Mesoscale Simulation for Heavy Petroleum System Using Structural Unit and Dissipative Particle Dynamics (SU–DPD) Frameworks

Abstract

In this paper, we present a mesoscale simulation method for heavy petroleum combing structural unit (SU) and dissipative particle dynamics (DPD). We proposed 16 basic SUs, which represent the basic structural fragments for heavy petroleum molecules. The SUs were then used as beads in DPD simulation. The process for bead partition and DPD parameter calculation were described. The presented method links the molecular compositional modeling with mesoscale modeling via a chemical-defined mapping process. The equilibrium state of aromatic hydrocarbons with different ring numbers was simulated by the SU−DPD method, proving that the self-assembly behavior of polycyclic aromatic hydrocarbon systems can be properly revealed. On this basis, we built the SU−DPD model for heavy petroleum in terms of averaged four-components molecules. Various heavy petroleum systems were simulated at a coarse-grained level, including pure asphaltene system, asphaltene− toluene system, heavy petroleum system, and heavy petroleum−water system. The simulation results were consistent with the Yen−Mullins model and experimental results.

Meeting the New Members of the Chinese Academy of Sciences (Chemistry)

“…[1] FNAs are DNA architecture with high structural stability and designable mechanical rigidity, which are suitable for organization of higher-ordered nanocomplexes and nanodevices ( Figure B). [2] As examples, we employed FNAs to engineer the biosensing interface and cytoplasmic interface for molecular computation ( Figure C), [3] diagnosis and imaging (Figure D). [4] Favorite Chemistry…”

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“…Jianlin Shi and his colleagues have newly raised a novel concept of "Nanocatalytic Medicine" for the treatments of serious diseases such as malignant tumors, which features the use of non-toxic or less toxic nanoparticles/molecules, rather than conventional highly toxic chemodrugs for chemotherapies, e.g., tumortherapy, without intrinsic harmful side-effects, [1] as schematically illustrated in the following Figure. This strategy can be fulfilled by the in-situ catalytic chemical reactions based on/from the intratumorally delivered non-toxic nanoparticles, for the generations of antitumor effects such as cell-destructive reactive oxygen species (hydroxyl radicals, super oxygen anions, singlet oxygen, etc. ), [2] total depletion of oxygen and nutrient supply, [2] and intratumoral oxygenation for facilitating clinic hypoxic tumor treatment by radiation/chemo-therapies, [4] etc., in response to the endogenous and/or exogeneous stimulations. As the delivered nanoparticles/molecules are almost non-toxic, the harmful side effects of conventiolnal chemodrugs can be essentially or totally mitigated even if most of the nanoparticles are still uptaken in normal tissues.…”

“…[1] Constucting a gene delivery system for tumor-specific expression of therapeutic proteins provides an alterantive strategy for checkpoint-based therapy -local expression was proved to reduce the irAEs caused by systemic blockade or activation of the immune checkpoints. [2] Aiming at the immunosuppressive tumor microenvironment, nanoparticles for tumor-targeted delivery of small molecular immunomodulators have been shown to relieve the immunosuppressive microenvironment and potentiate the response rates of PD-1 checkpoint inhibitors in several tumor types. [3] Accounting for the characteristics of immunotherapy, the integration of nanotechnology and immunotherapy may result in many new 'nano-immunotherapeutics' for clinical success.…”