: Please enter the coordinates of p23: 0 0 Please enter the coordinates of p31: 0 0 5 Please enter the coordinates of p24: 0 0 5 Does (0.0, 0.0) coincide with (0.0, 0.0, 5.0)? -- true Does (0.0, 0.0, 5.0) coincide with (0.0, 0.0)? -- true Does (0.0, 0.0, 5.0) coincide with (0.0, 0.0, 5.0)? -- true Does (0.0, 0.0, 5.0) coincide with (0.0, 0.0, 5.0)? -- true Does (0.0, 0.0) coincide with (0.0, 0.0, 5.0)? -- true Does (0.0, 0.0, 5.0) coincide with (0.0, 0.0)? -- true 该结果显然不符合事实,请分析原因并改进Point2D类的代码,使得上述TestPointV2类的代码能够得到正确的运行结果。
上述运行结果不正确的原因在于 Point2D p24 = new Point3D(p24x, p24y, p24z); 这一语句,将一个 Point3D 对象赋值给了 Point2D 类型的引用变量 p24,导致在调用 p24.equals(p33) 时出现了错误的结果。
为了解决这个问题,我们需要在 Point2D 类中添加一个 equals 方法,用于比较两个点是否相同。具体代码如下:
```java
public boolean equals(Object obj) {
if (obj instanceof Point2D) {
Point2D other = (Point2D) obj;
return this.x == other.x && this.y == other.y;
}
return false;
}
```
这个 equals 方法首先判断参数是否为 Point2D 类型,如果是,再将其转换为 Point2D 类型进行比较。这样就可以避免上述问题的出现。
修改后的 Point2D 类的完整代码如下:
```java
public class Point2D {
protected double x;
protected double y;
public Point2D() {
this(0, 0);
}
public Point2D(double x, double y) {
this.x = x;
this.y = y;
}
public double getX() {
return x;
}
public double getY() {
return y;
}
public void setX(double x) {
this.x = x;
}
public void setY(double y) {
this.y = y;
}
public boolean equals(Object obj) {
if (obj instanceof Point2D) {
Point2D other = (Point2D) obj;
return this.x == other.x && this.y == other.y;
}
return false;
}
}
```
修改后的 TestPointV2 类的完整代码如下:
```java
import java.util.Scanner;
public class TestPointV2 {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Please enter the coordinates of p23:");
double p23x = sc.nextDouble();
double p23y = sc.nextDouble();
Point2D p23 = new Point2D(p23x, p23y);
System.out.println("Please enter the coordinates of p31:");
double p31x = sc.nextDouble();
double p31y = sc.nextDouble();
double p31z = sc.nextDouble();
Point3D p33 = new Point3D(p31x, p31y, p31z);
System.out.println("Please enter the coordinates of p24:");
double p24x = sc.nextDouble();
double p24y = sc.nextDouble();
double p24z = sc.nextDouble();
sc.close();
// The reference of the parent class refers to the object of the subclass.
Point2D p24 = new Point3D(p24x, p24y, p24z);
System.out.println("Does " + p23 + " coincide with " + p33 + "? -- " + p23.equals(p33));
System.out.println("Does " + p33 + " coincide with " + p23 + "? -- " + p33.equals(p23));
System.out.println("Does " + p33 + " coincide with " + p24 + "? -- " + p33.equals(p24));
System.out.println("Does " + p24 + " coincide with " + p33 + "? -- " + p24.equals(p33));
System.out.println("Does " + p23 + " coincide with " + p24 + "? -- " + p23.equals(p24));
System.out.println("Does " + p24 + " coincide with " + p23 + "? -- " + p24.equals(p23));
}
}
```
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