In order to perfectly reflect the dynamic corrosion of reinforced concrete (RC) cover in practical engineering,an analytic model of non-uniform corrosion induced cracking was presented based on the elastic-plastic fra...In order to perfectly reflect the dynamic corrosion of reinforced concrete (RC) cover in practical engineering,an analytic model of non-uniform corrosion induced cracking was presented based on the elastic-plastic fracture mechanics theory.Comparisons with the published experimental data show that the predictions given by the present model are in good agreement with the results both for natural exposed experiments and short-time indoor tests (the best difference is about 2.7%).Also it obviously provides much better precision than those models under the assumption of uniform corrosion (the maximal improved precision is about 48%).Therefore,it is pointed out that the so-called uniform corrosion models to describe the cover cracking of RC should be adopted cautiously.Finally,the influences of thickness of local rusty layer around the reinforcing steel bar on the critical corrosion-induced crack indexes were investigated.It is found that the thickness of local rusty layer has great effect on the critical mass loss of reinforcing steel,threshold expansion pressure,and time to cover cracking.For local rusty layer thickness with a size of a=0.5 mm,the time to cover cracking will increase by about one times when a/b (a,semi-minor axis;b,semi-major axis) changes from 0.1 to 1 mm.展开更多
Brown tumour represents a serious complication of hyperparathyroidism.Definitive diagnosis is based on histological examination,clinical,radiological and laboratory data.Here we report a case of multiple brown tumours...Brown tumour represents a serious complication of hyperparathyroidism.Definitive diagnosis is based on histological examination,clinical,radiological and laboratory data.Here we report a case of multiple brown tumours localised in collarbone,rib and in the distal ulna due to secondary hyperparathyroidism in a 37-year-old women with chronic renal failure.The clinical management of brown tumour aimed primarily to reduce the elevated parathyroid hormone levels by pharmacological treatment.In our experience,clinicians usually consider brown tumor of hyperparathyroidism is caused by giant cell lesions in maintenance hemodialysis recipients,and multiple brown tumours are rarely seen in these patients.展开更多
基金Project(50925829) supported by the National Science Fund for Distinguished Young Scholars of ChinaProject(50908148) supported by the National Natural Science Foundation of ChinaProjects(2009-K4-23,2010-11-33) supported by the Research of Ministry of Housing and Urban Rural Development of China
文摘In order to perfectly reflect the dynamic corrosion of reinforced concrete (RC) cover in practical engineering,an analytic model of non-uniform corrosion induced cracking was presented based on the elastic-plastic fracture mechanics theory.Comparisons with the published experimental data show that the predictions given by the present model are in good agreement with the results both for natural exposed experiments and short-time indoor tests (the best difference is about 2.7%).Also it obviously provides much better precision than those models under the assumption of uniform corrosion (the maximal improved precision is about 48%).Therefore,it is pointed out that the so-called uniform corrosion models to describe the cover cracking of RC should be adopted cautiously.Finally,the influences of thickness of local rusty layer around the reinforcing steel bar on the critical corrosion-induced crack indexes were investigated.It is found that the thickness of local rusty layer has great effect on the critical mass loss of reinforcing steel,threshold expansion pressure,and time to cover cracking.For local rusty layer thickness with a size of a=0.5 mm,the time to cover cracking will increase by about one times when a/b (a,semi-minor axis;b,semi-major axis) changes from 0.1 to 1 mm.
文摘Brown tumour represents a serious complication of hyperparathyroidism.Definitive diagnosis is based on histological examination,clinical,radiological and laboratory data.Here we report a case of multiple brown tumours localised in collarbone,rib and in the distal ulna due to secondary hyperparathyroidism in a 37-year-old women with chronic renal failure.The clinical management of brown tumour aimed primarily to reduce the elevated parathyroid hormone levels by pharmacological treatment.In our experience,clinicians usually consider brown tumor of hyperparathyroidism is caused by giant cell lesions in maintenance hemodialysis recipients,and multiple brown tumours are rarely seen in these patients.
