科学评价生物多样性价值可为生物多样性和生态系统经济学(the Economics of Ecosystems and Biodiversity,TEEB)支持下的生物资源管理提供有效的技术方法和政策依据,对受威胁物种的保护尤为重要.从TEEB的理念和研究目标出发,以我国特有...科学评价生物多样性价值可为生物多样性和生态系统经济学(the Economics of Ecosystems and Biodiversity,TEEB)支持下的生物资源管理提供有效的技术方法和政策依据,对受威胁物种的保护尤为重要.从TEEB的理念和研究目标出发,以我国特有保护植物——翅果油树(Elaeagnus mollis)为例,采用选择试验法定量评估受访者对受威胁物种保护和开发的偏好以及支付意愿;针对种植面积、产品开发、树苗品种、保护投入和农户收益这5项物种属性,在多模型比较的基础上最终选择随机参数模型(RPL)和潜在分层模型(LCM)进行价值评估.结果表明:基于RPL模型得出受访者的偏好选择具有异质性,正选择偏好的属性变量按重要性表现为“保护增加投入”>“高低端产品同时开发”>“农户收益”>“树苗品种”>“种植面积”,其中对“保护增加投入”的支付意愿〔331.0元/(户·a)〕最高,其次为“高低端产品同时开发”〔242.71元/(户·a)〕;对“保护不投入”为负选择偏好,且支付意愿〔-154.71元/(户·a)〕最低.基于LCM模型可将受访者分为保护偏好型和发展偏好型2个潜在类别,前者所占样本比例远高于后者,他们更愿意在物种保护方面支付较多的费用,而后者更愿意在产品开发上支付较多的费用.补偿剩余分析得到,翅果油树保护和开发的最大价值为285.62元/(户·a).研究显示,选择试验法在受威胁物种保护及价值评估中具有良好的适用性,评估结果可为物种保护政策的制定提供科学依据.展开更多
This paper presents a first monolithic RF transceiver for DC-OFDM UWB applications.The proposed direct-conversion transceiver integrates all the building blocks including two receiver（Rx） cores,two transmitter （Tx...This paper presents a first monolithic RF transceiver for DC-OFDM UWB applications.The proposed direct-conversion transceiver integrates all the building blocks including two receiver（Rx） cores,two transmitter （Tx） cores and a dual-carrier frequency synthesizer（DC-FS） as well as a 3-wire serial peripheral interface（SPI） to set the operating status of the transceiver.The ESD-protected chip is fabricated by a TSMC 0.13-μm RF CMOS process with a die size of 4.5 x 3.6 mm2.The measurement results show that the wideband Rx achieves an NF of 5-6.2 dB,a max gain of 76-84 dB with 64-dB variable gain,an in-/out-of-band IIP3 of-6/＋4 dBm and an input loss S11 of〈-10 in all bands.The Tx achieves an LOLRR/IMGRR of-34/-33 dBc,a typical OIP3 of＋6 dBm and a maximum output power of -5 dBm.The DC-FS outputs two separate carriers simultaneously with an inter-band hopping time of〈1.2 ns.The full chip consumes a maximum current of 420 mA under a 1.2-V supply.展开更多
文摘科学评价生物多样性价值可为生物多样性和生态系统经济学(the Economics of Ecosystems and Biodiversity,TEEB)支持下的生物资源管理提供有效的技术方法和政策依据,对受威胁物种的保护尤为重要.从TEEB的理念和研究目标出发,以我国特有保护植物——翅果油树(Elaeagnus mollis)为例,采用选择试验法定量评估受访者对受威胁物种保护和开发的偏好以及支付意愿;针对种植面积、产品开发、树苗品种、保护投入和农户收益这5项物种属性,在多模型比较的基础上最终选择随机参数模型(RPL)和潜在分层模型(LCM)进行价值评估.结果表明:基于RPL模型得出受访者的偏好选择具有异质性,正选择偏好的属性变量按重要性表现为“保护增加投入”>“高低端产品同时开发”>“农户收益”>“树苗品种”>“种植面积”,其中对“保护增加投入”的支付意愿〔331.0元/(户·a)〕最高,其次为“高低端产品同时开发”〔242.71元/(户·a)〕;对“保护不投入”为负选择偏好,且支付意愿〔-154.71元/(户·a)〕最低.基于LCM模型可将受访者分为保护偏好型和发展偏好型2个潜在类别,前者所占样本比例远高于后者,他们更愿意在物种保护方面支付较多的费用,而后者更愿意在产品开发上支付较多的费用.补偿剩余分析得到,翅果油树保护和开发的最大价值为285.62元/(户·a).研究显示,选择试验法在受威胁物种保护及价值评估中具有良好的适用性,评估结果可为物种保护政策的制定提供科学依据.
基金supported by the National Science & Technology Major Projects of China(No.2009ZX03006-007-01)the National High Technology R&D Program of China(No.2009AA01 Z261)
文摘This paper presents a first monolithic RF transceiver for DC-OFDM UWB applications.The proposed direct-conversion transceiver integrates all the building blocks including two receiver（Rx） cores,two transmitter （Tx） cores and a dual-carrier frequency synthesizer（DC-FS） as well as a 3-wire serial peripheral interface（SPI） to set the operating status of the transceiver.The ESD-protected chip is fabricated by a TSMC 0.13-μm RF CMOS process with a die size of 4.5 x 3.6 mm2.The measurement results show that the wideband Rx achieves an NF of 5-6.2 dB,a max gain of 76-84 dB with 64-dB variable gain,an in-/out-of-band IIP3 of-6/＋4 dBm and an input loss S11 of〈-10 in all bands.The Tx achieves an LOLRR/IMGRR of-34/-33 dBc,a typical OIP3 of＋6 dBm and a maximum output power of -5 dBm.The DC-FS outputs two separate carriers simultaneously with an inter-band hopping time of〈1.2 ns.The full chip consumes a maximum current of 420 mA under a 1.2-V supply.
