diff --git a/Gemfile b/Gemfile
index f4697bf5..7dca07cd 100644
--- a/Gemfile
+++ b/Gemfile
@@ -63,7 +63,7 @@ gem 'elasticsearch-rails'
 gem 'oauth2'
 
 # xlsx
-gem 'axlsx_rails', '0.3.0'
+# gem 'axlsx_rails', '0.3.0'
 
 #Ruby 2.2+ has removed test/unit from the core library.
 if RUBY_VERSION>='2.2'
diff --git a/app/controllers/managements_controller.rb b/app/controllers/managements_controller.rb
index 53eb23ae..d4e08240 100644
--- a/app/controllers/managements_controller.rb
+++ b/app/controllers/managements_controller.rb
@@ -1416,7 +1416,8 @@ end
   def update_depart_identifier
     if params[:depart] && params[:identifier]
       @department = Department.where(:id => params[:depart]).first
-      @department.update_attributes(:identifier => params[:identifier]) if @department.present?
+      identifier = params[:identifier].strip.blank? ? nil : params[:identifier].strip
+      @department.update_attributes(:identifier => identifier) if @department.present?
     end
   end
 
diff --git a/app/models/school.rb b/app/models/school.rb
index 081f3c0c..fd925f9a 100644
--- a/app/models/school.rb
+++ b/app/models/school.rb
@@ -64,7 +64,7 @@ class School < ActiveRecord::Base
 
   def statistic_url
     dep = departments.where("identifier is not null").first
-    url = dep.present? ? "/colleges/#{dep.identifier}/statistics" : "/colleges/#{self.id}/statistics"
+    url = dep.present? && !dep.identifier.blank? ? "/colleges/#{dep.identifier}/statistics" : "/colleges/#{self.id}/statistics"
   end
 
   def course_act_time