民国时期河北文学期刊《学友》研究

《学友》期刊是民国时期由学友社主编、发行并在河北省保定市出版的文学类期刊。该期刊并无明确办刊宗旨,主要选取杂文、小说、诗歌、散文等一些新的文学体裁作品,内容上多反映当时的社会现状,表现文人以及当时青年学生的生活状态与内心活动。该刊封面设计与内文的排版相对简洁,其读者对象相对较窄,主要在保定市发行。该期刊作为文学类刊物具有一定的文学价值,且因其反映部分当时的社会现状,故也具有一定的史料价值。

Chemical Control of Herbicide Monosulfuron Plus Propazine 44% WP against Weeds in Millet Fields and Study on Factors Influencing Yield of Millet

[Objective] The paper was to resolve the poor efficacy or phytotoxicity problems in promotion of herbicide monosulfuron plus propazine 44% WP. [Method] Using orthogonal test and Duncan＇s new multiple range statistical analysis with four factors four levels and three factors two levels, the effects of factors such as herbi- cide dose, irrigation water volume, quality of soil preparation and soil moisture content on chemical control of monosulfuron plus propazine 44% WP against weeds and millet yield were compared in the test. [Result] Seven factors all had great impact on control effect of monosulfuron plus propazine 44% WP against weeds, of which her- bicide dose, irrigation water volume, quality of soil preparation and soil moisture content were the most important factors affecting millet yield. According to millet yield and economic benefit, the optimal scheme to ensure safe, efficient and economic control of monosulfuron plus propazine 44% WP against weeds was as follows： the dose of monosulfuron plus propazine 44% WP was 1 800 g/hm2, the soil was treat- ed after sowing and before seedling emergence; the soil should be smooth and sol- id; the soil moisture should reach 15%; the fields should not be irrigated after herbi- cide application, and the damage of weeds in millet fields could be effectively con- trolled within 45 d during high efficacy duration, especially the damage of dicotyledonous weeds. [Conclusion] The study provided useful information for comprehensive technology of weeds control and ensuring high yield and good harvest of millet.

On an ecology-friendly treatment reagent for oily wastewater

Bioflocculants have received increasing attention in research because they are low cost,non-toxic,biodegradable,operationally simple and useful in many water and wastewater treatment applications.In this study,we focused mainly on the screening of the flocculant-producing strain and its application in oily wastewater treatment.Bacteria strain B-6-1 was isolated by the pyridine screening method.UPC-1 reagent produced by B-6-1 had efficient flocculating activity.It was deduced that the main component of UPC-1 reagent was polysaccharide through purification and analysis.The influence of dosage of reagent,pH value,temperature and oil concentration on the flocculation effect of UPC-1 reagent was investigated.

Breeding New Knowledge at Home:The Case of the Albanian Olive Friendship Tree in China

This article uses the case of the Sino-Albanian Friendship Trees to examine the significance and the limits of transnational scientific exchange in China during the 1960s and 1970s.In 1964,Albania gave ten thousand olive trees to China as a symbol of the eternal friendship of the Chinese and Albanian people;it was then up to Chinese agricultural scientists and farmers to find suitable means to propagate and cultivate them.The author finds that,though the olive trees served as symbols of international friendship and scientific exchange,knowledge about olive trees produced and circulated in the PRC reflected science in context(that is,science within the national-level political context of 1960s–1970s China)more than knowledge in transit(that is,the transnational circulation of knowledge).The importation of olive trees from Albania ended up offering a new application for Chinese agricultural knowledge and for quintessentially“Cultural Revolution”-era systems of knowledge production and circulation.

Efficiency of Some Plant Essential Oils on Root-Knot Nematode Meloidogyne incognita

During the last few decades, researchers have been in the search for environmental friendly ways to cope with agricultural pests, instead of using chemical pesticides. The use of essential oils has a high potential to become an alternative control strategy against plant parasitic nematodes. This study was conducted to determine the toxicity of 10 essential oils （Artemisia absinthium, Citrus bergamia, Eucalyptus citriodora, Hypericum perforatum, Lavandula officinalis, Mentha arvensis, Ocimum basilicum, Piper nigrum, Thymus serpyllum and Zingiber officinale） against the second stage juveniles of the root-knot nematode Meloidogyne incognita. The aqueous solutions of these essential oils have been applied to the second stage juveniles in three different concentrations （1%, 3% and 5%） at four different application time intervals （12, 24, 48 and 72 h）. The interactions between the variables have been examined with repeated measure analysis of variance （ANOVA）. This showed that the interactions of essential oil-time and essential oil-concentration were statistically significant, and it is concluded that L. officinalis, A. absinthium, P. nigrum, C. bergamia and M. arvensis have the most toxic effect in all concentrations and times, respectively.

On Balance Index Set for the General Butterfly Graph

In this paper, we introduce the concept of the general butterfly graph B[m,n;d] for integers m,n ≥ 3, d ≥ 1, determine its balance index set, and give the necessary and sufficient condition for balanced graph B[m,n;d] to exist.

A novel low-cost and environment-friendly cathode with large channels and high structure stability for potassium-ion storage

Potassium-ion batteries (KIBs) are promising candidates for large-scale energy storage due to the abundance of potassium and its chemical similarity to lithium.Nevertheless,the performances of KIBs are still unsatisfactory for practical applications,mainly hindered by the lack of suitable cathode materials.Herein,combining the strong inductive effect of sulphate and the feasible preparation of Fe^(2+)-containing compounds in oxalate system,a compound with novel architecture,K_(4)Fe_(3)(C_(2)O_(4))_(3)(SO_(4))_(2),has been identified as a lowcost and environmentally friendly cathode for stable potassium-ion storage.Its unique crystal structure possesses an unprecedented two-dimensional framework of triple layers,with 3.379Åinterlayer distance and large intralayer rings in the size of 4.576×6.846Å.According to first-principles simulations,such a configuration is favorable for reversible K-ion migration with a very low volume change of 6.4%.Synchrotron X-ray absorption spectra and X-ray diffraction characterizations at different charging/discharging states and electrochemical performances based on its half and full cells further verify its excellent reversibility and structural stability.Although its performance needs to be improved via further composition tuning with multi-valent transition metals,doping,structural optimization,etc.,this study clearly presents a stable structural model for K-ion cathodes with merits of low cost and environmental friendliness.