为解决基于关节力矩的双足机器人参数辨识方法辨识精度不高,基于完整的足底力信息和运动捕捉数据的辨识方法对实验条件要求较高的问题,提出基于ZMP(zero moment point)数据的双足机器人惯性参数辨识方法。将理论ZMP与实际ZMP的位置偏差...为解决基于关节力矩的双足机器人参数辨识方法辨识精度不高,基于完整的足底力信息和运动捕捉数据的辨识方法对实验条件要求较高的问题,提出基于ZMP(zero moment point)数据的双足机器人惯性参数辨识方法。将理论ZMP与实际ZMP的位置偏差作为目标函数,考虑参数范围和机器人总质量两类约束条件,建立只使用双足机器人自身传感器采样数据的惯性参数辨识优化模型。针对所建模型无法拆分成线性形式的问题,推导目标函数关于参数矢量的梯度矢量和海塞矩阵,并给出了基于最速下降法和牛顿法的优化求解算法。使用GoRoBoT-II机器人的双足部分,进行腿部杆件的惯性参数辨识实验,将所提出方法得到的辨识结果与传统基于关节力矩的辨识结果进行对比,发现基于ZMP的辨识方法的结果更接近于三维几何建模得到的参数标称值,且理论ZMP与实际ZMP的偏差均值为4.6 mm,小于传统基于力矩辨识方法的12.4 mm,说明所提出的基于ZMP的惯性参数辨识方法能够得到比传统方法更好的结果。展开更多
During the exploitation of offshore oil and gas,it is easy to form severe slugging which can cause great harm in the riser connecting wellheads and offshore platform preprocessing system.The flow pattern and pressure ...During the exploitation of offshore oil and gas,it is easy to form severe slugging which can cause great harm in the riser connecting wellheads and offshore platform preprocessing system.The flow pattern and pressure fluctuation of severe slugging were studied in an experimental simulation system with inner diameter of 0.051 m.It is found that severe slugging can be divided into three severe slugging regimes：regime I at low gas and liquid flow rates with large pressure fluctuation,intermittent flow of liquid and gas in the riser,and apparent cutoff of liquid phase,regime II at high gas flow rate with non-periodic fluctuation and discontinuous liquid outflow and no gas cutoff,regime III at high liquid flow rate with degenerative pressure fluctuation in form of relatively stable bubbly or plug flow.The results indicate that severe slugging still occurs when the declination angle of pipeline is 0,and there are mainly two kinds of regimes：regime I and regime II.As the angle increases,the formation ranges of regime I and regime III increase slightly while that of regime II is not affected.With the increase of gas superficial velocity and liquid superficial velocity,the pressure fluctuation at the bottom of riser increases initially and then decreases.The maximum value of pressure fluctuation occurs at the transition boundary of regimes I and II.展开更多
Congenital hepatic fibrosis (CHF) is an autosomal recessive disorder that belongs to the family of fibropolycystic liver diseases. This family includes a spectrum of disorders which are usually found in combination wi...Congenital hepatic fibrosis (CHF) is an autosomal recessive disorder that belongs to the family of fibropolycystic liver diseases. This family includes a spectrum of disorders which are usually found in combination with each other and are usually inherited. Clinically fibropolycystic diseases have three effects being present in different proportions, those of a space occupying lesion, of portal hypertension and of cholangitis. In most patients, the first manifestations of CHF are signs and symptoms related to portal hypertension such as splenomegaly and varices. Portal hypertension in these patients has been attributed to the hypoplasia or compression of the portal vein radicles in the fibrous bands. Cavernous transformation of the portal vein (CTPV) is a relatively rare condition resulting from extrahepatic portal vein obstruction with recanalization or collateral vein formation to bypass the obstruction. It has been found that patients with CHF having an accompanying CTPV have relatively large splenomegaly and suffers more frequent episodes of bleeding from esophageal varices.We believe that CTPV is a congenital component of CHF and also one of the important causative factors of portal hypertension in these patients.展开更多
AIM:To assess the effectiveness of and complications associated with polyvinyl alcohol (PVA) and gelatin sponge particles embolization of splenic artery pseudoaneurysm complicating chronic alcoholic pancreatitis. METH...AIM:To assess the effectiveness of and complications associated with polyvinyl alcohol (PVA) and gelatin sponge particles embolization of splenic artery pseudoaneurysm complicating chronic alcoholic pancreatitis. METHODS: A 42-year-old man with splenic artery pseudoaneurysm formation secondary to chronic alcoholic pancreatitis was admitted. We used PVA and gelatin sponge particles embolization of splenic artery pseudoaneurysm by super-selective embolization techniques. RESULTS: The splenic artery pseudoaneurysm was successfully controlled with splenic embolization. The patient was discharged in 9 d with complete recovery. CONCLUSION: This case confirms that superselective transcatheter embolization by PVA and gelatin sponge particles may represent an effective treatment for pseudoaneurysm caused by chronic alcoholic pancreatitis in the absence of other therapeutic alternatives.展开更多
The present study was conducted to investigate the heavy metal contents （As, Ba, Cd, Co, Cr, Cu, Ga, Mo, Mn, Rb, Pb, Cu, Ni, V, U and Zn） in seawater samples, which were collected at two c （5 and 100 m）, from 9 di...The present study was conducted to investigate the heavy metal contents （As, Ba, Cd, Co, Cr, Cu, Ga, Mo, Mn, Rb, Pb, Cu, Ni, V, U and Zn） in seawater samples, which were collected at two c （5 and 100 m）, from 9 different sites of Azerbaijan sector of the Caspian Sea. The Agitent 7700x Series ICP-MS （inductively coupled plasma mass spectrometry） with HMI （high matrix introduction） system applied to analysis seawater. It was shown, the average concentrations of elements as Cr, Co, Cu, Mn, Pb and Zn in surface water slightly higher than their concentrations in depth water at 100 m. Practically it is not deference of the Mo, Rb and U average concentrations in surface and 100 m depth column water. There was little variation observed for nickel and vanadium. In contrast the concentrations of As, Ga and Ba in samples taken from 100 m, were significantly higher than the concentration in surface samples. Dependence concentration of elements from water columns depth can be explained in accordance with the geochemical system of classification of dissolved forms of elements in the sea water.展开更多
Setting out from the categories of totality and histori（ci）sm in Kosik＇s Dialectics of the Concrete, we look at the relationship between theory and praxis： empty, abstract totality versus concrete, reified and ali...Setting out from the categories of totality and histori（ci）sm in Kosik＇s Dialectics of the Concrete, we look at the relationship between theory and praxis： empty, abstract totality versus concrete, reified and alienated practice （Lukacs, Habermas, Honneth）; a bad totality, in which the real polydimensional subject is replaced by the one-dimensional, mythologized, fetishized, and economistically reduced ＂subject＂ of consummation （Marcuse, Baudrillard）. The dialectics of concrete totality implies a marxistic critique of the ethical and juristic universalism, in the context of the ＂positive＂ side of globalization and political unilateralism, as a concrete, militant, hegemonistic, post-colonial, and neo-imperial practice （Apel, Habermas, Chomsky, Zinoviev）; globalization as totali（tari）zation, the ＂last man,＂ the ＂end of history,＂ and the ＂end＂ of dialectics in its neo-liberal, eschatological, empty ideological ＂realization＂ （Hegel, Marx, Fukuyama, Arendt）; the totality of the （invariable） being as a pseudo-concrete and pseudo-dialectical ontologistic speculation （Heidegger）： A ＂return＂ to a concrete history and a return of the ＂positive＂ dialectics as a critical awareness, mind, and method in the discourse ＂game＂ of human＇s cognitive, creative, and practical powers. The assumption of Kosik＇s humanism is a synchrony of nature and history in the ＂absolute＂ totality of human＇s concrete existence （Lukacs, Goldmann, Adorno, Sartre, Kosik）.展开更多
文摘为解决基于关节力矩的双足机器人参数辨识方法辨识精度不高,基于完整的足底力信息和运动捕捉数据的辨识方法对实验条件要求较高的问题,提出基于ZMP(zero moment point)数据的双足机器人惯性参数辨识方法。将理论ZMP与实际ZMP的位置偏差作为目标函数,考虑参数范围和机器人总质量两类约束条件,建立只使用双足机器人自身传感器采样数据的惯性参数辨识优化模型。针对所建模型无法拆分成线性形式的问题,推导目标函数关于参数矢量的梯度矢量和海塞矩阵,并给出了基于最速下降法和牛顿法的优化求解算法。使用GoRoBoT-II机器人的双足部分,进行腿部杆件的惯性参数辨识实验,将所提出方法得到的辨识结果与传统基于关节力矩的辨识结果进行对比,发现基于ZMP的辨识方法的结果更接近于三维几何建模得到的参数标称值,且理论ZMP与实际ZMP的偏差均值为4.6 mm,小于传统基于力矩辨识方法的12.4 mm,说明所提出的基于ZMP的惯性参数辨识方法能够得到比传统方法更好的结果。
基金Supported by the National High Technology Research and Development Program of China(2006AA09Z302)
文摘During the exploitation of offshore oil and gas,it is easy to form severe slugging which can cause great harm in the riser connecting wellheads and offshore platform preprocessing system.The flow pattern and pressure fluctuation of severe slugging were studied in an experimental simulation system with inner diameter of 0.051 m.It is found that severe slugging can be divided into three severe slugging regimes：regime I at low gas and liquid flow rates with large pressure fluctuation,intermittent flow of liquid and gas in the riser,and apparent cutoff of liquid phase,regime II at high gas flow rate with non-periodic fluctuation and discontinuous liquid outflow and no gas cutoff,regime III at high liquid flow rate with degenerative pressure fluctuation in form of relatively stable bubbly or plug flow.The results indicate that severe slugging still occurs when the declination angle of pipeline is 0,and there are mainly two kinds of regimes：regime I and regime II.As the angle increases,the formation ranges of regime I and regime III increase slightly while that of regime II is not affected.With the increase of gas superficial velocity and liquid superficial velocity,the pressure fluctuation at the bottom of riser increases initially and then decreases.The maximum value of pressure fluctuation occurs at the transition boundary of regimes I and II.
文摘Congenital hepatic fibrosis (CHF) is an autosomal recessive disorder that belongs to the family of fibropolycystic liver diseases. This family includes a spectrum of disorders which are usually found in combination with each other and are usually inherited. Clinically fibropolycystic diseases have three effects being present in different proportions, those of a space occupying lesion, of portal hypertension and of cholangitis. In most patients, the first manifestations of CHF are signs and symptoms related to portal hypertension such as splenomegaly and varices. Portal hypertension in these patients has been attributed to the hypoplasia or compression of the portal vein radicles in the fibrous bands. Cavernous transformation of the portal vein (CTPV) is a relatively rare condition resulting from extrahepatic portal vein obstruction with recanalization or collateral vein formation to bypass the obstruction. It has been found that patients with CHF having an accompanying CTPV have relatively large splenomegaly and suffers more frequent episodes of bleeding from esophageal varices.We believe that CTPV is a congenital component of CHF and also one of the important causative factors of portal hypertension in these patients.
文摘AIM:To assess the effectiveness of and complications associated with polyvinyl alcohol (PVA) and gelatin sponge particles embolization of splenic artery pseudoaneurysm complicating chronic alcoholic pancreatitis. METHODS: A 42-year-old man with splenic artery pseudoaneurysm formation secondary to chronic alcoholic pancreatitis was admitted. We used PVA and gelatin sponge particles embolization of splenic artery pseudoaneurysm by super-selective embolization techniques. RESULTS: The splenic artery pseudoaneurysm was successfully controlled with splenic embolization. The patient was discharged in 9 d with complete recovery. CONCLUSION: This case confirms that superselective transcatheter embolization by PVA and gelatin sponge particles may represent an effective treatment for pseudoaneurysm caused by chronic alcoholic pancreatitis in the absence of other therapeutic alternatives.
文摘The present study was conducted to investigate the heavy metal contents （As, Ba, Cd, Co, Cr, Cu, Ga, Mo, Mn, Rb, Pb, Cu, Ni, V, U and Zn） in seawater samples, which were collected at two c （5 and 100 m）, from 9 different sites of Azerbaijan sector of the Caspian Sea. The Agitent 7700x Series ICP-MS （inductively coupled plasma mass spectrometry） with HMI （high matrix introduction） system applied to analysis seawater. It was shown, the average concentrations of elements as Cr, Co, Cu, Mn, Pb and Zn in surface water slightly higher than their concentrations in depth water at 100 m. Practically it is not deference of the Mo, Rb and U average concentrations in surface and 100 m depth column water. There was little variation observed for nickel and vanadium. In contrast the concentrations of As, Ga and Ba in samples taken from 100 m, were significantly higher than the concentration in surface samples. Dependence concentration of elements from water columns depth can be explained in accordance with the geochemical system of classification of dissolved forms of elements in the sea water.
文摘Setting out from the categories of totality and histori（ci）sm in Kosik＇s Dialectics of the Concrete, we look at the relationship between theory and praxis： empty, abstract totality versus concrete, reified and alienated practice （Lukacs, Habermas, Honneth）; a bad totality, in which the real polydimensional subject is replaced by the one-dimensional, mythologized, fetishized, and economistically reduced ＂subject＂ of consummation （Marcuse, Baudrillard）. The dialectics of concrete totality implies a marxistic critique of the ethical and juristic universalism, in the context of the ＂positive＂ side of globalization and political unilateralism, as a concrete, militant, hegemonistic, post-colonial, and neo-imperial practice （Apel, Habermas, Chomsky, Zinoviev）; globalization as totali（tari）zation, the ＂last man,＂ the ＂end of history,＂ and the ＂end＂ of dialectics in its neo-liberal, eschatological, empty ideological ＂realization＂ （Hegel, Marx, Fukuyama, Arendt）; the totality of the （invariable） being as a pseudo-concrete and pseudo-dialectical ontologistic speculation （Heidegger）： A ＂return＂ to a concrete history and a return of the ＂positive＂ dialectics as a critical awareness, mind, and method in the discourse ＂game＂ of human＇s cognitive, creative, and practical powers. The assumption of Kosik＇s humanism is a synchrony of nature and history in the ＂absolute＂ totality of human＇s concrete existence （Lukacs, Goldmann, Adorno, Sartre, Kosik）.
