Abstract: Embodiments of this application provide a downlink control information transmission method in which after receiving one piece of downlink control information (DCI), the terminal device learns whether blind detection of DCI needs to be continued. The method includes: A terminal device receives first DCI, where the first DCI includes first indication information, and the first indication information is used to indicate a first antenna port. The terminal device determines, based on the first antenna port and antenna port configuration information, whether second DCI exists. The configuration information may include an index of a CDM group to which each of a plurality of antenna ports belongs and a maximum quantity of CDM groups that is supported by the terminal device. Alternatively the configuration information may include one or more antenna port groups, and each of the one or more antenna port groups includes one or more antenna ports.

Abstract: A communication method and apparatus. A terminal device determines channel state information based on S indexes of S vectors. Each of the S vectors is included in a first vector quantization dictionary. The first vector quantization dictionary includes N1 vectors, where N1 and S are both positive integers. The terminal device sends the channel state information to a network device. Because a vector included in the vector quantization dictionary usually has a relatively large dimension, quantizing channel information by using the first vector quantization dictionary is equivalent to performing dimension expansion on the channel information or maintaining a relatively high dimension. High-precision feedback is implemented by using relatively low signaling overheads.

Abstract: The present invention discloses a method for preparing isocyanates by liquid-phase catalytic thermal cracking. In this method, in a reaction-rectification thermal cracking reactor, using a catalyst composition comprising a superfine powder metal oxide catalyst and an ionic liquid, an alkyl or aryl dialkylurethane, or multialkylurethane being a reactant is liquid-phase thermal cracked for a reaction time of 0.5-3 h under a reaction temperature of 160-220° C. and an absolute pressure of 1000-8000 Pa so as to prepare the corresponding isocyanate. The invention has the characteristics of low thermal cracking temperature, high yield of target products, relatively simple reaction apparatus and good universality for substrates (the yields of HDI, MDI, TDI, HMDI, NDI and IPDI or the like are all>85%) and the like.

Abstract: The present invention discloses a method for preparing isocyanates by liquid-phase catalytic thermal cracking. In this method, in a reaction-rectification thermal cracking reactor, using a catalyst composition comprising a superfine powder metal oxide catalyst and an ionic liquid, an alkyl or aryl dialkylurethane, or multialkylurethane being a reactant is liquid-phase thermal cracked for a reaction time of 0.5-3 h under a reaction temperature of 160-220° C. and an absolute pressure of 1000-8000 Pa so as to prepare the corresponding isocyanate. The invention has the characteristics of low thermal cracking temperature, high yield of target products, relatively simple reaction apparatus and good universality for substrates (the yields of HDI, MDI, TDI, HMDI, NDI and IPDI or the like are all >85%) and the like.