Optimal Control for Age Distribution and Weighted Size Competitive Species in a Polluted Environment

In the paper,we study an optimal control for a system representing a competitive species model with fertility and mortality depending on a weighted size in a polluted environment.A fixed point theorem is applied to obtain the existence and uniqueness exhibited by a non-negative solution of above mentioned model.A maximum principle helps to carefully verify the existence of the optimal control policy,and tangent-normal cone techniques help to obtain the optimal condition specific to control issue.

THE(p,q)-ANALOG OF MULTIVALENT BAZILEVIC FUNCTIONS ASSOCIATED WITH A LIMACON

This paper studies the problem of functional inequalities for analytic functions in classical geometric function theory.Using the di erential subordination principle and(p,q)-derivative operator,it introduces(p,q)-analog of a class of multivalently Bazilevic functions as-sociated with a limacon function,and obtains the corresponding coefficient estimates and the Fekete-Szego inequality,which extend and improve the related results for starlike functions,even q-starlike functions.

宁夏干旱、半干旱和风沙带地区苜蓿及草业经济发展要素分析

现代经济学认为经济增长主要来自与三个方面:资本、劳动、土地的投入;制度安排;技术创新。在结合宁夏干旱、半干旱和风沙带地区实际情况来探讨影响苜蓿及草业经济增长的要素,从这些要素着手,也可以转换一个角度把它们分为内生变量和外生变量来考虑,内生变量主要包括了土地、气候、劳动力和外生变量主要由技术、资金和政策和制度构成。在内生变量和外生变量的共同作用下,创造了草业经济的双向产出??经济效益和社会效益。

浅谈艺术教育教学模式的创新

艺术教育是以培养学生的审美意识和审美能力为核心,以发展学生的想象力和创造力为目的,以审美教育为中心的学科体系。艺术教育不仅要重视科学知识教育,更要重视艺术审美教育和创造性思维培养。在当前高校艺术教学模式创新中,教师应该创新教学观念,优化课程体系,科学运用教学手段,激发学生对艺术的兴趣和爱好。在未来的发展中,高校必须全面提高学生的综合素质,促进学生综合能力的提高,只有这样才能符合社会发展对人才培养的需求。因此高校艺术教师应该在教学模式方面进行创新和探索,使学生更好地掌握知识体系和掌握技能技巧。

一类求解常微分方程初值问题的线性多步方法

提出了一类求解非刚性常微分方程初值问题的线性多步方法,该类方法包括k步k阶显式方法和k步k+1阶隐式方法,其绝对稳定的实区间均大于Adams的绝对稳定的实区间。数值算例表明,该类方法优于Adams方法。

Controllable design of Zn-Ni-P on g-C_3N_4 for efficient photocatalytic hydrogen production

Synthesizing a stable and efficient photocatalyst has been the most important research goal up to now. Owing to the dominant performance of g-C3N4 (graphitized carbonitride), an ordered assemble of a composite photocatalyst, Zn-Ni-P@g-C3N4, was successfully designed and controllably prepared for highly efficient photocatalytic H2 evolution. The electron transport routes were successfully adjusted and the H2 evolution was greatly improved. The maximum amount of H2 evolved reached about 531.2 μmol for 5 h over Zn-Ni-P@g-C3N4 photocatalyst with a molar ratio of Zn to Ni of 1:3 under illumination of 5 W LED white light (wavelength 420 nm). The H2 evolution rate was 54.7 times higher than that over pure g-C3N4. Moreover, no obvious reduction in the photocatalytic activity was observed even after 4 cycles of H2 production for 5 h. This synergistically increased effect was confirmed through the results of characterizations such as XRD, TEM, SEM, XPS, N2 adsorption, UV-vis DRS, transient photocurrent, FT-IR, transient fluorescence, and Mott-Schottky studies. These studies showed that the Zn-Ni-P nanoparticles modified on g-C3N4 provide more active sites and improve the efficiency of photogenerated charge separation. In addition, the possible mechanism of photocatalytic H2 production is proposed.

Unique synergistic effects of ZIF-9（Co）-derived cobalt phosphide and CeVO4 heterojunction for efficient hydrogen evolution

The photocatalytic decomposition of water to produce hydrogen is an important process,through which solar energy can be converted to chemical energy.Non-precious metal phosphides have quietly attracted attention as an emerging inexpensive photocatalyst.In this study,we reported that a CoP/CeVO4 hybrid photocatalyst exhibited high hydrogen evolution efficiency owing to EY(eosin Y)sensitization under visible light irradiation for the first time,and the amount of generated hydrogen reached 444.6μmol in 5 h.The CoP/CeVO4 nanohybrids were synthesized by a simple chemical precipitation method.The coupling of CoP and CeVO4 with ZIF-9 as a precursor could be completed in one step.The CeVO4 particles were firmly attached to the surface of the CoP particles to form a"small point"to"big point"heterojunction.The results of X-ray diffraction,X-ray photoelectron spectroscopy,scanning electron microscopy,EDX,and transmission electron microscopy showed the formation of CoP and CeVO4 nanoparticles and the structure of the composite.Based on a detailed analysis of the Mott-Schottky plot,the UV-vis diffuse reflectance spectra,photocurrent-time(it)curve,Tafel curve,Nyquist curve(EIS),linear volt-ampere curve(LSV),and steady-state fluorescence spectra were studied.The time-resolved photoluminescence measurements indicated that the reason for the high-efficiency hydrogen evolution of CoP/CeVO4 was that the bands of CoP and CeVO4 were bent due to the existence of the Schottky barrier,and a heterojunction was formed between CoP and CeVO4,which generated an internal electric field and accelerated the charge transfer.In addition,the synergistic effect between CoP and CeVO4 provided a new hydrogen-evolution activity center for each of them.The improved carrier separation efficiency and the decrease in the photo-generated recombination rate led to the excellent photocatalytic hydrogen-evolution activity of the CoP/CeVO4 composite catalyst.This work provides a new strategy for modulating the electronic structure and carrier behavior of transition metal phosphide photocatalysts.

State-of-the-art catalysts for direct dehydrogenation of propane to propylene

With growing demand for propylene and increasing production of propane from shale gas,the technologies of propylene production,including direct dehydrogenation and oxidative dehydrogenation of propane,have drawn great attention in recent years.In particular,direct dehydrogenation of propane to propylene is regarded as one of the most promising methods of propylene production because it is an on-purpose technique that exclusively yields propylene instead of a mixture of products.In this critical review,we provide the current investigations on the heterogeneous catalysts(such as Pt,CrOx,VOx,GaOx-based catalysts,and nanocarbons)used in the direct dehydrogenation of propane to propylene.A detailed comparison and discussion of the active sites,catalytic mechanisms,influencing factors(such as the structures,dispersions,and reducibilities of the catalysts and promoters),and supports for different types of catalysts is presented.Furthermore,rational designs and preparation of high-performance catalysts for propane dehydrogenation are proposed and discussed.

Large-scale synthesis of noble-metal-free phosphide/CdS composite photocatalysts for enhanced H_2 evolution under visible light irradiation

Photocatalytic H2evolution under visible light irradiation is an ideal process for solving energy shortage.The low cost of photocatalysts and high efficiency of hydrogen evolution are the two key factors to realize the industrialization of the process.The substitution of a noble‐metal cocatalyst with a non‐noble‐metal catalyst can significantly reduce the cost of the photocatalyst.The largescale synthesis and assembly of semiconductors and non‐noble‐metal cocatalysts to form photocatalysts through a simple method can further decrease the cost of photocatalysis.Here,we report a large‐scale and low‐cost coprecipitation method to form phosphide/CdS photocatalysts to realize photocatalytic H2evolution.CoP and MoP cocatalysts significantly enhanced the photocatalytic production of hydrogen.The optimal H2production rates on CoP/CdS and MoP/CdS were140and78μmol/h,which were7.0and4.0times higher than those obtained with bare CdS,respectively,and2.0times and1.1times higher than those obtained with1.0%Pt/CdS,respectively.This work provides a practical method for the large‐scale preparation of low‐cost photocatalysts.

Efficient photocatalytic hydrogen evolution over graphdiyne boosted with a cobalt sulfide formed S-scheme heterojunction

Graphdiyne(GDY,g-C_(n)H_(2n-2)),a novel two-dimensional carbon hybrid material,has attracted significant attention owing to its unique and excellent properties.As a new type of carbon material,GDY has a layered structure and can be used in the field of photocatalytic water splitting.Therefore,herein,new progress in the preparation of graphene using Cu I powder as a catalytic material and the combination of a facile hydrothermal method to prepare a new composite material,Co_(9)S_(8)-GDY-Cu I,is reported.The hydrogen production activity of Co9S8-GDY-Cu I in the sensitization system reached 1411.82μmol g^(-1) h^(-1),which is 10.29 times that of pure GDY.A series of characterization techniques were used to provide evidence for the successful preparation of the material and its superior photocatalytic activity.Raman spectroscopy showed that the material contains acetylenic bonds,and the X-ray photoelectron spectroscopy carbon fitting peaks indicated the presence of C-C(sp^(2))and C-C(sp),further demonstrating that GDY was successfully prepared.A possible reaction mechanism was proposed by making use of UV-visible diffuse reflectance and Mott-Schottky analyses.The results showed that a double S-scheme heterojunction was constructed between the samples,which effectively accelerated the separation and transfer of electrons.In addition,the introduction of Co9S8 nanoparticles greatly improved the visible light absorption capacity of Co_(9)S_(8)-GDY-Cu I.Photoluminescence spectroscopy and related electrochemical characterization further proved that recombination of the electron-hole pairs in the composite material was effectively suppressed.

Effects of Different Nitrogen Application Rates and Methods on Root Nodule Growth and Yield of Soybean

This study was conducted wiffl a spring soybean variety Jindou 19 to test file effects of rhizobia inoculation or non-inoculation and nitrogen application rates at 0, 27, 54 and 75 kg/hm^2 （N1-4） on root nodule dry weight, root nodule number, yield and yield components of soybean. The results showed that the nitrogen fertilizer significantly affected soybean root noduce and soybean yield, the dry weight and number of root nodules increased gradually with the increase of nitrogen application rate, and the yield of file rhizobia inoculated treatment was significantly higher than that of file rhizobia non-inoculated treatment; and under file condition of file rhizobia inoculation, with nitrogen application amount at 75 kg/hm^2, file Jindou 19 performed a better nitrogen fixing effect in file growing stage, and its plot yield was 4 997.417 kg/hm^2, 4.06% higher than that of file treatment without inoculating rhizobium and 12.50% higher than that of the treatment without applying nitrogen fertilizer.

Mesoporous carbons as metal-free catalysts for propane dehydrogenation: Effect of the pore structure and surface property

Nanocarbon materials have been used as important metal-free catalysts for various reactions including alkane dehydrogenation.However,clarifying the active sites and tuning the nanocarbon structure for direct dehydrogenation have always been significantly challenging owing to the lack of fundamental understanding of the structure and surface properties of carbon materials.Herein,mesoporous carbon materials with different pore ordering and surface properties were synthesized through a soft-templating method with different formaldehyde/resorcinol ratios and carbonization temperatures and used for catalytic dehydrogenation of propane to propylene.The highly ordered mesoporous carbons were found to have higher catalytic activities than disordered and ordered mesoporous carbons,mainly because the highly ordered mesopores favor mass transportation and provide more accessible active sites.Furthermore,mesoporous carbons can provide a large amount of surface active sites owing to their high surface areas,which is favorable for propane dehydrogenation reaction.To control the surface oxygenated functional groups,highly ordered mesoporous carbons were carbonized at different temperatures(600,700,and 800℃).The propylene formation rates exhibit an excellent linear relationship with the number of ketonic C=O groups,suggesting that C=O groups are the most possible active sites.

Trifunctional strategy for the design and synthesis of a Ni-CeO_(2)@SiO_(2)catalyst with remarkable low-temperature sintering and coking resistance for methane dry reforming

In this study,a trifunctional strategy was developed to prepare a confined Ni-based catalyst(Ni-CeO_(2)@SiO_(2))for dry reforming of methane(DRM)of two main greenhouse gases-CO_(2)and CH_(4).The Ni-CeO_(2)@SiO_(2)catalyst was fabricated by utilizing the confinement effect of the SiO_(2)shell and the synergistic interaction between Ni-Ce and the decoking effect of CeO_(2).The catalysts were systematically characterized via X-ray diffraction,N_(2 )adsorption/desorption,transmission electron microscopy,energy dispersive X-ray spectroscopy,hydrogen temperature reduction and desorption set by program,oxygen temperature program desorption,Raman spectroscopy,thermogravimetric analysis,and in situ diffuse reflectance infrared Fourier transform spectroscopy measurements to reveal their physicochemical properties and reaction mechanism.The Ni-CeO_(2)@SiO_(2)catalyst exhibited higher activity and stability than the catalyst synthesized via the traditional impregnation method.In addition,no carbon deposition was detected over Ni-CeO_(2)@SiO_(2)after a 100 h durability test at 800℃,and the average particle size of Ni nanoparticles(NPs)in the catalyst increased from 5.01 to 5.77 nm.Remarkably,Ni-CeO_(2)@SiO_(2)also exhibited superior low-temperature stability;no coke deposition was observed when the catalyst was reacted at 600℃ for 20 h.The high coking and sintering resistance of this confined Ni-based DRM catalyst can be attributed to its trifunctional effect.The trifunctional strategy developed in this study could be used as a guideline to design other high-performance catalysts for CO_(2)and CH4 dry forming and accelerate their industrialization.

Enhanced photocatalytic NO removal and toxic NO2 production inhibition over ZIF‐8‐derived ZnO nanoparticles with controllable amount of oxygen vacancies

The controlled introduction of oxygen vacancies(OVs)in photocatalysts has been demonstrated to be an efficient approach for improving the separation of photogenerated charge carriers,and thus,for enhancing the photocatalytic performance of photocatalysts.In this study,a two‐step calcination method where ZIF‐8 was used as the precursor was explored for the synthesis of ZIF‐8‐derived ZnO nanoparticles with gradient distribution of OVs.Electron paramagnetic resonance measurements indicated that the concentration of OVs in the samples depended on the temperature treatment process.Ultraviolet–visible spectra supported that the two‐step calcined samples presented excellent light‐harvesting ability in the ultraviolet‐to‐visible light range.Moreover,it was determined that the two‐step calcined samples presented superior photocatalytic performance for the removal of NO,and inhibited the generation of NO2.These properties could be attributed to the contribution of the OVs present in the two‐step calcined samples to their photocatalytic performance.The electrons confined by the OVs could be transferred to O2 to generate superoxide radicals,which could oxidize NO to the final product,nitrate.In particular,the NO removal efficiency of Z 350‐400(which was a sample first calcined at 350℃ for 2 h,then at 400℃ for 1 h)was 1.5 and 4.6 times higher than that of Z 400(which was one‐step directly calcined at 400℃)and commercial ZnO,respectively.These findings suggested that OV‐containing metal oxides that derived from metal‐organic framework materials hold great promise as highly efficient photocatalysts for the removal of NO.

Construction of CuO-modified zeolitic imidazolate framework-9 for photocatalytic hydrogen evolution

An efficient CuO‐modified zeolitic imidazolate framework‐9(ZIF‐9)photocatalyst is successfully prepared at room temperature under mild conditions.It is observed that the ZIF‐9/CuO photocatalyst is effective for H2generation under visible light with sacrificial agent conditions.When the CuO is introduced,the photocatalytic properties of ZIF‐9are greatly improved and when the content of CuO is40%,the photocatalytic activity reaches a maximum of78.74μmol after5h.This results from the200–300nm cube structure of ZIF‐9being able to adsorb more dye molecules and the CuO,which connects with ZIF‐9,greatly improving the electronic transmission efficiency.Moreover,the interaction between the dye molecule Eosin Y(EY)and the catalyst is also studied by transient fluorescence spectroscopy.A series of characterizations,such as SEM,TEM,XPS,XRD,UV‐vis,FTIR,transient fluorescence and photocurrent,are conducted,and the results are in good agreement with the experimental result.In addition,the possible reaction mechanism over EY‐sensitized ZIF‐9/CuO under visible light irradiation is proposed.

Mechanochemical preparation and application of graphdiyne coupled with CdSe nanoparticles for efficient photocatalytic hydrogen production

Graphdiyne(GDY)has attracted considerable attention as a new two-dimensional(2D)carbon hybrid material because of its good conductivity,adjustable electronic structure,and special electron transfer enhancement properties.GDY has great potential in the field of photocatalytic water splitting for hydrogen evolution,owing to its unique properties.In this study,GDY was successfully prepared by the mechanochemical coupling of precursors C_(6)Br_(6) and CaC_(2) using a ball-milling approach.The prepared GDY,especially its microstructure and composition,was well characterized using different techniques such as X-ray diffraction,scanning electron microscopy,transmission electron microscopy,X-ray photoelectron spectroscopy(XPS),Fourier-transform infrared,and Raman characterization techniques.By exploiting the unique two-dimensional(2D)structure and outstanding light absorption properties of GDY,GDY/CdSe 2D/0D heterojunctions were successfully established and applied to photocatalytic hydrogen evolution.The hydrogen evolution activity of GDY/CdSe-20,a type of composite material,reached 6470μmol g^(-1) h^(-1),which is 461 and 40 times higher than that of GDY and CdSe,respectively.Moreover,the fine electrical conductivity of GDY enabled rapid and effective transfer of the photogenerated electrons in CdSe into the hydrogen evolution reaction.The transfer path of the photogenerated electrons was studied through XPS with in situ irradiation,and a reasonable mechanism for the hydrogen evolution reaction was proposed.This study provides a feasible approach for the large-scale preparation of GDY and demonstrates the prospects of GDY in the field of photocatalysis.

水煤浆添加剂的作用机理研究

水煤浆是由约65%的煤、35%的水和少量的添加剂通过物理加工而成，是一种新型煤基流体燃料。它既保持了煤炭原有的物理特性，又具有石油一样的流动性和稳定性，可以储存、泵送、雾化和稳定燃烧。水煤浆生产过程中，首先是对原煤进行破碎，再经机械（湿法或干法）研磨成一定粒径分布的煤粉分散于水介质中制成水煤浆。由于它是一种粗颗粒悬浮体，在水中极易形成沉淀。即使是很易成浆的煤种，不加入化学添加剂，要制成所希望的水煤浆也是不可能的。水煤浆添加剂的主要作用在于改变煤颗粒的表面性质，促使颗粒在水介质中均匀分散，且不易产生沉淀。使水煤浆在正常使用中具有较低的粘度、较好的流动性。一般用量占煤炭总量的0.5~1%之间。

化工行业含腈废水深度处理技术研究

内外对湿法腈纶生产的含腈废水深度处理进行了大量的试验研究，处理方法主要有：化学法（化学混凝、化学氧化以及微电解）；生物法（SBR法、生物接触氧化法、好氧生化法、酸化法预处理、生物滤塔和添加特殊菌种）；物理化学法（微孔过滤和吸附）。

The prescription rule analysis of the New Theory on Spleen Dampness Syndrome by Academician TONG Xiaolin

Objective To analyze the basic characteristics,drug features,prescription rules,and drug-symptom relationships of patients in the splenic deficiency and impairment stage,by data mining of medical records under the New Theory on Spleen Dampness Syndrome(Pi Dan Xin Lun,《脾瘅新论》).Methods Medical records listed in the“New Theory on Spleen Dampness Syndrome-Under-standing and Treatment of Metabolic Syndrome from the Perspective of Traditional Chinese Medicine”,and which were diagnosed with the spleen dampness syndrome at the splenic de-ficiency and impairment stage,during January 2004 and December 2016 were selected.These patients’data,including basic information,clinical symptoms,laboratory examination res-ults,traditional Chinese medicine(TCM)and western medicine diagnoses,treatment meth-ods,prescriptions,etc.,were collected.The collected data were subsequently compiled into a medical record database using the Epidata 3.1 data management software,followed by the use of Apriori algorithm provided in the SPSS Modeler 14.2 statistical software to investigate the association rules between drug-drug,drug-symptom,and drug-western medicine indices.Results(i)A total of 51 medical records were included,involving 17 types of syndromes.Among them,the top three with frequency≥3 included“Phlegm and blood stasis,and thoracic obstruction”“Deficiency-weakness of the spleen Qi,and static blood blocking collat-erals”,and“Deficiency-weakness of the spleen Qi,and static blood blocking collaterals”.Al-ternatively,of the 14 treatment methods,the top three treatments with frequency of≥3 in-cluded“Activating Yang and eliminating turbidity,and removing phlegm and dredging chan-nel blockage”“Strengthening the spleen and benefiting Qi,and eliminating phlegm to activ-ate the channels”,and“Warming Yang and benefiting Qi,and expelling cold to remove ob-structions”.Among the 15 prescriptions,the top three used with frequency≥3 included Huangqi Guizhi Wuwu Tang(黄芪桂枝五物汤),Gualou Xiebai Banxia Tang(瓜蒌薤白半夏汤),and Ganjiang Huangqin Huanglian Renshen Tang(干姜黄芩黄连人参汤).Lastly,of the 83 drugs used for a total of 476 times,those with frequency≥15 included Huanglian(Coptid-is Rhizoma),Huangqi(Astragali Radix),Jiudahuang(Wine-processed Rhei Radix et Rhizoma),Jixueteng(Spatholobi Caulis),Shengjiang(Zingiberis Rhizoma Recens),Huangqin(Scutellariae Radix),and Guizhi(Cinnamomi Ramulus).(ii)For the drug-drug associations,under the criteria of support≥15%and confidence=100%,seven second-order association rules,seven third-order rules,and six fourth-order roles were identified.The top-ranking rule of each was“Huangqin(Scutellariae Radix)→Huanglian(Coptidis Rhizoma)”“Ganjiang(Zingiberis Rhizoma)+Huangqin(Scutellariae Radix)→Huanglian(Coptidis Rhizoma)”,and“Baishao(Paeoniae Radix Alba)+Guizhi(Cinnamomi Ramulus)+Jixueteng(Spatho-lobi Caulis)→Huangqin(Scutellariae Radix)”,respectively.Alternatively,the drug-symptom associations were analyzed under the criteria of support≥5%and confidence=100%,which derived eight second-order association rules,31 third-order rules,and 30 fourth-order rules.The top-ranking association rule of each order was“Huangqi(Astragali Radix)→Limb ed-ema”“Guizhi(Cinnamomi Ramulus)+Jixueteng(Spatholobi Caulis)→Limb numbness and pain”,and“Guizhi(Cinnamomi Ramulus)+Jixueteng(Spatholobi Caulis)+Huangqi(As-tragali Radix)→Limb numbness and pain”,respectively.Similarly,the drug-western medi-cine index associations were investigated under the criteria of support≥5%and confidence=100%,and five second-order association rules,16 third-order rules,and 16 fourth-order rules were identified.In this category,the top-ranking association rule of each order was“Qinpi(Fraxini Cortex)→Uric acid”“Huanglian(Coptidis Rhizoma)+Ganjiang(Zingiberis Rhizoma)→Glycated hemoglobin”,and“Huanglian(Coptidis Rhizoma)+Ganjiang(Zing-iberis Rhizoma)+Huangqin(Scutellariae Radix)→Glycated hemoglobin”,respectively.Conclusion Through association rule mining,this study objectively and quantitatively demonstrated the drug-drug,drug-symptom,and drug-physicochemical index associations of patients with the spleen dampness syndrome at the splenic deficiency and impairment stage treated by Academician TONG Xiaolin.The results indicated that treatment for these patients adopted the“state-target”syndrome differentiation method.The drug combination was characterized by“small prescriptions”,targeting both the patient’s symptoms and signs(syndrome target)and western medicine indices(treatment target).This study could provide references for future research on the academic thoughts and medical experience of Academi-cian TONG Xiaolin.

First record of the genus Stenidius La Ferté-Sénectère(Coleoptera: Anthicidae) with three newly recorded species from China

A newly recorded genus Stenidius LaFerté-Sénectère of Anthicidae and three newly recorded species, namely S. dolosus Kejval, Anthelephia himalayana(Krekich-Strassoldo) and Sapintus anguliceps(LaFerté-Sénectère), are reported from China. Morphological descriptions, photographs and illustrations are given.