function lockStrategy(address _adr) private returns(uint256){
        HolderSchedule storage holderSchedule = holderList[_adr];
        uint256 interval=block.timestamp.sub(holderSchedule.startAt);
        uint256 unlockAmount=0;
        if(interval>=singleNodeTime){
            uint256 unlockNum=interval.div(singleNodeTime);
            uint256 nextUnlockNum=unlockNum.sub(holderSchedule.unlockNumed);
            if(nextUnlockNum>0){
                holderSchedule.unlockNumed=unlockNum;
                uint totalAmount=holderSchedule.lockAmount.add(holderSchedule.releasedAmount);
                uint singleAmount=totalAmount.div(totalUnlockNum);
                unlockAmount=singleAmount.mul(nextUnlockNum);
                if(unlockAmount>holderSchedule.lockAmount){
                    unlockAmount=holderSchedule.lockAmount;
                }
            }
        }
        return unlockAmount;
    }