A system and method are disclosed for effectively compensating for an unbalanced or non-zero centerline radio-frequency potential in a quadrupolar ion trap, the unbalanced centerline potential created by a compensation feature that minimizes non-linear field components created by one or more ejection slots in the ion trap. There is also disclosed a method for making the aerosol and methods for treatment and diagnosis using the aerosol. 10\u22126 K\u22121 from the coefficient of at least one of the two components. Moreover, when R2<Rc, the collision risk RI of a first-type obstacle is compared with a threshold value Rcc, and when R1\u2267Rcc, it is determined that there is danger of a collision, and auto braking or evasive steering are performed. The extension defines protrusions for attaching one or more liquid distribution apparatuses arranged to distribute liquid in a furrow well above the seeds, on the seeds, or both.