Longhai, a region located in North China, is home to a number of technical companies. Here are some of the most notable ones:

1. Longhai Iron and Steel Co., Ltd.: This company is one of the leading iron and steel producers in Longhai, specializing in the production of high-quality steels for various industries.

2. Longhai Electric Co., Ltd.: This company is another major player in the electric industry in Longhai. It specializes in the manufacturing of a wide range of electrical appliances, including power tools, electronic devices, and home appliances.

3. Longhai Chemical Industry Co., Ltd.: This company is one of the leading chemical industries in Longhai, specializing in the production of a wide range of chemicals for various industrial applications, such as pharmaceuticals, adhesives, polymers, and solvents.

In summary, Longhai has a thriving technical industry that produces a wide range of electrical appliances, chemicals, and other products. The companies listed above are just a few examples of the many technological companies located in Longhai.