碱性钙对‘秦冠’苹果块贮藏品质及生理特性的影响

目的 研究碱性钙对苹果块贮藏品质及生理特性的影响。方法 以‘秦冠’苹果为材料,采用不同Ca²⁺质量浓度的碱性钙对苹果块进行处理,于(4±1)℃下贮藏12d,研究不同Ca²⁺质量浓度的碱性钙对苹果块质地参数(硬度、咀嚼性、回复性、内聚性、弹性指数)、色泽、可溶性固形物、可滴定酸、可溶性蛋白和可溶性糖等品质指标及细胞膜透性、丙二醛(malondialdehyde, MDA)、多酚氧化酶(polyphenol oxidase, PPO)、过氧化物酶(peroxidase, POD)、超氧化物歧化酶(superoxide dismutase, SOD)和过氧化氢酶(catalase, CAT)等生理指标的影响。结果 与对照相比,不同Ca²⁺质量浓度的碱性钙处理均可不同程度地影响苹果块的贮藏品质及生理特性,其中Ca²⁺质量浓度为2.0 g/L的碱性钙处理效果最好,贮藏结束时硬度、咀嚼性、回复性、内聚性、弹性指数、可溶性固形物、可滴定酸、可溶性蛋白、还原糖、SOD和CAT分别比对照高68.83%、75.10%、...     

济宁三号煤矿选煤厂块煤浅槽分选系统技术应用

济宁三号煤矿选煤厂因入洗原煤煤质变化,原有块煤分选工艺不完善,分选精度低,设备老化等问题,不能满足块煤分选需要。针对济三选煤厂的煤质资料,分析了技术改造的方案和系统的设计工艺,将原有落后的动筛排矸系统改为重介质浅槽分选系统。经过技术改造后,提高了对煤质变化的分选适应性,减少了设备维护量,提高了系统的自动化水平。     

对油脂浸出生产实践中几个问题的探讨

分析了影响油脂浸出效果的几个因素 ,如浸出器正压大 ,豆粕出机温度高 ,粕中有结块 ,冷凝器易结垢 ,尾气中溶剂排放量大等 ,并提出了解决问题的措施 ,以供实际生产参考     

浅析薄煤层开采条件下如何提高块煤率

优质无烟煤在中国分布较广,但其末煤价格低,难以销售,而块煤价格高,产品供不应求。根据王河矿区薄煤层赋存条件和实际生产状况,探讨矿井在现有开采条件下,如何提高块煤率,增加煤炭销售收入,从而提升矿井经济效益。     

Bright,dark and dark-singular soliton solutions of nonlinear Schrödinger's equation with spatio-temporal dispersion

This article presents an analytical study of the propagation of solitons through optical fibres. We consider a nonlinear Schrödinger equation with spatio-temporal dispersion and quadratic–cubic nonlinearity. Jacobi elliptic functions are used as an ansatz to extract optical dark and bright solitons as well as Jacobi elliptic solutions. The extended direct algebraic method gives dark and dark-singular soliton solutions. The constraint conditions which guarantee the existence of soliton solutions are listed.     

不停炉情况下的高温炉瘤爆破

为解决某钢铁厂高炉内炉瘤堆积问题,通过爆破方案的选择和爆破参数的计算,确定采用高温氧割烧孔的钻孔爆破法和滑轮吊装药包裸露外敷接触爆破法,同时对爆破振动、飞石及爆炸冲击波进行计算分析,提出相应的爆破安全防护措施,最终利用强制通风、高温冷却、药包隔热等多种辅助手段,在不停炉情况下完成了高温炉瘤的爆破拆除。爆破后,通过对炉壁外侧的红外线探测以及人工观测获知,炉瘤清除较为彻底,爆破效果良好。实践表明,滑轮吊装药包裸露外敷接触及钻孔爆破法可有效去除各类炉瘤,大幅提高除瘤效率与施工安全,改善高炉生产能力,可为解决同类工程难题提供参考。     

Dynamics of Jacobi elliptic and soliton solutions for the modified quadratic-cubic nonlinear Schrödinger equation

We consider the quadratic-cubic nonlinear Schrödinger equation in the presence of external source, as an approximate model for a relatively quasi-1D Bose-Einstein condensate coupled to a waveguide. A scaling transformation is used to obtain a wide class of exact solutions for this model. It possesses fractional transform Jacobi elliptic solutions whose dynamics can be controlled by judicious choice of source and nonlinearity parameters. For other parametric conditions, this model exhibits bright/dark, Lorentzian-type and rational dark solitons. The presence of quadratic nonlinear term introduces a constant background and thus amplified the propagating wave. Further, the phase of the propagating wave is locked to the source and can be made either in- or out of-phase to the source wave through sign reversal of source parameter.     

高炉使用块矿冶炼的技术经济评价方法

根据高炉用外购块状铁矿石的购矿价、块矿品位、人关税、港杂费等诸多参数及高炉焦比和产量与影响因素间的计算原则,推导了外购块矿直接人高炉冶炼对吨铁效益影响的计算公式,并举例计算了炼铁盈亏平衡时,购矿价与块矿品位的定量关系,由计算公式可得出块矿品位每增加1％时,铁厂盈亏持平所对应的外购块矿到厂价格。     

采煤机螺旋滚筒截齿排列与块煤率的研究

本文通过对截齿排列的研究,在分析某型号采煤机三头螺旋叶片滚筒的基础上,认为滚筒截割的块煤率,与切削图的形状紧密相关。因而要达到一定的块煤率,关键是截齿的合理排列。     

Do envelope solitons radiate?

In dispersive wave systems, when leading-order nonlinear and dispersive effects, are taken into account the envelope of a small-amplitude narrow-band wave pulse is known to satisfy the nonlinear Schrödinger (NLS) equation which, under certain conditions, admits envelope-soliton solutions. These solitons describe locally confined wave groups with envelopes of permanent form and find applications in various physical contexts. Here, is addressed the question of whether NLS envelope solitons survive when higher-order effects are taken into account. Based on a kinematic argument first, it is suggested that oscillatory tails are inevitably emitted, and this claim is further supported by numerical computations by use of a fifth-order Korteweg-deVries equation as a simple example. The radiation of tails is caused by a resonance mechanism that lies beyond all orders of the usual multiple-scale expansion leading to the NLS equation, and a procedure for calculating these tails by use of exponential asymptotics is outlined. Despite having exponentially small amplitude in the asymptotic sense, the radiated tails can be significant when pulses of relatively short duration are considered.