An MPI+OpenACC-Based PRM Scalar Advection Scheme in the GRAPES Model over a Cluster with Multiple CPUs and GPUs

A moisture advection scheme is an essential module of a numerical weather/climate model representing the horizontal transport of water vapor. The Piecewise Rational Method(PRM) scalar advection scheme in the Global/Regional Assimilation and Prediction System(GRAPES) solves the moisture flux advection equation based on PRM. Computation of the scalar advection involves boundary exchange, and computation of higher bandwidth requirements is complicated and time-consuming in GRAPES. Recently, Graphic...     

RBC: A Memory Architecture for Improved Performance and Energy Efficiency

DRAM-based memory suffers from increasing row buffer conflicts, which causes significant performance degradation and power consumption. As memory capacity increases, the overheads of the row buffer conflict are increasingly worse as increasing bitline length, which results in high row activation and precharge latencies. In this work, we propose a practical approach called Row Buffer Cache(RBC) to mitigate row buffer conflict overheads efficiently. At the core of our proposed RBC architecture, the rows with good spatial locality are cached and protected,which are exempted from being interrupted by the accesses for rows with poor locality. Such an RBC architecture significantly reduces the overheads of performance and energy caused by row activation and precharge, and thus improves overall system performance and energy efficiency. We evaluate RBC architecture using SPEC CPU2006 on a DDR4 memory compared to a commodity baseline memory system. Results show that RBC improves the overall performance by up to 2:24(16:1% on average) and reduces the memory energy by up to 68:2%(23:6% on average) for single-core simulations. For multi-core simulations, RBC increases the overall performance by up to1:55(17% on average) and reduces memory energy consumption by up to 35:4%(21:3% on average).     

利用生物炭与石灰钝化(修复)琼北土壤中的铬污染

通过室内培养试验,研究了石灰、生物炭和石灰+生物炭三种改良剂对琼北土壤中铬污染的修复情况.结果表明:石灰、生物炭和石灰+生物炭三种改良剂对琼北铬污染土壤均有钝化(修复)作用,钝化剂对土壤中有效态铬的钝化效率为:生物炭+石灰>石灰>生物炭,其中,生物炭对铬的稳定效率为23%～46%;石灰为30%～54%,生物炭+石灰为38%～60%;除了B₃处理外,三种钝化剂对有效态铬含量的降低程度随钝化剂含量的增加而增大,且生物炭对铬污染土壤的最佳投加剂量为2%.生物炭对重金属铬的钝化主要是依靠提高土壤pH值及其表面的吸附效应.石灰的加入提高了土壤的pH,增加了土壤对铬的吸附能力,降低了铬的有效性,从而降低了土壤的重金属污染程度.     

电阻绝缘检测中低压脉冲信号注入法的算法改进

在有源式低压脉冲信号注入法的基础上,重新推导了计算电阻值的数学模型,并设计了一种运用该模型的有源式动力电池绝缘电阻监测系统,该系统可以有效地解决部分无源式和有源式绝缘检测法无法有效精确测量同时下降的正负端绝缘电阻与正负端单侧绝缘电阻的问题.此外,通过台架实验验证了该监测系统的有效性,在改进电动汽车动力电池监测系统方面具有一定的应用价值.     

辅助设计智能控制器的专家系统

对智能控制器CAD专家系统的设计思想进行了探索，模仿人在解决复杂问题时的行为功能，提出了辅助设计的二步模型化思想，并介绍了该系统的结构、功能概况、特点、智能控制器的设计过程、系统知识库的内容及模型仿真功能。     

盐度对龙虾叶状幼体发育和存活的影响

多个梯度多个重复的对比试验结果表明龙虾（Ｐａｎｕｌｉｒｕｓ）叶状幼体要求的海水的适宜盐度为３４‰－３５‰。投入金藻（Ｄｉｃｒａｔｅｒｉａｓｐ．）扁藻（Ｐｌａｔｙｍｏｎａｓ ｓｐ．）和光合细菌于水体中，养活作为龙虾叶状幼体饵料的丰年虫（Ａｒｔｅｍｉａ ｓａｌｉｎａ）幼体，可减少换水量，保持养殖水体的盐度稳定。３４‰－３５‰盐度的养殖水体能有效地抑制某些病原体的入侵。     

碳化锆/锆涂层炭纤维的制备及其拉伸性能研究

在一定反应温度范围内以熔盐为介质通过炭纤维与金属锆反应制备出碳化锆/锆涂层炭纤维,并在反应温度为800℃时,研究反应时间对碳化锆/锆涂层炭纤维表面相组成、形貌及其拉伸性能的影响。结果表明,800℃可制备均匀致密的碳化锆/锆涂层;且随着反应时间的延长,碳化锆/锆涂层厚度略有增加;涂层后炭纤维的拉伸强度和拉伸模量比原炭纤维的相应值略有减小。     

The effects of the guide field on the structures of electron density depletions in collisionless magnetic reconnection

Two-dimensional particle-in-cell simulations are performed to investigate the formation of electron density depletions in collisionless magnetic reconnection.In anti-parallel reconnection,the quadrupole structures of the out-of-plane magnetic field are formed,and four symmetric electron density depletion layers can be found along the separatrices due to the effects of magetic mirror.With the increase of the initial guide field,the symmetry of both the out-of-plane magnetic field and electron density depletion layers is distorted.When the initial guide field is sufficiently large,the electron density depletion layers along the lower left and upper right separatrices disappear.The parallel electric field in guide field reconnection is found to play an important role in forming such structures of the electron density depletion layers.The structures of the out-of-plane magnetic field By and electron depletion layers in anti-parallel and guide field reconnection are found to be related to electron flow or in-plane currents in the separatrix regions.In anti-parallel reconnection,electrons flow towards the X line along the separatrices,and are directed away from the X line along the magnetic field lines just inside the separatrices.In guide field reconnection,electrons can only flow towards the X line along the upper left and lower right separatrices due to the existence of the parallel electric field in these regions.     

植被根系含量对膨胀土持水和渗透特性的影响

为探究植被根系含量对膨胀土持水和渗透特性的影响规律,选取南宁市膨胀土地区的膨胀土,掺入狗牙根根系制备不同含根率的试样,进行室内压力板仪试验和变水头渗透试验,采用Van Genuchten-Mualem模型预测不同含根率的膨胀土非饱和渗透系数。结果表明:掺入根系后膨胀土持水能力减弱,根系掺入增加膨胀土内部大孔隙的比例,含根率越高,大孔隙体积占总孔隙体积比例越大,持水能力相较于纯土下降的幅度越大;饱和状态下,膨胀土渗透系数随含根率增大而增大;非饱和状态下,低吸力阶段（0～25 kPa）的膨胀土渗透性随含根率的增大而增大,随着基质吸力增加到高吸力阶段（200～1 000 kPa）,根系优势流效果减弱,含根膨胀土渗透性逐渐趋近低于纯土;细观结果表明根系的掺入使膨胀土内部产生贯通裂缝,是影响膨胀土持水和渗透能力的关键因素。本研究进一步揭示植被根系对膨胀土增渗作用的机理和规律,为综合评价植被防护膨胀土边坡效果提供参考。     

基于三维魔方模型的大运河沿线县域“三生”空间划定方法

三维魔方模型是研判空间要素多功能优势度分区的量化方法,能够直观表征空间功能的最优组合模式,为精准识别大运河沿线县域国土空间功能提供关键技术支撑。本文以“生态—生活—生产”三生空间功能为切入点,建立大运河沿线县域三生功能适宜性评价体系;基于三维魔方模型提出三生空间范围划定规则;以大运河流域青县段为研究对象,划定三生空间范围并提出优化建议。结果表明：基于三维魔方模型建立的单项功能适宜性和多项功能适宜性组合的三生空间划定规则,划定了大运河流域青县的生态、生产、生活空间范围,占比分别为60.46%、33.52%、6.02%。其中生态空间主要分布在大运河两侧,包括550.58 km2的生态功能高适宜和最高适宜空间,是大运河流域良好的生态本底;48.23 km2生活、生产功能中适宜、低适宜和不适宜空间,是大运河流域未来生态修复的重点区域。该研究成果丰富了“三生”空间范围划定的方法与技术手段,为大运河流域国土空间治理和综合利用提供理论基础。