An internal friction peak (PI) is measured a t 5 and 50 kHz without thermal hysteresis near the ferroelastic transition temperature T , of LNPP single crystal. The mechanism of internal friction due to a second-order transition is suggested. Experimental results show that the density of domain walls, N , in the ferroic phase is proportional approximately to (T, -T)-l with il remarkable hysteresis during heating and cooling. The peak P2, which appears a t N = (50 k 10) mm-I obtained by in situ observation, is attributed to the static hysteresis loss due to the motion of newly appearing domain walls. Applying a small stress during cooling below T , can freeze domains down to room temperature; as a result, Pz is suppressed and another broad peak (P3) appears a t a lower temperature without thermal hysteresis. The peak is ascribed to the "frozen" domain walls.I n der Nkhe der ferroelastischen Ubergangstemperatur T , von LNPP-Einkristallen wird ein Maximum der inneren Reibung (P,) bei 5 und 50 kHz ohne thermische Hysteresis gemessen.Ein Mechanismus der inneren Reibung, der auf einem ubergang zweiter Ordnung beruht, wird angenommen. Die experimentellen Ergebnisse zeigen, da13 die Dichte der Domanenwande, N in der Ferro-Phase niiherungsweise proportional ( T , -T ) -I ist, mit einer betrachtlichen Hysterese wiihrend des Heizens und Kuhlens. Das P,-Maximum, das bei N = (50 k 10) mm-1 auftritt, wie durch in-situ-Beobachtungen festgestellt wird, wird den statischen Hystereseverlusten infolge der Bewegung von neuauftretenden Domanenwanden zugeordnet. Durch Anlegen einer kleinen Spannung wahrend des Abkiihlens unter T , konnen Domanen bis zu Zimmertemperatur eingefroren werden, im Egebnis wird P, unterdruckt und ein anderes breites Maximum P3 tritt bei einer tieferen Temperatur ohne thermische Hysterese auf. Das Maximum wird den ,,eingefrorenen" Domanenwanden zugeschrieben.

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Background Chronic musculoskeletal pain (CMP) is a complex condition that is mainly treated with analgesic drugs. However, antidepressant intervention is also an important factor in the treatment of CMP. Duloxetine is an effective treatment option for patients with CMP as its antidepressant effect. The purpose of this article is to evaluate the efficacy and safety of duloxetine in treating CMP. Databases and data treatment We searched PubMed, Web of Science, Embase, Cochrane Library from inception to May, 2022. Randomized controlled trials (RCTs) evaluating the efficacy and safety of duloxetine versus placebo in patients with CMP were included. We identified 13 articles and studied a population of 4201 participants in 4 countries. Results This meta-analysis showed that the duloxetine has statistically significant compared with the placebo control, benefits on 24-hour average pain, living quality, physical function, and global impressions and there was no difference in the incidence of serious adverse event. In general, duloxetine can improve mood and pain level at the same time. Conclusions This review shows a significant contribution of duloxetine to CMP symptom relief. This meta-analysis improved that duloxetine can significantly reduce the pain level of patients, improve depressive symptoms and global impression, and has no obvious serious adverse reactions. However, additional studies are required to confirm the relationship between psychological diseases and chronic pain and explore their internal links.