Up to now, the studies in the world have demonstrated that CT-guided percutaneous neurolytic celiac plexus block (PNCPB) is an invaluable therapeutic modality in the treatment of refractory abdominal pain caused by cancer. Its efficacy of pain relief varied in reported studies. The main technical considerations which would affect the analgesic effects on abdominal pain included the patients' cooperation, needle entry approaches, combined use of blocking approaches, localization of the target area, dosage of the blocker, and so on. A success of PNCPB depends greatly on close cooperation with patients. The patient should be educated about the purpose and steps of the procedure, and trained of breathing in and breathing hold. The needle entry can be divided into the posterior approach and the anterior approach. The former one is the most commonly used in clinical practice, but the latter one is rarely used except in the cases that the posterior approach becomes technically difficult. Bilateral multiple blocking of celiac plexus and splanchnic nerves is often required to achieve optimal analgesia. The needle entry site, insertion course, and depth should be preselected and simulated on CT monitor prior to the procedure in order to ensure an accurate and safe celiac plexus block. The magnitude of analgesic effect is closely related to the degree of degeneration and necrosis of the celiac plexus. Maximally filling with blocker in the retropancreatic space is an indication of sufficient blocking. We also provided an overview of indications and contraindications, preoperative preparations, complications and its treatment of PNCPB.

In this paper, a mechanism-oriented control strategy is proposed to cut off the introduction process of negative damping caused by the Stribeck effect for suppressing the vehicle start-up judder. From the experimental analysis, the characteristic frequency of start-up judder is mainly concentrated at about 8.25 Hz, coinciding with the first-order natural frequency of the driveline system. A 13-degree-of-freedom powertrain branched model is established, whose validity and accuracy in reflecting the characteristics of start-up judder are verified by comparing with the experimental results in time–frequency domain. The start-up judder mechanism is profoundly revealed through explaining the introduction of negative damping and the origin of characteristic frequency. The positive-feedback closed loop caused by the negative gradient characteristic of the Stribeck effect is the determining factor that promotes the aggravation of the fluctuation in the rotational speed of clutch-driven plate, which is the manifestation of the negative damping. The core idea of the mechanism-oriented control strategy is to cut off the positive-feedback closed loop, which is achieved by fine-tuning the position of release bearing. The judder-suppression performance behaves well both in simulation and in experiment.