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[Objective] How to rationally allocate agricultural land resources based on the farmland multifunctions and meet the diverse needs of human society for the products and services generated by farmland is currently a hot and challenging issue for farmland conservation. It is also a key scientific question that urgently needs to be addressed in the research field of farmland resource systems. [Methods] Thus, this study used systematic literature review to examine the research progress in the connotation and characterization of the multifunctional supply and demand of farmland, identification of supply-demand matching conditions and spatiotemporal evolution, factors affecting supply and demand, supply-demand mismatch effects, and policy regulations. It also discussed the future key areas and directions of research. [Results] The findings show that existing studies have mostly focused on the changes and trade-offs/synergies of multifunctionality from the supply perspective, with less research conducted from the demand and integrated supply-demand perspectives. Progress has been made in characterizing the supply and demand of multifunctional farmland. However, there is a limited usage of standardized evaluation methods and models, leading to the challenge of comparing quantitative results longitudinally and cross-sectional. While efforts have been made to identify the matching status of multifunctional farmland supply and demand, as well as the associated influencing factors, there is still a lack of in-depth research on the dynamic evolution patterns and driving mechanisms of multifunctional farmland supply-demand matching. [Conclusion] Future research should focus on the interactions between the farmland resource system and natural and socioeconomic systems, and further improve the analytical framework and characterization methods for regional multifunctional supply-demand matching of farmlands. By combining research at the macro and micro scales to deepen the understanding of the spatiotemporal evolution patterns and driving mechanisms of multifunctional supply-demand matching of farmlands. Decision-making mechanisms and regulatory approaches should also be explored to address multifunctional farmland management toward a Chinese-style modernization.

The soluble organic fractions (SOF) in diesel exhaust particulates have been extracted with ultrasonic separator and analyzed by gas chromatography/mass spectrometry (GC/ MS). The GC/MS conditions were as follows: an HP SE-50 capillary column (30 m x 0.2 mm i. d. x 0.2 microm); temperature programming started at 100 degrees C, holding for 2.0 min, then increased to 160 degrees C at a rate of 4.0 degrees C /min, then to 250 degrees C at 8 degrees C/min, finally, kept at 250 degrees C for 31.75 min; boiling chamber temperature 260 degrees C; helium gas as carrier; chapiter pressure 45 kPa; sample size 1 microL; electron impact energy of mass spectrometer 70 eV; multiplier voltage 1 800 V; mass range 300 - 500 u. The results showed that under exhaust temperature, about 80% of SOF in particulates were normal or isomeric alkanes with carbon numbers from 9 to 28. The rest of the fractions of SOF were polycyclic aromatic hydrocarbons (homologs of indene, fluorene, phenanthrene, naphthalene etc.) and other organic substances. It is demonstrated that most of SOF were from unburned diesel and engine oils. The testing conclusion should be useful in designing and evaluating particulate filters.