A simple description of the temperature dependence of the width of the fission-fragment mass yield in ^(197)Au and ^(209)Bi at intermediate energies

A simple approach is proposed to describe the experimental data for the widths of the fission-fragment mass yields in^(197)Au and^(209)Bi at low and intermediate energies.The approach is based on the expressions for the temperature dependence of the width of the fission-fragment mass yield and the mass of the most probable fragment.The expression for the width of the fission-fragment mass yield depends on the mass of the most probable fragment,the surface terms of the energy level density parameter,the temperature and the stiffness parameter of the potential related to mass-asymmetric degree of freedom.It is shown that the contribution of the surface term of the energy level density parameter is important for describing the experimental data in a wide range of energies.

Mass Yield Distribution in Intermediate Energy Heavy Ion Reactions

The production cross sections of the target residues were measured for the 40 MeV/u40Ar+Cu reaction by γ-ray spectroscopic technique and the mass yield distribution was deduced.The ex-perimental data were compared with the theoretical results from both the GEMINI code based on the statis-tical binary decay model and the McFRAG code based on the fusion-fragmentation model.

Product yields for the photofission of ^(232)Th,^(234,238)U,^(237)Np,and ^(239,240,242)Pu actinides at various incident photon energies

Photofission fragments mass yield for^(232)Th,^(234;238) U,^(237) Np, and^(239;240;242) Pu isotopes are investigated.The calculations are done using a developed approach based on Gorodisskiy's phenomenological formalism. The Gorodisskiy's method is developed to be applied for the neutron-induced fission. Here we revised it for application to photofission. The effect of emitted neutron prior to fission on the fission fragment mass yields has also been studied. The peak-to-valley ratio is extracted for the240 Pu isotope as a function of energy. Obtained results of the present formalism are compared with the available experimental data. Satisfactory agreement is achieved between the results of present approach and the experimental data.

Influences of strain softening and seepage on elastic and plastic solutions of circular openings in nonlinear rock masses

Considering the influence of strain softening, the solutions of stress, displacement, plastic softening region radius and plastic residual region radius were derived for circular openings in nonlinear rock masses subjected to seepage. The radial stress distribution curve, ground reaction curve, and relation curve between plastic softening region radius and supporting force in three different conditions were drawn respectively. From the comparisons among these results for different conditions, it is found that when the supporting force is the same, the displacement of tunnel wall considering both seepage and strain softening is 85.71% greater than that only considering seepage. The increase values of radial displacement at 0.95 m and plastic softening region radius at 6.6 m show that the seepage and strain softening have the most unfavorable effects on circular opening stability in strain softening rock masses.

Measuring Herbage Mass by Non-Destructive Methods： A Review

Accurate assessment of herbage mass （HM） in pasture is a key to budgeting forage in grazing systems worldwide. Different non-destructive techniques to measuring pasture yield are commented. The methods compared include visual estimations, manual and electronic pasture meters and remote sensing. All methods are associated with a moderate to high error, showing that some indirect methods of yield estimation are appropriate under most appropriate because many factors as climate variations, soil certain conditions. In general terms, no method was found as the characteristics, plant phenology, pasture management and species composition must be taken into account to make local calibrations from a general model. Best results were found modifying general methods under local calibrations and under local conditions. In order to give farmers the best method to manage adequately their own grazing systems, researchers must select the most suitable technique considering the scale of operation, the desired accuracy and the resources available.

Temperature of intermediate mass fragments in simulated ^(40)Ca + ^(40)Ca reactions around the Fermi energies by AMD model

The primary fragments in ^(40)Ca +^(40)Ca reactions at 35,50,80,100,140,and 300 MeV/u were simulated using the antisymmetrized molecular dynamics model,in the phase space at t=300 fm/c with a coalescence radius R_c=5 fm.The standard Gogny interactions g0,g0 as,and gOass were adopted in simulating the collisions at an impact parameter of b=0 fm.It was found,using an isobaric yield ratio method,that temperature of the primary fragment depends on the incident energy and hardness of the interaction potential.The temperature obtained in this work agrees with the results by the self-consistent fitting method.

Dependence of the Yield of Alfalfa on Plant Density and Diet

In this study, under conditions of enclosed soil, experiments were conducted on the dependence of the yield (weight of green mass) of alfalfa (Medicago) on plant density and diet. The experiments were carried out in five variants, in different values of the integrated density of plants and lasted 89 days. As a feed, specially prepared bio fertilizer was used and added with the calculation of 1 kg per 1 m2 of area. In the corresponding control variants, bio fertilizer was not used. Analysis of the experimental results showed that the feeding regime made it possible to obtain a maximum yield at higher integral density. At the same time, the increase in the weight of green mass when using bio fertilizers was about 36%.

The efficacy and safety of endoscopic ultrasound-guided fine-needle biopsy in gallbladder masses

Background: Endoscopic ultrasound-guided fine-needle biopsy(EUS-FNB) is a widely used modality for acquiring various target samples, but its efficacy in gallbladder masses is unknown. The aim of this retrospective study was to evaluate the efficacy and safety of EUS-FNB in patients with gallbladder masses. Methods: The study samples were composed of patients from March 2015 to July 2019 who needed to identify the nature of gallbladder masses through EUS-FNB. The outcomes of this study were the adequacy of specimens, diagnostic yields, technical feasibility, and adverse events of the EUS-FNB in gallbladder masses. Results: A total of 27 consecutive patients with a median age of 58 years were included in this study. The 22-gauge FNB needle was feasible in all lesions. The median follow-up period of the patients was 294 days. The specimens sufficient for diagnosis account for 89%(24/27) and 93%(25/27) in cytology and histology, respectively. The overall diagnostic yields for malignancy showed the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 95.45% [95% confidence interval(CI): 75.12%-99.76%], 100%(95% CI: 46.29%-10 0%), 10 0%(95% CI: 80.76%-100%), 83.33%(95% CI: 36.48%-99.12%), and 96.30%(95% CI: 80.20%-99.99%), respectively. The subgroup analysis revealed that FNB could obtain sufficient specimens and high diagnostic yields in both gallbladder mass < 20.5 mm group and ≥20.5 mm group. One patient experienced mild abdominal pain after the procedure and recovered within one day. Conclusions: EUS-FNB is a reasonable diagnostic tool for the pretreatment diagnosis of patients with gallbladder masses, especially for patients who may miss the opportunity of surgery and need sufficient specimens to identify the pathological type so as to determine chemotherapy regimens. Further largescale studies are needed to confirm our conclusion.

Predicting Mass Transfer Extraction with Steam Flow, Applying Boundary-Layer Concepts

Theory and concepts of boundary layer mass transfer is applied to correlate experimental data on extraction of essential oils from vegetable leaves and stems, using steam. From these theory, concepts and experimental data with seven systems, two correlations are developed to predict the Sherwood number and mass transfer coefficient as function of Reynolds and Schmidt numbers. From these equations, the molar flux, the amount of solute extracted, and the yield of extraction is predicted. A steam of higher temperature normally improves the mass transfer and the yield. A method to estimate the enhancement for temperature increase is proposed. The correlations developed are applied to a case with industrial size that was no part of the data for correlation generation. Theory may be applied for industrial applications.

Yield of iodine isotopes from interaction of 47 MeV/u ^(12)C with ^(133)Cs

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两级叠置式加湿除湿海水淡化装置性能研究

空气加湿除湿海水淡化是极具应用前景的淡水生产技术。然而,由于加湿、除湿腔内存在喷淋不均匀现象,且喷淋不均对加湿过程的影响更大,致使加湿除湿过程的热质传递系数不匹配,进而致使其单位体积产水量偏低。为此,提出一种两级叠置式加湿除湿海水淡化装置,其两个加湿腔共用一个除湿腔,从而缩小了装置体积,提高了单位体积产水量。研究了供料海水流量、温度及预热对其性能的影响。结果表明,装置产水量随供料海水流量、温度的升高而增加。供料海水流量由0.45 t/h增至0.96 t/h,产水量从18.7 kg/h增加到27.1 kg/h;供料海水温度为85℃,产水量达33.7 kg/h,对应热利用系数为0.9;预热装置,可将其产水量提高6.8%。此外,其单位体积产水量可达33.7 kg(/m^(3)∙h),远高于传统两级空气加湿除湿海水淡化装置。

桃专用有机肥及配套施肥技术对桃园土壤理化性质及收益的影响

旨在比较桃专用有机肥及配套施肥技术与化肥、农家肥对桃园土壤理化性质、鲜桃产量及效益的影响。在10 a生桃园(品种:浅涧白桃)基肥设置为,化肥(CK)、农家肥(T_(1))、桃专用有机肥及配套施肥(T_(2))3个处理组(各处理追肥相同)。结果显示,T_(1)和T_(2)处理与CK相比均降低土壤体积质量,增加土壤贮水量,显著提高土壤有机质含量,在0~20 cm土层中有机质较CK分别提高36.77%和33.73%;T_(2)处理提高土壤中速效养分含量,其0~60 cm土层碱解氮、有效磷、速效钾平均含量分别较CK提高7.34%、9.05%、5.90%;各处理桃年均产量为T_(2)>T_(1)≥CK,T_(2)处理的果实含糖量达到23°,糖酸比为33.23;专用肥及配套施肥技术能显著提高鲜桃的产量和品质,改善桃园土壤结构,提高土壤肥力。

增氧灌溉对温室番茄生长及光响应特征的影响

为提高温室番茄产量和光能利用能力,基于温室盆栽试验,设置了3个溶解氧质量浓度梯度5,15,25 mg/L(即处理A1,A2和A3),采用直角双曲线模型、非直角双曲线模型等6种模型对温室番茄叶片进行了光响应曲线拟合,分析了不同增氧水平对温室番茄生物量、产量、光响应曲线模型及光响应参数的影响.结果表明:处理A2下番茄地上部鲜质量、干质量,地下部鲜质量、干质量,根冠比和产量均达到最大,较处理A1分别提升了25.65%,17.62%,13.35%,36.80%,16.25%和33.82%(P<0.05).番茄地上部质量和产量与气孔导度(G S)、胞间CO 2浓度(C i)和蒸腾速率(T r)呈极显著正相关,地下部干质量与G S,C i呈显著正相关,与T r呈极显著正相关.处理A2下温室番茄叶片的最大净光合速率(P n max)、光饱和点(LSP)、暗呼吸速率(R d)和表观量子效率(α)等光响应参数达到最大,光补偿点(LCP)达到最小.6种模型中,直角双曲线修正模型拟合的光响应曲线其R 2最大,均高于0.992,而RMSE和MAE最小,分别在0.447和0.383以下;对P n max,LSP,LCP和R d等参数的拟合值更接近于实测值.因此,溶解氧质量浓度为15 mg/L更有助于温室番茄高产;直角双曲线修正模型是适合增氧灌溉下温室番茄光响应曲线拟合的最优模型.

引黄灌区连续减施化肥对春小麦产量稳定性的影响

【目的】探索宁夏引黄灌区连续减施化肥对土壤氮、磷、钾养分供应及春小麦产量的影响,并分析影响产量稳定性的因素,为化肥合理减施、春小麦高产稳产提供理论依据。【方法】以宁春4号春小麦为供试作物,2019-2022年连续4年开展化肥减施田间定位试验,试验设置常规施肥(CF,N 270 kg·hm^(-2)、P_(2)O_(5)150 kg·hm^(-2)、K_(2)O 75 kg·hm^(-2))、减量施肥下限(RF1,N 180 kg·hm^(-2)、P_(2)O_(5)45 kg·hm^(-2)、K_(2)O 30 kg·hm^(-2),与传统施肥相比减N 33.3%、减P_(2)O_(5)70.0%、减K_(2)O 60.0%)、减量施肥上限(RF2,N 225 kg·hm^(-2)、P_(2)O_(5)75 kg·hm^(-2)、K_(2)O 45 kg·hm^(-2),与传统施肥相比减N 17.0%、减P_(2)O_(5)50.0%、减K_(2)O 40.0%)及不施肥(CK)处理,分析春小麦生育期间气候因素,播前土壤水分含量,播前和收获期土壤矿质态氮、速效磷、速效钾含量,收获期春小麦地上部干物质累积量、籽粒产量及产量构成因素的差异及相互关系。【结果】2019-2022年播前土壤水分含量存在年际差异,其中2022年的较低,平均值仅为19.5%;除2020年受施肥处理显著影响外,其余年份各施肥处理之间无显著差异。播前和收获期土壤矿质态氮、速效钾和速效磷含量均以常规施肥(CF)处理较高,RF2处理次之,且两者之间无显著差异,而RF1处理的趋于降低。2019年,地上部干物质累积量和产量均以CF处理最高,分别为23261.7和9449.0 kg·hm^(-2),较RF2处理增幅分别为2.8%-4.5%和3.2%-16.0%,而2020-2022年均以RF2处理较高,但与CF处理之间无显著差异,且4年籽粒产量表现最稳定;从年际变化来看,所有施肥处理的公顷穗数、千粒重、产量均呈逐年下降的趋势,因此施肥量并不是造成产量年际差异的主要原因,而是与播前土壤水分、降水量、气温、湿度和风速有密切关系,其中2022年产量的降低主要与较低的播前土壤水分、灌浆期的干热风现象及氮肥基追比的改变有关。【结论】宁夏引黄灌区连续适量减施化肥(N225 kg·hm^(-2)、P_(2)O_(5)75 kg·hm^(-2)、K_(2)O 45 kg·hm^(-2),相对常规施肥减N 17.0%,减P_(2)O_(5)50.0%,减K_(2)O 40.0%)不会显著降低土壤氮、磷、钾的供应能力,且一定程度上提高了春小麦公顷穗数、穗粒数和千粒重,促进地上部干物质量向籽粒的转移和积累,从而趋于提高春小麦的籽粒产量。但是,春小麦产量受降雨、风速、湿度等气候因素和土壤墒情、连作障碍、氮肥追施比等的影响而存在年际差异,其中,气温、相对湿度和风速是影响小麦产量差异的主要因素,其对施肥效果的影响需做进一步研究。

夏玉米光谱特征和产量对滴灌氮磷调控的响应

【目的】研究滴灌条件下氮磷调控对夏玉米冠层光谱特征及产量的影响。【方法】2022—2023年连续开展田间试验,2022年试验设置3个氮肥水平(0、120、240kg/hm^(2))(以纯N计)和2个磷肥水平(0、100 kg/hm^(2))(以P2O5计),2023年施氮处理与2022年一致,磷肥增加为3个水平(0、60、120 kg/hm^(2))。研究滴灌氮磷调控对夏玉米冠层光谱特征、干物质积累量和产量等指标影响。【结果】①施氮和施磷处理夏玉米光谱反射率明显增加,与不施氮不施磷处理相比,施氮后光谱反射率增加9.61%~18.60%,施磷后光谱反射率增加了3.06%~7.06%;②夏玉米地上部干物质量和产量均随施氮量和施磷量增加而增加,氮磷配施显著提高了夏玉米地上部生物量和籽粒产量,与仅施氮处理产量相比,氮磷配施处理较不施氮不施磷处理的增产幅度提高了8.82%~24.27%;与仅施磷产量处理相比,氮磷配施处理较不施氮不施磷处理的增产幅度提高15.75%~65.79%,氮磷交互作用对地上部干物质量和产量均有显著影响(P<0.01);③拔节期、抽穗期和灌浆期的地上部干物质量与任意2波段差值植被指数(DVI)和归一化植被指数(NDVI)相关性较好,相关系数最大值达到0.93。【结论】拔节期最佳植被指数的估测参数可选DVI(810,680),抽穗期可选MCARI1,灌浆期可选DVI(761,383);N2P1(N:240kg/hm^(2)、P2O5:100kg/hm^(2))处理可作为该地区夏玉米优化施肥模式。

垢对蜡沉积物强度及聚乙烯管道清管特性的影响

油井采出原油中含有泥沙、垢等颗粒物,在管输过程中颗粒物与原油中的蜡分子协同沉积,导致管道输量降低,严重时可能造成管道堵塞,影响原油管道安全输送。对掺垢蜡沉积物进行了屈服应力测试实验和显微特性实验;对室内聚乙烯管道进行了清管实验;基于清管实验结果,利用π定理建立了清管效率预测模型。结果表明,碳酸钙垢对蜡沉积物强度的影响存在临界垢质量分数;沉积物中含垢,会提高清管器的蜡层破坏力和清管效率;通过室内实验和第三方文献实验数据,验证了所建立的模型。

施氮量和收获时间对羊草种子产量的影响

羊草(Leymus chinensis)种植过程中常见发芽率低、分蘖低,甚至颗粒无收的现象,增施氮肥能在一定程度上改善这种情况,收获时间是影响种子产量的关键因素。为此,研究施氮量[不施氮、150、300 kg·(hm^(2)·a)^(-1)]和收获时间(盛花期后25、30、35、40、45 d)对羊草种子产量的影响,以明确新疆地区羊草的施氮量和最佳收获时间。结果表明:1)施氮量和收获时间对羊草种子发芽率、产量及其构成因素产生显著影响。盛花期后35 d收获与40、45 d收获相比,羊草种子发芽率、产量及产量构成因素没有显著差异。盛花期后25 d收获,150 kg·(hm^(2)·a)^(-1)处理的种子发芽率比不施氮和300 kg·(hm^(2)·a)^(-1)处理分别增加了31.25%和12.51%。2)施氮量显著提高了羊草各部位的全氮含量,收获时间对羊草各部位全氮含量并没有显著影响,羊草各部位全磷含量随着施氮量的增加呈现先增加后降低的趋势。研究结果显示,在新疆羊草种子生产时,适宜的施氮量是150 kg·(hm^(2)·a)^(-1),最佳收获时间为盛花期后35 d。

塔吉克斯坦某金矿全尾砂静动态絮凝沉降规律试验研究

塔吉克斯坦某金矿使用深锥浓密技术进行全尾砂深度脱水。为探究尾砂浆给料稀释浓度、给料速度以及絮凝剂单耗对全尾砂絮凝沉降效果的影响规律,掌握浓密机运行的适宜参数范围,依据静态沉降理论,开展了静动态絮凝沉降试验,对底流、溢流及沉降过程进行了多指标检测分析。研究结果表明:静态絮凝沉降情况下,边界稀释浓度为10%~12.5%,超过此范围,絮凝沉降效率降低,上清液澄清度降低显著;对应最优絮凝剂单耗为25 g/t,所能达到的最大固体通量为1.70 t/(m^(2)·h);较合理的给料速度为0.28~0.59 t/(m^(2)·h),考虑泥层压密时长12 h,拟合计算最终排放底流浓度可达到66%左右。研究结果为塔吉克斯坦某金矿深锥浓密机运行参数优化提供了参考。

木薯物质累积特征及其施肥效应

以传统品种华南205及新育品种华南5号为材料,通过田间试验,研究了木薯生物量与产量累积规律,探讨了品种改良及施肥措施对木薯物质形成规律的影响。结果表明,不同品种生物量累积动态相似,生长前期生物量累积缓慢,且以地上部分为主,到8月中下旬块根快速生长,物质累积速率迅速提高,累积重心由地上部逐渐转移到地下部;不同品种间物质累积速率及分配比例有所差异,分枝早且多、茎叶生长旺盛的大株型品种(华南5号)物质累积速率大于小株型品种(华南205),但地上部分生物量比例相对较高,降低了收获指数。氮素是木薯物质形成累积的主要养分限制因子,其次是钾素,磷素影响最小。氮、磷、钾配合施用(1.0∶0.4∶1.0)可显著提高木薯物质累积速率及产量,不同木薯品种物质累积对施肥依赖程度不同,可能与品种的营养需求量、根系发达程度有关。

稻田保护性耕作研究——I.免耕对水稻产量、生长动态及害虫数量的影响

通过对水稻免耕与常耕栽培对比实验,结果表明,免耕抛秧水稻的产量性状优于对照(常耕移栽)和其它处理,产量比对照高3.95%～11.57%,处理4与处理1之间差异达到5%显著水平,其它处理间差异不显著.处理4水稻的有效穗数多于其它处理,叶面积指数和干物质积累均大于其它处理.在分蘖盛期、拔节期、孕穗期和黄熟期,免耕处理的根系活力比常耕处理分别强28.1%、7.4%、28.3%和34.9%.常耕处理的二化螟和稻纵卷叶螟比免耕处理分别多16%和94%.