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The control technique for linepack of natural gas pipeline network has been studied to ensure the safe and stable operation of gas pipeline network. The classification, control principle and control standard of linepack were elaborated based on the current production and operation experience of natural gas pipeline network, and the control technique for linepack was analyzed in detail from four aspects: selling in spring and autumn, guaranteed supply in winter and summer, gas distribution and prediction of accident pipeline survival time. The results suggest that linepack should be actively controlled for a uniform change according to the weekly inhomogeneity sale in spring and autumn, and it should be raised to the emergencyhigh level or the highest level to ensure the gas supply in winter and summer. The gas from the natural gas pipeline network can be reasonably distributed based on the control area of the linepack, and the survival time of the accident pipeline can be predicted according to the low linepack limit of natural gas pipeline.

1,3-Diacylglycerol (DAG) has been well recognized as a safe food component. The metabolic pathway of DAG in the body is different from that of triacylglycerol, and DAG has been demonstrated to contribute to improving metabolism and preventing obesity and cardiovascular diseases. However, the mass fraction of natural DAG in edible oils and fats is less than 10%, so the preparation of high-purity DAG has received widespread attention in recent years. Enzymatic synthesis is the method of choice for the industrial preparation of DAG due to the advantages of eco-friendliness, safety and desirable selectivity over chemical synthesis. Edible livestock and poultry fats, as by-products of slaughter and processing, have a special flavor and nutritional value. However, their undesirable physicochemical properties, especially high melting points and high levels of saturated fatty acids and cholesterols, highly limit their applications in the food industry. In light of this, the synthesis of DAG from edible livestock and poultry fats is a promising approach for their high-value utilization. The current status of the enzymatic synthesis and the potential application of DAG from livestock and poultry fats are reviewed in this article. It is anticipated that this review will provide new ideas for researchers interested in the enzymatic preparation and high-value utilization of DAG from livestock and poultry fats.