Abstract: An in-situ analyzer for a nutritive salt includes an injector, a calorimetric detector (11), a mixing ring (12), a sample pipeline, a pure water bin, a standard solution bin and various reagent bins of the analyzer which are correspondingly connected to ports of a multi-way valve (5). A microprocessor is connected to a first motor driver and a first motor in turn, and then connected to an injection pump (6) of the injector. The microprocessor is connected to a second motor driver and a second motor in turn, and then connected to the multi-way valve (5) for controlling one port in the multi-way valve connected to the injector to be in respective and corresponding communication with other ports in the multi-way valve (5). The colorimetric detector (11) is connected with the microprocessor.

Abstract: The present invention provides two ways to form a special permeability discontinuity unit inside every sub-lens of a multi-axis magnetic lens, which either has a simpler configuration or has more flexibility in manufacturing such as material selection and mechanical structure. Accordingly several types of multi-axis magnetic lens are proposed for various applications. One type is for general application such as a multi-axis magnetic condenser lens or a multi-axis magnetic transfer lens, another type is a multi-axis magnetic non-immersion objective which can require a lower magnetomotive force, and one more type is a multi-axis magnetic immersion objective lens which can generate smaller aberrations. Due to using permeability-discontinuity units, every multi-axis magnetic lens in this invention can also be electrically excited to function as a multi-axis electromagnetic compound lens so as to further reduce aberrations thereof and/or realize electron beam retarding for low-voltage irradiation on specimen.