China's offshore oil and gas exploration sector has delivered encouraging news. CNOOC's Tianjin Branch recently announced the successful completion of a challenging exploration well in a Bohai oilfiel...

CF-4, CH-4, CI-4, and CJ-4 are quality grades for diesel engine oils. For example, CH-4 indicates a CH-grade quality level, with the “4” signifying it is for four-stroke engines. Currently, CF-4 and C...