diff --git a/ruoyi-ngtools/src/main/java/com/ruoyi/ngCalTools/controller/GasController.java b/ruoyi-ngtools/src/main/java/com/ruoyi/ngCalTools/controller/GasController.java
index b580443..48634f9 100644
--- a/ruoyi-ngtools/src/main/java/com/ruoyi/ngCalTools/controller/GasController.java
+++ b/ruoyi-ngtools/src/main/java/com/ruoyi/ngCalTools/controller/GasController.java
@@ -27,12 +27,12 @@ return  tempPar;
     }
     public int NG_Cal_Init() {
         //create object for calculating density
-        if (null == detailService) {
+        if (null == (detailService=new DetailService())) {
             return GasConstants.MEMORY_ALLOCATION_ERROR;
         }
 
         //create object for calculating thermodynamic properties
-        if (null == thermService) {
+        if (null == (thermService=new ThermService())) {
             return GasConstants.MEMORY_ALLOCATION_ERROR;
         }
 
@@ -48,7 +48,7 @@ return  tempPar;
     }
     public double SOS(GasProps gasProps) {
         // check if library is ready; initialize if necessary 
-        if (null == detailService || null == thermService) {
+        if (null == (detailService=new DetailService()) || null == (thermService=new ThermService())) {
             NG_Cal_UnInit();
             NG_Cal_Init();
         }
@@ -81,7 +81,7 @@ return  tempPar;
         int i;
 
         //check objects for readiness; try to initialize if not 
-        if (null == detailService || null == thermService)
+        if (null == (detailService=new DetailService()) || null == (thermService=new ThermService()))
         {
             NG_Cal_UnInit();
 
@@ -146,7 +146,7 @@ return  tempPar;
     }
     public double Zcal(GasProps gasProps, double dPlenumVelocity)
     {
-        if (null == detailService || null == thermService)
+        if (null == (detailService=new DetailService()) || null == (thermService=new ThermService()))
         {
             NG_Cal_UnInit();
             if (GasConstants.NG_Cal_INITIALIZED != NG_Cal_Init())