In this study,the rotary movement of the tungsten needle in gas tungsten arc welding(GTAW)process was realized by direct current motor.The arc characteristics,the flow of molten pool and the microstructure and propert...In this study,the rotary movement of the tungsten needle in gas tungsten arc welding(GTAW)process was realized by direct current motor.The arc characteristics,the flow of molten pool and the microstructure and properties of the weld bead were studied.The results showed that the rotary motion of the tungsten needle transferred circumferential momentum to the arc as well as the molten pool,thereby conferring the latter with rotating fluid flow characteristics.Under the action of a relatively spiraling shielding gas,arc constriction occurred,and molten pool width dropped considerably.A finer and more uniform precipitated phase in the matrix,as well as a fewer large-medium pores,were achieved in the 5A06 aluminum alloy weld metal using this modified GTAW process,which noticeably increased the bending strength and tensile strength of weld metal and the microhardness of fusion zone.展开更多
The morphology of early allergic contact dermatitis reactions was studied in formaldehyde allergic individuals exposed to a cream product preserved with 4 different concentrations of diazolidinyl urea. The study was m...The morphology of early allergic contact dermatitis reactions was studied in formaldehyde allergic individuals exposed to a cream product preserved with 4 different concentrations of diazolidinyl urea. The study was made using a dose-escalating design in 3 different anatomical regions, the upper arm, neck and face. On the arm and neck, the dominant initial morphology was an eczematous papular eruption. In the face, the initial skin changes were more homogeneous and infiltrated erythema.展开更多
Background Deafferentation pain is a kind of chronic pain syndrome and hard to manipulate. To evaluate the effectiveness and safety of junctional dorsal root entry zone （DREZ） coagulation, 23 consecutive patients wi...Background Deafferentation pain is a kind of chronic pain syndrome and hard to manipulate. To evaluate the effectiveness and safety of junctional dorsal root entry zone （DREZ） coagulation, 23 consecutive patients with intractable deafferentation pain syndrome were studied.Methods Twenty-three patients underwent junctional DREZ coagulation （C5-T1 for upper extremities and L2-S1 for lower extremities） under general anesthesia. The pain severity was evaluated by the short McGill pain questionnaire （MPQ） and the visual analog scale （VAS）, and the depression and anxiety of patients were assessed by Hamilton rating scale for depression （HRSD）, Hamilton anxiety scale （HAMA）, self-rating anxiety scale （SAS） and self-rating depression scale （SDS）.Results All the patients experienced significant pain reduction immediately after surgery. The scales of short MPQ and VAS at pre-operation, 6-month and 12-month follow-up were 31.5±3.4 and 8.8±1.5, 6.5±1.9 and 2.5±2.2, 7.1±2.1 and 2.9±1.9, respectively. The postoperative scores comparing to pre-operative scores showed a statistically significant difference （P 〈0.01）. The depression and anxiety state was also significantly relieved. At 12-month follow-up 6 patients had complete pain relief, 11 had excellent results with more than 75% pain relief, 17 had good results with more than 50% pain relief （73.9%）. The main postoperative complications were transient slight hemiplegia （8）, hypesthesia and paresthesia （15）, a bearing down feeling of affected extremity （6）, and deep sensory disability in the lower limbs （4） on the operated side. Because of the long time and prone position of the operation, 13 cases had a transient hyperalgesia in the upper chest. Conclusion DREZ coagulation is a safe and effective procedure in the treatment of deafferentation pain syndromes.展开更多
基金supported by National Natural Science Foundation of China(52175305)National Natural Science Foundation of China(U22B20127)Taishan Scholars Project(tstp20230618).
文摘In this study,the rotary movement of the tungsten needle in gas tungsten arc welding(GTAW)process was realized by direct current motor.The arc characteristics,the flow of molten pool and the microstructure and properties of the weld bead were studied.The results showed that the rotary motion of the tungsten needle transferred circumferential momentum to the arc as well as the molten pool,thereby conferring the latter with rotating fluid flow characteristics.Under the action of a relatively spiraling shielding gas,arc constriction occurred,and molten pool width dropped considerably.A finer and more uniform precipitated phase in the matrix,as well as a fewer large-medium pores,were achieved in the 5A06 aluminum alloy weld metal using this modified GTAW process,which noticeably increased the bending strength and tensile strength of weld metal and the microhardness of fusion zone.
文摘The morphology of early allergic contact dermatitis reactions was studied in formaldehyde allergic individuals exposed to a cream product preserved with 4 different concentrations of diazolidinyl urea. The study was made using a dose-escalating design in 3 different anatomical regions, the upper arm, neck and face. On the arm and neck, the dominant initial morphology was an eczematous papular eruption. In the face, the initial skin changes were more homogeneous and infiltrated erythema.
文摘Background Deafferentation pain is a kind of chronic pain syndrome and hard to manipulate. To evaluate the effectiveness and safety of junctional dorsal root entry zone （DREZ） coagulation, 23 consecutive patients with intractable deafferentation pain syndrome were studied.Methods Twenty-three patients underwent junctional DREZ coagulation （C5-T1 for upper extremities and L2-S1 for lower extremities） under general anesthesia. The pain severity was evaluated by the short McGill pain questionnaire （MPQ） and the visual analog scale （VAS）, and the depression and anxiety of patients were assessed by Hamilton rating scale for depression （HRSD）, Hamilton anxiety scale （HAMA）, self-rating anxiety scale （SAS） and self-rating depression scale （SDS）.Results All the patients experienced significant pain reduction immediately after surgery. The scales of short MPQ and VAS at pre-operation, 6-month and 12-month follow-up were 31.5±3.4 and 8.8±1.5, 6.5±1.9 and 2.5±2.2, 7.1±2.1 and 2.9±1.9, respectively. The postoperative scores comparing to pre-operative scores showed a statistically significant difference （P 〈0.01）. The depression and anxiety state was also significantly relieved. At 12-month follow-up 6 patients had complete pain relief, 11 had excellent results with more than 75% pain relief, 17 had good results with more than 50% pain relief （73.9%）. The main postoperative complications were transient slight hemiplegia （8）, hypesthesia and paresthesia （15）, a bearing down feeling of affected extremity （6）, and deep sensory disability in the lower limbs （4） on the operated side. Because of the long time and prone position of the operation, 13 cases had a transient hyperalgesia in the upper chest. Conclusion DREZ coagulation is a safe and effective procedure in the treatment of deafferentation pain syndromes.
