北仑：抗生素剂量不一致更新

kernel/src/main/java/com/lantone/qc/kernel/catalogue/beilun/threelevelward/THR03076.java

@@ -196,7 +196,7 @@ public class THR03076 extends QCCatalogue {
                                 infoAppend(sb, ai.getKey(), adDateStr);
                             }
                             if(wardUsage.size() == 0){
-                                sb = null;
+                                sb = new StringBuffer();
                                 break;
                             }
                         }