diff --git a/src/Chemistry/Compounds/Implements/Compound.cs b/src/Chemistry/Compounds/Implements/Compound.cs
index 2f8569b..97e2cf5 100644
--- a/src/Chemistry/Compounds/Implements/Compound.cs
+++ b/src/Chemistry/Compounds/Implements/Compound.cs
@@ -113,7 +113,6 @@ public class Compound
         Array.Empty<BaseBond>():
         Bonds.Where(bond => !bond.Connected && bond.Energy > bond.BondingEnergy);
     
-
     /// <summary>
     /// string used to save the compound
     /// </summary>
@@ -161,6 +160,7 @@ public class Compound
             .Select(group => $"{group.First().Element}"+ (group.Count() > 1 ? group.Count().ToString() : "") )
             .DefaultIfEmpty("")
             .Aggregate((a, b) => a + b);
+    
     /// <summary>
     /// dump the compound into save string
     /// </summary>
@@ -175,7 +175,6 @@ public class Compound
             atomMap[atom] = $"({atom.Element}.{atomMap.Count})";
         foreach (BaseBond bond in Bonds.Where(bond => bond.Connected))
             bondMap[bond] = $"<{bond.BondType}.{bondMap.Count}>";
-        
         foreach (BaseAtom atom in Atoms)
         {
             if (atom.Bonds.All(bond => !bond.Connected))
@@ -183,7 +182,6 @@ public class Compound
                 records.Add($"{atomMap[atom]}-<xxx.0>-<xxx.0>-(xxx.0)");
                 continue;
             }
-
             foreach (BaseBond bond in atom.Bonds.Where(bond => bond.Connected))
             {
                 if (bond == bond.ConnectedBond)
@@ -474,4 +472,8 @@ public class Compound
     /// 
     /// </summary>
     public CacheItem<double> FreeDensity { get; }
+
+    public double FreeVolume => Amount / FreeDensity.Get;
+
+    public double Volume => HomogeneousMixture.Volume * Concentration;
 }
\ No newline at end of file
diff --git a/src/Chemistry/Mixtures/Implements/HeterogeneousMixture.cs b/src/Chemistry/Mixtures/Implements/HeterogeneousMixture.cs
index 17d6630..90eb146 100644
--- a/src/Chemistry/Mixtures/Implements/HeterogeneousMixture.cs
+++ b/src/Chemistry/Mixtures/Implements/HeterogeneousMixture.cs
@@ -154,5 +154,22 @@ public class HeterogeneousMixture
             h.HeatExchange();
         }
     }
+
+    public void RemoveTop()
+    {
+        if (Layers.Count == 0)
+            return;
+        HomogeneousMixture x = LayerOrder.First.Value;
+        RemoveLayer(x);
+        
+    }
+
+    public void RemoveBottom()
+    {
+        if (Layers.Count == 0)
+            return;
+        HomogeneousMixture x = LayerOrder.Last.Value;
+        RemoveLayer(x);
+    }
 }
 
diff --git a/src/Chemistry/Mixtures/Implements/HomogeneousMixture.cs b/src/Chemistry/Mixtures/Implements/HomogeneousMixture.cs
index b6cabc5..b8649f2 100644
--- a/src/Chemistry/Mixtures/Implements/HomogeneousMixture.cs
+++ b/src/Chemistry/Mixtures/Implements/HomogeneousMixture.cs
@@ -564,6 +564,54 @@ public class HomogeneousMixture
     /// higher level mixture can resolve lower level mixture
     /// </summary>
     public double ResolveLevel => Compounds.Sum(c => c.Concentration * c.ResolveLevel);
+    /// <summary>
+    /// eigen resolvability of other mixture
+    /// </summary>
+    /// <param name="oth"></param>
+    /// <returns></returns>
+    public double EigenResolvability(HomogeneousMixture oth)
+    {
+        LieSU3 s = oth.LogStateMatrix.Get ^ LogStateMatrix.Get;
+        C3 a = new(1, 0.5, 1);
+        C3 b = new(0.5, 1, 0.5);
+        Complex w = a * s * b;
+        ComplexFieldStructure.Structure.Fix(w);
+        double res = w.Phase;
+        if (res > Math.PI)
+            res = 2 * Math.PI - res;
+        return res;
+    }
+    
+    /// <summary>
+    /// eigen resolvability from -pi to pi
+    /// </summary>
+    /// <param name="c"></param>
+    /// <returns></returns>
+    public double EigenResolvability(Compound c)
+    {
+        LieSU3 s = c.LogStateMatrix.Get ^ LogStateMatrix.Get;
+        C3 a = new(1, 0.5, 1);
+        C3 b = new(0.5, 1, 0.5);
+        Complex w = a * s * b;
+        w = ComplexFieldStructure.Structure.Fix(w);
+        double res = w.Phase;
+        if (res > Math.PI)
+            res = 2 * Math.PI - res;
+        return res;
+    }
+    /// <summary>
+    /// calculate resolvability from eigen resolvability
+    /// </summary>
+    /// <param name="eigenRes"></param>
+    /// <returns></returns>
+    public double Resolvability(double eigenRes)
+    {
+        double res = -Math.Tan((Math.Sin(eigenRes) * Math.PI - Math.PI) / 2);
+        if (Math.Abs(res) < 1E-6)
+            return res;
+        return res;
+    }
+    
     /// <summary>
     /// ability to resolve other compound
     /// </summary>
@@ -632,10 +680,17 @@ public class HomogeneousMixture
         HashSet<Compound> toAbsorb = new ();
         foreach (Compound c in hOther.Compounds)
         {
-            double maxRes = Resolvability(c);
+            double eigenRes = EigenResolvability(c);
+            double maxRes = Resolvability(eigenRes);
             double oRes = hOther.Resolvability(c);
-            if(oRes < 0 || maxRes < 0 || maxRes < oRes)
+            if(oRes < 0 || maxRes < oRes)
                 continue;
+            if (eigenRes.IsEqualApprox(0))
+            {
+                toAbsorb.Add(c);
+                continue;
+            }
+
             double maxResAmount = Amount;
             foreach (Compound ct in Compounds)
                 if (ct.IsometricTo(c))
@@ -652,7 +707,12 @@ public class HomogeneousMixture
             toAbsorb.Add(cSplit);
         }
         foreach (Compound c in toAbsorb)
+        {
+            double v = c.Volume;
+            hOther.Volume -= v;
+            Volume += v;
             AddCompound(c);
+        }
         if(hOther.Amount.IsEqualApprox(0))
             HeterogeneousMixture.RemoveLayer(hOther);
     }