Difference-frequency ultrasound generation from microbubbles under dual-frequency excitation

The difference-frequency (DF) ultrasound generated by using parametric effect promises to improve detection depth owing to its low attenuation, which is beneficial for deep tissue imaging. With ultrasound contrast agents infusion, the harmonic components scattered from the microbubbles, including DF, can be generated due to the nonlinear vibration. A theoretical study on the DF generation from microbubbles under the dual-frequency excitation is proposed in formula based on the solution of the RPNNP equation. The optimisation of the DF generation is discussed associated with the applied acoustic pressure, frequency, and the microbubble size. Experiments are performed to validate the theoretical predictions by using a dual-frequency signal to excite microbubbles. Both the numerical and experimental results demonstrate that the optimised DF ultrasound can be achieved as the difference frequency is close to the resonance frequency of the microbubble and improve the contrast-to-tissue ratio in imaging.     

福建省复杂地形下旬平均气温分布式模拟

为建立高时空分辨率的福建省复杂地形下气温栅格数据集,利用福建省及其周边33个常规气象站观测资料,基于数字高程模型（DEM）数据,综合考虑海拔、太阳总辐射、地表长波有效辐射对旬平均气温的影响,模拟了福建省复杂地形下旬均温的空间分布。结果表明：1）常规站验证结果显示：各旬气温绝对误差平均值（MAE）最小为0.46℃,最大为2.3℃,全年平均为0.87℃;加密站验证结果显示,MAE最大为2.3℃,最小0.5℃,全年平均为0.96℃。2）模拟结果能反映旬均温的宏观分布规律与局地细节特征。宏观范围内,旬均温受纬度影响较大,由北至南气温逐渐升高,沿海地区旬均温整体高于内陆,山区旬均温明显较低;局地范围内,各坡向上气温差异显著,海拔越高、坡度越大,差异越明显;地形因子对旬平均温的影响具有季节差异,具体表现为冬季时地形因子对旬均温的影响最大,秋季次之,春夏季节中地形因子对旬均温的影响最弱。     

基于GridMet模型的浙江省温湿指数空间分布及地形影响分析

温湿指数是气候舒适度评价模型之一,通过温度与湿度的组合反映人体与周围环境的热量交换,本文利用2003-2018年浙江省及其周边71个气象站点月平均气温、地面水汽压数据,以及MODIS水汽产品,基于GridMet模型模拟了浙江省各月温湿指数空间分布（100 m×100 m）,分析了浙江省温湿指数随地形因子（海拔、坡度、坡向）变化的特征;讨论了各地形因子对温湿指数空间分布的影响程度。结果表明：① 海拔、坡度、坡向3个地形因子中,1月温湿指数随坡向的变化最大,7月最小;② 同坡向上,坡度变化对1月温湿指数影响较大,而海拔变化则是对7月影响最大;③ 南坡1月温湿指数随海拔和坡度增加均略为增加,南坡其他月份及北坡各月均为随海拔和坡度增加温湿指数减小;④ 北坡相对于南坡而言,海拔和坡度对温湿指数的影响更为明显。浙江大部分山区由于地形影响,夏季较为“舒适”,适宜建立避暑消夏的旅游项目。     

加强监管 落实责任 做好矿业权评估和储量评审工作

矿业权评估和储量评审工作在矿产资源管理中处于中介、中立地位,在矿业权市场建设中发挥着不可替代的重要作用.做好矿业权评估和储量评审工作,意义重大.     

精心组织统筹协调有力有序推进矿产资源利用现状调查工作

为全面掌握矿产资源利用现状,掌控全国矿产资源储量家底,加强矿业权管理,进一步做好矿产资源规划、管理、保护和合理利用工作,国土资源部决定在全国范围内开展矿产资源利用现状调查工作.     

做好储量工作服务科学发展

当前,我省正处在工业化、城镇化加快发展时期.今年二季度以来,我省经济呈现明显回升势头,企业信心明显增强,国际金融危机对我省实体经济的负面影响随着政策效应不断显现而明显减弱,经济发展态势良好,矿产资源开发和消费不断扩大,储量消耗的增长快于储量发现的增长,资源保障程度呈下降态势.矿产资源保障面临的突出问题是,需求持续增长,部分省内资源供需失衡,对外依存度攀高,利用两个市场和两种资源的风险在不断加大,形势比较严峻.     

日照豪迈码头港池布局对泥沙输移影响研究

港池的布局会改变其周边海域水动力条件及其泥沙冲淤状况,为了进一步了解其影响程度,本文以山东日照豪迈重工临港厂区运输码头的改造工程为研究对象,利用平面二维数值模型MIKE21/3 Integrated Models,建立了潮流和波浪耦合作用下的泥沙输移数值模型,对该工程附近海域进行了波浪、潮流和泥沙输移的数值模拟。同时采用实测数据对数值模型进行了验证,数值模拟结果与实测资料拟合较好,表明MIKE21能有效地模拟运输码头及其周围海域潮流的变化过程。以日照豪迈重工临港厂区运输码头为依托,基于数值模拟结果,分析不同改造方案下的水动力条件和泥沙冲淤状况。结果表明:港池布局对水动力条件影响甚微,对地形地貌冲淤影响较大;模拟结果确定港池南向开口为最佳改造方案,为工程的规划和设计提供科学依据。     

地理国情监测成果在农业、旅游领域中的应用

开展地理国情监测工作的目的是为了获取自然与人类社会经济活动引起的地表变化信息,具体包括地表自然要素、人文地理要素和社会经济信息的空间分布特征及其相互关系,是基本国情的重要组成部分,为政府管理决策、企业生产运营、人民群众生活提供数据基础和决策依据。本文基于地理国情监测数据,结合多种测绘地理信息数据和技术手段,探讨如何利用地理国情监测成果促进农业与旅游业的发展,以期深入挖掘和提升监测成果价值,全面拓展监测成果应用服务的新思路、新方向。     

Chlorophenols in marine organisms from the southern coast of Hangzhou Bay,China, and an assessment of risks posed to human health

The composition of chlorophenols in marine organisms from the southern coast of Hangzhou Bay, China, was analyzed and the health risks posed to humans assessed. A total of 19 chlorophenols from 16 types of marine organism were analyzed across nine survey sections in Hangzhou Bay. The chlorophenols were analyzed by gas chromatography-mass spectrometry using a DB-5MS quartz capillary column. The concentrations of monochlorophenol, dichlorophenol, trichlorophenol, tetrachlorophenol, and pentachlorophenol ranged from below the detection limit(ND) to 132 μg/kg, ND–51.0 μg/kg, ND–42.5 μg/kg, ND–69.0 μg/kg, and ND–9.06 μg/kg, respectively. Additionally, concentration differences between each type of chlorophenol were not significant( P 0.05). However, significant differences were found between monochlorophenol( F =8.13, P 0.01) and total chlorophenol(F =5.19, P 0.01) concentrations. As the noncarcinogenic risk indices were 0.1(10-5 –10-2) for all of the organisms, no high risk was posed by 2-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, 2,4,5-trichlorophenol, 2,3,4,6-tetrachlorophenol, and pentachlorophenol to humans consuming marine organisms from the study area. Furthermore, the carcinogenic risks posed by 2,4,6-trichlorophenol and pentachlorophenol were lower than limits set by the International Commission on Radiological Protection and the US Environmental Protection Agency. However, the noncarcinogenic and carcinogenic risks posed by chlorophenols in marine organisms from four of the survey sections(Sizaopu, Niluoshan, Longshan Town and Xinhong zha) were higher than the other survey sections.     

近岸波浪破碎区不规则波浪的数值模拟

基于近岸不规则波浪传播的抛物型缓坡方程和两类波浪破碎能量损耗因子,对近岸波浪破碎区不规则波浪的波高分布进行了数值模拟,并结合实验结果对数值模拟结果进行了验证分析,结果表明采用两类波浪破碎能量损耗因子所模拟的破碎区波高与实测值均吻合良好,波浪破碎能量损耗因子及波浪破碎指标对破碎区波浪波高分布影响较明显。