mlsa-iai-msu-lab/ru_sci_bench_zho_cite_reranking huggingface dataset:
Ultracompact, Reflection-Free and High-Efficiency Channel Drop Filters Based on Photonic Crystal Nanobeam Cavities

We propose an ultracompact channel drop filter (CDF) based on photonic crystal nanobeam cavities. The conditions for implementing such an ideal CDF are derived from the temporal coupled-mode equations governing the operation of the CDF. By considering the intercoupling of the two involved nanobeam cavities, some ambiguities of the previous equivalent circuit model analysis are cleared up. Practical configurations on silicon-on-insulator (SOI) for the proposed CDF are suggested with a typical length less than 15 μm. Finite difference time domain (FDTD) method calculations show that the proposed filter can achieve drop efficiency higher than 99% without any reflection. Compared to the λ/4-shifted Bragg grating resonators based CDF, the proposed CDF is more compact, high-efficient and reflection-free. It is also easy to implement a low-power tunable filter due to the ultrahigh quality factor Q and ultrasmall modal volume V of the involved photonic crystal nanobeam cavities.
Analysis of the Cooling Water Temperature Rise of Accelerating Electrodes in EAST Neutral Beam Injector Beam Extraction

Neutral beam injection is recognized as one of the most effective means of plasma heating. The preliminary data of beam power deposition in different electrodes during beam extraction are obtained on the EAST neutral beam injector test stand. The measurement of the cooling water temperature rise of accelerating electrodes is reported. The data given can guide the optimization of beam extraction parameters and decrease the damage to the accelerating electrodes following long pulse beam extraction.
Matched Field Source Localization via Environmental Focalization

In a realistic application of matched field processing for source localization, the ability to localize an acoustic source is strongly affected by the uncertainty of the environment. However, accurate environment measurement is a difficult task in large regions of the ocean. We employ a Bayesian approach, referred to here as focalization, to overcome the mismatch by including the environment in the parameter search space. Focalization maximizes the posterior probability density over the unknown source and environmental parameters. The broadband signals recorded by a vertical line array in a Yellow Sea experiment are presented to demonstrate the feasibility of focalization.
Dependence of Charged Particle Pseudorapidity Distributions on Centrality in Pb—Pb Collisions at (1/2)8_(NN) = 2.76 TeV

The dependence of charged particle pseudorapidity distributions on centrality in Pb—Pb collisions at (1/2)8_(NN) = 2.76 TeV is studied by using a multi-source thermal model (previously the two-cylinder model or the multi-source ideal gas model). The rapidity shifts of the interacting system are almost independent of the centrality class. The contribution of leading nucleons increases with the increasing centrality class (percent). The calculated results are compared and found to be in agreement with the experimental data of the ATLAS, ALICE, and CMS collaborations.
Dosimetric Characteristics of a LKB:Cu,Mg Solid Thermoluminescence Detector

We present the main thermoluminescence characteristics of a newly borate glass dosimeter modified with lithium and potassium carbonate (LKB) and co-doped with CuO and MgO. An enhancement of about three times has been shown with the increment of 0.1mol% MgO as a co-dopant impurity. The effects of dose linearity, storage capacity, effective atomic number and energy dose response are studied. The proposed dosimeter shows a simple glow curve, good linearity up to 10~3 Gy, close effective atomic number and photon energy independence. The current results suggest using the proposed dosimeter in different dosimetric applications.
A Micro-Community Structure Merging Model Using a Community Sample Matrix

Detecting an overlapping and hierarchical community structure can give a significant insight into structural and functional properties in complex networks. We propose a micro-community structure merging model to detect overlapping and hierarchical communities. The algorithm maps communities to random variables using the community sample matrix to evaluate similarity between communities. After finding density-based microcommunity structures, the algorithm merges these reasonable micro-communities iteratively to form communities. Simulation results in three real networks show that the proposed algorithm is more accurate than some existing mechanisms. In this way, we can obtain a detailed understanding of the overlapping and hierarchical communities.
DUF640基因BEAK-SHAPED GRAIN1/TRIANGULAR HULL1影响水稻粒形和粒重

种粒的形状和大小都会影响其重量并最终影响产量,然而对于种粒形状和大小的分子调控机制仍然未被研究清楚.最近本研究组分离到一株粒形呈鸟嘴状的水稻突变体beak-shaped grain1(bsg1),其粒长、粒厚和粒重都有所减少,内外颖也发生弯曲而导致其无法完全闭合.与野生型相比,突变体种子的淀粉粒呈现不规则状.组织切片显示bsg1内外颖的外薄壁细胞层细胞变小且数目减少,与粒形的表型一致.图位克隆表明,BSG1基因编码一个DUF640蛋白TRIANGULAR HULL1(TH1).定量PCR和启动子活性分析表明,BSG1主要在幼穗和茎杆中表达.BSG1的突变影响细胞分裂相关基因以及粒宽基因GW2的表达.实验结果表明,BSG1可能通过调控细胞分裂和扩展来影响种粒形状及大小.
Kerr黑洞隧穿辐射的新处理

自2000年Parikh和Wilczek采用半经典隧穿图像研究了静态球对称黑洞的Hawking辐射之后,其工作受到了极大的关注并被推广到各种情形.但是在几乎所有后来的工作中,存在两个重要的缺陷:(1)与无质量粒子的情形不同的是,对有质量粒子的测地线方程采用了不同的、而且非常牵强的推导方法;(2)对转动黑洞的隧穿辐射处理需要在拖曳坐标系中进行分析.本文采用新的思路对Kerr黑洞隧穿辐射重新作了研究,即利用Lagrange分析方法对Kerr黑洞中的有质量粒子和无质量粒子的测地线运动作了自洽的、统一的、新的处理,同时克服了上述两个重大缺陷,使得Parikh-Wilczek方法更加完善.
处理弱酸性工业废水的pH控制方法探讨

以强碱、弱酸中和反应为理论基础,通过两个工程实例对聚酯和PTA弱酸性工业废水处理调试过程中pH的控制过程进行了分析,建议在调节池投加液碱,增加弱酸的电离时间;同时在厌氧反应区投加碳酸氢钠建立弱碱性缓冲溶液体系,以降低因进水pH波动对池内微生物活性的影响,保证了系统的稳定运行。
北京2008年奥运会媒体村给排水设计与思考

简要介绍了北京2008年奥运媒体村给排水及消防系统设计。设计遵循赛时充分保障、赛后合理利用为原则,兼顾赛时、赛后需求,最大限度地节约投资,减少赛后改造工作量与成本,贯彻落实中水回用与雨水利用,充分实现2008年北京奥运会绿色、可持续发展的理念。
黔北务正道地区铝土矿矿化过程与稀土元素次生富集作用

铝土矿成矿作用是赤道湿热气候条件下含铝岩石强烈化学风化和富集改造的结果,成矿作用的实质是非成矿(杂质)元素从成矿体系中大量活化并分离移出、而成矿元素发生相对富集的过程。了解铝土矿矿床成矿过程中不同性质元素的活化、迁移和贫化与富集行为,是研究铝土矿成矿条件、成矿机制和移出元素次生富集成矿的核心内容,也是深化铝土矿矿床勘查工作的理论基础。在贵州务正道地区铝土矿成矿作用研究中,通过对不同基底岩系之上发育的铝土矿剖面进行系统的地球化学示踪分析和质量平衡计算,发现除少数高场强元素外,其他绝大多数元素,包括成矿元素Al均发生了不同程度的活化和迁移,并在矿床剖面不同部位形成了稀土元素(REE)的次生富集。
X连锁腓骨肌萎缩症家系GJB1基因突变分析

目的探讨一个腓骨肌萎缩症(Charcot-Marie-Tooth,CMT)家系的分子遗传学病因。方法对先证者及家系成员进行临床分析、电生理检查和系谱分析后,用直接测序法对先证者及家系成员进行GJB1(gap junction proteinβ1)基因突变分析。结果该家系9例患者临床表现及系谱分析符合X连锁显性遗传型CMT(CMTXD)特征;肌电图提示先证者及其父上、下肢多发对称性感觉/运动神经纤维脱髓鞘损害,合并轴索损害;基因分析显示该家系5例患者发生了GJB1 c.44G>A突变,女性为杂合子突变,男性为半合子突变。结论该家系为X连锁显性遗传型CMT家系,GJB1 c.44G>A突变是家系患者的分子遗传学病因。
时间分辨荧光免疫分析法检测干血滤纸片17α-羟孕酮的影响因素分析

目的分析时间分辨荧光免疫分析法(TrFIA)检测干血滤纸片17α-羟孕酮(17α-OHP)的影响因素并提出对策,以提高新生儿先天性肾上腺皮质增生症(CAH)的筛查质量。方法将干血滤纸片标本分别按抗血清和铕示踪剂的加样量(150μL、110μL、100μL、90μL、50μL)分5组,采用TrFIA法测定干血滤纸片17α-OHP的浓度;比较58孔微孔板底部去除水汽前、后的17α-OHP浓度;比较30例干血斑不同取样部位(中央和边缘)的17α-OHP浓度。结果抗血清和铕示踪剂的加样量对测定结果的影响与100μL组比较,差异有统计学意义(P<0.01);微孔板底部水汽存在与否对检测结果的影响有统计学意义(P<0.01);取样部位(中央和边缘)对测定结果影响不大,差异无统计学意义(P>0.05)。结论新生儿CAH筛查试验时应保证试剂加样量准确,微孔板底部干燥。
全新世太阳活动驱动的太平洋上层热力结构的瞬变演化

在中等复杂程度地球系统模式(UViC-ESCM)中,受过去7千年来瞬变太阳活动驱动,北半球冬季太平洋上层水体热力结构表现出百年尺度变化特征,西太平洋暖池(WPWP)的三维热力响应被大幅度增强.太阳活动最大值期,热带西太平洋表层海水温度变化幅度比Nino3区域大30%左右,而次表层海水温度变化幅度在副热带北太平洋比赤道西太平洋大40%;太平洋纬向表层海温梯度(西-东)和经向次表层海温梯度(北-南)同时增强,且在百年尺度周期上线性响应于太阳活动驱动.表层海温梯度的208a周期最为显著,而次表层海温梯度在大于208a的周期上更为显著.此外,表层海温梯度在百年尺度周期上的相位滞后(响应时间)要比次表水海温略小,表层海温梯度中出现的148和102a周期并未见于次表层海温梯度.上述模拟结果初步指示WPWP古海洋记录中的全新世百年尺度波动可能来源于太阳活动变化.
不同针灸方法治疗带状疱疹RCT临床研究镇痛效应观察

目的对不同针灸方法治疗带状疱疹后主要疼痛指标以及后遗神经痛(PHN)发生率指标,观察其差异,为临床提供参考。方法将符合纳入标准的500例带状疱疹患者随机分为A组(基础针刺组)、B组(铺棉灸组)、C组(火针组)、D组(叩刺拔罐组)和E组(西药组)5组,分别于第1 ~ 10天进行临床治疗,并记录相关指标:疼痛强度(VAS)、疼痛开始缓解时间、疼痛持续时间、镇痛起效时间和维持时间、PHN发生率。结果从第5天开始,五组疼痛强度即表现出差异(P<0.05);五组疼痛持续时间具有统计学差异(P<0.05);五组后遗神经痛发生率具有统计学差异(P<0.05)。结论针灸方法较西药疗法更能有效减轻疼痛强度,缩短疼痛持续时间以及减少PHN发生率,但针灸方法之间无差异。
中枢神经系统表面铁沉积症合并神经梅毒一例

中枢神经系统表面铁沉积症(superficial siderosis of the central nervous system,SSCN)为一种罕见的神经系统疾病,临床表现为小脑性共济失调、感觉神经性耳聋、痴呆及锥体束征。影像学上磁共振表现为脑、脊髓表面存在含铁血黄素沉积信号。常见病因为慢性蛛网膜下腔出血、外伤等,但多数患者病因不明。目前国内外尚未见SSCN合并神经梅毒的报道,我们在临床上诊断1例,现报道如下。
微创内固定系统在复杂型股骨中下端骨折中的应用研究

[目的]对成人复杂型股骨中下段骨折采用微创内固定系统与普通接骨板内固定的疗效进行比较研究。[方法]从2007~2012年分别对65例成年人复杂型股骨中下段骨折的患者采用微创内固定系统与普通接骨板内固定治疗。应用微创内固定系统31例,男25例,女6例,平均年龄41.3岁;应用普通接骨板34例,男22例,女12例,平均年龄37.2岁,术后根据HSS评分法得分、骨折愈合时间等指标进行临床统计学评估。[结果]随访时间微创内固定系统平均为14个月(12~16个月),愈合时间平均(5.05±2.04)个月,无骨不连发生,膝关节评分平均为(85.30±7.65)分;普通接骨板随访时间平均为18个月(12~21个月),愈合时间平均7.78个月,2例发生骨不连,2例均再次手术植骨后愈合,膝关节评分平均为(77.48±8.57)分。[结论]微创内固定系统治疗成人复杂型股骨中下段骨折是一种理想的内固定材料,在骨愈合时间以及膝关节功能恢复方面较传统接骨板有明显优势。
Synthesis and characterization of a tetranuclear copper(II) complex with a chiral Schiff base ligand

The title complex l-[Cu~(II)_4(Hvap)_2(vap)_2(MeOH)_2](ClO_4)_2 1 has been synthesized and characterized by EA, IR, TGA, solid-state CD spectra and X-ray single-crystal analyses (l-H2vap: a Schiff base ligand derived from the condensation of o-vanillin and l-2-amino-3-phenyl-l-propanol). Complex 1 crystallizes in monoclinic system, chiral space group P2_1 with a = 10.4257(18), b = 21.695(4), c = 15.721(3)A, β = 94.443(3)°, V= 3545.1(11)A~3, Z = 2, Cu_4C_(70)H_(78)N_4O_(22)Cl_2, Mr = 1652.42, Dc = 1.548 g/cm3, F(0 0 0) = 1704 and μ(MoKcα) = 1.338 mm~(-1). The final R = 0.0682 and wR = 0.1420 for 6170 observed reflections with I > 2σ(I) and R = 0.1775 and wR = 0.1830 for all data. The structure of complex 1 contains a boat-shaped {Cu_4O_4} motif. The solid-state CD spectra confirm the chiral nature of complex 1.
Nanocrystalline TiO_2-HClO_4: A novel, efficient and recyclable catalyst for the chemoselective N-Boc protection of amines under solvent-free conditions

Nanocrystalline TiO_2-HClO_4, as newly reported catalyst, has been used as an efficient and reusable catalyst for the chemoselective N-Boc protection of amines. The clean, mild acidity condition, quantitative yields of products, short reaction time and low reaction temperature are attractive features of this reaction. In practice, this method is a combination of a satisfactory synthesis and more significantly easy product isolation and purification.
A simple and green route to transparent boron nitride/PVA nanocomposites with significantly improved mechanical and thermal properties

A simple and green method is developed to prepare hexagonal boron nitride (h-BN)/poly(vinyl alcohol) (PVA) nanocomposites by using water as a common solvent of h-BN nanosheets and PVA. The obtained h-BN/PVA nanocomposites are highly transparent, and have significantly improved mechanical and thermal properties. They may outperform nano-clay and nano-alumina/PVA nanocomposites as flexible optoelectronic devices, optical windows and heat-releasing materials operated in oxidative or corrosive environment.
正交设计法优选怀山药软化切制工艺

目的研究怀山药的最佳软化切制工艺。方法以尿囊素、水溶性浸出物、醇溶性浸出物为指标,选择浸泡时间、闷润时间、干燥温度、干燥时间为因素,选用L_9(3~4)正交实验设计对上述四个因素进行最佳工艺优选,以综合加权评分法分析实验结果。结果浸泡时间、闷润时间、干燥温度对实验有显著影响,干燥时间对实验结果无显著影响,最佳软化切制工艺为先浸泡10 h,闷润22h,然后切成3 mm厚片,最后70℃干燥2.5 h。结论该工艺条件合理,稳定性好,对怀山药工业化生产和质量控制提供了工艺参数,具有一定的科学价值。
典型WAGR综合征一例

总之,WAGR综合征是一个罕见的遗传性疾病,病因主要与llp13上WT1和PAX6缺失有关,主要临床特征可有典型的Wilms瘤、虹膜缺失、泌尿生殖系统畸形及智力发育迟缓四联征,部分患者可不同时表现出典型的四联征,对体征不典型者可通过淋巴细胞高敏法染色体分析检测和分子细胞遗传学FISH检测来明确诊断。WAGR综合征诊断明确后,临床医生应该对患者进行Wilms瘤的筛查,发现Wilms瘤要及时进行手术,必要时给予放疗和(或)化疗等综合治疗。
Recent advances for aerosol and environment study in Asia

Rapid economic development over the past two decades in Asian countries such as China and India has raised awareness of pollution control measures necessary to protect public health and welfare. The 7th Asian Aerosol Conference (AAC) of the Asian Aerosol Research Assembly (AARA), was held in Xi’an, China, during August 17–20, 2011. The 7th AAC engaged 550 participants from the sciences, industry, and regulatory communities from 21 countries. The conference included ～350 plenary, platform, and poster presentations. In this special issue of PARTICUOLOGY, 15 peer-reviewed scientific articles have been selected to publish from the conference abstracts to represent recent advances for aerosol and environment study in Asia.
Source apportionment of atmospheric particulate carbon in Las Vegas, Nevada, USA

A study was conducted to quantify wintertime contributions of source types to carbonaceous PM_(2.5) at four urban sites in the Las Vegas Valley, one of the most rapidly growing urban areas in the southwestern United States. Twenty-four hour average ambient samples were collected for mass, ions, elements, organic carbon (OC), elemental carbon (EC), and trace organic markers analysis. Additional measurements were made to determine diurnal patterns in light-absorbing black carbon (BC) as a marker for combustion sources. Carbonaceous PM sources of on-road gasoline vehicles, on-road diesel vehicles, and off-road diesel engines were characterized with their chemical profiles, as well as fuel-based emission factors, using an In-Plume Sampling System. The Effective Variance Chemical Mass Balance (EV-CMB) source apportionment model was applied to the ambient samples collected, using source profiles developed in this study as well as profiles from other relevant studies. Four main sources contributed to PM_(2.5) carbon within the Las Vegas Valley: (1) paved road dust, (2) on-road gasoline vehicles, (3) residential wood combustion, and (4) on-road diesel vehicles. CMB estimated that on-road mixed fleet gasoline vehicles are the largest source for OC and EC at all the sites. The contribution of paved road dust to both OC and EC was 5–10% at the four sites. On-road diesel vehicles contribute 22% of the OC and 34% of the EC at a site near the city center, which is located immediately downwind of a major freeway. Residential wood combustion is a more important source than on-road diesel vehicles for two residential neighborhood sites. These results are consistent with our conceptual model, and the research methodology may be applied to studying other urban areas.
Variation of PM_(2.5) concentration in Hangzhou, China

This observational study investigates the variation of PM_(2.5) concentration and its ratio against PM_(10) concentration under different weather systems and pollution types. The study was conducted in Hangzhou on east China's Yangtze River Delta using data collected at seven ambient air quality monitoring stations around the metropolitan area between 2006 and 2008 and using weather information in the same period. Nine predominant weather systems affecting the city were classified through careful analysis of the 11-year surface and upper air weather charts from 1996 to 2006. Each observational day was then assigned to one of the nine weather systems. It was found that the PM_(2.5) concentration varied greatly for different weather systems, with the highest PM_(2.5) concentration associated with the post-cold-frontal system at 0.091 mg/m3 and the lowest PM_(2.5) concentration with the easterlies system at 0.038 mg/m~3, although the PM_(2.5)/PM_(10) ratio remained consistently above 0.5 for all systems. The post-cold-frontal system typically occurs in autumn and winter while the easterlies system is more a summer phenomenon. Among all types of pollution, the highest PM_(2.5) concentration of 0.117 mg/m~3 coincided with the large-scale continuous pollution events, suggesting that this type of pollution was more conducive to the formation of secondary particulate matters. The ratio of PM_(2.5)/PM_(10) was above 0.5 in non-pollution days and all pollution types but one under the influence of dust storms when the ratio decreased to 0.3 or less. The outcomes of this study could be used to develop a rudimental predictive model of PM_(2.5) concentration based on weather system and pollution type.
Elemental compositions of PM_(2.5) and TSP in Lijiang, southeastern edge of Tibetan Plateau during pre-monsoon period

PM_(2.5) and total suspended particulate (TSP) samples were collected at Lijiang, southeastern Tibetan Plateau, China. Sixteen elements (Al, Si, S, K, Ca, Cr, Mn, Ti, Fe, Ni, Zn, As, Br, Sb, Pb and Cu) were analyzed to investigate their elemental compositions during the pre-monsoon period. The results showed that Ca was the most abundant element in both PM_(2.5) and TSP samples. The enrichment factors (EFs) of Si, Ti, Ca, Fe, K and Mn were all below 10 for both PM_(2.5) and TSP, and these elements also had lower PM_(2.5)/TSP ratios (0.32–0.34), suggesting that they were mainly derived from crustal sources. Elements Cu, Zn, S, Br and Sb showed strong enrichment in PM_(2.5) and TSP samples, with their PM_(2.5)/TSP ratios ranging from 0.66 to 0.97, indicating that they were enriched in the fine fractions and influenced by anthropogenic sources. Analysis of the wind field at 500 hPa and calculations of back trajectories indicated that Al, Si, Ca, Ti, Cr, Mn and Fe can be influenced by transport from northwestern China during the dust-storm season, and that S, K, Ni, Br and Pb reached high concentrations during westerly transport from south Asia. Combined with the principle component analysis and correlation analysis, elements of PM_(2.5) samples were mainly from crustal sources, biomass burning emissions and regional traffic-related sources.
PM_(2.5) in an industrial district of Zhengzhou, China: Chemical composition and source apportionment

Zhengzhou is a developing city in China, that is heavily polluted by high levels of particulate matter. In this study, fine particulate matter (PM_(2.5)) was collected and analyzed for their chemical composition (soluble ions, elements, elemental carbon (EC) and organic carbon (OC)) in an industrial district of Zhengzhou in 2010. The average concentrations of PM_(2.5) were 181, 122, 186 and 211 μg/m~3 for spring, summer, autumn and winter, respectively, with an annual average of 175 μg/m~3, far exceeding the PM_(2.5) regulation of USA National Air Quality Standards (15 μg/m~3). The dominant components of PM_(2.5) in Zhengzhou were secondary ions (sulphate and nitrate) and carbon fractions. Soluble ions, total carbon and elements contributed 41%, 13% and 3% of PM_(2.5) mass, respectively. Soil dust, secondary aerosol and coal combustion, each contributing about 26%, 24% and 23% of total PM_(2.5) mass, were the major sources of PM_(2.5), according to the result of positive matrix factorization analysis. A mixed source of biomass burning, oil combustion and incineration contributed 13% of PM_(2.5). Fine particulate matter arising from vehicles and industry contributed about 10% and 4% of PM_(2.5), respectively.
Chemical characteristics of PM_(2.5) during dust storms and air pollution events in Chengdu, China

Daily fine particulate (PM_(2.5)) samples were collected in Chengdu from April 2009 to February 2010 to investigate their chemical profiles during dust storms (DSs) and several types of pollution events, including haze (HDs), biomass burning (BBs), and fireworks displays (FDs). The highest PM2.5 mass concentrations were found during DSs (283.3 μg/m~3), followed by FDs (212.7 μg/m~3), HDs (187.3 μg/m~3), and BBs (130.1 μg/m~3). The concentrations of most elements were elevated during DSs and pollution events, except for BBs. Secondary inorganic ions (NO_3~?, SO_4~(2?), and NH_4~+) were enriched during HDs, while PM_(2.5) from BBs showed high K~+ but low SO_4~(2?). FDs caused increases in K~+ and enrichment in SO_4~(2?). Ca~(2+) was abundant in DS samples. Ion-balance calculations indicated that PM_(2.5) from HDs and FDs was more acidic than on normal days, but DS and BB particles were alkaline. The highest organic carbon (OC) concentration was 26.1 μg/m~3 during FDs, followed by BBs (23.6 μg/m~3), HDs (19.6 μg/m~3), and DSs (18.8 μg/m~3). In contrast, elemental carbon (EC) concentration was more abundant during HDs (10.6 μg/m~3) and FDs (9.5 μg/m~3) than during BBs (6.2 μg/m~3) and DSs (6.0 μg/m~3). The highest OC/EC ratios were obtained during BBs, with the lowest during HDs. SO_4~(2?)/K~+ and TCA/SO_4~(2?) ratios proved to be effective indicators for differentiating pollution events. Mass balance showed that organic matter, SO_4~(2?), and NO_3~? were the dominant chemical components during pollution events, while soil dust was dominant during DSs.
Role of Carbon Substrates Added in the Transformation of Surplus Nitrate to Organic Nitrogen in a Calcareous Soil

Excessive amounts of nitrate have accumulated in many soils on the North China Plain due to the large amounts of chemical N fertilizers or manures used in combination with low carbon inputs. We investigated the potential of different carbon substrates added to transform soil nitrate into soil organic N (SON). A 56-d laboratory incubation experiment using the 15N tracer (K15NO3) technique was carried out to elucidate the proportion of SON derived from accumulated soil nitrate following amendment with glucose or maize straw at controlled soil temperature and moisture. The dynamics and isotopic abundance of mineral N (NO_3~- and NH_4~+) and SON and greenhouse gas (N_2O and CO_2) emissions during the incubation were investigated. Although carbon amendments markedly stimulated transformation of nitrate to newly formed SON, this was only a substitution effect of the newly formed SON with native SON because SON at the end of the incubation period was not significantly different (P > 0.05) from that in control soil without added C. At the end of the incubation period, amendment with glucose, a readily available C source, increased nitrate immobilization by 2.65 times and total N_2O-N emission by 33.7 times, as compared with maize straw amendment. Moreover, the differences in SON and total N_2O-N emission between the treatments with glucose and maize straw were significant (P < 0.05). However, the total N_2O-N emission in the straw treatment was not significantly (P >0.05) greater than that in the control. Straw amendment may be a potential option in agricultural practice for transformation of nitrate N to SON and minimization of N_2O emitted as well as restriction of NO_3-N leaching.
Changes in Soil Physicochemical Properties Following Land Use Change from Paddy Fields to Greenhouse and Upland Fields in the Southeastern Basin of Dianchi Lake, Yunnan Province, China

Paddy fields in the southeastern basin of Dianchi Lake have rapidly changed to greenhouses since 1999. A total of 61 surface soil samples, including 43 greenhouse soils, 12 upland soils, and 6 paddy soils, were collected from a flat lowland area mainly used for agricultural production fields in the southeastern basin of Dianchi Lake. Analyses of the soil samples indicated that the greenhouse soils were characterized by a lower organic matter content, lower pH, and higher soluble nutrients than the paddy soils in the area. The lower organic matter content of the greenhouse soils was ascribed to environmental or management factors rather than the clay content of the soil. Accumulation of soluble nutrients, especially inorganic N, was due to over-application of fertilizers, which also caused soil acidification. The average amount of readily available N, P, and K accumulated in the greenhouse soils was estimated to be equal to or higher than the annual input of these nutrients as a fertilizer, indicating that a reduction in fertilizer application was possible and recommended. In contrast, a very low available Si content was observed in the paddy soils, suggesting the need for Si application for rice production.